Photoreactivation of ultraviolet light-induced sister chromatid exchanges in potorous cells

International Nuclear Information System (INIS)

Ishizaki, K.; Nikaido, O.; Takebe, H.

1980-01-01

Exposure to visible light after UV-irradiation showed a remarkable effect on UV-induced sister chromatid exchanges (SCEs). After 6-h exposure to visible light (3 x 10 5 J/m 2 ), two-thirds of the UV-induced SCEs were prevented, confirming Kato's findings. (Nature 249, 552-3, 1974) Exposure to visible light before UV irradiation had no effect. This effect of visible light on UV-induced CSEs was temperature dependent, suggesting the presence of enzymatic photoreactivation. (author)

RPA Mediates Recruitment of MRX to Forks and Double-Strand Breaks to Hold Sister Chromatids Together.

Science.gov (United States)

Seeber, Andrew; Hegnauer, Anna Maria; Hustedt, Nicole; Deshpande, Ishan; Poli, Jérôme; Eglinger, Jan; Pasero, Philippe; Gut, Heinz; Shinohara, Miki; Hopfner, Karl-Peter; Shimada, Kenji; Gasser, Susan M

2016-12-01

The Mre11-Rad50-Xrs2 (MRX) complex is related to SMC complexes that form rings capable of holding two distinct DNA strands together. MRX functions at stalled replication forks and double-strand breaks (DSBs). A mutation in the N-terminal OB fold of the 70 kDa subunit of yeast replication protein A, rfa1-t11, abrogates MRX recruitment to both types of DNA damage. The rfa1 mutation is functionally epistatic with loss of any of the MRX subunits for survival of replication fork stress or DSB recovery, although it does not compromise end-resection. High-resolution imaging shows that either the rfa1-t11 or the rad50Δ mutation lets stalled replication forks collapse and allows the separation not only of opposing ends but of sister chromatids at breaks. Given that cohesin loss does not provoke visible sister separation as long as the RPA-MRX contacts are intact, we conclude that MRX also serves as a structural linchpin holding sister chromatids together at breaks. Copyright © 2016 Elsevier Inc. All rights reserved.

Induction of sister chromatid exchange in the presence of gadolinium-DTPA and its reduction by dimethyl sulfoxide

International Nuclear Information System (INIS)

Yamazaki, Etsuo; Fukuda, Hozumi; Shibuya, Hitoshi; Matsubara, Sho

1996-01-01

The authors investigate the frequency of sister chromatid exchange (SCE) after the addition of gadolinium (Gd)-DTPA to venous blood samples. Venous blood was obtained from nonsmokers. Samples were incubated with Gd-DTPA alone or in combination with mitomycin C, cytarabine, and dimethyl sulfoxide (DMSO), and then evaluated for SCEs. The frequency of SCE increased with the concentration of Gd-DTPA and as each chemotherapeutic agent was added. Sister chromatid exchange frequencies were lower when the blood was treated with a combination of Gd-DTPA and DMSO compared with Gd-DTPA alone. The increase in frequency of SCE seen after the addition of Gd-DTPA was decreased by the addition of DMSO, indicating the production of hydroxyl radicals. The effect likely is dissociation-related. 14 refs., 6 tabs

A CO-FISH assay to assess sister chromatid segregation patterns in mitosis of mouse embryonic stem cells.

Science.gov (United States)

Sauer, Stephan; Burkett, Sandra S; Lewandoski, Mark; Klar, Amar J S

2013-05-01

Sister chromatids contain identical DNA sequence but are chiral with respect to both their helical handedness and their replication history. Emerging evidence from various model organisms suggests that certain stem cells segregate sister chromatids nonrandomly to either maintain genome integrity or to bias cellular differentiation in asymmetric cell divisions. Conventional methods for tracing of old vs. newly synthesized DNA strands generally lack resolution for individual chromosomes and employ halogenated thymidine analogs with profound cytotoxic effects on rapidly dividing cells. Here, we present a modified chromosome orientation fluorescence in situ hybridization (CO-FISH) assay, where identification of individual chromosomes and their replication history is achieved in subsequent hybridization steps with chromosome-specific DNA probes and PNA telomere probes. Importantly, we tackle the issue of BrdU cytotoxicity and show that our method is compatible with normal mouse ES cell biology, unlike a recently published related protocol. Results from our CO-FISH assay show that mitotic segregation of mouse chromosome 7 is random in ES cells, which contrasts previously published results from our laboratory and settles a controversy. Our straightforward protocol represents a useful resource for future studies on chromatid segregation patterns of in vitro-cultured cells from distinct model organisms.

UBL5 is essential for pre-mRNA splicing and sister chromatid cohesion in human cells

DEFF Research Database (Denmark)

Oka, Yasuyoshi; Varmark, Hanne; Vitting-Seerup, Kristoffer

2014-01-01

UBL5 is an atypical ubiquitin-like protein, whose function in metazoans remains largely unexplored. We show that UBL5 is required for sister chromatid cohesion maintenance in human cells. UBL5 primarily associates with spliceosomal proteins, and UBL5 depletion decreases pre-mRNA splicing efficien...

Possible mechanisms of chromosomal aberrations: VII. Comparative dynamics of sister chromatid disjunction and realization of radiation-induced chromosomal aberrations during mitosis

International Nuclear Information System (INIS)

Lebedeva, L.I.; Akhmamet'eva, E.M.

1994-01-01

An increase in radiation-induced chromosomal aberrations during c-metaphase sister chromatid disjunction was demonstrated in murine bone marrow cells exposed to a total γ-irradiation at 0.5 Gy. Caffeine (Cf) treatment during mitosis partially suppressed the chromatid disjunction rate and increased the number of radiation-induced aberrations in this mitosis. Nalidixic acid (NA) treatment of c-metaphase cells completely suppressed chromatid disjunction and the realization of induced aberrations. Topoisomerase 2 was assumed to be involved during mitosis in both processes

A proposal of a standardised nomenclature for terminal minute sister chromatid exchanges

Directory of Open Access Journals (Sweden)

Máximo E. Drets

2006-01-01

Full Text Available We described spontaneous minute sister chromatid exchanges (SCE in telomeric regions of human and Chinese hamster ovary (CHO chromosomes more than 10 years ago. These structures, which we called t-SCE, were detected by means of highly precise quantitative microphotometrical scanning and computer graphic image analysis. Recently, several authors using the CO-FISH method also found small SCEs in telomeric regions and called them T-SCE. The use of different terms for designating the same phenomenon should be avoided. We propose ter SCE as a uniform nomenclature for minute telomeric SCEs.

Roles of the sister chromatid cohesion apparatus in gene expression, development, and human syndromes

Science.gov (United States)

Dorsett, Dale

2006-01-01

The sister chromatid cohesion apparatus mediates physical pairing of duplicated chromosomes. This pairing is essential for appropriate distribution of chromosomes into the daughter cells upon cell division. Recent evidence shows that the cohesion apparatus, which is a significant structural component of chromosomes during interphase, also affects gene expression and development. The Cornelia de Lange (CdLS) and Roberts/SC phocomelia (RBS/SC) genetic syndromes in humans are caused by mutations affecting components of the cohesion apparatus. Studies in Drosophila suggest that effects on gene expression are most likely responsible for developmental alterations in CdLS. Effects on chromatid cohesion are apparent in RBS/SC syndrome, but data from yeast and Drosophila point to the likelihood that changes in expression of genes located in heterochromatin could contribute to the developmental deficits. PMID:16819604

Ultraviolet-induced formation of micronuclei and sister chromatid exchange in cultured fibroblasts of patients with cutaneous malignant melanoma

International Nuclear Information System (INIS)

Roser, M.; Boehm, A.O.; Oldigs, M.; Weichenthal, M.; Reimers, U.; Schmidt-Preuss, U.; Breitbart, E.W.; Ruediger, H.W.

1989-01-01

Genetically enhanced sensitivity to ultraviolet (UV) radiation may play an important role in the development of cutaneous malignant melanoma (CMM). This was studied in cultured fibroblasts of 26 CMM patients and controls by micronucleus (MN) test and sister chromatid exchange (SCE) after UV irradiation (375 J/m2). Sister chromatid exchange and MN formation were used as parameters to detect the UV-induced genotoxic damage in the individual cell strains. We found that the UV-induced level of MN was significantly increased in CMM patients (p = 0.0005), being most pronounced in the familial cases (p = 0.0001). Ultraviolet-induced SCE was also elevated in CMM patients (p = 0.001), but there was no difference between familial and nonfamilial cases. The present findings indicate that genetic predisposition contributes to the development of CMM in a subset of CMM patients and may be due to an enhanced susceptibility to UV light

Chiasmata promote monopolar attachment of sister chromatids and their co-segregation toward the proper pole during meiosis I.

Directory of Open Access Journals (Sweden)

Yukinobu Hirose

2011-03-01

Full Text Available The chiasma is a structure that forms between a pair of homologous chromosomes by crossover recombination and physically links the homologous chromosomes during meiosis. Chiasmata are essential for the attachment of the homologous chromosomes to opposite spindle poles (bipolar attachment and their subsequent segregation to the opposite poles during meiosis I. However, the overall function of chiasmata during meiosis is not fully understood. Here, we show that chiasmata also play a crucial role in the attachment of sister chromatids to the same spindle pole and in their co-segregation during meiosis I in fission yeast. Analysis of cells lacking chiasmata and the cohesin protector Sgo1 showed that loss of chiasmata causes frequent bipolar attachment of sister chromatids during anaphase. Furthermore, high time-resolution analysis of centromere dynamics in various types of chiasmate and achiasmate cells, including those lacking the DNA replication checkpoint factor Mrc1 or the meiotic centromere protein Moa1, showed the following three outcomes: (i during the pre-anaphase stage, the bipolar attachment of sister chromatids occurs irrespective of chiasma formation; (ii the chiasma contributes to the elimination of the pre-anaphase bipolar attachment; and (iii when the bipolar attachment remains during anaphase, the chiasmata generate a bias toward the proper pole during poleward chromosome pulling that results in appropriate chromosome segregation. Based on these results, we propose that chiasmata play a pivotal role in the selection of proper attachments and provide a backup mechanism that promotes correct chromosome segregation when improper attachments remain during anaphase I.

Mutagen-induced sister chromatid exchanges in xeroderma pigmentosum and normal lymphocytes

International Nuclear Information System (INIS)

Perry, P.E.; Jager, M.; Evans, H.J.

1978-01-01

The induction of sister chromatid exchanges (SCE), by ultra-violet irradiation and by three chemical mutagens that differ in the type of repair response that they elicit, has been compared in lymphocytes from a control and from an individual suffering from the DNA excision repair deficiency syndrome, xeroderma pigmentosum (XP). The XP lymphocytes were found to be more sensitive in terms of SCE response, not only to UV irradiation, but also to all of the chemicals studied. The results indicate that the abnormality of DNA repair in this XP patient is expressed not only in the defective excision of thymine dimers, or other UV photoproducts, but also in a reduced ability to repair other types of DNA lesion. (author)

Drosophila TDP-43 RNA-Binding Protein Facilitates Association of Sister Chromatid Cohesion Proteins with Genes, Enhancers and Polycomb Response Elements.

Directory of Open Access Journals (Sweden)

Amanda Swain

2016-09-01

Full Text Available The cohesin protein complex mediates sister chromatid cohesion and participates in transcriptional control of genes that regulate growth and development. Substantial reduction of cohesin activity alters transcription of many genes without disrupting chromosome segregation. Drosophila Nipped-B protein loads cohesin onto chromosomes, and together Nipped-B and cohesin occupy essentially all active transcriptional enhancers and a large fraction of active genes. It is unknown why some active genes bind high levels of cohesin and some do not. Here we show that the TBPH and Lark RNA-binding proteins influence association of Nipped-B and cohesin with genes and gene regulatory sequences. In vitro, TBPH and Lark proteins specifically bind RNAs produced by genes occupied by Nipped-B and cohesin. By genomic chromatin immunoprecipitation these RNA-binding proteins also bind to chromosomes at cohesin-binding genes, enhancers, and Polycomb response elements (PREs. RNAi depletion reveals that TBPH facilitates association of Nipped-B and cohesin with genes and regulatory sequences. Lark reduces binding of Nipped-B and cohesin at many promoters and aids their association with several large enhancers. Conversely, Nipped-B facilitates TBPH and Lark association with genes and regulatory sequences, and interacts with TBPH and Lark in affinity chromatography and immunoprecipitation experiments. Blocking transcription does not ablate binding of Nipped-B and the RNA-binding proteins to chromosomes, indicating transcription is not required to maintain binding once established. These findings demonstrate that RNA-binding proteins help govern association of sister chromatid cohesion proteins with genes and enhancers.

Phospho-H1 Decorates the Inter-chromatid Axis and Is Evicted along with Shugoshin by SET during Mitosis.

Science.gov (United States)

Krishnan, Swathi; Smits, Arne H; Vermeulen, Michiel; Reinberg, Danny

2017-08-17

Precise control of sister chromatid separation during mitosis is pivotal to maintaining genomic integrity. Yet, the regulatory mechanisms involved are not well understood. Remarkably, we discovered that linker histone H1 phosphorylated at S/T18 decorated the inter-chromatid axial DNA on mitotic chromosomes. Sister chromatid resolution during mitosis required the eviction of such H1S/T18ph by the chaperone SET, with this process being independent of and most likely downstream of arm-cohesin dissociation. SET also directed the disassembly of Shugoshins in a polo-like kinase 1-augmented manner, aiding centromere resolution. SET ablation compromised mitotic fidelity as evidenced by unresolved sister chromatids with marked accumulation of H1S/T18ph and centromeric Shugoshin. Thus, chaperone-assisted eviction of linker histones and Shugoshins is a fundamental step in mammalian mitotic progression. Our findings also elucidate the functional implications of the decades-old observation of mitotic linker histone phosphorylation, serving as a paradigm to explore the role of linker histones in bio-signaling processes. Copyright © 2017 Elsevier Inc. All rights reserved.

The Scc2/Scc4 complex acts in sister chromatid cohesion and transcriptional regulation by maintaining nucleosome-free regions

Science.gov (United States)

Lopez-Serra, Lidia; Kelly, Gavin; Patel, Harshil; Stewart, Aengus; Uhlmann, Frank

2014-01-01

The cohesin complex is at the heart of many chromosomal activities, including sister chromatid cohesion and transcriptional regulation1-3. Cohesin loading onto chromosomes depends on the Scc2/Scc4 cohesin loader complex4-6, but the chromatin features that form cohesin loading sites remain poorly understood. Here, we show that the RSC chromatin remodeling complex recruits budding yeast Scc2/Scc4 to broad nucleosome-free regions, that the cohesin loader itself helps to maintain. Consequently, inactivation of the cohesin loader or RSC complex have similar effects on nucleosome positioning, gene expression and sister chromatid cohesion. These results reveal an intimate link between local chromatin structure and higher order chromosome architecture. Our findings pertain to the similarities between two severe human disorders, Cornelia de Lange syndrome, caused by mutations in the human cohesin loader, and Coffin-Siris syndrome, resulting from mutations in human RSC complex components7-9. Both could arise from gene misregulation due to related changes in the nucleosome landscape. PMID:25173104

Influence of irradiation at different stages of mitotic cycle upon production of sister chromatid exchanges in cultured Chinese hamster cells

International Nuclear Information System (INIS)

Antoshina, M.M.; Poryadkova, N.A.; Luchnik, N.V.

1982-01-01

Frequency of sister chromatid exchanges (SCE) and microexchanges in Chinese hamster cells has been studied by means of the method of differential staining of chromatids on irradiation at different stages of the mitotic cycle. It is shown that the irradiation enhances frequency of SCE and microexchanges if it is carried out before the end of DNA replication synthesis. Comparison of frequency depenedence of radiation-induced microexchanges and SCE at different stages of the mitotic cycle results in the conclusion that the microexchanges are none other than small SCE

Relationship of DNA repair to chromosome aberrations, sister-chromatid exchanges and survival during liquid-holding recovery in X-irradiated mammalian cells

International Nuclear Information System (INIS)

Fornace, A.J. Jr.; Nagasawa, H.; Little, J.B.

1980-01-01

The repair of X-ray-induced DNA single strand breaks and DNA-protein cross-links was investigated in stationary phase, contact-inhibited mouse cells by the alkaline-elution technique. Approx. 90% of X-ray-induced single strand breaks were rejoined during the first hour of repair, whereas most of the remaining breaks were rejoined more slowly during the next 5 h. At early repair times, the number of residual non-rejoined sungle strand breaks was approx. proportional to the X-ray dose. DNA-protein cross-links were removed at a slower rate (Tsub(1/2) approx. 10-12 h). Cells were held in stationary growth for various periods of time after irradiation before subculture at low density to score for colony survival (potentially lethal damage repair), chromosome aberrations in the first mitosis, and sister-chromatid exchanges in the second mitosis. Both cell killing and the frequency of chromosome aberrations decreased during the first several hours of recovery, reaching a minimum level by 6 h; this decrease correlated temporally with the repair of the slowly rejoining DNA-strand breaks. Relatively few sister-chromatid exchanges were observed when the cells were subcultured immediately after X-ray. The exchange frequency rose to maximum levels after a 4-h recovery interval, and returned to control levels after 12 h of recovery. The possible relationship of DNA repair to these changes in survival, chromosome aberrations, and sister-chromatid exchanges during liquid-holding recovery is discussed. (orig.)

Sister chromatid cohesion defects are associated with chromosome instability in Hodgkin lymphoma cells

International Nuclear Information System (INIS)

Sajesh, Babu V; Lichtensztejn, Zelda; McManus, Kirk J

2013-01-01

Chromosome instability manifests as an abnormal chromosome complement and is a pathogenic event in cancer. Although a correlation between abnormal chromosome numbers and cancer exist, the underlying mechanisms that cause chromosome instability are poorly understood. Recent data suggests that aberrant sister chromatid cohesion causes chromosome instability and thus contributes to the development of cancer. Cohesion normally functions by tethering nascently synthesized chromatids together to prevent premature segregation and thus chromosome instability. Although the prevalence of aberrant cohesion has been reported for some solid tumors, its prevalence within liquid tumors is unknown. Consequently, the current study was undertaken to evaluate aberrant cohesion within Hodgkin lymphoma, a lymphoid malignancy that frequently exhibits chromosome instability. Using established cytogenetic techniques, the prevalence of chromosome instability and aberrant cohesion was examined within mitotic spreads generated from five commonly employed Hodgkin lymphoma cell lines (L-1236, KM-H2, L-428, L-540 and HDLM-2) and a lymphocyte control. Indirect immunofluorescence and Western blot analyses were performed to evaluate the localization and expression of six critical proteins involved in the regulation of sister chromatid cohesion. We first confirmed that all five Hodgkin lymphoma cell lines exhibited chromosome instability relative to the lymphocyte control. We then determined that each Hodgkin lymphoma cell line exhibited cohesion defects that were subsequently classified into mild, moderate or severe categories. Surprisingly, ~50% of the mitotic spreads generated from L-540 and HDLM-2 harbored cohesion defects. To gain mechanistic insight into the underlying cause of the aberrant cohesion we examined the localization and expression of six critical proteins involved in cohesion. Although all proteins produced the expected nuclear localization pattern, striking differences in RAD21

Sister-chromatid exchange induced by X-ray of human lymphocytes and the effect of L-crysteine

International Nuclear Information System (INIS)

Abramovski, I.; Vorsanger, G.; Hirschhorn, K.

1978-01-01

A staining technique that detects sister-chromatid exchanges (SCEs) has been used to examine the response of human lymphocyte chromosomes to various dosages of X-irradiation. The SCE frequency was markedly increased following irradiation. However, the increase was of a significantly smaller magnitude when irradiation occurred in the presence of an antimutagenic agent. Scoring SCEs may provide a useful technique for assaying the mutagenic effects of environmental carcinogens as well as the protective effects of antimutagenic agents. (Auth.)

Sister chromatid exchange in children of Seventh-Day Adventists and matched controls.

Science.gov (United States)

Hermansen, R; Waksvik, H; Fønnebø, V

1991-03-01

The low risk of cancer in Seventh-Day Adventists (SDAs) has been suggested to be due to genetic selection. To investigate this claim we examined the sister chromatid exchange (SCE) frequency in peripheral blood lymphocytes in 16 SDA children in Tromsø, all aged 0.5-8 years and 16 controls matched for sex and age. In 12 of 16 pairs, the SDA children had a lower SCE frequency than the controls. The mean difference was 4.06 (95% confidence interval -17.02-8.89, P = 0.51). There was no sex difference, and no correlation between age and SCE frequency. The genetic starting point with regard to SCE frequency seems to be the same for SDA children and controls.

Sister chromatid exchange induced by X-irradiation of retinoblastoma lymphocytes

International Nuclear Information System (INIS)

Abramovsky-Kaplan, I.; Jones, I.S.

1984-01-01

Lymphocyte cultures were employed to assess the degree of spontaneous and induced chromosomal fragility in retinoblastoma. Sister chromatid exchange (SCEs) were scored in metaphases. Three unilateral, three bilateral, eleven family members and controls were studied. Retinoblastoma (RB) lymphocytes did not exhibit increased spontaneous fragility. X-irradiation (25-200 rad) did not significantly increase SCE in unilateral retinoblastoma lymphocytes when compared with controls (P greater than 0.50). However, bilaterally affected subjects and three unaffected relatives demonstrated a statistically significant increase in SCE (P less than 0.01). In conclusion, hereditary retinoblastoma lymphocytes appear more radiosensitive than sporadic retinoblastoma, perhaps, reflecting the increased second malignancies in germinal mutation retinoblastoma. In addition, the analysis of radiation-induced SCE in peripheral blood lymphocytes of RB patients and family members may provide a valuable tool increasing the accuracy of genetic counseling for this disorder. Additional studies of RB patients and families are needed to assess the relevance of this approach to genetic counseling

Elevated sister chromatid exchange frequencies in New Zealand Vietnam War veterans.

Science.gov (United States)

Rowland, R E; Edwards, L A; Podd, J V

2007-01-01

From July 1965 until November 1971, New Zealand Defence Force Personnel fought in the Vietnam War. During this time more than 76,500,000 litres of phenoxylic herbicides were sprayed over parts of Southern Vietnam and Laos, the most common being known as 'Agent Orange'. The current study aimed to ascertain whether or not New Zealand Vietnam War veterans show evidence of genetic disturbance arising as a consequence of their now confirmed exposure to these defoliants. A sample group of 24 New Zealand Vietnam War veterans and 23 control volunteers were compared using an SCE (sister chromatid exchange) analysis. The results from the SCE study show a highly significant difference (P Vietnam War veterans studied here were exposed to a clastogenic substance(s) which continues to exert an observable genetic effect today, and suggest that this is attributable to their service in Vietnam. Copyright 2007 S. Karger AG, Basel.

Rec8p, a meiotic recombination and sister chromatid cohesion phosphoprotein of the Rad21p family conserved from fision yeast to humans.

NARCIS (Netherlands)

S. Parisi; M.J. McKay (Michael); M. Molnar; M.A. Thompson (Anne); P.J. van der Spek (Peter); E. van Drunen-Schoenmaker; R. Kanaar (Roland); E. Lehmann; J.H.J. Hoeijmakers (Jan); J. Kohli

1999-01-01

textabstractOur work and that of others defined mitosis-specific (Rad21 subfamily) and meiosis-specific (Rec8 subfamily) proteins involved in sister chromatid cohesion in several eukaryotes, including humans. Mutation of the fission yeast Schizosaccharomyces pombe rec8 gene was previously shown to

In vitro and occupational induction of sister-chromatid exchanges in human lymphocytes with furfuryl alcohol and furfural

Energy Technology Data Exchange (ETDEWEB)

Gomez-Arroyo, S.; Souza, V.

1985-06-01

Sister-chromatid exchanges (SCEs) in human lymphocytes were studied using the FPG technique in order to determine the cytogenetic effect of furfural and furfuryl alcohol. The induction of SCEs was also investigated in workers occupationally exposed to these solvents that are commonly used in the manufacture of furoic resins. The results obtained from the in vitro treatments show that furfural increased the number of SCEs, while furfuryl alcohol did not. In exposed workers, neither of these solvents increased the spontaneous frequency of SCEs per metaphase.

Use of a ring chromosome and pulsed-field gels to study interhomolog recombination, double-strand DNA breaks and sister-chromatid exchange in yeast

International Nuclear Information System (INIS)

Game, J.C.; Sitney, K.C.; Cook, V.E.; Mortimer, R.K.

1989-01-01

The authors describe a system that uses pulsed-field gels for the physical detection of recombinant DNA molecules, double-strand DNA breaks (DSB) and sister-chromatid exchange in the yeast Saccharomyces cerevisiae. The system makes use of a circular variant of chromosome II (Chr. III). Meiotic recombination between this ring chromosome and a linear homolog produces new molecules of sizes distinguishable on gels from either parental molecule. They demonstrate that these recombinant molecules are not present either in strains with two linear Chr. III molecules or in rad50 mutants, which are defective in meiotic recombination. In conjunction with the molecular endpoints. They present data on the timing of commitment to meiotic recombination scored genetically. They have used x-rays to linearize circular Chr. III, both to develop a sensitive method for measuring frequency of DSB and as a means of detecting double-size circles originating in part from sister-chromatid exchange, which they find to be frequent during meiosis

Indirect intergenic suppression of a radiosensitive mutant of Sordaria macrospora defective in sister-chromatid cohesiveness.

Science.gov (United States)

Huynh, A D; Leblon, G; Zickler, D

1986-01-01

Six ultra violet (UV) mutageneses were performed on the spo76 UV-sensitive mutant of Sordaria macrospora. Spo76 shows an early centromere cleavage associated with an arrest at the first meiotic division and therefore does not form ascospores. Moreover, it exhibits altered pairing structure (synaptonemal complex), revealing a defect in the sister-chromatid cohesiveness. From 37 revertants which partially restored sporulation, 34 extragenic suppressors of spo76 were isolated. All suppressors are altered in chromosomal pairing but, unlike spo76, show a wild type centromere cleavage. The 34 suppressors were assigned to six different genes and mapped. Only one of the suppressor genes is involved in repair functions.

Evaluation of the persistence in the induction of Sister Chromatid Exchanges (SCE) by alkylating agents

International Nuclear Information System (INIS)

Rodriguez R, R.; Huerta V, C.; MOrales R, P.R.

2006-01-01

The persistence in the induction of sister chromatid exchanges (SCE) by the alkylating agents methyl and ethyl-methanesulfonates (MMS and EMS) was evaluated. For it, to groups of mice its were administered a dose of these agents and later its were analyzed the induced SCE's in two periods: early and late. Both agents caused high increments of SCE in the early period and small in the late one; however, the caused lately by EMS was significantly bigger. This late induction of SCE by EMS possibly is associated with an epigenetic change or with the presence of etiladucts in the phosphodiester bonds of the DNA. (Author)

Regulation of Centromere Localization of the Drosophila Shugoshin MEI-S332 and Sister-Chromatid Cohesion in Meiosis

Science.gov (United States)

Nogueira, Cristina; Kashevsky, Helena; Pinto, Belinda; Clarke, Astrid; Orr-Weaver, Terry L.

2014-01-01

The Shugoshin (Sgo) protein family helps to ensure proper chromosome segregation by protecting cohesion at the centromere by preventing cleavage of the cohesin complex. Some Sgo proteins also influence other aspects of kinetochore-microtubule attachments. Although many Sgo members require Aurora B kinase to localize to the centromere, factors controlling delocalization are poorly understood and diverse. Moreover, it is not clear how Sgo function is inactivated and whether this is distinct from delocalization. We investigated these questions in Drosophila melanogaster, an organism with superb chromosome cytology to monitor Sgo localization and quantitative assays to test its function in sister-chromatid segregation in meiosis. Previous research showed that in mitosis in cell culture, phosphorylation of the Drosophila Sgo, MEI-S332, by Aurora B promotes centromere localization, whereas Polo phosphorylation promotes delocalization. These studies also suggested that MEI-S332 can be inactivated independently of delocalization, a conclusion supported here by localization and function studies in meiosis. Phosphoresistant and phosphomimetic mutants for the Aurora B and Polo phosphorylation sites were examined for effects on MEI-S332 localization and chromosome segregation in meiosis. Strikingly, MEI-S332 with a phosphomimetic mutation in the Aurora B phosphorylation site prematurely dissociates from the centromeres in meiosis I. Despite the absence of MEI-S332 on meiosis II centromeres in male meiosis, sister chromatids segregate normally, demonstrating that detectable levels of this Sgo are not essential for chromosome congression, kinetochore biorientation, or spindle assembly. PMID:25081981

Sister chromatid exchanges and micronuclei analysis in lymphocytes of men exposed to simazine through drinking water.

Science.gov (United States)

Suárez, Susanna; Rubio, Arantxa; Sueiro, Rosa Ana; Garrido, Joaquín

2003-06-06

In some cities of the autonomous community of Extremadura (south-west of Spain), levels of simazine from 10 to 30 ppm were detected in tap water. To analyse the possible effect of this herbicide, two biomarkers, sister chromatid exchanges (SCE) and micronuclei (MN), were used in peripheral blood lymphocytes from males exposed to simazine through drinking water. SCE and MN analysis failed to detect any statistically significant increase in the people exposed to simazine when compared with the controls. With respect to high frequency cells (HFC), a statistically significant difference was detected between exposed and control groups.

Inhibition of protein synthesis does not antagonize induction of UV-induced sister-chromatid exchange in xeroderma pigmentosum cells

International Nuclear Information System (INIS)

Sono, Akira; Sakaguchi, Kengo.

1988-01-01

Cycloheximide strongly antagonizes the induction of sisterchromatid exchanges by ethyl methanesulfonate or mitomycin C in human skin fibroblast and xeroderma pigmentosum cells (group A). Analogous behavior has been observed in several other species including Chinese hamster and plant cells. This report documents an exception to that pattern: cycloheximide fails to antagonize UV-induced sister chromatid exchange in xeroderma pigmentosum cells, whereas it does in normal human skin fibroblast cells. A genetic defect in these cells is postulated to alter the UV-mediated DNA recombination process. (author)

Sister chromatid exchanges induced in CHO cells by X-rays or 5.5 MeV neutrons

International Nuclear Information System (INIS)

Bocian, E.; Rosiek, O.; Sablinski, J.; Ziemba-Zoltowska, B.

1986-01-01

The induction of sister chromatid exchanges (SCEs) by X-rays (1-9 Gy) and 5.5 MeV neutrons (0.5-4 Gy) was studied in CHO cells. A dose-dependent increase of the frequency of SCE was found for both radiations when cells with BrdUrd substituted DNA were irradiated. The similar doubling dose, approx. 4 Gy, was found for X-rays and neutrons. The increase of the SCE frequency was not clearly dependent on the dose when cells with BrdUrd unsubstituted DNA were irradiated. In this case a dose of 4 Gy enhanced the SCE frequency only by the factor of 1.3. (author)

Sister kinetochores are mechanically fused during meiosis I in yeast.

Science.gov (United States)

Sarangapani, Krishna K; Duro, Eris; Deng, Yi; Alves, Flavia de Lima; Ye, Qiaozhen; Opoku, Kwaku N; Ceto, Steven; Rappsilber, Juri; Corbett, Kevin D; Biggins, Sue; Marston, Adèle L; Asbury, Charles L

2014-10-10

Production of healthy gametes requires a reductional meiosis I division in which replicated sister chromatids comigrate, rather than separate as in mitosis or meiosis II. Fusion of sister kinetochores during meiosis I may underlie sister chromatid comigration in diverse organisms, but direct evidence for such fusion has been lacking. We used laser trapping and quantitative fluorescence microscopy to study native kinetochore particles isolated from yeast. Meiosis I kinetochores formed stronger attachments and carried more microtubule-binding elements than kinetochores isolated from cells in mitosis or meiosis II. The meiosis I-specific monopolin complex was both necessary and sufficient to drive these modifications. Thus, kinetochore fusion directs sister chromatid comigration, a conserved feature of meiosis that is fundamental to Mendelian inheritance. Copyright © 2014, American Association for the Advancement of Science.

Increased sister chromatid cohesion and DNA damage response factor localization at an enzyme-induced DNA double-strand break in vertebrate cells.

LENUS (Irish Health Repository)

Dodson, Helen

2009-10-01

The response to DNA damage in vertebrate cells involves successive recruitment of DNA signalling and repair factors. We used light microscopy to monitor the genetic dependencies of such localization to a single, induced DNA double strand break (DSB) in vertebrate cells. We used an inducible version of the rare-cutting I-SceI endonuclease to cut a chromosomally integrated I-SceI site beside a Tet operator array that was visualized by binding a Tet repressor-GFP fusion. Formation of gamma-H2AX foci at a single DSB was independent of ATM or Ku70. ATM-deficient cells showed normal kinetics of 53Bp1 recruitment to DSBs, but Rad51 localization was retarded. 53Bp1 and Rad51 foci formation at a single DSB was greatly reduced in H2AX-null DT40 cells. We also observed decreased inter-sister chromatid distances after DSB induction, suggesting that cohesin loading at DSBs causes elevated sister chromatid cohesion. Loss of ATM reduced DSB-induced cohesion, consistent with cohesin being an ATM target in the DSB response. These data show that the same genetic pathways control how cells respond to single DSBs and to multiple lesions induced by whole-cell DNA damage.

Can consumption of raw vegetables decrease the count of sister chromatid exchange? Results from a cross-sectional study in Krakow, Poland

OpenAIRE

Galas, Aleksander; Cebulska-Wasilewska, Antonina

2014-01-01

Background Sister chromatid exchange (SCE) is a widely used sensitive cytogenetic biomarker of exposure to genotoxic and cancerogenic agents. Results of human monitoring studies and cytogenetic damage have revealed that biological effects of genotoxic exposures are influenced by confounding factors related to life-style. Vegetable and fruit consumption may play a role, but available results are not consistent. The purpose of the study was to investigate the effect of consumption of raw and co...

In vivo persistence of sister chromatid exchanges (SCE) induced by gamma rays in mouse bone marrow cells

International Nuclear Information System (INIS)

Morales-Ramirez, P.; Vallarino-Kelly, T.; Rodriguez-Reyes, R.

1984-01-01

The sister chromatid exchange (SCE) frequencies induced in bone marrow cells by in vivo irradiation with gamma rays before or after bromodeoxyuridine (BrdUrd) incorporation were compared. The frequency of SCE at different postirradiation times was also measured in bone marrow cells in vivo, irradiated before BrdUrd incorporation. Increased sensitivity to SCE induction by radiation was found in cells after BrdUrd incorporation for one cycle when compared with cells irradiated before BrdUrd incorporation. The increased SCE frequency persisted for at least 72 hr after the initial irradiation, implying that the gamma ray-induced lesion(s) capable of eliciting an SCE are persistent and cannot be easily repaired

Amount of sister chromatid exchanges and survival of Chinese hamster V79-4 cells after irradiation with 0,7 MeV neutrons

International Nuclear Information System (INIS)

Lapidus, I.L.; Nasonova, E.A.

1987-01-01

The dependence of the survival and induction of sister chromatid exchanges (SCEs) in Chinese hamster V79-4 cells on the dose of γ-rays and neutrons with average energy 0.7 MeV has been analysed. The value of RBE for neutrons was 5.5. It has been shown that the number of SCE increased with the dose of γ-irradiation and no induction could be detected after neutron irradiation

Acute wood or coal exposure with carbon monoxide intoxication induces sister chromatid exchange

Energy Technology Data Exchange (ETDEWEB)

Ozturk, S.; Vatansever, S.; Cefle, K.; Palanduz, S.; Guler, K.; Erten, N.; Erk, O.; Karan, M.A.; Tascioglu, C. [University of Istanbul, Istanbul (Turkey). Istanbul Faculty of Medicine

2002-07-01

The object of this study was to investigate the genotoxic effect of acute overexposure to combustion products originating from coal or wood stoves in patients presenting with acute carbon monoxide intoxication. The authors analyzed the frequency of sister chromatid exchange and the carboxyhemoglobin concentration in 20 consecutive patients without a history of smoking or drug use who had been treated in the Emergency Care Unit of Istanbul Medical Faculty due to acute carbon monoxide intoxication. All of these cases were domestic accidents due to dysfunctioning coal or wood stoves. The results were compared with a control group of 20 nonsmoking, nondrug-using healthy individuals matched for age, sex, and absence of other chemical exposure. It was concluded that acute exposure to combustion products of wood or coal is genotoxic to DNA. Potential causes of genotoxicity include known mutagenic compounds present in coal or wood smoke and ash, oxygen radicals formed during combustion, as well as hypoxic and reperfusion injury mechanisms initiated by carbon monoxide intoxication.

Sister chromatid exchange analysis and chromosoma aberration studies in interventional cardiology laboratory workers. One year follow up study

International Nuclear Information System (INIS)

Erol, M.K.; Oztas, S.; Bozkurt, E.; Karakelleoglu, S.

2002-01-01

Invasive cardiology laboratory workers are occupationally exposed to chronic ionizing radiation. It is known that ionizing radiation has a damaging effect on chromosomes. In present study, we investigated the frequency of sister chromatid exchange (SCE) and chromosomal aberrations in 11 invasive cardiology laboratory workers and 11 healthy controls. After a vacation period, we took blood samples for chromosome analysis in months 0, 4, 8 and 12 (last two month period was the nonradiation time). The SCE frequencies did not change significantly after exposure to ionizing radiation in any worker. Our study has revealed that non-specific structural chromosome aberrations such as gaps, isogaps, acentric chromosomes, chromatids and chromosome breakage could be in the 4th and 8th months after ionizing radiation exposure in the metaphase plaques. All abnormal chromosomal effects had disappeared by the end of the two month non-exposure period in each worker. In conclusion, the results suggest that SCE frequencies are not significantly affected in invasive cardiology laboratory workers who are exposed occupationally to ionizing radiation, although some degree of reversible chromosomal aberrations did appear. (author)

Variations in dysfunction of sister chromatid cohesion in esco2 mutant zebrafish reflect the phenotypic diversity of Roberts syndrome

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Stefanie M. Percival

2015-08-01

Full Text Available Mutations in ESCO2, one of two establishment of cohesion factors necessary for proper sister chromatid cohesion (SCC, cause a spectrum of developmental defects in the autosomal-recessive disorder Roberts syndrome (RBS, warranting in vivo analysis of the consequence of cohesion dysfunction. Through a genetic screen in zebrafish targeting embryonic-lethal mutants that have increased genomic instability, we have identified an esco2 mutant zebrafish. Utilizing the natural transparency of zebrafish embryos, we have developed a novel technique to observe chromosome dynamics within a single cell during mitosis in a live vertebrate embryo. Within esco2 mutant embryos, we observed premature chromatid separation, a unique chromosome scattering, prolonged mitotic delay, and genomic instability in the form of anaphase bridges and micronuclei formation. Cytogenetic studies indicated complete chromatid separation and high levels of aneuploidy within mutant embryos. Amongst aneuploid spreads, we predominantly observed decreases in chromosome number, suggesting that either cells with micronuclei or micronuclei themselves are eliminated. We also demonstrated that the genomic instability leads to p53-dependent neural tube apoptosis. Surprisingly, although many cells required Esco2 to establish cohesion, 10-20% of cells had only weakened cohesion in the absence of Esco2, suggesting that compensatory cohesion mechanisms exist in these cells that undergo a normal mitotic division. These studies provide a unique in vivo vertebrate view of the mitotic defects and consequences of cohesion establishment loss, and they provide a compensation-based model to explain the RBS phenotypes.

Very low sister-chromatid exchange rate in Seventh-Day Adventists.

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Wulf, H C; Iversen, A S; Husum, B; Niebuhr, E

1986-08-01

42 Seventh-Day Adventists (SDAs) and 42 controls matched for sex, age and occupation had their sister-chromatid exchange (SCE) examined in peripheral blood lymphocytes. This was done to examine if the SCE frequency was lower in this group of people, who are known to have a decreased cancer risk compared to the general population. The average SCE/cell in 30 cells from each person was 5.54 +/- 0.07 (mean +/- standard error of the mean) for the SDAs and 8.00 +/- 0.15 for the controls, the difference being statistically significant (p less than 0.00001). No difference in SCE frequency was found between SDAs eating only an ovo-lacto-vegetarian diet and those eating some fish or meat. The mitotic index (MI) was significantly higher and the replication index (RI) was significantly lower in SDAs than in controls. No correlation was found between gamma (a statistical transformation of SCEs/cell) and MI or RI within the groups of SDAs or controls. In the pooled data there was a negative correlation of gamma and MI and a positive correlation of gamma and RI. Of the interpersonal variation in gamma 8% and 14% could be explained by MI and RI. The finding of a lower SCE frequency in a group of SDAs who have a low risk of cancer might indirectly indicate a relation between SCE and cancer and encourages further studies of SCE and diet.

Role of oxygen free radicals in the induction of sister chromatid exchanges by cigarette smoke

International Nuclear Information System (INIS)

Lee, C.K.; Brown, B.G.; Rice, W.Y. Jr.; Doolittle, D.J.

1989-01-01

Cigarette smoke has been reported to contain free radicals and free radical generators in both the gas and particulate phases. Studies in our laboratory have shown that both cigarette smoke condensate (CSC) and smoke bubbled through phosphate buffered saline solution (smoke-PBS) increased sister chromatid exchanges (SCE) in Chinese hamster ovary cells in a dose-dependent manner. Since oxygen free radicals have been shown to cause SCEs and other chromosomal damage, we investigated the role of these radicals in the induction of SCEs by CSC and smoke-PBS. Addition of the antioxidant enzymes catalase and superoxide dismutase or the oxygen-radical scavenger ascorbic acid failed to reduce the SCE frequency in the presence of either CSC or smoke-PBS. Additional studies indicated that the quantity of hydrogen peroxide produced in CSC or smoke-PBS is too small to account for the observed SCE induction. It appears, therefore, that SCE induction by CSC or smoke-PBS does not involve the participation of oxygen free radicals

Effects of radiation on frequency of chromosomal aberrations and sister chromatid exchange in the benthic worm Neanthes arenaceodentata

International Nuclear Information System (INIS)

Harrison, F.L.; Rice, D.W. Jr.; Moore, D.H.; Varela, M.

1983-04-01

Traditional bioassays are unsuitable for assessing sublethal effects of low levels of radioactivity because mortality and phenotypic responses are not anticipated. We compared the usefulness of chromosomal aberration (CA) and sister chromatid exchange (SCE) induction as measures of low-level radiation effects in a sediment-dwelling marine worm, Neanthes arenaceodentata. Newly hatched larvae were exposed to two radiation exposure regimes. Groups of 100 larvae were exposed to either x rays delivered at high dose rates (0.7 Gy min -1 ) or to 60 Co gamma rays delivered at low dose rates (4.8 X 10 -5 to 1.2 X 10 -1 Gy h -1 ). After irradiation, the larvae were exposed to 3 X 10 -5 M bromodeoxyuridine (BrdUrd) for 28 h (x-ray-irradiated larvae) or for 54 h ( 60 Co-irradiated larvae). Slides of larval cells were prepared for observation of CAs and SCEs. Frequencies of CAs were determined in first division cells; frequencies of SCEs were determined in second division cells. Results from x-ray irradiation indicated that dose-related increases occur in chromosome and chromatid deletions, but an x-ray dose greater than or equal to 2 Gy was required to observe a significant increase. Worm larvae receiving 60 Co irradiation showed elevated SCE frequencies; a significant increase in SCE frequency was observed at 0.6 Gy. 49 references, 2 figures

Sister chromatid exchanges and structural chromosome aberrations in lymphocytes in operating room personnel

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Husum, B; Niebuhr, E; Wulf, H C; Norgaard, I

1983-06-01

Information on possible chromosomal damage in humans after long-term exposure to trace concentrations of waste anaesthetic gases is scarce. We examined peripheral lymphocytes in operating room personnel for both chromosome aberrations and sister chromatid exchanges (SCE). Following a standardized procedure of cultivation and staining, 30 cells from each person were scored for SCE and 100 cells from each person were examined for chromosome aberrations. A total of 45 persons were examined, representing anaesthetists (n . 15), operating room nurses assisting the surgeon (n . 10), nurses circulating in the operating room (n . 8) and healthy, unexposed controls (n . 12). The median duration of working in the operating room was 102 months, respectively. Time-weighted concentration levels of 2.5-4.3 p.p.m. of halothane and 25-400 p.p.m. of nitrous oxide were measured in the breathing zones of the anaesthetists during mask anaesthesia. Examination of SCE and chromosome aberrations yielded corresponding qualitative results. With both tests, no statistically significant difference was observed between the four groups of persons. It was concluded that by examination of both SCE and chromosome aberrations in peripheral lymphocytes in operating room personnel, no indication was found of a mutagenic effect of long-term exposure to trace concentrations of waste anaesthetic gases.

Defects in the Fanconi Anemia Pathway and Chromatid Cohesion in Head and Neck Cancer.

Science.gov (United States)

Stoepker, Chantal; Ameziane, Najim; van der Lelij, Petra; Kooi, Irsan E; Oostra, Anneke B; Rooimans, Martin A; van Mil, Saskia E; Brink, Arjen; Dietrich, Ralf; Balk, Jesper A; Ylstra, Bauke; Joenje, Hans; Feller, Stephan M; Brakenhoff, Ruud H

2015-09-01

Failure to repair DNA damage or defective sister chromatid cohesion, a process essential for correct chromosome segregation, can be causative of chromosomal instability (CIN), which is a hallmark of many types of cancers. We investigated how frequent this occurs in head and neck squamous cell carcinoma (HNSCC) and whether specific mechanisms or genes could be linked to these phenotypes. The genomic instability syndrome Fanconi anemia is caused by mutations in any of at least 16 genes regulating DNA interstrand crosslink (ICL) repair. Since patients with Fanconi anemia have a high risk to develop HNSCC, we investigated whether and to which extent Fanconi anemia pathway inactivation underlies CIN in HNSCC of non-Fanconi anemia individuals. We observed ICL-induced chromosomal breakage in 9 of 17 (53%) HNSCC cell lines derived from patients without Fanconi anemia. In addition, defective sister chromatid cohesion was observed in five HNSCC cell lines. Inactivation of FANCM was responsible for chromosomal breakage in one cell line, whereas in two other cell lines, somatic mutations in PDS5A or STAG2 resulted in inadequate sister chromatid cohesion. In addition, FANCF methylation was found in one cell line by screening an additional panel of 39 HNSCC cell lines. Our data demonstrate that CIN in terms of ICL-induced chromosomal breakage and defective chromatid cohesion is frequently observed in HNSCC. Inactivation of known Fanconi anemia and chromatid cohesion genes does explain CIN in the minority of cases. These findings point to phenotypes that may be highly relevant in treatment response of HNSCC. ©2015 American Association for Cancer Research.

Alkaline DNA fragmentation, DNA disentanglement evaluated viscosimetrically and sister chromatid exchanges, after treatment in vivo with nitrofurantoin.

Science.gov (United States)

Parodi, S; Pala, M; Russo, P; Balbi, C; Abelmoschi, M L; Taningher, M; Zunino, A; Ottaggio, L; de Ferrari, M; Carbone, A; Santi, L

1983-07-01

Nitrofurantoin was not positive as a carcinogen in long term assays. In vitro it was positive in some short term tests and negative in others. We have examined Nitrofurantoin for its capability of inducing DNA damage in vivo. With the alkaline elution technique, Nitrofurantoin appeared clearly positive in all the tissues examined (liver, kidney, lung, spleen and bone marrow). In the liver we also observed some cross-linking effect. In bone marrow cells Nitrofurantoin was also clearly positive in terms of sister chromatid exchanges (SCEs) induction. DNA damage in vivo was also examined with a viscosimetric method, more sensitive than alkaline elution. With this method the results were essentially negative, suggesting that the two methods detect different types of damage. In view of its positivity in many organs and in two short term tests in vivo, the carcinogenic potential of Nitrofurantoin should be reconsidered.

Merotelic kinetochore attachment in oocyte meiosis II causes sister chromatids segregation errors in aged mice.

Science.gov (United States)

Cheng, Jin-Mei; Li, Jian; Tang, Ji-Xin; Hao, Xiao-Xia; Wang, Zhi-Peng; Sun, Tie-Cheng; Wang, Xiu-Xia; Zhang, Yan; Chen, Su-Ren; Liu, Yi-Xun

2017-08-03

Mammalian oocyte chromosomes undergo 2 meiotic divisions to generate haploid gametes. The frequency of chromosome segregation errors during meiosis I increase with age. However, little attention has been paid to the question of how aging affects sister chromatid segregation during oocyte meiosis II. More importantly, how aneuploid metaphase II (MII) oocytes from aged mice evade the spindle assembly checkpoint (SAC) mechanism to complete later meiosis II to form aneuploid embryos remains unknown. Here, we report that MII oocytes from naturally aged mice exhibited substantial errors in chromosome arrangement and configuration compared with young MII oocytes. Interestingly, these errors in aged oocytes had no impact on anaphase II onset and completion as well as 2-cell formation after parthenogenetic activation. Further study found that merotelic kinetochore attachment occurred more frequently and could stabilize the kinetochore-microtubule interaction to ensure SAC inactivation and anaphase II onset in aged MII oocytes. This orientation could persist largely during anaphase II in aged oocytes, leading to severe chromosome lagging and trailing as well as delay of anaphase II completion. Therefore, merotelic kinetochore attachment in oocyte meiosis II exacerbates age-related genetic instability and is a key source of age-dependent embryo aneuploidy and dysplasia.

Evidence that cyclophosphamide can to induce exchanges in the sister chromatids (ICH) through secondary injuries

International Nuclear Information System (INIS)

Morales R, P.; Rodriguez R, R.

1997-01-01

By means of the use of destination protocol of ICH inductive injuries (DLI-ICH), it was studied if interchanges in the sister chromatids (ICH) induced by cyclophosphamide (CP), in the second post-treatment division (ICH-2) are produced by secondary injuries or by fresh injuries. For discard between these possibilities it was administered CP at different periods before of the first post-treatment division, taking as reference the administered time for high dose of bromodeoxyuridine (BrdU ) which was approximately at the beginning of this division. The ICH frequencies that occur in the first, the second and the third synthesis stages (S) were determined. It was observed that when the administered CP was four hours before BrdU , the ICH frequencies of the second and the third S were reduced. The frequency of the first ICH increased lightly in relation to those of the normal protocol (0.5 h before BrdU ) and that the supplying of CP six hours before caused almost a total reduction of ICH of second and third S and an important increment of ICH of first S.This was interpreted as evidence that the ICH-2 are product of secondary injuries. (Author)

X-ray sensitization of chromatids with unifilarly and bifilarly substituted DNA

International Nuclear Information System (INIS)

Wolff, S.

1981-01-01

When cells are grown for two rounds of DNA replication in the presence of the thymidine analogue 5-bromodeoxyuridine, chromosomes containing one chromatid with unifilarly substituted DNA and one with bifilarly substituted DNA are found. These can be distinguished by harlequin staining techniques that stain one chromatid dark and one light. When the degree of substitution is 60% or greater, 3 times as many X-ray-induced chromatid breaks are produced as in unsubstituted chromatids. This represents maximal sensitization. The unifilarly substituted (dark) chromatid is as sensitive as its bifilarly substituted (light) sister chromatid. If cells are grown in low concentrations of 5-bromodeoxyuridine (BrdUrd), then the amount of substitution is less and the bifilarly substituted chromatic is more sensitive than the unifilarly substituted one. When large numbers of cells are grown in very low concentrations of BrdUrd, the analogue is almost completely depleted during the first round of replication leading to harlequin chromosomes containing one unsubstituted (dark) and one unifilarly substituted (light) chromatid. Under these conditions a maximal sensitization between light-staining and dark-staining chromatids can occur. This can be confused with the differential sensitivity between unifilarly and bifilarly substituted chromatids. The apparent discrepant results obtained by different investigators are most likely caused by the use of very low levels of BrdUrd in some of the experiments. (orig.)

Enhanced stimulation of chromosomal translocations and sister chromatid exchanges by either HO-induced double-strand breaks or ionizing radiation in Saccharomyces cerevisiae yku70 mutants

International Nuclear Information System (INIS)

Fasullo, Michael; St Amour, Courtney; Zeng Li

2005-01-01

DNA double-strand break (DSB) repair occurs by homologous recombination (HR) or non-homologous endjoining (NHEJ). In Saccharomyces cerevisiae, expression of both MAT a and MATα inhibits NHEJ and facilitates DSB-initiated HR. We previously observed that DSB-initiated recombination between two his3 fragments, his3-Δ5' and his3-Δ3'::HOcs is enhanced in haploids and diploids expressing both MAT a and MATα genes, regardless of the position or orientation of the his3 fragments. Herein, we measured frequencies of DNA damage-associated translocations and sister chromatid exchanges (SCEs) in yku70 haploid mutants, defective in NHEJ. Translocation and SCE frequencies were measured in strains containing the same his3 fragments after DSBs were made directly at trp1::his3-Δ3'::HOcs. Wild type and yku70 cells were also exposed to ionizing radiation and radiomimetic agents methyl methanesulfonate (MMS), phleomycin, and 4-nitroquinolone-1-oxide (4-NQO). Frequencies of X-ray-associated and DSB-initiated translocations were five-fold higher in yku70 mutants compared to wild type; however, frequencies of phleomycin-associated translocations were lower in the yku70 haploid mutant. Frequencies of DSB-initiated SCEs were 1.8-fold higher in the yku70 mutant, compared to wild type. Thus, DSB-initiated HR between repeated sequences on non-homologous chromosomes and sister chromatids occurs at higher frequencies in yku70 haploid mutants; however, higher frequencies of DNA damage-associated HR in yku70 mutants depend on the DNA damaging agent

Sister chromatid exchanges in X-ray irradiated blood lymphocytes from patients with hereditary diseases with radioresistant DNA synthesis

International Nuclear Information System (INIS)

Pleskach, N.M.; Andriadze, M.I.; Mikhel'son, V.M.; Zhestyanikov, V.D.

1988-01-01

X-ray irradiation induced sister chromatid exchanges (SCE) in blood lymphocytes from patient with Down's syndrome and adult progeria (in both the cases radioresistant DNA synthesis takes place). In normal lymphocytes (in which ionizing radiation inhibits the replicative synthesis of DNA) the rate of SCE rises with the rise of radiation dose. Thus, the rate of SCE in X-ray irradiated lymphocytes is in reverse dependence with radioresistance of replicative synthesis of DNA. The data obtained are explained in accordance with the replicative hypothesis of the SCE nature (Painter, 1980a): in cells of patients with Down's syndrome, xeroderma pigmentosum from 2 and progeria of adults the time of existence of partly replicated clusters of replicons is decreased due to radioresistant replicative synthesis of DNA, but the presence of partly replicated clusters of replicons in necessary for SCE formation. Therefore the rate of SCF in X-irradiated cells of these patients decreases

A comparative investigation of DNA strand breaks, sister chromatid exchanges and K-ras gene mutations induced by cadmium salts in cultured human cells

International Nuclear Information System (INIS)

Mouron, Silvana Andrea; Grillo, Claudia Alejandra; Dulout, Fernando Noel; Golijow, Carlos Daniel

2004-01-01

Cadmium (Cd) is a toxic heavy metal of continuing occupational and environmental concern with a wide variety of adverse effects. Several studies have shown that cadmium produces DNA strand breaks, DNA-protein cross-links, oxidative DNA damage, chromosomal aberrations, dysregulation of gene expression resulting in enhanced proliferation, depressed apoptosis and/or altered DNA repair. This study was undertaken to investigate the ability of cadmium chloride (CdCl 2 ) and cadmium sulphate (CdSO 4 ) to induce point mutations in codon 12 of the K-ras protooncogene assessed by polymerase chain reaction-single strand conformation polymorphisms (PCR-SSCP) and RFLP-enriched PCR methods. Also their genotoxic effects were analyzed by the comet assay and sister chromatid exchanges test. The human lung fibroblast cell line MRC-5 was used for the experiments. Sister chromatid exchanges assay (SCEs) frequencies were significantly increased in cells exposed to cadmium salts in relation to controls (p < 0.001). Despite the slow increment observed in the three comet parameters considered when cells were treated with cadmium chloride, significant differences between groups were only found in the variable comet moment (CM) (p < 0.005). On the other hand, when cells were exposed to cadmium sulphate, the Kruskal-Wallis test showed highly significant differences between groups for migration, tail moment and comet moment parameters (p < 0.001). Nevertheless, a null or weak point mutation induction in K-ras protooncogene was detected using polymerase chain reaction-low ionic strength-single strand conformation polymorphisms (PCR-LIS-SSCP) and RFLP-enriched PCR methods when cells were treated with cadmium salts. Thus, inorganic cadmium produces genotoxicity in human lung fibroblast MRC-5 cells, in the absence of significant point mutation of the K-ras gene

Elastatinal and leupeptin: effects on u.v.-induced mutation and sister-chromatid exchanges in Chinese hamster cells

International Nuclear Information System (INIS)

Paul, P.; Fujiwara, Y.

1981-01-01

Microbial protease inhibitors elastatinal and leupeptin were tested for cytotoxicity and for effects on spontaneous and u.v.-induced 6-thioguanine-resistant (6TGsup(r)) mutation and sister-chromatid exchange (SCE) in V79 Chinese hamster cells. Continuous treatment with elastatinal exhibited marked cytotoxicity, while leupeptin was almost non-cytotoxic. Elastatinal rapidly induced cytotoxic effects as a function of its concentration and time of exposure. Near maximum cytotoxicity was reached after exposures of 6-8 h and this was partially abolished by the presence of 2.5 μg cycloheximide per ml. Concentrations of either protease inhibitor which gave 60-80% survival had no appreciable effects on u.v. survival and frequencies of spontaneous and u.v.-induced 6TGsup(r) mutation and SCE. However, reconstruction experiments revealed that pretreatments of 6TGsup(r) and 6TGsup(s) (wild-type) cells with these inhibitors for 6 days tended to block metabolic co-operation in their co-cultures. Thus, elastatinal and leupeptin are neither clastogenic nor mutagenic by themselves, and do not alter mutation fixation and expression. (author)

Elastatinal and leupeptin: effects on u.v.-induced mutation and sister-chromatid exchanges in Chinese hamster cells

International Nuclear Information System (INIS)

Paul, P.; Fujiwara, Y.

1981-01-01

Microbial protease inhibitors elastatinal and leupeptin were tested for cytotoxicity and for effects on spontaneous and u.v.-induced 6-thioguanine-resistant (6TGr) mutation and sister-chromatid exchange (SCE) in V79 Chinese hamster cells. Continuous treatment with elastatinal exhibited marked cytotoxicity, while leupeptin was almost non-cytotoxic. Elastatinal rapidly induced cytotoxic effects as a function of its concentration and time of exposure. Near maximum cytotoxicity was reached after exposure of 6-8 h and this was partially abolished by the presence of 2.5 micrograms cycloheximide per ml. Concentrations of either protease inhibitor which gave 60-80% survival had no appreciable effects on u.v. survival and frequencies of spontaneous and u.v.-induced 6TGr mutation and SCE. However, reconstruction experiments revealed that pretreatments of 6TGr and 6TGs (wild-type) cells with these inhibitors for 6 days tended to block metabolic co-operation in their co-cultures. Thus, elastatinal and leupeptin are neither clastogenic mutagenic by themselves, and do not alter mutation fixation and expression

Regulation of the Drosophila Enhancer of split and invected-engrailed gene complexes by sister chromatid cohesion proteins.

Directory of Open Access Journals (Sweden)

Cheri A Schaaf

2009-07-01

Full Text Available The cohesin protein complex was first recognized for holding sister chromatids together and ensuring proper chromosome segregation. Cohesin also regulates gene expression, but the mechanisms are unknown. Cohesin associates preferentially with active genes, and is generally absent from regions in which histone H3 is methylated by the Enhancer of zeste [E(z] Polycomb group silencing protein. Here we show that transcription is hypersensitive to cohesin levels in two exceptional cases where cohesin and the E(z-mediated histone methylation simultaneously coat the entire Enhancer of split and invected-engrailed gene complexes in cells derived from Drosophila central nervous system. These gene complexes are modestly transcribed, and produce seven of the twelve transcripts that increase the most with cohesin knockdown genome-wide. Cohesin mutations alter eye development in the same manner as increased Enhancer of split activity, suggesting that similar regulation occurs in vivo. We propose that cohesin helps restrain transcription of these gene complexes, and that deregulation of similarly cohesin-hypersensitive genes may underlie developmental deficits in Cornelia de Lange syndrome.

Cell elongation is an adaptive response for clearing long chromatid arms from the cleavage plane

Science.gov (United States)

Kotadia, Shaila; Montembault, Emilie; Sullivan, William

2012-01-01

Chromosome segregation must be coordinated with cell cleavage to ensure correct transmission of the genome to daughter cells. Here we identify a novel mechanism by which Drosophila melanogaster neuronal stem cells coordinate sister chromatid segregation with cleavage furrow ingression. Cells adapted to a dramatic increase in chromatid arm length by transiently elongating during anaphase/telophase. The degree of cell elongation correlated with the length of the trailing chromatid arms and was concomitant with a slight increase in spindle length and an enlargement of the zone of cortical myosin distribution. Rho guanine-nucleotide exchange factor (Pebble)–depleted cells failed to elongate during segregation of long chromatids. As a result, Pebble-depleted adult flies exhibited morphological defects likely caused by cell death during development. These studies reveal a novel pathway linking trailing chromatid arms and cortical myosin that ensures the clearance of chromatids from the cleavage plane at the appropriate time during cytokinesis, thus preserving genome integrity. PMID:23185030

Effect of chlorophyllin on frequency radiation-induced of sister chromatid exchanges (SCE) and other cytogenetic events in mice bone marrow cells In Vivo

International Nuclear Information System (INIS)

Garcia Rodriguez, M.C.

1992-01-01

The effect of chlorophyllin on gamma radiation induced Sister chromatid exchanges (SCE) and on the mitotic index (IM) and average generation time was determined. Groups of mice were treated in one of the following regimens: (1) untreated, (2) treated with chlorophyllin only, (3) irradiated and (4) treated with chlorophyllin and irradiated intraperitoneal administration of chlorophyllin preceding gamma radiation exposure protected again SCE induction and diminution of IM. However, radioprotection was not reflected in the average generation time for the chlorophyllin per se acceleration the average generation time. The results suggest that, under the experimental conditions of the study the SCE and IM are caused by free radicals produced by radiation and wat the action mechanics of chlorophyllin is scavenger free radicals. (Author)

Health assessment of gasoline and fuel oxygenate vapors: micronucleus and sister chromatid exchange evaluations.

Science.gov (United States)

Schreiner, Ceinwen A; Hoffman, Gary M; Gudi, Ramadevi; Clark, Charles R

2014-11-01

Micronucleus and sister chromatid exchange (SCE) tests were performed for vapor condensate of baseline gasoline (BGVC), or gasoline with oxygenates, methyl tert-butyl ether (G/MTBE), ethyl tert butyl ether (G/ETBE), t-amyl methyl ether (G/TAME), diisopropyl ether (G/DIPE), t-butyl alcohol (TBA), or ethanol (G/EtOH). Sprague Dawley rats (the same 5/sex/group for both endpoints) were exposed to 0, 2000, 10,000, or 20,000mg/m(3) of each condensate, 6h/day, 5days/week over 4weeks. Positive controls (5/sex/test) were given cyclophosphamide IP, 24h prior to sacrifice at 5mg/kg (SCE test) and 40mg/kg (micronucleus test). Blood was collected from the abdominal aorta for the SCE test and femurs removed for the micronucleus test. Blood cell cultures were treated with 5μg/ml bromodeoxyuridine (BrdU) for SCE evaluation. No significant increases in micronucleated immature erythrocytes were observed for any test material. Statistically significant increases in SCE were observed in rats given BGVC alone or in female rats given G/MTBE. G/TAME induced increased SCE in both sexes at the highest dose only. Although DNA perturbation was observed for several samples, DNA damage was not expressed as increased micronuclei in bone marrow cells. Inclusion of oxygenates in gasoline did not increase the effects of gasoline alone or produce a cytogenetic hazard. Copyright © 2014 Elsevier Inc. All rights reserved.

Frequencies of chromosomal aberrations and sister chromatid exchanges in the benthic worm Neanthes arenaceodentata exposed to ionizing radiation

International Nuclear Information System (INIS)

Harrison, F.L.; Rice, D.W. Jr.; Moore, D.H.

1984-07-01

Traditional bioassays are unsuitable for assessing sublethal effects from ocean disposal of low-level radioactive waste because mortality and phenotypic responses are not anticipated. We compared the usefulness of chromosomal aberration and sister chromatid exchange (SCE) induction as measures of low-level radiation effects in a sediment-dwelling marine worm, Neanthes arenaceodentata. The SCEs, in contrast to chromosomal aberrations, do not alter the overall chromosome morphology and in mammalian cells appear to be a more sensitive indicator of DNA alterations caused by environmental mutagens. Newly hatched larvae were exposed to two radiation-exposure regimes of either x rays at a high dose rate of 0.7 Gy (70 rad)/min for as long as 5.5 min or to 60 Co gamma rays at a low dose rate of from 4.8 x 10 -5 to 1.2 x 10 -1 Gy (0.0048 to 12 rad)/h for 24 h. After irradiation, the larvae were exposed to 3 x 10 -5 M bromodeoxyuridine (BrdUrd) for 28 h (x-ray-irradiated larvae) or for 54 h ( 60 Co-irradiated larvae). Larval cells were examined for the proportion of cells in first, second, and third or greater division. Frequencies of chromosomal aberrations and SCEs were determined in first and second division cells, respectively. Results from x-ray irradiation indicated that dose-related increases occur in chromosome and chromatid deletions, but a dose of equal or greater 2 Gy (equal to or greater than 200 rad) was required to observe a significant increase. Worm larvae receiving 60 Co irradiation showed elevated SCE frequencies with a significant increase of 0.6 Gy (60 rad). We suggest that both SCEs and chromosomal aberrations may be useful for measuring effects on genetic material induced by radiation. 56 references, 7 figures, 9 tables

Increased UV-induced sister-chromatid exchange in cultured fibroblasts of first-degree relatives of melanoma patients

International Nuclear Information System (INIS)

Knees-Matzen, S.; Roser, M.; Reimers, U.; Ehlert, U.; Weichenthal, M.; Breitbart, E.W.; Ruediger, H.W.

1991-01-01

Cultured fibroblasts of 17 first-degree relatives of familial melanoma patients and six first-degree relatives of cutaneous melanoma (CMM) patients with multiple CMM primaries were tested for in vitro sensitivity to UV light. Fibroblasts of nine familial CMM patients with a known UV-sensitivity and 19 healthy probands served as a control. Sister chromatid exchange (SCE) was used as a parameter to detect UV-induced genotoxic damage. The authors found significantly (p less than 0.001) increased UV-induced SCE levels in familial melanoma patients, as well as in first-degree relatives of familial melanoma patients (p less than 0.001) after UV-A,B irradiation (375 J/m2), compared to the healthy probands without a family history of CMM. A significant (p less than 0.001) increase of UV-induced SCE was also observed in the relatives of CMM patients with multiple CMM primaries. In addition, the spontaneous SCE were significantly increased (p less than 0.05) in familial CMM patients. This study shows that increased UV sensitivity is a familial phenomenon. It is consistent with the concept of a genetic predisposition to CMM, which is based on increased UV sensitivity and may help to define groups with an elevated risk of developing cutaneous malignant melanoma

Assessment of DNA Damage in Peripheral Blood Lymphocytes of Radiation Workers at Al-Tuwaitha Site by Using the Sister Chromatid Exchange and the Comet Assay

International Nuclear Information System (INIS)

Ali, A.K.; Muttar, A.J.; Khayon, S.K.; Haider, Y.L.; Ali, H.F.; Abdullah, A.K.

2015-01-01

The sister chromatid exchange was performed on peripheral blood lymphocytes obtained from 40 individuals of workers occupationally exposed to low ionizing radiation doses in Al-Tuwaitha site due to decommissioning to radioactive contamination then compared with 40 control individuals living in Baghdad. SCEs were scored in metaphase chromosomes were identified by fluorescent plus Giemsa staining (Figure 2).The mean frequencies of SCEs per cell differed significantly (p≺0 0.05) between individuals of radiation workers and control, being 7.78 0.45 SCE/cells and 6.28 0.22 SCE/cells , respectively. However SCE frequency was statistically significant (P≺0 0.05) among radiation workers as compared to control individuals.

Effect of chlorophyllin on induction of exchanges in sister chromatids by gamma irradiation in mice spermatogonia in vivo

International Nuclear Information System (INIS)

Mendiola C, M.T.

1994-01-01

Mouse were exposed to different doses of gamma radiation and the effect on Sister Chromatid Exchange (SCE) frequency in spermatogonias was evaluated. The effect was analyzed before and after Bromodeoxyuridine (BrdU) incorporation to determine the interference of such agent with the cellular response induced by radiation. The capacity of chlorophyllin (sodium and Copper salt derivative from chlorophyll) to reduce SCE induction by radiation in normal and BrdU radio sensitized spermatogonia was also determined. The results indicate that there was a significant increase in SCE frequency by gamma radiation exposure in these cells, such effect was higher irradiating after BrdU incorporation than before. This fact confirms previous observations that BrdU sensitizes some cells to SCE induction. With regard to the chlorophyllin effect, it was determined that this salt acts as a radioprotector reducing gamma-rays induced SCE before or after BrdU incorporation Total protection was obtained with 200 μg of chlorophyllin per g of body weight in both protocols. Under the experimental conditions this study there was no evidence of genotoxicity induced by chlorophyllin itself. The results suggest that this agent may act as a radioprotector by scavenging free radicals produced by gamma-radiation which cause DNA lesions that are involved in SCE formation. (Author)

Effects of hyperthermia and x irradiation on sister chromatid exchange (SCE) frequency in Chinese hamster ovary (CHO) cells

International Nuclear Information System (INIS)

Livingston, G.K.; Dethlefsen, L.A.

1979-01-01

The BrdUrd labeling method was used to evaluate the effects of hyperthermia, x irradiation, and the combined treatment on the incidence of sister chromatid exchange (SCE) in Chinese hamster ovary (CHO) cells. Cells cultured in McCoy's 5A media containing 10 μM 5-bromodeoxyuridine were synchronized after one cell cycle by mitotic shake-off. Early-G 1 cells were heated by submerging culture flasks in a 44 +- 0.05 0 C water bath for periods of 20, 40, and 60 min. By the same method, other cultures were x irradiated at doses of 100, 200, 400, and 600 rad. A third protocol involved combined treatment of 20 min at 44 0 C followed immediately by one of the above radiation doses. A fourth protocol reversed the sequence of the combined treatment applying x irradiation (200 or 400 rad) followed immediately by hyperthermia. The data showed that hyperthermia and x irradiation both elevated the frequency of SCEs significantly whether applied separately or together. The combined treatment (heat: 20 min at 44 0 C plus varying x-radiation doses) produced results suggestive of a synergistic interaction. The sequence of the heat and x irradiation did not appear to have a significant effect on the production of SCE

Protection of halogenated DNA from strand breakage and sister-chromatid exchange induced by the topoisomerase I inhibitor camptothecin

International Nuclear Information System (INIS)

Orta, Manuel Luis; Mateos, Santiago; Cantero, Gloria; Wolff, Lisa J.; Cortes, Felipe

2008-01-01

The fundamental nuclear enzyme DNA topoisomerase I (topo I), cleaves the double-stranded DNA molecule at preferred sequences within its recognition/binding sites. We have recently reported that when cells incorporate halogenated nucleosides analogues of thymidine into DNA, it interferes with normal chromosome segregation, as shown by an extraordinarily high yield of endoreduplication, and results in a protection against DNA breakage induced by the topo II poison m-AMSA [F. Cortes, N. Pastor, S. Mateos, I. Dominguez, The nature of DNA plays a role in chromosome segregation: endoreduplication in halogen-substituted chromosomes, DNA Repair 2 (2003) 719-726; G. Cantero, S. Mateos, N. Pastor; F. Cortes, Halogen substitution of DNA protects from poisoning of topoisomerase II that results in DNA double-strand breaks (DSBs), DNA Repair 5 (2006) 667-674]. In the present investigation, we have assessed whether the presence of halogenated nucleosides in DNA diminishes the frequency of interaction of topo I with DNA and thus the frequency with which the stabilisation of cleavage complexes by the topo I poison camptothecin (CPT) takes place, in such a way that it protects from chromosome breakage and sister-chromatid exchange. This protective effect is shown to parallel a loss in halogen-substituted cells of the otherwise CPT-increased catalytic activity bound to DNA

The Relationship between Dioxin Congeners in the Breast Milk of Vietnamese Women and Sister Chromatid Exchange

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Hiroyuki Suzuki

2014-04-01

Full Text Available The aim of this study was to clarify the relationship between dioxin concentrations in breast milk and the sister chromatid exchange (SCE frequency in women from herbicide-sprayed and non sprayed areas. Blood samples were taken from 21 women with high TCDD (tetrachlorodibenzo-p-dioxin levels from sprayed areas, 23 women with moderate TCDD levels from sprayed areas, and 19 women from non sprayed areas to determine their SCE frequency. The SCE frequencies for the high and moderate TCDD groups from the sprayed area and for the non sprayed area group were 2.40, 2.19, and 1.48 per cell, respectively. Multiple regression analysis showed that the standardized β values for 1,2,3,6,7,8-hexaCDD (β = 0.60, 1,2,3,4,6,7,8-heptaCDD (β = 0.64, and octaCDD (β = 0.65 were higher than those for TCDD (β = 0.34 and 1,2,3,7,8-pentaCDD (β = 0.42. The adjusted R2 value for polyCDDs (R2 = 0.38 was higher than that for polyCDD toxic equivalents (TEQ (toxic equivalents; R2 = 0.23. This study therefore shows that levels of hexa-, hepta-, and octaCDD, which were previously regarded as being less toxic than TCDD, are closely related to SCE frequency and that the level of dioxin (pg/g lipid is potentially more useful as an indicator than TEQ value for explaining SCE frequency.

Cleavage of cohesin rings coordinates the separation of centrioles and chromatids.

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Schöckel, Laura; Möckel, Martin; Mayer, Bernd; Boos, Dominik; Stemmann, Olaf

2011-07-10

Cohesin pairs sister chromatids by forming a tripartite Scc1-Smc1-Smc3 ring around them. In mitosis, cohesin is removed from chromosome arms by the phosphorylation-dependent prophase pathway. Centromeric cohesin is protected by shugoshin 1 and protein phosphatase 2A (Sgo1-PP2A) and opened only in anaphase by separase-dependent cleavage of Scc1 (refs 4-6). Following chromosome segregation, centrioles loosen their tight orthogonal arrangement, which licenses later centrosome duplication in S phase. Although a role of separase in centriole disengagement has been reported, the molecular details of this process remain enigmatic. Here, we identify cohesin as a centriole-engagement factor. Both premature sister-chromatid separation and centriole disengagement are induced by ectopic activation of separase or depletion of Sgo1. These unscheduled events are suppressed by expression of non-cleavable Scc1 or inhibition of the prophase pathway. When endogenous Scc1 is replaced by artificially cleavable Scc1, the corresponding site-specific protease triggers centriole disengagement. Separation of centrioles can alternatively be induced by ectopic cleavage of an engineered Smc3. Thus, the chromosome and centrosome cycles exhibit extensive parallels and are coordinated with each other by dual use of the cohesin ring complex.

Evaluation of the persistence in the induction of Sister Chromatid Exchanges (SCE) by alkylating agents; Evaluacion de la persistencia en la induccion de Intercambio en las Cromatidas Hermanas (ICH) por agentes alquilantes

Energy Technology Data Exchange (ETDEWEB)

Rodriguez R, R.; Huerta V, C.; MOrales R, P.R. [ININ, 52045 Ocoyoacac, Estado de Mexico (Mexico)

2006-07-01

The persistence in the induction of sister chromatid exchanges (SCE) by the alkylating agents methyl and ethyl-methanesulfonates (MMS and EMS) was evaluated. For it, to groups of mice its were administered a dose of these agents and later its were analyzed the induced SCE's in two periods: early and late. Both agents caused high increments of SCE in the early period and small in the late one; however, the caused lately by EMS was significantly bigger. This late induction of SCE by EMS possibly is associated with an epigenetic change or with the presence of etiladucts in the phosphodiester bonds of the DNA. (Author)

Evaluation of the persistence in the induction of Sister Chromatid Exchanges (SCE) by alkylating agents; Evaluacion de la persistencia en la induccion de Intercambio en las Cromatidas Hermanas (ICH) por agentes alquilantes

Energy Technology Data Exchange (ETDEWEB)

Rodriguez R, R; Huerta V, C; MOrales R, P R [ININ, 52045 Ocoyoacac, Estado de Mexico (Mexico)

2006-07-01

The persistence in the induction of sister chromatid exchanges (SCE) by the alkylating agents methyl and ethyl-methanesulfonates (MMS and EMS) was evaluated. For it, to groups of mice its were administered a dose of these agents and later its were analyzed the induced SCE's in two periods: early and late. Both agents caused high increments of SCE in the early period and small in the late one; however, the caused lately by EMS was significantly bigger. This late induction of SCE by EMS possibly is associated with an epigenetic change or with the presence of etiladucts in the phosphodiester bonds of the DNA. (Author)

Persistence of sister chromatid exchanges and in vitro morphological transformation of Syrian hamster fetal cells by chemical and physical carcinogens

International Nuclear Information System (INIS)

Popescu, N.C.; Amsbaugh, S.C.; DiPaolo, J.A.

1985-01-01

The induction of neoplastic cell transformation is closely associated with DNA alterations which occur shortly after carcinogen exposure. Sister chromatid exchange (SCE) formation is a sensitive indicator of carcinogen-DNA interaction and correlates with the induction of morphological cell transformation. The persistence of lesions generating SCE produced by chemical and physical carcinogens and its relevance to the induction of morphologic transformation was evaluated in coordinated experiments with cultured Syrian hamster fetal cells (HFC). Exponentially growing HFC were exposed for 1 h to benzo[a]pyrene (BP), methyl-methanesulfonate (MMS), cis-platinum (II) diaminedichloride (cis Pt II), N-methyl-N'-nitrosourea (MNU), mitomycin C (MMC), N-methyl-N'-nitro-N-nitrosoguanidine (MNNG), N-acetoxy-2-fluorenyl-acetamide (AcAAF) or u.v. light irradiated. SCE analysis demonstrates that for a period of 48 h after carcinogen exposure, during which time the cells undergo at least four replicative cycles, DNA damage generating SCE induced by all chemical carcinogens either persisted or was partially removed, whereas u.v.-induced lesions were completely removed. An elevated SCE frequency persisted after two additional cell cycles after treatment with BP, AcAAF or MMC without increased cell lethality as compared to other carcinogens whose lesions were completely eliminated during the same period

Trex2 enables spontaneous sister chromatid exchanges without facilitating DNA double-strand break repair.

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Dumitrache, Lavinia C; Hu, Lingchuan; Son, Mi Young; Li, Han; Wesevich, Austin; Scully, Ralph; Stark, Jeremy; Hasty, Paul

2011-08-01

Trex2 is a 3' → 5' exonuclease that removes 3'-mismatched sequences in a biochemical assay; however, its biological function remains unclear. To address biology we previously generated trex2(null) mouse embryonic stem (ES) cells and expressed in these cells wild-type human TREX2 cDNA (Trex2(hTX2)) or cDNA with a single-amino-acid change in the catalytic domain (Trex2(H188A)) or in the DNA-binding domain (Trex2(R167A)). We found the trex2(null) and Trex2(H188A) cells exhibited spontaneous broken chromosomes and trex2(null) cells exhibited spontaneous chromosomal rearrangements. We also found ectopically expressed human TREX2 was active at the 3' ends of I-SceI-induced chromosomal double-strand breaks (DSBs). Therefore, we hypothesized Trex2 participates in DNA DSB repair by modifying 3' ends. This may be especially important for ends with damaged nucleotides. Here we present data that are unexpected and prompt a new model. We found Trex2-altered cells (null, H188A, and R167A) were not hypersensitive to camptothecin, a type-1 topoisomerase inhibitor that induces DSBs at replication forks. In addition, Trex2-altered cells were not hypersensitive to γ-radiation, an agent that causes DSBs throughout the cell cycle. This observation held true even in cells compromised for one of the two major DSB repair pathways: homology-directed repair (HDR) or nonhomologous end joining (NHEJ). Trex2 deletion also enhanced repair of an I-SceI-induced DSB by both HDR and NHEJ without affecting pathway choice. Interestingly, however, trex2(null) cells exhibited reduced spontaneous sister chromatid exchanges (SCEs) but this was not due to a defect in HDR-mediated crossing over. Therefore, reduced spontaneous SCE could be a manifestation of the same defect that caused spontaneous broken chromosomes and spontaneous chromosomal rearrangements. These unexpected data suggest Trex2 does not enable DSB repair and prompt a new model that posits Trex2 suppresses the formation of broken

In vivo study on the replicative model validity of sister chromatid exchanges production

International Nuclear Information System (INIS)

Cruz V, V.L.

1996-01-01

The sister chromatid exchanges (SCE) frequency determination has been used as index of damage to DNA, however the biological meaning of this event is still ignored. Different models in order to explain the mechanism of their formation have been proposed and they could be contained in two categories: a) those that consider that the SCE is produced by means of discreet lesions to the DNA and that they occur in the place of the lesion, and b) those that propose that the SCE is caused by a group of lesions and that therefore the place in which they occur could not be associated with a lesion in particular. The model of Painter (1980) belongs to this last group. It suggests that the region of the DNA where the clusters are united, is the only place in which the exchange of double chain could happen during the synthesis of the DNA and makes the prediction that since the x rays retard the beginning of the duplication, the pretreatment with ionizing radiation would reduce the frequency of SCE induced by agents capable to block the lengthening of the chain of DNA, that are the most efficient SCE inducers. The objective of the present work was to establish the validity of this replicative model for the SCE formation, based in its prediction. The effect of the unilateral preexposition of mouse to gamma radiation was determined on the SCE induction by Mitomycin C (MMC), in cells of the femoral bone marrow In vivo. This strategy allows to determine the effect of the pretreatment in the same organism, minimizing the variability of the response between individuals. There was not a significant variability between the frequencies of SCE, basal and induced by gamma radiation or MMC in the same organism. The animals that received the gamma radiation pretreatment, showed a reduction of approximately the 30 % in the frequency of SCE, assuming an additive effect of the radiation with the MMC. These results coincide with the prediction of the model of Painter, however it is not

Micronuclear and sister chromatid exchange analyses in peripheral lymphocytes of patients with oral lichen planus--a pilot study.

Science.gov (United States)

Ergun, S; Warnakulasuriya, S; Duman, N; Saruhanoğlu, A; Sevinç, B; Oztürk, S; Ozel, S; Cefle, K; Palanduz, S; Tanyeri, H

2009-10-01

The purpose of this study was to determine the genetic instability of peripheral blood lymphocytes from patients diagnosed with oral lichen planus (OLP) by investigation of frequencies of micronuclei (MN) and sister chromatid exchange (SCE). A total of 22 newly diagnosed and untreated patients with OLP of same severity scores and twenty healthy controls participated in this study. They were all non-smokers with no previous history or family history of cancer. The periodontal status, flow rate and buffering capacity of whole mouth saliva were recorded. SCE and MN analyses were performed on peripheral blood lymphocytes of OLP patients and healthy controls. The frequencies of MN (50.00 +/- 22.36) and SCE (6.89 +/- 1.48) in OLP patients were found to be significantly elevated compared with that in normal individuals (25.20 +/- 9.52 and 5.93 +/- 1.31; z = 3.946, P = 0.0001; z = 2.346, P = 0.019). There were no significant differences in the MN frequency and SCE between the two subgroups with reticular or erosive types of OLP. These pilot data indicate an increased genomic instability in peripheral blood lymphocytes of a cohort of Turkish patients diagnosed with oral lichen planus as compared with that of healthy individuals. As patients with OLP may have an increased or potential risk for oral malignancy, these assays could be used in translational research to monitor beneficial effects of interventions and long-term prognosis.

Effect of low 60Co dose rates on sister chromatid exchange incidence in the benthic worm. Neanthes arenaceodentata

International Nuclear Information System (INIS)

Harrison, F.L.; Rice, D.W. Jr.

1981-01-01

The usefulness of sister chromatid exchange (SCE) induction as a measure of low-level radiation effect was examined in a benthic marine worm, Neanthes arenaceodentata. Larvae were exposed to 60 Co radiation for 12 to 24 h at total doses ranging from 0.5 to 309 R and at dose rates from 0.04 to 13 R/h. Animals exposed at intermediate dose rates (0.5, 0.6, 1.25, 2.0, and 2.5 R/h) had SCE frequencies per chromosome about twice that of those receiving no radiation (controls), whereas those exposed at the higher dose rates (7.0 and 13 R/h) had SCE frequencies lower than the controls. Animals exposed at the lower dose rates (0.04 and 0.1 R/h) had lower SCE frequencies than those exposed at intermediate dose rates (and higher SCE frequencies than controls). The length of chromosome pair number one differed among metaphase spreads and was used as an index of chromosome condensation in a given metaphase. Because there is a possibility that chromosome morphology may affect the ability to resolve SCEs, morphology will be monitored in future studies. A preliminary experiment was performed to assess the effects of 2.2 and 11.5 R/h for 24 h on growth and development. Larvae observed at 6 and 17 d after irradiation did not have significantly different numbers of abnormal larvae or survival rates

Differences in sensitivity of murine spermatogonia and somatic cells in vivo to sister-chromatid exchange induction by nitrosoureas.

Science.gov (United States)

Morales-Ramírez, P; Cruz-Vallejo, V; Rodríguez-Reyes, R

2001-07-01

Previously published data indicate that spermatogonia (SPG) are less sensitive to a sister-chromatid exchange (SCE) induction for different mutagens. In an earlier study, we have observed that bromodeoxyuridine (BrdU) substituted murine SPG are less sensitive to SCE induction by gamma ray in cells, than bone marrow (BM) and salivary gland (SG) cells in vivo. This was interpreted to mean that SPG are more efficient in DNA repair or are less prone to SCE induction. That the lower induction of SCE could be due to a reduced accessibility of mutagens to the SPG by virtue of a physiological barrier, was discarded by using gamma radiation. The aim of the present study was to establish whether or not there are differences in SCE induction by nitrosoureas among SPG, SG and BM cells with BrdU substituted or unsubstituted DNA. It was observed that SCE induction by methylnitrosourea (MNU) or by ethylnitrosourea (ENU) in SPG was, respectively, five and two times lower than in SG, and ten and three times lower than in BM. In SPG after BrdU incorporation, there was no increase in efficiency of SCE induction; in fact, there was even a slight decrease by exposure to MNU or ENU. BM and SG cells showed an increased efficiency in SCE induction after BrdU incorporation. This implies that SPG are also less sensitive to SCE induction by nitrosoureas, which cause a different kind of damage from previously assayed mutagens.

Can consumption of raw vegetables decrease the count of sister chromatid exchange? Results from a cross-sectional study in Krakow, Poland.

Science.gov (United States)

Galas, Aleksander; Cebulska-Wasilewska, Antonina

2015-03-01

Sister chromatid exchange (SCE) is a widely used sensitive cytogenetic biomarker of exposure to genotoxic and cancerogenic agents. Results of human monitoring studies and cytogenetic damage have revealed that biological effects of genotoxic exposures are influenced by confounding factors related to life-style. Vegetable and fruit consumption may play a role, but available results are not consistent. The purpose of the study was to investigate the effect of consumption of raw and cooked vegetables and fruits on SCE frequency. A total of 62 participants included colorectal cancer (CRC) patients, hospital-based controls and healthy laboratory workers. SCE frequency was assessed in blood lymphocytes. Frequency of vegetable and fruit consumption was gathered by structured semi-quantitative food frequency questionnaire. SCE frequency was lowest among hospital-based controls (4.4 ± 1.1), a bit higher in CRC patients (4.5 ± 1.0) and highest among laboratory workers (7.4 ± 1.2) (p consumption, but not so for intake of cooked vegetables and fruits. The results of the study have shown the beneficial effect of consumption of raw vegetables on disrupted replication of DNA measured by SCE frequency, implying protection against genotoxic agents. Further effort is required to verify the role of cooked vegetables and fruits.

Variation in sister chromatid exchange frequencies between human and pig whole blood, plasma leukocyte, and mononuclear leukocyte cultures

International Nuclear Information System (INIS)

Larramendy, M.L.; Reigosa, M.A.

1986-01-01

Sister chromatid exchange (SCE) induction by ultraviolet (UV) light was studied in both human and pig whole blood cultures (WBC) and plasma leukocyte cultures (PLC). No variation in SCE frequency was observed between pig WBC and PLC in control as well as in treated cells. Conversely, SCE frequencies of human PLC were consistently higher than those of WBC in control and UV-exposed cells. Thus, red blood cells (RBCs) do not influence the sensitivity of lymphocytes to UV LIGHT exposure, and there must be some different culture condition(s) in the inducation of SCEs between human WBC and PLC but not in swine lymphocyte cultures. Since the BrdUrd/lymphocyte ratio of WBC was halved in PLC, the effect of BrdUrd concentration in inducing the SCE baseline frequency of PLC may be ruled out. Neither the cell separation technique nor polymorphonuclear leukocytes had a significant role in the elevated SCE frequency of human PLC or MLC. Experiments where human RBCs were titrated into human PLC showed that the induction of an elevated SCE frequency of PLC was suppressed in a dose-dependent manner by the presence of RBCs in the culture medium. Since the incorporation of pig or human RBCs into human PLC as well as into MLC reduced the SCE frequency to that of WBC, a common component and/or function existing in these cells is suggested. Analysis of different RBC components showed that RBCs, specifically RBC ghosts, release a diffusible but not dialyzable corrective factor into culture medium that is able to reduce the SCE frequencies of PLC

Separase Is Required for Homolog and Sister Disjunction during Drosophila melanogaster Male Meiosis, but Not for Biorientation of Sister Centromeres.

Science.gov (United States)

Blattner, Ariane C; Chaurasia, Soumya; McKee, Bruce D; Lehner, Christian F

2016-04-01

Spatially controlled release of sister chromatid cohesion during progression through the meiotic divisions is of paramount importance for error-free chromosome segregation during meiosis. Cohesion is mediated by the cohesin protein complex and cleavage of one of its subunits by the endoprotease separase removes cohesin first from chromosome arms during exit from meiosis I and later from the pericentromeric region during exit from meiosis II. At the onset of the meiotic divisions, cohesin has also been proposed to be present within the centromeric region for the unification of sister centromeres into a single functional entity, allowing bipolar orientation of paired homologs within the meiosis I spindle. Separase-mediated removal of centromeric cohesin during exit from meiosis I might explain sister centromere individualization which is essential for subsequent biorientation of sister centromeres during meiosis II. To characterize a potential involvement of separase in sister centromere individualization before meiosis II, we have studied meiosis in Drosophila melanogaster males where homologs are not paired in the canonical manner. Meiosis does not include meiotic recombination and synaptonemal complex formation in these males. Instead, an alternative homolog conjunction system keeps homologous chromosomes in pairs. Using independent strategies for spermatocyte-specific depletion of separase complex subunits in combination with time-lapse imaging, we demonstrate that separase is required for the inactivation of this alternative conjunction at anaphase I onset. Mutations that abolish alternative homolog conjunction therefore result in random segregation of univalents during meiosis I also after separase depletion. Interestingly, these univalents become bioriented during meiosis II, suggesting that sister centromere individualization before meiosis II does not require separase.

Comparison of 6-thioguanine-resistant mutation and sister chromatid exchanges in Chinese hamster V79 cells with forty chemical and physical agents

International Nuclear Information System (INIS)

Nishi, Y.; Hasegawa, M.M.; Taketomi, M.; Ohkawa, Y.; Inui, N.

1984-01-01

The induction of sister chromatid exchanges (SCE) and mutation at the hypoxanthine-guanine phosphoribosyl transferase locus and toxicities of 40 different chemical and physical agents were examined on Chinese hamster V79 cells. These agents included mono-, di-, tri-, and polyfunctional alkylating agents, intercalators, gamma-rays, and UV light irradiation. Mutation was measured as resistance to 6-thioguanine and toxicity as loss of cell-plating efficiency. SCE were examined 29 hr after treatment. With the agents examined, a highly positive correlation existed between SCE-inducing and mutagenic potencies, when expressed as increase in the number per a unit dose over the control values. But the great difference of the ratios of mutagenic potencies versus SCE-inducing potencies among agents was observed, the maximal difference in the ratios being about 200-fold. The agents that showed the higher values of the ratio (agents producing more mutations than SCE) were bleomycin, cobalt-60 gamma-rays, all ethylating agents (N-ethyl-N-nitrosourea, N-ethyl-N'-nitro-N-nitrosoguanidine, ethyl methanesulfonate, and diethylsulfate), N-propyl-N-nitrosourea, N-butyl-N-nitrosourea, isopropyl methanesulfonate, intercalating acridine compounds (2-methoxy-6-chloro-9-[3-(ethyl-2-chloroethyl)aminopropylamino]-acridine X 2HCl and 2-methoxy-6-chloro-9-[3-(chloroethyl)-aminopropylamino]acridine 2HCl) and UV light at 254 nm

Excision and crosslink repair of DNA and sister chromatid exchanges in cultured human fibroblasts with different repair capacities

Energy Technology Data Exchange (ETDEWEB)

Fujiwara, Y; Kano, Y; Paul, P; Goto, K; Yamamoto, K [Kobe Univ. (Japan). School of Medicine

1981-01-01

Xeroderma pigmentosum (XP) groups A to G lacked the initial stage of ultraviolet (UV) excision repair in the order of A = G > C > D > E asymptotically equals F, while the XP variant was weakly defective in the later repair steps. Killing sensitivities were in the orders of A >= G > D > C > E asymptotically equals F asymptotically equals variant > normal to UV, A = G > D > F > C = E > variant > normal to 4-nitroquinoline-1-oxide (4NQO), and A > C > D = E = F = variant > G = normal to decarbamoyl mitomycin-C(DCMC). The induced sister chromatid exchange (SCE) frequency was unrelated to the extent of repair deficiency. The SCE induction rate was consistently 3 - 6 fold higher by these UV-like mutagens in XP group A cells than in normal cells. However, repair-proficient Cockayne's syndrome (CS) cells showed a higher SCE induction by UV, which was normalized by NAD/sup +/, suggesting that chromatin lesions as well as DNA damage contribute to SCE. Two-step crosslink repair involves a first rapid half-excision and a second slow nucleotide-excision repair. Fanconi's anemia (FA) cells had an impaired first half-excision and were supersensitive to MC, but not to UV and DCMC. The SCE frequency induced by MC (1 hr) was higher in FA cells than in normal cells despite their normal response to DCMC, and vice versa in XP cells. FA cells lacked the first rapid decline and showed higher remaining SCEs. Thus, part of the crosslink seems to lead to SCE formation. Caffeine synergistically elevated UV-induced SCEs, but not UV induced mutations in V79 cells, implying that SCE may not necessarily involve mutation.

Excision and crosslink repair of DNA and sister chromatid exchanges in cultured human fibroblasts with different repair capacities

International Nuclear Information System (INIS)

Fujiwara, Yoshisada; Kano, Yoshio; Paul, P.; Goto, Kaoru; Yamamoto, Kazuo

1981-01-01

Xeroderma pigmentosum (XP) groups A to G lacked the initial stage of ultraviolet (UV) excision repair in the order of A = G > C > D > E asymptotically equals F, while the XP variant was weakly defective in the later repair steps. Killing sensitivities were in the orders of A >= G > D > C > E asymptotically equals F asymptotically equals variant > normal to UV, A = G > D > F > C = E > variant > normal to 4-nitroquinoline-1-oxide (4NQO), and A > C > D = E = F = variant > G = normal to decarbamoyl mitomycin-C(DCMC). The induced sister chromatid exchange (SCE) frequency was unrelated to the extent of repair deficiency. The SCE induction rate was consistently 3 - 6 fold higher by these UV-like mutagens in XP group A cells than in normal cells. However, repair-proficient Cockayne's syndrome (CS) cells showed a higher SCE induction by UV, which was normalized by NAD + , suggesting that chromatin lesions as well as DNA damage contribute to SCE. Two-step crosslink repair involves a first rapid half-excision and a second slow nucleotide-excision repair. Fanconi's anemia (FA) cells had an impaired first half-excision and were supersensitive to MC, but not to UV and DCMC. The SCE frequency induced by MC (1 hr) was higher in FA cells than in normal cells despite their normal response to DCMC, and vice versa in XP cells. FA cells lacked the first rapid decline and showed higher remaining SCEs. Thus, part of the crosslink seems to lead to SCE formation. Caffeine synergistically elevated UV-induced SCEs, but not UV induced mutations in V79 cells, implying that SCE may not necessarily involve mutation. (J.P.N.)

Excision and crosslink repair of DNA and sister chromatid exchanges in cultured human fibroblasts with different repair capacities

Energy Technology Data Exchange (ETDEWEB)

Fujiwara, Y.; Kano, Y.; Paul, P.; Goto, K.; Yamamoto, K. (Kobe Univ. (Japan). School of Medicine)

1981-01-01

Xeroderma pigmentosum (XP) groups A to G lacked the initial stage of ultraviolet (UV) excision repair in the order of A = G > C > D > E asymptotically equals F, while the XP variant was weakly defective in the later repair steps. Killing sensitivities were in the orders of A >= G > D > C > E asymptotically equals F asymptotically equals variant > normal to UV, A = G > D > F > C = E > variant > normal to 4-nitroquinoline-1-oxide (4NQO), and A > C > D = E = F = variant > G = normal to decarbamoyl mitomycin-C(DCMC). The induced sister chromatid exchange (SCE) frequency was unrelated to the extent of repair deficiency. The SCE induction rate was consistently 3 - 6 fold higher by these UV-like mutagens in XP group A cells than in normal cells. However, repair-proficient Cockayne's syndrome (CS) cells showed a higher SCE induction by UV, which was normalized by NAD/sup +/, suggesting that chromatin lesions as well as DNA damage contribute to SCE. Two-step crosslink repair involves a first rapid half-excision and a second slow nucleotide-excision repair. Fanconi's anemia (FA) cells had an impaired first half-excision and were supersensitive to MC, but not to UV and DCMC. The SCE frequency induced by MC (1 hr) was higher in FA cells than in normal cells despite their normal response to DCMC, and vice versa in XP cells. FA cells lacked the first rapid decline and showed higher remaining SCEs. Thus, part of the crosslink seems to lead to SCE formation. Caffeine synergistically elevated UV-induced SCEs, but not UV induced mutations in V79 cells, implying that SCE may not necessarily involve mutation.

Repairability during G 1 phase of inducting lesions of sister chromatid exchange produced by mitomycin C in salivary gland cells of mice In Vivo

International Nuclear Information System (INIS)

Cruz Vallejo, V.L.

1991-01-01

The repairability of the injuries that lead to the formation of sister chromatid exchange (SCE) produced by mitomycin C (MMC) with a dose of 2.1 mg/g in vivo, during the G 1 phase in the first cycle of cellular division (before the incorporation of BrdU [5-bromo-2 deoxyurine] to the DNA), as well as during the G 1 phase of the second cycle of cellular division (after the incorporation of BrdU) were analyzed. A 35.1% decrease in the frequency of SCE produced by Mitomycin C was observed, in the early G 1 phase of the first division, with respect to the frequency of SCE induced in the later G 1 phase. When Mitomycin C is given to cells whose DNA is substituted with BrdU in only one of the chain's filaments such decrease is not observed. The results suggest that the injuries caused by MMC, which give place to the SCE, in cells of the salivary glands of the mouse in vivo, are partially repaired only when induced in DNA which has not been substituted with BrdU. (Author)

Sister chromatid exchanges in the bone marrow cells of in vivo rats induced by gamma radiation and chemical mutagens

International Nuclear Information System (INIS)

Rodriguez R, R.G.

1981-01-01

Sister chromatid exchanges (SCE) in the bone marrow of in vivo rats induced by gamma radiation doses and by the chemical mutagens, mitomycin C (MMC), cyclophosphamide (CP), and sulphonate-methylmethane (SMM), were studied. The purpose was to evaluate the sensitivity and reproducibility of a simplified SCE in vivo detecting system developed in our laboratory and to compare the results obtained with those reported elsewhere. Simplification consisted in administering the amounts of 5-bromo-2'-deoxyuridine (BrdU) necessary to observe the SCE, after first adsorbing the BrdU in activated carbon and then injecting it interperitoneally, into the rats. The results were a longer time in vivo ADN incorporation without convulsions in the rats, and a reduction in the time course as compared to other methods. We observed a basal rate of 3.6+-0.37 SCE/cell and that: 0.44 Gy of gamma radiation induced 7.7+-0.73 SCE/cell; 1.6 μg/g of MMC induced 8.1+-1.20 SCE/cell; 5 μg/g of CP induced 8.25+-1.5 SCE/cell, 40 μg/g of SMM induced 22.0+-5 SCE/cell and 380 μg/g of sulphonate-ethylmethane induced 8.6+-1.2 SCE/cell. This showed that all the agents were capable of inducing SCE in the bone marrow cells of rats in vivo under our conditions. We noted a greater induced efficiency for gamma radiation than the obtained by other investigators and a relatively similar efficiency in the case of chemical mutagens as reported in other studies. (author)

Left-right symmetry breaking in mice by left-right dynein may occur via a biased chromatid segregation mechanism, without directly involving the Nodal gene

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Sauer, Stephan; Klar, Amar J. S., E-mail: sauers@mail.nih.gov, E-mail: klara@mail.nih.gov [Gene Regulation and Chromosome Biology Laboratory, Frederick National Laboratory for Cancer Research, Frederick, MD (United States)

2012-11-16

Ever since cloning the classic iv (inversedviscerum) mutation identified the “left-right dynein” (lrd) gene in mice, most research on body laterality determination has focused on its function in motile cilia at the node embryonic organizer. This model is attractive, as it links chirality of cilia architecture to asymmetry development. However, lrd is also expressed in blastocysts and embryonic stem cells, where it was shown to bias the segregation of recombined sister chromatids away from each other in mitosis. These data suggested that lrd is part of a cellular mechanism that recognizes and selectively segregates sister chromatids based on their replication history: old “Watson” versus old “Crick” strands. We previously proposed that the mouse left-right axis is established via an asymmetric cell division prior to/or during gastrulation. In this model, left-right dynein selectively segregates epigenetically differentiated sister chromatids harboring a hypothetical “left-right axis development 1” (“lra1”) gene during the left-right axis establishing cell division. Here, asymmetry development would be ultimately governed by the chirality of the cytoskeleton and the DNA molecule. Our model predicts that randomization of chromatid segregation in lrd mutants should produce embryos with 25% situs solitus, 25% situs inversus, and 50% embryonic death due to heterotaxia and isomerism. Here we confirmed this prediction by using two distinct lrd mutant alleles. Other than lrd, thus far Nodal gene is the most upstream function implicated in visceral organs laterality determination. We next tested whether the Nodal gene constitutes the lra1 gene hypothesized in the model by testing mutant’s effect on 50% embryonic lethality observed in lrd mutants. Since Nodal mutation did not suppress lethality, we conclude that Nodal is not equivalent to the lra1 gene. In summary, we describe the origin of 50% lethality in lrd mutant mice not yet explained by any other

Left-right symmetry breaking in mice by left-right dynein may occur via a biased chromatid segregation mechanism, without directly involving the Nodal gene

International Nuclear Information System (INIS)

Sauer, Stephan; Klar, Amar J. S.

2012-01-01

Ever since cloning the classic iv (inversedviscerum) mutation identified the “left-right dynein” (lrd) gene in mice, most research on body laterality determination has focused on its function in motile cilia at the node embryonic organizer. This model is attractive, as it links chirality of cilia architecture to asymmetry development. However, lrd is also expressed in blastocysts and embryonic stem cells, where it was shown to bias the segregation of recombined sister chromatids away from each other in mitosis. These data suggested that lrd is part of a cellular mechanism that recognizes and selectively segregates sister chromatids based on their replication history: old “Watson” versus old “Crick” strands. We previously proposed that the mouse left-right axis is established via an asymmetric cell division prior to/or during gastrulation. In this model, left-right dynein selectively segregates epigenetically differentiated sister chromatids harboring a hypothetical “left-right axis development 1” (“lra1”) gene during the left-right axis establishing cell division. Here, asymmetry development would be ultimately governed by the chirality of the cytoskeleton and the DNA molecule. Our model predicts that randomization of chromatid segregation in lrd mutants should produce embryos with 25% situs solitus, 25% situs inversus, and 50% embryonic death due to heterotaxia and isomerism. Here we confirmed this prediction by using two distinct lrd mutant alleles. Other than lrd, thus far Nodal gene is the most upstream function implicated in visceral organs laterality determination. We next tested whether the Nodal gene constitutes the lra1 gene hypothesized in the model by testing mutant’s effect on 50% embryonic lethality observed in lrd mutants. Since Nodal mutation did not suppress lethality, we conclude that Nodal is not equivalent to the lra1 gene. In summary, we describe the origin of 50% lethality in lrd mutant mice not yet explained by any other

Left-right symmetry breaking in mice by left-right dynein may occur via a biased chromatid segregation mechanism, without directly involving the Nodal gene

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Stephan eSauer

2012-11-01

Full Text Available Ever since cloning the classic iv mutation identified the ‘left-right dynein’ (lrd gene in mice, most research on body laterality determination has focused on its function in motile cilia at the node embryonic organizer. This model is attractive, as it links chirality of cilia architecture to asymmetry development. However, lrd is also expressed in blastocysts and embryonic stem cells, where it was shown to bias the segregation of recombined sister chromatids away from each other in mitosis. These data suggested that lrd is part of a cellular mechanism that recognizes and selectively segregates sister chromatids based on their replication history: old ‘Watson’ vs. old ‘Crick’ strands. We previously proposed that the mouse left-right axis is established via an asymmetric cell division prior to/or during gastrulation. In this model, left-right dynein selectively segregates epigenetically differentiated sister chromatids harboring a hypothetical ‘left-right axis development 1’ (‘lra1’ gene during the left-right axis establishing cell division. Here, asymmetry development would be ultimately governed by the chirality of the cytoskeleton and the DNA molecule. Our model predicts that randomization of chromatid segregation in lrd mutants should produce embryos with 25% situs solitus, 25% situs inversus, and 50% embryonic death due to heterotaxia and isomerism. Here we confirmed this prediction by using two distinct lrd mutant alleles. Other than lrd, thus far Nodal gene is the most upstream function implicated in visceral organs laterality determination. We next tested whether the Nodal gene constitutes the lra1 gene hypothesized in the model by testing mutant’s effect on 50% embryonic lethality observed in lrd mutants. Since Nodal mutation did not suppress lethality, we conclude that Nodal is not equivalent to the lra1 gene. In summary, we describe the origin of 50% lethality in lrd mutant mice not yet explained by any other

Characterization of the enhancing effect of caffeine on sister-chromatid exchanges induced by ultraviolet radiation in excision-proficient xeroderma pigmentosum lymphoblastoid cells

International Nuclear Information System (INIS)

Thoda, Hiroko; Oikawa, Atsushi

1988-01-01

Cells of some excision-proficient xeroderma pigmentosum (XP) cell lines are highly sensitive to post-UV caffeine treatment in terms of sister-chromatid exchange (SCE) induction as well as cell lethality. In the present study, the authors conducted a detailed investigation of the enhancing effect of caffeine on SCE frequency induced by UV in excision-proficient XP cells, and obtained the following results. (1). Continuous post-UV treatment with 1mM caffeine markedly enhances UV-induced SCEs and such enhanced SCEs occur with similar frequency during either the 1st or the 2nd cell cycle in the presence of caffeine and 5-bromodeoxyuridine (BrdUrd). (2) The high sensitivity of the cells to post-UV caffeine treatment persists for at least 2 days after UV when irradiated cells are held in either the proliferating of the nonproliferating state prior to the addition of BrdUrd. (3) Caffeine exerts its effect on cells in S phase. The most likely explanation for our findings is as follows. In excision-proficient XP cells, the cause of SCE formation such as UV-induced lesions or resulting perturbations of DNA replication persists untill the 2nd round or more of post-UV DNA replication. If caffeine is given as post-UV treatment, such abnormalities may be amplified, resulting in a synergistic increase in SCE frequency. (author). 21 refs.; 4 figs.; 4 tabs

Cytotoxicity and genotoxicity of UVA irradiation in Chinese hamster ovary cells measured by specific locus mutations, sister chromatid exchanges and chromosome aberrations

International Nuclear Information System (INIS)

Lundgren, Karsten; Wulf, H.C.

1988-01-01

The increasing use of artificial UVA (320-400 nm) suntanning devices has brought attention to possible hazardous effects of UVA. In contrast with earlier studies, several groups recently have described that UVA possibly is mutagenic. We evaluate the genotoxic properties of broad band UVA using CHO cells and three different assays: specific locus (HGPRT) mutations, chromosome aberrations, and sister chromatid exchanges (SCEs). The UVA-source was an UVASUN 2000 S (Mutzhas), emitting UVA above 340 nm. The survival curve of the cells exhibited a shoulder up to 200 kJ/m 2 , that was followed by exponential killing at higher fluences. Mutations were induced linearly in the fluence range of 0-200 kJ/m 2 to a level seven fold higher than the spontaneous, followed by a decrease at fluences above 300 kJ/m 2 . Over the total range of tested fluences (0-300 kJ/m 2 ) a linear dose-response relationship was observed for UVA-induced SCEs. A significantly higher percentage of the cells showed chromosomes with aberrations at the higher levels of exposure (200, 300 and 400 kJ/m 2 ), but no dose response was demonstrated. Our results confirm recent findings showing that UVA is mutagenic in mammalian cells and suggest that UVA exposure may contribute to the total burden of genetic damage caused by exposure to ultraviolet light. (author)

Effects of a tumor promoter and an anti-promoter on spontaneous and UV-induced 6-thioguanine-resistant mutations and sister-chromatid exchanges in V79 Chinese hamster cells

International Nuclear Information System (INIS)

Fujiwara, Y.; Kano, Y.; Tatsumi, M.; Paul, P.

1980-01-01

The effects of a tumor promoter 12-O-tetradecanoylphorbol-13-acetate (TPA) and/or an anti-promoter antipain (protease inhibitor) on spontaneous and ultraviolet-induced sister-chromatid exchanges (SCEs) and 6-thioguanine-resistant (6TGsup(r)) recessive mutations were examined in V79 Chinese hamster cells in culture. TPA and/or antipain neither significantly altered base-line and UV-induced immediate SCE frequencies, nor decreased the level of delayed SCEs which persisted 6-7 days after irradiation. TPA and/or antipain appeared to enhance the recovery of UV-induced 6TGsup(r) colonies at the plateau expression phase despite non-mutagenicity by themselves and unaltered metabolic cooperation. Thus, the results conceivably imply that the 6TGsup(r)-recessive mutation expression, but not fixation, can be modulated at the cell level by TPA and/or antipain. Our results, together with the recent results of Loveday and Latt, may argue against the notion that TPA enhances the antipain-suppressible SCEs as an index of mitotic recombination in relevance with a tumor-promotion mechanism. (orig.)

Absence of SUN-domain protein Slp1 blocks karyogamy and switches meiotic recombination and synapsis from homologs to sister chromatids

Science.gov (United States)

Vasnier, Christelle; de Muyt, Arnaud; Zhang, Liangran; Tessé, Sophie; Kleckner, Nancy E.; Zickler, Denise; Espagne, Eric

2014-01-01

Karyogamy, the process of nuclear fusion is required for two haploid gamete nuclei to form a zygote. Also, in haplobiontic organisms, karyogamy is required to produce the diploid nucleus/cell that then enters meiosis. We identify sun like protein 1 (Slp1), member of the mid–Sad1p, UNC-84–domain ubiquitous family, as essential for karyogamy in the filamentous fungus Sordaria macrospora, thus uncovering a new function for this protein family. Slp1 is required at the last step, nuclear fusion, not for earlier events including nuclear movements, recognition, and juxtaposition. Correspondingly, like other family members, Slp1 localizes to the endoplasmic reticulum and also to its extensions comprising the nuclear envelope. Remarkably, despite the absence of nuclear fusion in the slp1 null mutant, meiosis proceeds efficiently in the two haploid “twin” nuclei, by the same program and timing as in diploid nuclei with a single dramatic exception: the normal prophase program of recombination and synapsis between homologous chromosomes, including loading of recombination and synaptonemal complex proteins, occurs instead between sister chromatids. Moreover, the numbers of recombination-initiating double-strand breaks (DSBs) and ensuing recombinational interactions, including foci of the essential crossover factor Homo sapiens enhancer of invasion 10 (Hei10), occur at half the diploid level in each haploid nucleus, implying per-chromosome specification of DSB formation. Further, the distribution of Hei10 foci shows interference like in diploid meiosis. Centromere and spindle dynamics, however, still occur in the diploid mode during the two meiotic divisions. These observations imply that the prophase program senses absence of karyogamy and/or absence of a homolog partner and adjusts the interchromosomal interaction program accordingly. PMID:25210014

Relationship of the demethylation of the DNA with the induction of the sister chromatid exchanges (SCE) In vivo

International Nuclear Information System (INIS)

Toribio E, E.

2005-01-01

The methylation of the DNA is an epigenetic modification that has an important paper in the regulation of the functionality of the genome of the organisms. It can be altered by demethylation processes, either natural or experimentally induced. The 5-azacytidine (Aza) is a compound that causes the demethylation of the DNA (dm-DNA), inducing with it, expression genic and increase in the frequency of the Sister Chromatid Exchange (SCE). The SCE is a genotoxicity indicator, caused by diverse mutagens and carcinogen. Since the biological meaning and the formation mechanism of this phenomenon has not been totally illustrious, the exploration of the relation between the dm-DNA and the induction of SCE, it could offer new knowledge to explain those queries. The purpose of this work was to study in cells of the mouse bone marrow In vivo, the effect of the Aza on the induction of SCE, based on two aspects: 1) dose answer and 2) the effectiveness of multiple exhibition. To six groups of three to five animals, they are administered Aza to dose of 5, 10, 15 or 20 mg/Kg of weight; in sharp or multiple form, previously to the bromodeoxyuridine supply and 24 h was sacrificed after this; 2 h after an injection with colchicine. Preparations of those metaphases were made, those which were dyed by means of a technique of fluorescence more Giemsa. It was observed that to sharp low dose, the Aza produced an increment in the frequency of SCE that although small it was proportional and statistically significant. To sharp and multiple high doses, the Aza doesn't cause additional increments of SCE, but if toxicity at cellular level and of individuals. It is concluded that a relationship exists between the dm-DNA and the induction of SCE. It is suggested that the total demethylation of the DNA causes 2 SCE/Cell in cells of the mouse bone marrow, or that the cytotoxicity prevents to evidence a bigger induction. (Author)

Effect of interleukin-2 on cell proliferation, sister-chromatid exchange induction, and nuclear stress protein phosphorylation in PHA-stimulated Fischer 344 rat spleen lymphocytes: Modulation by 2-mercaptoethanol

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Morris, S.M.; Aidoo, A.; Domon, O.E.; McGarrity, L.J.; Kodell, R.L.; Schol, H.M.; Hinson, W.G.; Pipkin, J.L.; Casciano, D.A. (National Center for Toxicological Research, Jefferson, AR (USA))

1990-01-01

The effect of interleukin-2 (IL-2) on cell proliferation, sister-chromatid exchange (SCE) frequency, and the phosphorylation of nuclear stress proteins was evaluated in phytohemagglutinin (PHA)-stimulated spleen lymphocytes isolated from Fischer 344 rats. In addition, the ability of 2-mercaptoethanol (2-ME) to modulate the induction of these biological responses was characterized. Cell proliferation, as measured by the mitotic index, increased significantly. The average generation time (AGT) did not respond to IL-2 in a concentration-dependent manner and decreased significantly. The number of SCE increased significantly from control frequencies, to frequencies of 18.5 to 21.5 SCE per cell as the concentration of IL-2 in the culture medium increased to 50 half-maximal units per ml. A reduction in SCE frequency was observed when cells were cultured with 20 {mu}M 2-ME and IL-2 compared to IL-2 alone. Three nuclear proteins, with relative molecular masses of approximately 13,000-18,000, 20,000, and 80,000, were phosphorylated in IL-2-exposed G{sub 1}-phase nuclei. Elicitation of these nuclear proteins in IL-2-exposed cells was not affected by exposure to 2-ME.

Variation in the human lymphocyte sister chromatid exchange frequency as a function of time: results of daily and twice-weekly sampling

Energy Technology Data Exchange (ETDEWEB)

Tucker, J.D.; Christensen, M.L.; Strout, C.L.; McGee, K.A.; Carrano, A.V.

1987-01-01

The variation in lymphocyte sister chromatid exchange (SCE) frequency was investigated in healthy nonsmokers who were not taking any medication. Two separate studies were undertaken. In the first, blood was drawn from four women twice a week for 8 weeks. These donors recorded the onset and termination of menstruation and times of illness. In the second study, blood was obtained from two women and two men for 5 consecutive days on two separate occasions initiated 14 days apart. Analysis of the mean SCE frequencies in each study indicated that significant temporal variation occurred in each donor, and that more variation occurred in the longer study. Some of the variation was found to be associated with the menstrual cycle. In the daily study, most of the variation appeared to be random, but occasional day-to-day changes occurred that were greater than those expected by chance. To determine how well a single SCE sample estimated the pooled mean for each donor in each study, the authors calculated the number of samples that encompassed that donor's pooled mean within 1 or more standard errors. For both studies, about 75% of the samples encompassed the pooled mean within 2 standard errors. An analysis of high-frequency cells (HFCs) was also undertaken. The results for each study indicate that the proportion of HFCs, compared with the use of Fisher's Exact test, is significantly more constant than the means, which were compared by using the t-test. These results coupled with our previous work suggest that HFC analysis may be the method of choice when analyzing data from human population studies.

DNA asymmetry in stem cells - immortal or mortal?

Science.gov (United States)

Yadlapalli, Swathi; Yamashita, Yukiko M

2013-09-15

The immortal strand hypothesis proposes that stem cells retain a template copy of genomic DNA (i.e. an 'immortal strand') to avoid replication-induced mutations. An alternative hypothesis suggests that certain cells segregate sister chromatids non-randomly to transmit distinct epigenetic information. However, this area of research has been highly controversial, with conflicting data even from the same cell types. Moreover, historically, the same term of 'non-random sister chromatid segregation' or 'biased sister chromatid segregation' has been used to indicate distinct biological processes, generating a confusion in the biological significance and potential mechanism of each phenomenon. Here, we discuss the models of non-random sister chromatid segregation, and we explore the strengths and limitations of the various techniques and experimental model systems used to study this question. We also describe our recent study on Drosophila male germline stem cells, where sister chromatids of X and Y chromosomes are segregated non-randomly during cell division. We aim to integrate the existing evidence to speculate on the underlying mechanisms and biological relevance of this long-standing observation on non-random sister chromatid segregation.

Influence of GSTM1 and GSTT1 genotypes and confounding factors on the frequency of sister chromatid exchange and micronucleus among road construction workers.

Science.gov (United States)

Kumar, Anil; Yadav, Anita; Giri, Shiv Kumar; Dev, Kapil; Gautam, Sanjeev Kumar; Gupta, Ranjan; Aggarwal, Neeraj

2011-07-01

In the present study, we have investigated the influence of polymorphism of GSTM1 and GSTT1 genes and confounding factors such as age, sex, exposure duration and consumption habits on cytogenetic biomarkers. Frequency of sister chromatid exchanges (SCEs), high frequency cell (HFC) and cytokinesis blocked micronuclei (CBMN) were evaluated in peripheral blood lymphocytes of 115 occupationally exposed road construction workers and 105 unexposed individuals. The distribution of null and positive genotypes of glutathione-S transferase gene was evaluated by multiplex PCR among control and exposed subjects. An increased frequency of CBMN (7.03±2.08); SCE (6.95±1.76) and HFC (6.28±1.69) were found in exposed subjects when compared to referent (CBMN - 3.35±1.10; SCE - 4.13±1.30 and HFC - 3.98±1.56). These results were found statistically significant at p<0.05. When the effect of confounding factors on the frequency of studied biomarkers was evaluated, a strong positive interaction was found. The individuals having GSTM1 and GSTT1 null genotypes had higher frequency of CBMN, SCE and HFC. The association between GSTM1 and GSTT1 genotypes and studied biomarkers was found statistically significant at p<0.05. Our findings suggest that individuals having null type of GST are more susceptible to cytogenetic damage by occupational exposure regardless of confounding factors. There is a significant effect of polymorphism of these genes on cytogenetic biomarkers which are considered as early effects of genotoxic carcinogens. Copyright © 2011 Elsevier Ltd. All rights reserved.

As to the clastogenic-, sister-chromatid exchange inducing-and cytotoxic activity of inosine triphosphate in cultures of human peripheral lymphocytes.

Science.gov (United States)

Vormittag, W; Brannath, W

2001-05-09

The influence of commercial inosine triphosphate (ITP) on the chromosome aberration rate, the mitotic rate, sister-chromatid exchange (SCE) frequency, and the proportion of first (X1), second (X2) and third (X3) division metaphases was investigated in 72h cultures of human peripheral lymphocytes. The blood donors had mild inactive arthrosis and a normal health check-up. All cultures of each volunteer were set-up simultaneously. In contrast to a previous report [Arch. Biochem. Biophys. 278 (1990) 238-244], it was demonstrated in two preliminary studies (number of subjects, n=5 each) that ITP at a final concentration of 100 microM does not induce chromosomal aberrations and, furthermore, that not ITP concentrations higher than 100 microM but ITP doses higher than 3.8mM prohibit culture growth. Based on these results, cultures with a final ITP concentration of 3.6mM (max.) and 1.8mM (max./2) were compared with control cultures (number of subjects n=10; three males and seven females, mean age x=57.6 years). Whereas no increase in the chromosomal breakage rate was observed in cultures with an ITP concentration of 1.8mM and only a marginally significant one (P=0.048) for 3.6mM ITP cultures, a highly significant induction of SCEs, not only at an ITP concentration of 3.6mM (Prate from 0 to 1.8mM as well as from 1.8 to 3.6mM in the aberration studies (all P values are equal to smallest possible one for a sample size of 10, namely, 0.002), and in the SCE studies there is a significant decrease in the X3 frequency when ITP is increased (0-1.8mM: P=0.0061 and 1.8-3.6mM: Pchanges significantly only at the second dose step (0-1.8mM ITP: P=0.22 and 1.8-3.6mM ITP: P<0.0001). The results are discussed.

Evidence that cyclophosphamide can to induce exchanges in the sister chromatids (ICH) through secondary injuries; Evidencia de que la ciclofosfamida puede inducir intercambios en las cromatidas hermanas (ICH) a traves de lesiones secundarias

Energy Technology Data Exchange (ETDEWEB)

Morales R, P.; Rodriguez R, R. [Instituto Nacional de Investigaciones nucleares, A.P. 18-1027, 11801 Mexico D.F. (Mexico)

1997-07-01

By means of the use of destination protocol of ICH inductive injuries (DLI-ICH), it was studied if interchanges in the sister chromatids (ICH) induced by cyclophosphamide (CP), in the second post-treatment division (ICH-2) are produced by secondary injuries or by fresh injuries. For discard between these possibilities it was administered CP at different periods before of the first post-treatment division, taking as reference the administered time for high dose of bromodeoxyuridine (BrdU ) which was approximately at the beginning of this division. The ICH frequencies that occur in the first, the second and the third synthesis stages (S) were determined. It was observed that when the administered CP was four hours before BrdU , the ICH frequencies of the second and the third S were reduced. The frequency of the first ICH increased lightly in relation to those of the normal protocol (0.5 h before BrdU ) and that the supplying of CP six hours before caused almost a total reduction of ICH of second and third S and an important increment of ICH of first S.This was interpreted as evidence that the ICH-2 are product of secondary injuries. (Author)

Strand-seq : A unifying tool for studies of chromosome segregation

NARCIS (Netherlands)

Falconer, Ester; Lansdorp, Peter M.

2013-01-01

Non random segregation of sister chromatids has been implicated to help specify daughter cell fate (the Silent Sister Hypothesis [1]) or to protect the genome of long-lived stem cells (the Immortal Strand Hypothesis [2]). The idea that sister chromatids are non-randomly segregated into specific

Modelling and testing the molecular mechanism of radiation-induced chromatid breaks

International Nuclear Information System (INIS)

Bryant, P. E.

2001-01-01

Chromatid breaks induced by ionizing radiation in the G2 phase of the cell cycle are considered as markers of individual human radiosensitivity and may indicate the presence of low-penetrance genes regulating susceptibility to breast and other cancers). Together with our own study of Scottish (Tayside) breast cancer patients and a group of normal controls these studies show an overall 10-fold variation in chromatid break frequency (the parameter defining individual chromosomal 'radiosensitivity'). Thus, an understanding of the mechanisms and genes involved in determining these widely different responses should help to clarify the reasons for individual radiosensitivity and may lead us to identify key genes involved in cancer susceptibility. The presence of colour-switches at around 16% of chromatid break points (detected in harlequin-stained chromosomes) indicates that this type of chromatid break is formed by a chromatin rearrangement involving one or more large chromatin domains of the order of 3 - 5 Mbp, possibly representing transcription 'factories'. The signal model of chromatid breaks assumes that all chromatid breaks are the result of chromatin rearrangements, and that the initiating DNA double-strand break (dsb) is itself not involved in the rearrangement but signals its presence (possibly via ATM protein or DNAPK) leading to the initiation of the chromatin rearrangement. Experimental evidence from radiosensitive cell lines (e.g. human AT and hamster irs2) and with the nucleoside analogue araA (9-β-D-arabinofuranosyladenine) demonstrates the lack of correspondence between the rejoining kinetics of dsb and that of disappearance of chromatid breaks, thus supporting the signal model. Coupled with the linear induction of chromatid breaks with dose in both human and rodent cell lines of various types, and the production of chromatid breaks by single dsb in genetically engineered cell lines the classical 'breakage-first' model of chromatid breaks is no longer

The Monopolin Complex Crosslinks Kinetochore Components to Regulate Chromosome-Microtubule Attachments

Energy Technology Data Exchange (ETDEWEB)

Corbett, Kevin D.; Yip, Calvin K.; Ee, Ly-Sha; Walz, Thomas; Amon, Angelika; Harrison, Stephen C. (Harvard-Med); (MIT)

2010-09-27

The monopolin complex regulates different types of kinetochore-microtubule attachments in fungi, ensuring sister chromatid co-orientation in Saccharomyces cerevisiae meiosis I and inhibiting merotelic attachment in Schizosaccharomyces pombe mitosis. In addition, the monopolin complex maintains the integrity and silencing of ribosomal DNA (rDNA) repeats in the nucleolus. We show here that the S. cerevisiae Csm1/Lrs4 monopolin subcomplex has a distinctive V-shaped structure, with two pairs of protein-protein interaction domains positioned {approx}10 nm apart. Csm1 presents a conserved hydrophobic surface patch that binds two kinetochore proteins: Dsn1, a subunit of the outer-kinetochore MIND/Mis12 complex, and Mif2/CENP-C. Csm1 point-mutations that disrupt kinetochore-subunit binding also disrupt sister chromatid co-orientation in S. cerevisiae meiosis I. We further show that the same Csm1 point-mutations affect rDNA silencing, probably by disrupting binding to the rDNA-associated protein Tof2. We propose that Csm1/Lrs4 functions as a molecular clamp, crosslinking kinetochore components to enforce sister chromatid co-orientation in S. cerevisiae meiosis I and to suppress merotelic attachment in S. pombe mitosis, and crosslinking rDNA repeats to aid rDNA silencing.

Unique geometry of sister kinetochores in human oocytes during meiosis I may explain maternal age-associated increases in chromosomal abnormalities

Directory of Open Access Journals (Sweden)

Jessica Patel

2016-02-01

Full Text Available The first meiotic division in human oocytes is highly error-prone and contributes to the uniquely high incidence of aneuploidy observed in human pregnancies. A successful meiosis I (MI division entails separation of homologous chromosome pairs and co-segregation of sister chromatids. For this to happen, sister kinetochores must form attachments to spindle kinetochore-fibres emanating from the same pole. In mouse and budding yeast, sister kinetochores remain closely associated with each other during MI, enabling them to act as a single unified structure. However, whether this arrangement also applies in human meiosis I oocytes was unclear. In this study, we perform high-resolution imaging of over 1900 kinetochores in human oocytes, to examine the geometry and architecture of the human meiotic kinetochore. We reveal that sister kinetochores in MI are not physically fused, and instead individual kinetochores within a pair are capable of forming independent attachments to spindle k-fibres. Notably, with increasing female age, the separation between kinetochores increases, suggesting a degradation of centromeric cohesion and/or changes in kinetochore architecture. Our data suggest that the differential arrangement of sister kinetochores and dual k-fibre attachments may explain the high proportion of unstable attachments that form in MI and thus indicate why human oocytes are prone to aneuploidy, particularly with increasing maternal age.

SOLO: a meiotic protein required for centromere cohesion, coorientation, and SMC1 localization in Drosophila melanogaster.

Science.gov (United States)

Yan, Rihui; Thomas, Sharon E; Tsai, Jui-He; Yamada, Yukihiro; McKee, Bruce D

2010-02-08

Sister chromatid cohesion is essential to maintain stable connections between homologues and sister chromatids during meiosis and to establish correct centromere orientation patterns on the meiosis I and II spindles. However, the meiotic cohesion apparatus in Drosophila melanogaster remains largely uncharacterized. We describe a novel protein, sisters on the loose (SOLO), which is essential for meiotic cohesion in Drosophila. In solo mutants, sister centromeres separate before prometaphase I, disrupting meiosis I centromere orientation and causing nondisjunction of both homologous and sister chromatids. Centromeric foci of the cohesin protein SMC1 are absent in solo mutants at all meiotic stages. SOLO and SMC1 colocalize to meiotic centromeres from early prophase I until anaphase II in wild-type males, but both proteins disappear prematurely at anaphase I in mutants for mei-S332, which encodes the Drosophila homologue of the cohesin protector protein shugoshin. The solo mutant phenotypes and the localization patterns of SOLO and SMC1 indicate that they function together to maintain sister chromatid cohesion in Drosophila meiosis.

The chromosome damage induced by x-ray radiation doses. Comparison between dicentric chromosomes, micronuclei and Sister Chromatid Exchanges analyses. Valoracion de dao cromosomico originado por una dosis de rayos X. Comparacion de los analisis de cromosomas dicentricos, micronucleos e intercambios entre cromatidas hermanas

Energy Technology Data Exchange (ETDEWEB)

Fernandez, J.L.; Losada, C.; Losada, G.; Veiras, C. (Centro Oncologico de Galicia. La Corua (Spain)); Goyanes, V.J. (Hospital ' ' Teresa Herrera' ' . La Corua (Spain))

1993-01-01

Exposure to ionizing radiations is a well-known source of chromosome damage. Here we present a comparison among three different methodologies employed to recognize cytogenetic damage, after an acute exposure of human lymphocytes to 3 Gy of X-rays (100kVp). Scoring of dicentric chromosomes, present in first mitosis ''in vitro'', was the method of preference as dicentrics increased 937.5 times with respect to background. Micronucleus scoring in binucleated-cytokinesis blocked cells showed an increase of 32.5 times, while it was only of 1.46 times when Sister Chromatid Exchanges (SCEs) were analyzed. The estimated probability of an acentric fragment becoming a micronucleus was around 0.25. Intercellular distribution of dicentrics agree with Poisson, while micronucleus were overdispersed. When analyzed at second cycle after damage induction, the dicentrics yield as well as the level of cells with unstable cromosome aberrations, decreased around a half. Finally, SCEs level was similar in cells with or without unstable structural chromosome aberrations. (Author)

Sister chromatid exchanges and high-frequency cells in men environmentally and occupationally exposed to ambient air pollutants. An intergroup comparison with respect to seasonal changes and smoking habit

Energy Technology Data Exchange (ETDEWEB)

Pendzich, Joanna; Motykiewicz, Grazyna; Michalska, Jadwiga; Kostowska, Alina; Chorazy, Mieczyslaw [Department of Tumor Biology, Institute of Oncology, Gliwice (Poland); Wang, Li You [Graduate Institute of Epidemiology, College of Public Health, National Taiwan University, Taipei (Taiwan, Province of China)

1997-11-28

Sister chromatid exchanges (SCE) and high-frequency cells (HFC) were measured in peripheral blood lymphocytes from men environmentally and occupationally exposed to a mixture of ambient air pollutants. The environmentally exposed individuals were inhabitants of the industrial region of Upper Silesia; those occupationally exposed were Silesian cokery or steel plant workers, while the control group consisted of rural region residents. A total of 147 males were enrolled in the study. Blood samples were collected in winter (February) and summer (September) seasons. Three major areas were investigated during the study: exposure-based dose dependency, seasonal changes, and influence of smoking habits on the SCE frequencies. The latter is frequently reported as a confounding factor in SCE analyses. In both winter and summer samples, statistically significant increases of SCE were observed in the environmentally and occupationally exposed groups compared to the controls (p<0.001). The difference between both exposed groups was also significant (p<0.001). An intergroup comparison was based on ANOVA after adjustment for smoking status. In all three groups of interest, a seasonal variation was found with higher levels in winter. However, in a part of the study in which each donor served as his own control, statistical differences were only found within the exposed groups. Control region inhabitants did not have significantly higher frequencies of SCE in winter, compared to summer samples. The impact of two major confounders, age of the donor and smoking habit, was investigated by multiple regression analysis. Smoking was a major factor influencing the level of SCE. Nevertheless, the effect was seen in winter samples only, which suggests an additive response and adds new information to this known effect

G2-chromatid breaks and rejoining in HO8910 cells induced by γ-rays

International Nuclear Information System (INIS)

Wang Zhuanzi; Liu Bing; Duan Xin

2006-01-01

The premature chromosome condensation technique was used to estimate the dosage effect on the G2-chromosome breaks in HO8910 after exposure to γ-rays, and to investigate the time effect on the rejoining of the G2-chromosome breaks. The results show that the number of G2 chromatid-type breaks linearly increased with doses and the number of G2 iso-chromatid breaks increased with dose in a linear-square manner. With the prolongation of culture time, G2 chromatid-type breaks obviously got repaired, and almost 65% chromatid-type breaks got repaired in the early 24 hour post-irradiation, whereas only about 20% iso-chromatid breaks got repaired during the same time. Furthermore, the rejoining of the two types of chromatid breaks occurred mostly in 2 hours after irradiation and from 12 to 24 hours after irradiation, the number of chromatid breaks was found to get stabilized basically, which indicates that the repairing process is over in the early 24 hours of post-irradiation. (authors)

Chiasmatic and achiasmatic inverted meiosis of plants with holocentric chromosomes

Science.gov (United States)

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

2014-01-01

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

Strand-seq: A unifying tool for studies of chromosome segregation

OpenAIRE

Falconer, Ester; Lansdorp, Peter M.

2013-01-01

Non random segregation of sister chromatids has been implicated to help specify daughter cell fate (the Silent Sister Hypothesis [1]) or to protect the genome of long-lived stem cells (the Immortal Strand Hypothesis [2]). The idea that sister chromatids are non-randomly segregated into specific daughter cells is only marginally supported by data in sporadic and often contradictory studies. As a result, the field has moved forward rather slowly. The advent of being able to directly label and d...

Characterization of muntjac DNA

International Nuclear Information System (INIS)

Davis, R.C.

1981-01-01

Sister chromatid exchange (SCE) in muntjac chromosomes is generally proportional to the chromosomal DNA content, but the SCE frequency is reduced in the heterochromatic neck region of the X chromosome. The physical properties of muntjac DNA and the kinetics of repair of UV damage in muntjac heterochromatin and euchromatin were examined and compared with the distribution of sister chromatid exchange

Characterization of muntjac DNA

Energy Technology Data Exchange (ETDEWEB)

Davis, R.C.

1981-05-27

Sister chromatid exchange (SCE) in muntjac chromosomes is generally proportional to the chromosomal DNA content, but the SCE frequency is reduced in the heterochromatic neck region of the X chromosome. The physical properties of muntjac DNA and the kinetics of repair of UV damage in muntjac heterochromatin and euchromatin were examined and compared with the distribution of sister chromatid exchange.

Baseline frequency of chromosomal aberrations and sister chromatid exchanges in peripheral blood lymphocytes of healthy individuals living in Turin (North-Western Italy): assessment of the effects of age, sex and GSTs gene polymorphisms on the levels of genomic damage.

Science.gov (United States)

Santovito, Alfredo; Cervella, Piero; Delpero, Massimiliano

2016-05-01

The increased exposure to environmental pollutants has led to the awareness of the necessity for constant monitoring of human populations, especially those living in urban areas. This study evaluated the background levels of genomic damage in a sample of healthy subjects living in the urban area of Turin (Italy). The association between DNA damage with age, sex and GSTs polymorphisms was assessed. One hundred and one individuals were randomly sampled. Sister Chromatid Exchanges (SCEs) and Chromosomal Aberrations (CAs) assays, as well as genotyping of GSTT1 and GSTM1 genes, were performed. Mean values of SCEs and CAs were 5.137 ± 0.166 and 0.018 ± 0.002, respectively. Results showed age and gender associated with higher frequencies of these two cytogenetic markers. The eldest subjects (51-65 years) showed significantly higher levels of genomic damage than younger individuals. GSTs polymorphisms did not appear to significantly influence the frequencies of either markers. The CAs background frequency observed in this study is one of the highest reported among European populations. Turin is one of the most polluted cities in Europe in terms of air fine PM10 and ozone and the clastogenic potential of these pollutants may explain the high frequencies of chromosomal rearrangements reported here.

Effect of chlorophyllin on induction of exchanges in sister chromatids by gamma irradiation in mice spermatogonia in vivo; Efecto de la clorofilina sobre la induccion de intercambios en las cromatidas hermanas (ICH) por radiacion gamma en espermatogonias de raton In vivo

Energy Technology Data Exchange (ETDEWEB)

Mendiola C, M T

1994-12-31

Mouse were exposed to different doses of gamma radiation and the effect on Sister Chromatid Exchange (SCE) frequency in spermatogonias was evaluated. The effect was analyzed before and after Bromodeoxyuridine (BrdU) incorporation to determine the interference of such agent with the cellular response induced by radiation. The capacity of chlorophyllin (sodium and Copper salt derivative from chlorophyll) to reduce SCE induction by radiation in normal and BrdU radio sensitized spermatogonia was also determined. The results indicate that there was a significant increase in SCE frequency by gamma radiation exposure in these cells, such effect was higher irradiating after BrdU incorporation than before. This fact confirms previous observations that BrdU sensitizes some cells to SCE induction. With regard to the chlorophyllin effect, it was determined that this salt acts as a radioprotector reducing gamma-rays induced SCE before or after BrdU incorporation Total protection was obtained with 200 {mu}g of chlorophyllin per g of body weight in both protocols. Under the experimental conditions this study there was no evidence of genotoxicity induced by chlorophyllin itself. The results suggest that this agent may act as a radioprotector by scavenging free radicals produced by gamma-radiation which cause DNA lesions that are involved in SCE formation. (Author).

Sisters Hope

DEFF Research Database (Denmark)

Lawaetz, Anna; Worre Hallberg, Gry

2011-01-01

Sisters Hope invites young scholars to visit our elite-school for run-away youngsters. Maybe you will be the next one to be collected and accepted?......Sisters Hope invites young scholars to visit our elite-school for run-away youngsters. Maybe you will be the next one to be collected and accepted?...

In vitro and in vivo genotoxicity of 1,3-butadiene and metabolites.

OpenAIRE

Arce, G T; Vincent, D R; Cunningham, M J; Choy, W N; Sarrif, A M

1990-01-01

1,3-Butadiene and two major genotoxic metabolites 3,4-epoxybutene (EB) and 1,2:3,4-diepoxybutane (DEB) were used as model compounds to determine if genetic toxicity findings in animal and human cells can aid in extrapolating animal toxicity data to man. Sister chromatid exchange (SCE) and micronucleus induction results indicated 1,3-butadiene was genotoxic in the bone marrow of the mouse but not the rat. This paralleled the chronic bioassays which showed mice to be more susceptible than rats ...

Similar kinetics of chromatid aberrations in X-irradiated xrs 5 and wild-type Chinese hamster ovary cells

International Nuclear Information System (INIS)

MacLeod, R.A.F.; Bryant, P.E.

1990-01-01

We have studied the kinetics of chromatid aberrations in cells of the Chinese hamster ovary (CHO-K1) derived, X-ray sensitive cell line xrs 5 irradiated in the G 2 phase at 37 0 C, as well as during a cell cycle extended by transient hypothermia at 33 0 C. While a given X-ray dose was estimated to produce about 4 times as many chromatid break and twice the frequency of exchanges in xrs 5 cells as in the parent line, there was no difference between the lines in the rates of disappearance of chromatid breaks during G 2 at either temperature; and similar patterns of chromatid exchange kinetics were observed in the two lines. Both the frequencies and distributions of chromatid breaks at different times after irradiation are consistent with the view that the disappearance of these during incubation represents a repair process. These results imply that the G 2 chromosomal radiosensitivity of the xrs 5 mutant resides at the level of initial chromatid damage. (author)

In Vivo Cytogenetic Studies on Aspartame

Directory of Open Access Journals (Sweden)

Entissar S. AlSuhaibani

2010-01-01

Full Text Available Aspartame (a-Laspartyl-L-phenylalanine 1-methylester is a dipeptide low-calorie artificial sweetener that is widely used as a nonnutritive sweetener in foods and drinks. The safety of aspartame and its metabolic breakdown products (phenylalanine, aspartic acid and methanol was investigated in vivo using chromosomal aberration (CA test and sister chromatid exchange (SCE test in the bone marrow cells of mice. Swiss Albino male mice were exposed to aspartame (3.5, 35, 350 mg/kg body weight. Bone marrow cells isolated from femora were analyzed for chromosome aberrations and sister chromatid exchanges. Treatment with aspartame induced dose dependently chromosome aberrations at all concentrations while it did not induce sister chromatid exchanges. On the other hand, aspartame did not decrease the mitotic index (MI. However, statistical analysis of the results show that aspartame is not significantly genotoxic at low concentration.

DNA damage in the kidney tissue cells of the fish Rhamdia quelen after trophic contamination with aluminum sulfate

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Tatiane Klingelfus

2015-01-01

Full Text Available Abstract Even though aluminum is the third most common element present in the earth's crust, information regarding its toxicity remains scarce. It is known that in certain cases, aluminum is neurotoxic, but its effect in other tissues is unknown. The aim of this work was to analyze the genotoxic potential of aluminum sulfate in kidney tissue of the fish Rhamdia quelen after trophic contamination for 60 days. Sixty four fish were subdivided into the following groups: negative control, 5 mg, 50 mg and 500 mg of aluminum sulfate per kg of fish. Samples of the posterior kidney were taken and prepared to obtain mitotic metaphase, as well as the comet assay. The three types of chromosomal abnormalities (CA found were categorized as chromatid breaks, decondensation of telomeric region, and early separation of sister chromatids. The tests for CA showed that the 5 mg/kg and 50 mg/kg doses of aluminum sulfate had genotoxic potential. Under these treatments, early separation of the sister chromatids was observed more frequently and decondensation of the telomeric region tended to increase in frequency. We suggest that structural changes in the proteins involved in DNA compaction may have led to the decondensation of the telomeric region, making the DNA susceptible to breaks. Moreover, early separation of the sister chromatids may have occurred due to changes in the mobility of chromosomes or proteins that keep the sister chromatids together. The comet assay confirmed the genotoxicity of aluminum sulfate in the kidney tissue of Rhamdia quelen at the three doses of exposure.

Repairability during G1 of the inductor leisure of exchanges in the sister chromatid induced by alkylating agents in DNA substituted and no substituted with BUDR, in cells of the salivary gland of mouse In vivo

International Nuclear Information System (INIS)

Gonzalez B, F.

2004-01-01

In this work you determines the repair of the lesions inductoras of Sister chromatid exchange (ICHs) generated in the cells of the salivary gland of mouse, for the treatment with the N-Methyl-N-Nitrosourea (MNU), the N-Ethyl-N-Nitrosourea (ENU), the Methyl methanesulfonate (MMS) and the Ethyl methanesulfonate (EMS) in early and slow G1 of the first one and the second cellular division, that is to say before and after the cells incorporate 5-bromine-2 -Desoxyuridine (BrdU) in the DNA. Groups witness non treaties were included with mutagen. The cells of the salivary gland repaired the generated lesions partially by the MNU, the MMS and the EMS in the 1st division, and only the lesions induced by the ENU and MMS were repaired partially in the 2nd division. The ENU generates injure that they were not repaired in the 1st division and those taken place by the EMS were little repaired in the 2nd division. The methylating agents generated but ICHs that the ethylating. One observes that the BrdU makes to the molecule of the DNA but susceptible to the damage generated by the alkylating agents that induce the formation of the ICHs. This susceptibility was incremented around 150% for the treatment with the MNU, the ENU and the MMS, on the other hand for the EMS it was 3 times minor. It is proposed that the one electronegative atom of this analog of the timine would to work as a nucleophyllic center with which the electrophyllic compounds react. (Author)

In vivo study on the replicative model validity of sister chromatid exchanges production; Estudio In vivo sobre la validez del modelo replicativo de produccion de intercambios en las cromatidas hermanas

Energy Technology Data Exchange (ETDEWEB)

Cruz V, V L

1997-12-31

The sister chromatid exchanges (SCE) frequency determination has been used as index of damage to DNA, however the biological meaning of this event is still ignored. Different models in order to explain the mechanism of their formation have been proposed and they could be contained in two categories: (a) those that consider that the SCE is produced by means of discrete lesions to the DNA and that they occur in the place of the lesion, and (b) those that propose that the SCE is caused by a group of lesions and that therefore the place in which they occur could not be associated with a lesion in particular. The model of Painter (1980) belongs to this last group. It suggests that the region of the DNA where the clusters are united, is the only place in which the exchange of double chain could happen during the synthesis of the DNA and makes the prediction that since the x rays retard the beginning of the duplication, the pretreatment with ionizing radiation would reduce the frequency of SCE induced by agents capable to block the lengthening of the chain of DNA, that are the most efficient SCE inducers. The objective of the present work was to establish the validity of this replicative model for the SCE formation, based in its prediction. The effect of the unilateral preexposition of mouse to gamma radiation was determined on the SCE induction by Mitomycin C (MMC), in cells of the femoral bone marrow In vivo. This strategy allows to determine the effect of the pretreatment in the same organism, minimizing the variability of the response between individuals. There was not a significant variability between the frequencies of SCE, basal and induced by gamma radiation or MMC in the same organism. The animals that received the gamma radiation pretreatment, showed a reduction of approximately the 30 % in the frequency of SCE, assuming an additive effect of the radiation with the MMC. These results coincide with the prediction of the model of Painter. (Abstract Truncated)

Sisters Hope - the exposed self

DEFF Research Database (Denmark)

Lawaetz, Anna; Hallberg, Gry Worre

Sisters Hope is an art-educational method and a practice-led research tool, rooted in the construction of a fictional parallel universe revolving around the twin sisters Coco and Coca Pebber. Our work is rooted in the ambition to democratize the aesthetic dimension through ‘affective engineering......’ and the establishment of fictional spaces outside the institutional art context. In the Unfolding Academia-context Sisters Hope investigates new forms of research and (re)presentation through the creation of interactive and affective learning-spaces. At Collective Futures Sisters Hope explored questions such as: How...

A comparison of G2 phase radiation-induced chromatid break kinetics using calyculin-PCC with those obtained using colcemid block.

Science.gov (United States)

Bryant, Peter E; Mozdarani, Hossein

2007-09-01

To study the possible influence of cell-cycle delay on cells reaching mitosis during conventional radiation-induced chromatid break experiments using colcemid as a blocking agent, we have compared the chromatid break kinetics following a single dose of gamma rays (0.75 Gy) in metaphase CHO cells using calyculin-induced premature chromosome condensation (PCC), with those using colcemid block. Calyculin-induced PCC causes very rapid condensation of G2 cell chromosomes without the need for a cell to progress to mitosis, hence eliminating any effect of cell-cycle checkpoint on chromatid break frequency. We found that the kinetics of the exponential first-order decrease in chromatid breaks with time after irradiation was similar (not significantly different) between the two methods of chromosome condensation. However, use of the calyculin-PCC technique resulted in a slightly increased rate of disappearance of chromatid breaks and thus higher frequencies of breaks at 1.5 and 2.5 h following irradiation. We also report on the effect of the nucleoside analogue ara A on chromatid break kinetics using the two chromosome condensation techniques. Ara A treatment of cells abrogated the decrease in chromatid breaks with time, both using the calyculin-PCC and colcemid methods. We conclude that cell-cycle delay may be a factor determining the absolute frequency of chromatid breaks at various times following irradiation of cells in G2 phase but that the first-order disappearance of chromatid breaks with time and its abrogation by ara A are not significantly influenced by the G2 checkpoint.

Detection of Ultrafine Anaphase Bridges

DEFF Research Database (Denmark)

Bizard, Anna H; Nielsen, Christian F; Hickson, Ian D

2018-01-01

Ultrafine anaphase bridges (UFBs) are thin DNA threads linking the separating sister chromatids in the anaphase of mitosis. UFBs are thought to form when topological DNA entanglements between two chromatids are not resolved prior to anaphase onset. In contrast to other markers of defective...

Perturbation of Incenp function impedes anaphase chromatid movements and chromosomal passenger protein flux at centromeres.

Science.gov (United States)

Ahonen, Leena J; Kukkonen, Anu M; Pouwels, Jeroen; Bolton, Margaret A; Jingle, Christopher D; Stukenberg, P Todd; Kallio, Marko J

2009-02-01

Incenp is an essential mitotic protein that, together with Aurora B, Survivin, and Borealin, forms the core of the chromosomal passenger protein complex (CPC). The CPC regulates various mitotic processes and functions to maintain genomic stability. The proper subcellular localization of the CPC and its full catalytic activity require the presence of each core subunit in the complex. We have investigated the mitotic tasks of the CPC using a function blocking antibody against Incenp microinjected into cells at different mitotic phases. This method allowed temporal analysis of CPC functions without perturbation of complex assembly or activity prior to injection. We have also studied the dynamic properties of Incenp and Aurora B using fusion protein photobleaching. We found that in early mitotic cells, Incenp and Aurora B exhibit dynamic turnover at centromeres, which is prevented by the anti-Incenp antibody. In these cells, the loss of centromeric CPC turnover is accompanied by forced mitotic exit without the execution of cytokinesis. Introduction of anti-Incenp antibody into early anaphase cells causes abnormalities in sister chromatid separation through defects in anaphase spindle functions. In summary, our data uncovers new mitotic roles for the CPC in anaphase and proposes that CPC turnover at centromeres modulates spindle assembly checkpoint signaling.

Investigations into the molecular mechanism of chromatid breakage in the G2-phase of mammalian cells

International Nuclear Information System (INIS)

Bryant, P.E.; Armstrong, G.N.; Gray, L.; Frankenberg, D.; Mozdarani, H.

2003-01-01

Chromatid breakage following irradiation of cells in the G2-phase of the cell cycle results from the induction of DNA double-strand breaks (dsb). The conversion of dsb into chromatid breaks (cb) has a genetic basis, seemingly different from that of dsb rejoining. The variation in extent of this conversion is exemplified by the stiking variation in frequency of cb in irradiated cycling T-lymphocytes between different normal individuals. Elevated cb frequency in lymphocytes of around 40% of breast cancer patients and their first-degree relatives suggests the presence of mutations in low penetrance cancer predisposing genes that also affect conversion of dsb to cb. Investigation of the mechanism of chromatid radiosensitivity using genetically engineered rodent cell lines containing unique dsb break sites indicate that a single isolated dsb is sufficient to cause a cb. The single-event nature of chromatid breakage is confirmed by the fact that cb are induced as a linear function of radiation dose. Moreover, we have recently shown that ultrasoft carbon-K X-rays also induce chromatid breakage. In this case the energy of the secondary electrons produced by carbon-K X-rays is too low to span more than one DNA double helix, thus further supporting our conclusion that a single dsb is responsible for the formation of a cb. Chromatid breakage is thought to involve a rearrangement between DNA strands at the crossover points of chromatin loop(s) triggered by the presence of a dsb within the loop structure. The occasional observation of 'looped-out' sections of chromatin at cb sites supports this hypothesis. The occurrence of 'colour-switches' between FPG stained chromatids at a proportion of break sites (e.g. about 16% in CHO cells) shows that a significant proportion of cb definitely result from chromatin rearrangements. Measurements of altered colour-switch ratio (csr) in mutant rodent and human cells (irs1 and AT cells respectively) also indicate a genetic basis for the

Differential features of sister-chromatid exchange responses to ultraviolet radiation and caffeine in xeroderma pigmentosum lymphoblastoid cell lines

International Nuclear Information System (INIS)

Tohda, H.; Oikawa, A.

1983-01-01

Sister-chromatic exchange (SCE) induced by ultraviolet (UV) irradiation and viability after UV irradiation were studied in lymphoblastoid cell lines derived from 7 patients with xeroderma pigmentosum (XP) and 6 normal donors. UV irradiation caused significant increases of SCEs in both XP and normal cells. In 3 XP cell lines, which were deficient in unscheduled DNA synthesis (UDS) and sensitive to the killing effect of UV, very high SCE frequencies were observed after UV irradiation. Cells from a patient with the De Sanctis-Cacchione syndrome were the most sensitive to UV in terms of both SCE induction and cell killing. In 2 of 4 UDS-proficient XP cell lines tested, the incidences of UV-induced SCEs were similar to those in normal cell lines, but in 2 other UDS-proficient lines from 2 XP patients with skin cancer, the frequencies of UV-induced SCEs were significantly higher than in normal cells. (orig./AJ)

[Inverted meiosis and its place in the evolution of sexual reproduction pathways].

Science.gov (United States)

Bogdanov, Yu F

2016-05-01

Inverted meiosis is observed in plants (Cyperaceae and Juncaceae) and insects (Coccoidea, Aphididae) with holocentric chromosomes, the centromeres of which occupy from 70 to 90% of the metaphase chromosome length. In the first meiotic division (meiosis I), chiasmata are formed and rodlike bivalents orient equationally, and in anaphase I, sister chromatids segregate to the poles; the diploid chromosome number is maintained. Non-sister chromatids of homologous chromosomes remain in contact during interkinesis and prophase II and segregate in anaphase II, forming haploid chromosome sets. The segregation of sister chromatids in meiosis I was demonstrated by example of three plant species that were heterozygous for chromosomal rearrangements. In these species, sister chromatids, marked with rearrangement, segregated in anaphase I. Using fluorescent antibodies, it was demonstrated that meiotic recombination enzymes Spo11 and Rad5l, typical of canonical meiosis, functioned at the meiotic prophase I of pollen mother cells of Luzula elegance and Rhynchospora pubera. Moreover, antibodies to synaptonemal complexes proteins ASY1 and ZYP1 were visualized as filamentous structures, pointing to probable formation of synaptonemal complexes. In L. elegance, chiasmata are formed by means of chromatin threads containing satellite DNA. According to the hypothesis of the author of this review, equational division of sister chromatids at meiosis I in the organisms with inverted meiosis can be explained by the absence of specific meiotic proteins (shugoshins). These proteins are able to protect cohesins of holocentric centromeres from hydrolysis by separases at meiosis I, as occurs in the organisms with monocentric chromosomes and canonical meiosis. The basic type of inverted meiosis was described in Coccoidea and Aphididae males. In their females, the variants of parthenogenesis were also observed. Until now, the methods of molecular cytogenetics were not applied for the analysis of

Sequential loading of cohesin subunits during the first meiotic prophase of grasshoppers.

Directory of Open Access Journals (Sweden)

Ana M Valdeolmillos

2007-02-01

Full Text Available The cohesin complexes play a key role in chromosome segregation during both mitosis and meiosis. They establish sister chromatid cohesion between duplicating DNA molecules during S-phase, but they also have an important role during postreplicative double-strand break repair in mitosis, as well as during recombination between homologous chromosomes in meiosis. An additional function in meiosis is related to the sister kinetochore cohesion, so they can be pulled by microtubules to the same pole at anaphase I. Data about the dynamics of cohesin subunits during meiosis are scarce; therefore, it is of great interest to characterize how the formation of the cohesin complexes is achieved in order to understand the roles of the different subunits within them. We have investigated the spatio-temporal distribution of three different cohesin subunits in prophase I grasshopper spermatocytes. We found that structural maintenance of chromosome protein 3 (SMC3 appears as early as preleptotene, and its localization resembles the location of the unsynapsed axial elements, whereas radiation-sensitive mutant 21 (RAD21 (sister chromatid cohesion protein 1, SCC1 and stromal antigen protein 1 (SA1 (sister chromatid cohesion protein 3, SCC3 are not visualized until zygotene, since they are located in the synapsed regions of the bivalents. During pachytene, the distribution of the three cohesin subunits is very similar and all appear along the trajectories of the lateral elements of the autosomal synaptonemal complexes. However, whereas SMC3 also appears over the single and unsynapsed X chromosome, RAD21 and SA1 do not. We conclude that the loading of SMC3 and the non-SMC subunits, RAD21 and SA1, occurs in different steps throughout prophase I grasshopper meiosis. These results strongly suggest the participation of SMC3 in the initial cohesin axis formation as early as preleptotene, thus contributing to sister chromatid cohesion, with a later association of both RAD21

The cohesion protein SOLO associates with SMC1 and is required for synapsis, recombination, homolog bias and cohesion and pairing of centromeres in Drosophila Meiosis.

Science.gov (United States)

Yan, Rihui; McKee, Bruce D

2013-01-01

Cohesion between sister chromatids is mediated by cohesin and is essential for proper meiotic segregation of both sister chromatids and homologs. solo encodes a Drosophila meiosis-specific cohesion protein with no apparent sequence homology to cohesins that is required in male meiosis for centromere cohesion, proper orientation of sister centromeres and centromere enrichment of the cohesin subunit SMC1. In this study, we show that solo is involved in multiple aspects of meiosis in female Drosophila. Null mutations in solo caused the following phenotypes: 1) high frequencies of homolog and sister chromatid nondisjunction (NDJ) and sharply reduced frequencies of homolog exchange; 2) reduced transmission of a ring-X chromosome, an indicator of elevated frequencies of sister chromatid exchange (SCE); 3) premature loss of centromere pairing and cohesion during prophase I, as indicated by elevated foci counts of the centromere protein CID; 4) instability of the lateral elements (LE)s and central regions of synaptonemal complexes (SCs), as indicated by fragmented and spotty staining of the chromosome core/LE component SMC1 and the transverse filament protein C(3)G, respectively, at all stages of pachytene. SOLO and SMC1 are both enriched on centromeres throughout prophase I, co-align along the lateral elements of SCs and reciprocally co-immunoprecipitate from ovarian protein extracts. Our studies demonstrate that SOLO is closely associated with meiotic cohesin and required both for enrichment of cohesin on centromeres and stable assembly of cohesin into chromosome cores. These events underlie and are required for stable cohesion of centromeres, synapsis of homologous chromosomes, and a recombination mechanism that suppresses SCE to preferentially generate homolog crossovers (homolog bias). We propose that SOLO is a subunit of a specialized meiotic cohesin complex that mediates both centromeric and axial arm cohesion and promotes homolog bias as a component of chromosome

Interview: Tatyana Lipovskaya, Sisters Sexual Assault Recovery Centre, Moscow, Russia.

Science.gov (United States)

1998-11-01

The Sisters' Sexual Assault Recovery Center was established in Moscow, Russia, in 1993, to address the needs of victims of sexual violence. The Center's help-line received 4029 crisis calls in 1994-97. Most clients are seeking information about medical services or legal aid. Others call about employment, HIV/AIDS, alcoholism, and drug abuse. Services are available without regard to age, sex, occupation, or sexual orientation. Program funding has come entirely from Western foundations and organizations. Although Russia has not passed a law on domestic violence, the post-Communism government is reluctantly starting to acknowledge that rape and domestic violence are serious social problems. The Center runs an educational program for law enforcement officers to increase their sensitivity and create an environment of safety for women who report sexual violence.

Dealing with conflict - The role of the ward sister

Directory of Open Access Journals (Sweden)

L.M. Cremer

1980-09-01

Full Text Available In the course of her duties, the ward sister has to contend with many forms of conflict, discord and dissension. These involve conflict of the intrapersonal, interpersonal and intergroup varieties. Conflict is in the main, disruptive and dysfunctional. Skilful management, however, embodying cooperative effort in its reduction can produce constructive and positive results. Conflict management strategies are therefore either restrictive or constructive. Persons in serious conflict suffer varied degrees of personality disequilibrium, which necessitates emotional first aid or crisis intervention. Such primary preventive care is applicable to patients, their relatives, and members of the nursing staff in such need.

Post-irradiation treatment of human lymphocytes with spermidine reduced frequency of chromatid breaks

International Nuclear Information System (INIS)

Bocian, E.; Rosiek, O.; Ziemba-Zoltowska, B.

1978-01-01

Human lymphocyte cultures were X-irradiated with a single dose of 100 or 200 rad 46 h after phytohemagglutinin stimulation. In dose-fractionation experiments, 2h later the second dose was applied. All the cultures were harvested at 54 h after their initiation. In lymphocytes irradiated with a single dose of 200 rad, 2h post-irradiation contact with 10 -5 M exogeneous spermidine resulted in reduction of chromatid breaks by 34 %. Introduction of spermidine into culture medium for fractionation interval between the 2 doses of 100 rad reduced the frequency of chromatid breaks by 42 %. (author)

Chromatid interchanges at intrachromosomal telomeric DNA sequences

International Nuclear Information System (INIS)

Fernandez, J.L.; Vazquez-Gundin, F.; Bilbao, A.; Gosalvez, J.; Goyanes, V.

1997-01-01

Chinese hamster Don cells were exposed to X-rays, mitomycin C and teniposide (VM-26) to induce chromatid exchanges (quadriradials and triradials). After fluorescence in situ hybridization (FISH) of telomere sequences it was found that interstitial telomere-like DNA sequence arrays presented around five times more breakage-rearrangements than the genome overall. This high recombinogenic capacity was independent of the clastogen, suggesting that this susceptibility is not related to the initial mechanisms of DNA damage. (author)

Abnormal centromere-chromatid apposition (ACCA) and Peters' anomaly.

Science.gov (United States)

Wertelecki, W; Dev, V G; Superneau, D W

1985-08-01

Abnormal centromere-chromatid apposition (ACCA) was noted in a patient with Peters' anomaly. Previous reports of ACCA emphasized its association with tetraphocomelia and other congenital malformations (Roberts, SC Phocomelia, Pseudothalidomide Syndromes). This report expands the array of congenital malformations associated with ACCA and emphasizes the diagnostic importance of ocular defects for the ascertainment of additional cases of ACCA and its possible relationship with abnormal cell division.

Role of oxidative stress and intracellular calcium in nickel carbonate hydroxide-induced sister-chromatid exchange, and alterations in replication index and mitotic index in cultured human peripheral blood lymphocytes

Energy Technology Data Exchange (ETDEWEB)

M' Bemba-Meka, Prosper [Universite de Montreal, Human Toxicology Research Group (TOXHUM), Department of Environmental and Occupational Health, Main Station, P.O. Box 6128, Montreal, QC (Canada); University of Louisville, Department of Pharmacology and Toxicology, Center for Genetics and Molecular Medicine, Louisville, KY (United States); Lemieux, Nicole [Universite de Montreal, Department of Pathology and Cellular Biology, Faculty of Medicine, Main Station, P.O. Box 6128, Montreal, QC (Canada); Chakrabarti, Saroj K. [Universite de Montreal, Human Toxicology Research Group (TOXHUM), Department of Environmental and Occupational Health, Main Station, P.O. Box 6128, Montreal, QC (Canada)

2007-02-15

Human peripheral lymphocytes from whole blood cultures were exposed to either soluble form of nickel carbonate hydroxide (NiCH) (0-60 {mu}M), or of nickel subsulfide (Ni{sub 3}S{sub 2}) (0-120 {mu}M), or of nickel oxide (NiO) (0-120 {mu}M), or nickel sulfate (NiSO{sub 4}) (0-120 {mu}M) for a short duration of 2 h. The treatments occurred 46 h after the beginning of the cultures. The cultures were harvested after a total incubation of 72 h, and sister-chromatid exchange (SCE), replication index (RI), and mitotic index (MI) were measured for each nickel compound. The soluble form of NiCH at 30 {mu}M but those of Ni{sub 3}S{sub 2} and NiO at 120 {mu}M produced significant increase in the SCE per cell compared to the control value, whereas NiSO{sub 4} failed to produce any such significant increase. Except NiSO{sub 4}, the soluble forms of NiCH, Ni{sub 3}S{sub 2}, and NiO produced significant cell-cycle delay (as measured by the inhibition of RI) as well as significant inhibition of the MI at respective similar concentrations as mentioned above. Pretreatment of human blood lymphocytes with catalase (H{sub 2}O{sub 2} scavenger), or superoxide dismutase (superoxide anion scavenger), or dimethylthiourea (hydroxyl radical scavenger), or deferoxamine (iron chelator), or N-acetylcysteine (general antioxidant) inhibited NiCH-induced SCE, and changes in RI and MI. This suggests the participation of oxidative stress involving H{sub 2}O{sub 2}, the superoxide anion radical, the hydroxyl radical, and iron in the NiCH-induced genotoxic responses. Cotreatment of NiCH with either verapamil (inhibitor of intracellular calcium ion ([Ca{sup 2+}]{sub i}) movement through plasma membranes), or dantrolene (inhibitor of [Ca{sup 2+}]{sub i} release from sarcoplasmic reticulum), or BAPTA (Ca{sup 2+} chelator) also inhibited the NiCH-induced responses. These results suggest that [Ca{sup 2+}]{sub i} is also implicated in the genotoxicity of NiCH. Overall these data indicate that various types

Teenage pregnancy: the impact of maternal adolescent childbearing and older sister's teenage pregnancy on a younger sister.

Science.gov (United States)

Wall-Wieler, Elizabeth; Roos, Leslie L; Nickel, Nathan C

2016-05-25

Risk factors for teenage pregnancy are linked to many factors, including a family history of teenage pregnancy. This research examines whether a mother's teenage childbearing or an older sister's teenage pregnancy more strongly predicts teenage pregnancy. This study used linkable administrative databases housed at the Manitoba Centre for Health Policy (MCHP). The original cohort consisted of 17,115 women born in Manitoba between April 1, 1979 and March 31, 1994, who stayed in the province until at least their 20(th) birthday, had at least one older sister, and had no missing values on key variables. Propensity score matching (1:2) was used to create balanced cohorts for two conditional logistic regression models; one examining the impact of an older sister's teenage pregnancy and the other analyzing the effect of the mother's teenage childbearing. The adjusted odds of becoming pregnant between ages 14 and 19 for teens with at least one older sister having a teenage pregnancy were 3.38 (99 % CI 2.77-4.13) times higher than for women whose older sister(s) did not have a teenage pregnancy. Teenage daughters of mothers who had their first child before age 20 had 1.57 (99 % CI 1.30-1.89) times higher odds of pregnancy than those whose mothers had their first child after age 19. Educational achievement was adjusted for in a sub-population examining the odds of pregnancy between ages 16 and 19. After this adjustment, the odds of teenage pregnancy for teens with at least one older sister who had a teenage pregnancy were reduced to 2.48 (99 % CI 2.01-3.06) and the odds of pregnancy for teen daughters of teenage mothers were reduced to 1.39 (99 % CI 1.15-1.68). Although both were significant, the relationship between an older sister's teenage pregnancy and a younger sister's teenage pregnancy is much stronger than that between a mother's teenage childbearing and a younger daughter's teenage pregnancy. This study contributes to understanding of the broader topic "who is

Interchromosomal distribution of gamma ray-induced chromatid aberrations in Chinese hamster ovary cells

International Nuclear Information System (INIS)

Martinez-Lopez, Wilner; Porro, Valentina; Folle, Gustavo A.; Mendez-Acuna, Leticia; Obe, Guenter; Savage, John R.K.

2000-01-01

Inter chromosomal distributions of breakpoints from chromatid-type aberrations induced by gamma rays in Chinese hamster ovary cells were analyzed. In most chromosomes the distribution was as expected from chromosome lengths for simple breaks or the respective relative corrected length in case of exchanges. There were deviations from expectation in a few chromosomes for chromatid breaks, interchanges, intra-arm intra changes and inter-arm intra changes. Especially interesting are the results concerning chromosomes 2 and 8, which were more often involved in exchanges than expected. An 'exchange phenotype' for these chromosomes is proposed and possible explanations for the nonrandom distribution of chromosome breakpoints are presented. (author)

Consumerism and the Sister Carrie's American Dream%Consumerism and the Sister Carrie''s American Dream

Institute of Scientific and Technical Information of China (English)

卢亚丽

2017-01-01

From the aspect of consumerism to this text analyze Sister Carrie's"American dream"destruction. The author wholly and deeply analyzes the embodiment of consumerism in Dreiser's Sister Carrie and Dreiser's outlook and values under the effect of consumerism. To prove that the reason for destruction of Carrie's American dream is consumerism.

Mps1 kinase-dependent Sgo2 centromere localisation mediates cohesin protection in mouse oocyte meiosis I

NARCIS (Netherlands)

Yakoubi, W. El; Buffin, E.; Cladiere, D.; Gryaznova, Y.; Berenguer, I.; Touati, S.A.; Gomez, R.; Suja, J.A.; Deursen, J.M.A. van; Wassmann, K.

2017-01-01

A key feature of meiosis is the step-wise removal of cohesin, the protein complex holding sister chromatids together, first from arms in meiosis I and then from the centromere region in meiosis II. Centromeric cohesin is protected by Sgo2 from Separase-mediated cleavage, in order to maintain sister

Somatomedin C deficiency in Asian sisters.

OpenAIRE

McGraw, M E; Price, D A; Hill, D J

1986-01-01

Two sisters of Asian origin showed typical clinical and biochemical features of primary somatomedin C (SM-C) deficiency (Laron dwarfism). Abnormalities of SM-C binding proteins were observed, one sister lacking the high molecular weight (150 Kd) protein.

Analysis of chromosomal aberrations, sister-chromatid exchanges and micronuclei in peripheral lymphocytes of pharmacists before and after working with cytostatic drugs.

Science.gov (United States)

Roth, S; Norppa, H; Järventaus, H; Kyyrönen, P; Ahonen, M; Lehtomäki, J; Sainio, H; Sorsa, M

1994-12-01

The frequencies of chromosome aberrations, SCEs and micronuclei (cytokinesis-block method) in blood lymphocytes were compared among six nonsmoking female pharmacists before and after 1 year of working with cytostatic drugs. All possible precautions were taken to avoid exposure to cytostatics, including proper protective clothing and a monitored, negative-pressured working environment with vertical laminar flow cabinet. As referents, an age-matched group of six nonsmoking female hospital workers not dealing with cytostatics was simultaneously sampled twice with the same time interval. The pharmacists showed a marginally higher mean frequency of SCEs/cell (6.3; P = 0.049) after the working period than 1 year earlier (5.8). On the other hand, the referents, with no obvious exposure, had a higher mean number of cells with chromatid-type aberrations, gaps excluded, in the second sampling (2.0%; P = 0.048) than in the first one (0.5%). In addition, a slight (P = 0.055) trend towards a higher frequency of micronucleated binucleate cells was observed in the second sampling for both the exposed and control subjects. As such findings suggest technical variation in the cytogenetic parameters, the small difference observed in SCEs for the pharmacists between the two samplings was probably not related to the cytostatics exposure. No statistically significant differences were observed for any of the cytogenetic parameters in comparisons between the pharmacists and the referents. The findings suggest that caution should be exercised in comparing results obtained from two different samplings in prospective cytogenetic studies.

Eruptive history of South Sister, Oregon Cascades

Science.gov (United States)

Fierstein, J.; Hildreth, W.; Calvert, A.T.

2011-01-01

South Sister is southernmost and highest of the Three Sisters, three geologically dissimilar stratovolcanoes that together form a spectacular 20km reach along the Cascade crest in Oregon. North Sister is a monotonously mafic edifice as old as middle Pleistocene, Middle Sister a basalt-andesite-dacite cone built between 48 and 14ka, and South Sister is a basalt-free edifice that alternated rhyolitic and intermediate modes from 50ka to 2ka (largely contemporaneous with Middle Sister). Detailed mapping, 330 chemical analyses, and 42 radioisotopic ages show that the oldest exposed South Sister lavas were initially rhyolitic ~50ka. By ~37ka, rhyolitic lava flows and domes (72-74% SiO2) began alternating with radially emplaced dacite (63-68% SiO2) and andesite (59-63% SiO2) lava flows. Construction of a broad cone of silicic andesite-dacite (61-64% SiO2) culminated ~30ka in a dominantly explosive sequence that began with crater-forming andesitic eruptions that left fragmental deposits at least 200m thick. This was followed at ~27ka by growth of a steeply dipping summit cone of agglutinate-dominated andesite (56-60.5% SiO2) and formation of a summit crater ~800m wide. This crater was soon filled and overtopped by a thick dacite lava flow and then by >150m of dacitic pyroclastic ejecta. Small-volume dacite lavas (63-67% SiO2) locally cap the pyroclastic pile. A final sheet of mafic agglutinate (54-56% SiO2) - the most mafic product of South Sister - erupted from and drapes the small (300-m-wide) present-day summit crater, ending a summit-building sequence that lasted until ~22ka. A 20kyr-long-hiatus was broken by rhyolite eruptions that produced (1) the Rock Mesa coulee, tephra, and satellite domelets (73.5% SiO2) and (2) the Devils Chain of ~20 domes and short coulees (72.3-72.8% SiO2) from N-S vent alignments on South Sister's flanks. The compositional reversal from mafic summit agglutinate to recent rhyolites epitomizes the frequently changing compositional modes of the

Induction and disappearance of G2 chromatid breaks in lymphocytes after low doses of low LET γ - rays and high LET fast neutrons

International Nuclear Information System (INIS)

Vral, Anne; Thierens, Hubert; Baeyens, Ans; De Ridder, Leo

2001-01-01

In view of the potential importance of the G2 assay for detecting chromosomal radiosensitivity and possible predisposition to cancer the need to elucidate the mechanism underlying the formation of chromatid breaks, observed with the G2 assay after low dose irradiation, has been recognised. In this study we irradiated blood samples of 4 healthy donors with low LET γ-rays and high LET neutrons, which initially produce the same number of dsb but of a different quality. By means of the G2 assay, we determined the number of chromatid breaks induced by γ-rays and neutrons and compared the kinetics of chromatid break rejoining for radiations of different quality. In a first set of experiments a dose-response curve for the formation of chromatid breaks was carried out for γ-rays and neutrons with doses ranging between 0.1 and 0.5 Gy. In a second set of experiments the kinetics of chromatid break formation and disappearance was investigated after a dose of 0.5 Gy using post-irradiation times ranging between 0.5 h and 3.5 h. For the highest dose of 0.5 Gy the number of isochromatid breaks were also scored. No significant differences in the number of chromatid breaks were observed between low LET γ-rays and high LET neutrons for the 4 donors at any of the doses given. The dose response curves for the formation of chromatid breaks are linear for both radiation qualities and RBE values equal to one were obtained. Scoring of isochromatid breaks at the highest dose of 0.5 Gy revealed that high LET neutrons are however more effective at inducing isochromatid breaks (RBE of 6.2). The rejoining experiments further showed that the kinetics of disappearance of chromatid breaks following irradiation with low LET γ-rays or high-LET neutrons are not significantly different. T 1/2 0.92 h for γ-rays and t 1/2 = 0.84 h for neutrons were obtained. In conclusion, our results show that at low doses of radiation the induction as well as the disappearance of G2 chromatid breaks is LET

Relationship of the demethylation of the DNA with the induction of the sister chromatid exchanges (SCE) In vivo; Relacion de la desmetilacion del ADN con la induccion de intercambios en las cromatidas hermanas (ICH) In vivo

Energy Technology Data Exchange (ETDEWEB)

Toribio E, E

2005-07-01

The methylation of the DNA is an epigenetic modification that has an important paper in the regulation of the functionality of the genome of the organisms. It can be altered by demethylation processes, either natural or experimentally induced. The 5-azacytidine (Aza) is a compound that causes the demethylation of the DNA (dm-DNA), inducing with it, expression genic and increase in the frequency of the Sister Chromatid Exchange (SCE). The SCE is a genotoxicity indicator, caused by diverse mutagens and carcinogen. Since the biological meaning and the formation mechanism of this phenomenon has not been totally illustrious, the exploration of the relation between the dm-DNA and the induction of SCE, it could offer new knowledge to explain those queries. The purpose of this work was to study in cells of the mouse bone marrow In vivo, the effect of the Aza on the induction of SCE, based on two aspects: 1) dose answer and 2) the effectiveness of multiple exhibition. To six groups of three to five animals, they are administered Aza to dose of 5, 10, 15 or 20 mg/Kg of weight; in sharp or multiple form, previously to the bromodeoxyuridine supply and 24 h was sacrificed after this; 2 h after an injection with colchicine. Preparations of those metaphases were made, those which were dyed by means of a technique of fluorescence more Giemsa. It was observed that to sharp low dose, the Aza produced an increment in the frequency of SCE that although small it was proportional and statistically significant. To sharp and multiple high doses, the Aza doesn't cause additional increments of SCE, but if toxicity at cellular level and of individuals. It is concluded that a relationship exists between the dm-DNA and the induction of SCE. It is suggested that the total demethylation of the DNA causes 2 SCE/Cell in cells of the mouse bone marrow, or that the cytotoxicity prevents to evidence a bigger induction. (Author)

Relationship of the demethylation of the DNA with the induction of the sister chromatid exchanges (SCE) In vivo; Relacion de la desmetilacion del ADN con la induccion de intercambios en las cromatidas hermanas (ICH) In vivo

Energy Technology Data Exchange (ETDEWEB)

Toribio E, E

2005-07-01

The methylation of the DNA is an epigenetic modification that has an important paper in the regulation of the functionality of the genome of the organisms. It can be altered by demethylation processes, either natural or experimentally induced. The 5-azacytidine (Aza) is a compound that causes the demethylation of the DNA (dm-DNA), inducing with it, expression genic and increase in the frequency of the Sister Chromatid Exchange (SCE). The SCE is a genotoxicity indicator, caused by diverse mutagens and carcinogen. Since the biological meaning and the formation mechanism of this phenomenon has not been totally illustrious, the exploration of the relation between the dm-DNA and the induction of SCE, it could offer new knowledge to explain those queries. The purpose of this work was to study in cells of the mouse bone marrow In vivo, the effect of the Aza on the induction of SCE, based on two aspects: 1) dose answer and 2) the effectiveness of multiple exhibition. To six groups of three to five animals, they are administered Aza to dose of 5, 10, 15 or 20 mg/Kg of weight; in sharp or multiple form, previously to the bromodeoxyuridine supply and 24 h was sacrificed after this; 2 h after an injection with colchicine. Preparations of those metaphases were made, those which were dyed by means of a technique of fluorescence more Giemsa. It was observed that to sharp low dose, the Aza produced an increment in the frequency of SCE that although small it was proportional and statistically significant. To sharp and multiple high doses, the Aza doesn't cause additional increments of SCE, but if toxicity at cellular level and of individuals. It is concluded that a relationship exists between the dm-DNA and the induction of SCE. It is suggested that the total demethylation of the DNA causes 2 SCE/Cell in cells of the mouse bone marrow, or that the cytotoxicity prevents to evidence a bigger induction. (Author)

Non-random intrachromosomal distribution of radiation-induced chromatid aberrations in Vicia faba. [Aberration clustering

Energy Technology Data Exchange (ETDEWEB)

Schubert, I; Rieger, R [Akademie der Wissenschaften der DDR, Gatersleben. Zentralinst. fuer Genetik und Kulturpflanzenforschung

1976-04-01

A reconstructed karyotype of Vicia faba, with all chromosomes individually distinguishable, was treated with X-rays, fast neutrons, (/sup 3/H) uridine (/sup 3/HU). The distribution within metaphase chromosomes of induced chromatid aberrations was non-random for all agents used. Aberration clustering, in part agent specific, occurred in chromosome segments containing heterochromatin as defined by the presence of G bands. The pattern of aberration clustering found after treatment with /sup 3/HU did not allow the recognition of chromosome regions active in transcription during treatment. Furthermore, it was impossible to obtain unambiguous indications of the presence of AT- and GC-base clusters from the patterns of /sup 3/HT- and /sup 3/HC-induced chromatid aberrations, respectively. Possible reasons underlying these observations are discussed.

MHF1-2/CENP-S-X performs distinct roles in centromere metabolism and genetic recombination.

Science.gov (United States)

Bhattacharjee, Sonali; Osman, Fekret; Feeney, Laura; Lorenz, Alexander; Bryer, Claire; Whitby, Matthew C

2013-09-11

The histone-fold proteins Mhf1/CENP-S and Mhf2/CENP-X perform two important functions in vertebrate cells. First, they are components of the constitutive centromere-associated network, aiding kinetochore assembly and function. Second, they work with the FANCM DNA translocase to promote DNA repair. However, it has been unclear whether there is crosstalk between these roles. We show that Mhf1 and Mhf2 in fission yeast, as in vertebrates, serve a dual function, aiding DNA repair/recombination and localizing to centromeres to promote chromosome segregation. Importantly, these functions are distinct, with the former being dependent on their interaction with the FANCM orthologue Fml1 and the latter not. Together with Fml1, they play a second role in aiding chromosome segregation by processing sister chromatid junctions. However, a failure of this activity does not manifest dramatically increased levels of chromosome missegregation due to the Mus81-Eme1 endonuclease, which acts as a failsafe to resolve DNA junctions before the end of mitosis.

Two Nepali Sisters

DEFF Research Database (Denmark)

Hansen, Annette Skovsted

Diaspora is an expansion of a national or family network that can be activated for the benefit of the family and home nation in multiple ways. The argument is based on two life stories. Two Nepali sisters attended Association of Overseas Technical Scholarships (AOTS) training courses in Japan...... at different times during the 1980s. The training was partly funded by official development assistance provided through the Japanese Ministry of International Trade and Industry (MITI). They used their training very differently, but between the two of them extended a family network from Japan and India...... still pursuing a career in a Japanese company. Their children have or are studying in Japan, India, and the USA. The Nepal-based sister is a key stakeholder in the regional cooperation in South Asia. By engaging network theories of weak ties and scaled networks, the life stories become templates...

Developing skills in clinical leadership for ward sisters.

Science.gov (United States)

Fenton, Katherine; Phillips, Natasha

The Francis report has called for a strengthening of the ward sister's role. It recommends that sisters should operate in a supervisory capacity and should not be office bound. Effective ward leadership has been recognised as being vital to high-quality patient care and experience, resource management and interprofessional working. However, there is evidence that ward sisters are ill equipped to lead effectively and lack confidence in their ability to do so. University College London Hospitals Foundation Trust has recognised that the job has become almost impossible in increasingly large and complex organisations. Ward sisters spend less than 40% of their time on clinical leadership and the trust is undertaking a number of initiatives to support them in this role.

Consumerism and the Sister Carrie's American Dream

Institute of Scientific and Technical Information of China (English)

卢亚丽

2017-01-01

From the aspect of consumerism to this text analyze Sister Carrie's"American dream"destruction. The author wholly and deeply analyzes the embodiment of consumerism in Dreiser's Sister Carrie and Dreiser's outlook and values under the effect of consumerism. To prove that the reason for destruction of Carrie's American dream is consumerism.

Mps1 kinase-dependent Sgo2 centromere localisation mediates cohesin protection in mouse oocyte meiosis I.

Science.gov (United States)

El Yakoubi, Warif; Buffin, Eulalie; Cladière, Damien; Gryaznova, Yulia; Berenguer, Inés; Touati, Sandra A; Gómez, Rocío; Suja, José A; van Deursen, Jan M; Wassmann, Katja

2017-09-25

A key feature of meiosis is the step-wise removal of cohesin, the protein complex holding sister chromatids together, first from arms in meiosis I and then from the centromere region in meiosis II. Centromeric cohesin is protected by Sgo2 from Separase-mediated cleavage, in order to maintain sister chromatids together until their separation in meiosis II. Failures in step-wise cohesin removal result in aneuploid gametes, preventing the generation of healthy embryos. Here, we report that kinase activities of Bub1 and Mps1 are required for Sgo2 localisation to the centromere region. Mps1 inhibitor-treated oocytes are defective in centromeric cohesin protection, whereas oocytes devoid of Bub1 kinase activity, which cannot phosphorylate H2A at T121, are not perturbed in cohesin protection as long as Mps1 is functional. Mps1 and Bub1 kinase activities localise Sgo2 in meiosis I preferentially to the centromere and pericentromere respectively, indicating that Sgo2 at the centromere is required for protection.In meiosis I centromeric cohesin is protected by Sgo2 from Separase-mediated cleavage ensuring that sister chromatids are kept together until their separation in meiosis II. Here the authors demonstrate that Bub1 and Mps1 kinase activities are required for Sgo2 localisation to the centromere region.

Resolving RAD51C function in late stages of homologous recombination

Directory of Open Access Journals (Sweden)

Kuznetsov Sergey G

2007-06-01

Full Text Available Abstract DNA double strand breaks are efficiently repaired by homologous recombination. One of the last steps of this process is resolution of Holliday junctions that are formed at the sites of genetic exchange between homologous DNA. Although various resolvases with Holliday junctions processing activity have been identified in bacteriophages, bacteria and archaebacteria, eukaryotic resolvases have been elusive. Recent biochemical evidence has revealed that RAD51C and XRCC3, members of the RAD51-like protein family, are involved in Holliday junction resolution in mammalian cells. However, purified recombinant RAD51C and XRCC3 proteins have not shown any Holliday junction resolution activity. In addition, these proteins did not reveal the presence of a nuclease domain, which raises doubts about their ability to function as a resolvase. Furthermore, oocytes from infertile Rad51C mutant mice exhibit precocious separation of sister chromatids at metaphase II, a phenotype that reflects a defect in sister chromatid cohesion, not a lack of Holliday junction resolution. Here we discuss a model to explain how a Holliday junction resolution defect can lead to sister chromatid separation in mouse oocytes. We also describe other recent in vitro and in vivo evidence supporting a late role for RAD51C in homologous recombination in mammalian cells, which is likely to be resolution of the Holliday junction.

Biomonitoring of genotoxic risk in radar facility workers: comparison of the comet assay with micronucleus assay and chromatid breakage assay

International Nuclear Information System (INIS)

Garaj-Vrhovac, V.; Kopjar, N.

2003-01-01

Genotoxic risks of occupational exposure in a radar facility were evaluated by using alkaline comet assay, micronucleus assay and chromatid breakage assay on peripheral blood leukocytes in exposed subjects and corresponding controls. Results show that occupational exposure to microwave radiation correlates with an increase of genome damage in somatic cells. The levels of DNA damage in exposed subjects determined by using alkaline comet assay were increased compared to control and showed interindividual variations. Incidence of micronuclei was also significantly increased compared to baseline control values. After short exposure of cultured lymphocytes to bleomycin, cells of occupationally exposed subjects responded with high numbers of chromatid breaks. Although the level of chromosome damage generated by bleomycin varied greatly between individuals, in exposed subjects a significantly elevated number of chromatid breaks was observed. Our results support data reported in literature indicating that microwave radiation represents a potential DNA-damaging hazard. Alkaline comet assay is confirmed as a sensitive and highly reproducible technique for detection of primary DNA damage inflicted in somatic cells. Micronucleus assay was confirmed as reliable bio-markers of effect and chromatid breakage assay as sensitive bio-marker of individual cancer susceptibility. The results obtained also confirm the necessity to improve measures and to perform accurate health surveillance of individuals occupationally exposed to microwave radiation

Cytogenetic diagnosis of Roberts SC phocomelia syndrome: First report from Kashmir

Directory of Open Access Journals (Sweden)

Tahir M. Malla

2016-01-01

Full Text Available There are several syndromes in which specific mitotic chromosomal abnormalities can be seen, like premature centromere separation, premature (sister chromatid separation, and somatic aneuploidies. Identifications of such specific cytogenetic findings can be the key factor that leads towards the diagnosis of syndromes like Roberts SC phocomelia. The case presented here as Roberts SC phocomelia syndrome was identified as a child with multiple congenital anomalies and dysmorphic features. Conventional cytogenetic analysis of the case revealed premature sister chromatid separation. The premature centromeric separation was also confirmed by C banding analysis of the child. It is the first and the only case of Roberts SC phocomelia diagnosed from this part of the world. The present case report emphasizes the importance of conventional cytogenetics in the diagnosis of such syndromes.

Fulltext PDF

Indian Academy of Sciences (India)

Prakash

2010-02-03

Feb 3, 2010 ... proposed as a mechanism for brain hemispheric laterality specification ... By theory, sister chromatids of translocation-containing chromosomes are randomly segregated. ... the left and the other on the right side of the embryo.

Uncoupling of Sister Replisomes during Eukaryotic DNA Replication

NARCIS (Netherlands)

Yardimci, Hasan; Loveland, Anna B.; Habuchi, Satoshi; van Oijen, Antoine M.; Walter, Johannes C.

2010-01-01

The duplication of eukaryotic genomes involves the replication of DNA from multiple origins of replication. In S phase, two sister replisomes assemble at each active origin, and they replicate DNA in opposite directions. Little is known about the functional relationship between sister replisomes.

little sister: An Afro-Temporal Solo-Play.

Science.gov (United States)

De Berry, Misty

2017-07-03

little sister: An Afro-Temporal Solo-Play is at once a memory-scape and a mytho-biography set to poetry, movement, and mixed media. A performance poem spanning from the Antebellum South to present-moment Chicago, it tells the story of a nomadic spirit named little-she who shape-shifts through the memories and imaginings of her sister, the narrator. Through the characters little-she and the narrator, the solo-performance explores embodied ways to rupture and relieve the impact of macro forms of violence in the micro realm of the everyday. To this end, little sister witnesses and disrupts the legacy of violence in the lives of queer Black women through a trans-temporal navigation of everyday encounters within familial, small groups and intimate partner spaces.

INDUCTION OF DNA STRAND BREAKS BY TRIHALOMETHANES IN PRIMARY HUMAN LUNG EPITHELIAL CELLS

Science.gov (United States)

Abstract Trihalomethanes (TEMs) are disinfection by-products and suspected human carcinogens present in chlorinated drinking water. Previous studies have shown that many THMs induce sister chromatid exchanges and DNA strand breaks in human peripheral blood lymphocyte...

Interaction between a pair of gypsy insulators or between heterologous gypsy and Wari insulators modulates Flp site-specific recombination in Drosophila melanogaster.

Science.gov (United States)

Krivega, Margarita; Savitskaya, Ekaterina; Krivega, Ivan; Karakozova, Marina; Parshikov, Aleksander; Golovnin, Anton; Georgiev, Pavel

2010-08-01

Chromatin insulators block the action of transcriptional enhancers when interposed between an enhancer and a promoter. An Flp technology was used to examine interactions between Drosophila gypsy and Wari insulators in somatic and germ cells. The gypsy insulator consists of 12 binding sites for the Su(Hw) protein, while the endogenous Wari insulator, located on the 3' side of the white gene, is independent from the Su(Hw) protein. Insertion of the gypsy but not Wari insulator between FRT sites strongly blocks recombination between Flp dimers bound to FRT sites located on the same chromatid (recombination in cis) or in sister chromatids (unequal recombination in trans). At the same time, the interaction between Wari and gypsy insulators regulates the efficiency of Flp-mediated recombination. Thus, insulators may have a role in controlling interactions between distantly located protein complexes (not only those involved in transcriptional gene regulation) on the same chromosome or on sister chromatids in somatic and germ cells. We have also found that the frequency of Flp-mediated recombination between FRT sites is strongly dependent on the relative orientation of gypsy insulators. Taken together, our results indicate that the interactions between insulators can be visualized by Flp technology and that insulators may be involved in blocking undesirable interactions between proteins at the two-chromatid phase of the cell cycle.

The Lehman Sisters Hypothesis

NARCIS (Netherlands)

I.P. van Staveren (Irene)

2014-01-01

markdownabstract__Abstract__ This article explores the Lehman Sisters Hypothesis. It reviews empirical literature about gender differences in behavioral, experimental, and neuro-economics as well as in other fields of behavioral research. It discusses gender differences along three dimensions of

Organization of Sisters of Mercy During World War One

Directory of Open Access Journals (Sweden)

Sribnaia Anna

2014-10-01

Full Text Available The article examines the labour organization of Russian sisters of mercy during World War One. The author indicates two periods which took place before and after the February Revolution. Based on archive documents and offi cial publications the article describes general structure of Russian Red Cross Society institutions and basic principles of sisters of mercy communities’ work. It examines the rules of new sisters’ employment, their training, service assignment and professional duties. The emphasis is put on nurses’ work in wartime. During first years of war sisters’ position was stable. Due to specifi c hierarchy in the managing structure sisters’ work was productive and demanded. After the February Revolution the managing system changed drastically as well as the status of sisters of mercy and their reception in society. The author gives a thorough examination of sisters’ position after reorganization of Russian Red Cross Society. In time of political instability Russian sisters of mercy were able to organize themselves into one big organization thus creating All-Russian Union of Sisters of Mercy. This article for the first time ever implements into scientific research a huge amount of documents which allowed a signifi cant extension of views on Bolsheviks’ political approaches to Russian Red Cross Society and institution of sisters of mercy.

The C-terminal domain of the Bloom syndrome DNA helicase is essential for genomic stability

Directory of Open Access Journals (Sweden)

Noonan James P

2001-07-01

Full Text Available Abstract Background Bloom syndrome is a rare cancer-prone disorder in which the cells of affected persons have a high frequency of somatic mutation and genomic instability. Bloom syndrome cells have a distinctive high frequency of sister chromatid exchange and quadriradial formation. BLM, the protein altered in BS, is a member of the RecQ DNA helicase family, whose members share an average of 40% identity in the helicase domain and have divergent N-terminal and C-terminal flanking regions of variable lengths. The BLM DNA helicase has been shown to localize to the ND10 (nuclear domain 10 or PML (promyelocytic leukemia nuclear bodies, where it associates with TOPIIIα, and to the nucleolus. Results This report demonstrates that the N-terminal domain of BLM is responsible for localization of the protein to the nuclear bodies, while the C-terminal domain directs the protein to the nucleolus. Deletions of the N-terminal domain of BLM have little effect on sister chromatid exchange frequency and chromosome stability as compared to helicase and C-terminal mutations which can increase SCE frequency and chromosome abnormalities. Conclusion The helicase activity and the C-terminal domain of BLM are critical for maintaining genomic stability as measured by the sister chromatid exchange assay. The localization of BLM into the nucleolus by the C-terminal domain appears to be more important to genomic stability than localization in the nuclear bodies.

Localization of two mammalian cyclin dependent kinases during mammalian meiosis

NARCIS (Netherlands)

Ashley, T.; Walpita, D.; de rooij, D. G.

2001-01-01

Mammalian meiotic progression, like mitotic cell cycle progression, is regulated by cyclins and cyclin dependent kinases (CDKs). However, the unique requirements of meiosis (homologous synapsis, reciprocal recombination and the dual divisions that segregate first homologues, then sister chromatids)

Single-cell template strand sequencing by Strand-seq enables the characterization of individual homologs

NARCIS (Netherlands)

Sanders, Ashley D; Falconer, Ester; Hills, Mark; Spierings, Diana C J; Lansdorp, Peter M.

The ability to distinguish between genome sequences of homologous chromosomes in single cells is important for studies of copy-neutral genomic rearrangements (such as inversions and translocations), building chromosome-length haplotypes, refining genome assemblies, mapping sister chromatid exchange

"Sister to the tailor"

DEFF Research Database (Denmark)

Simonton, Deborah

2017-01-01

Milliners, and their sisters, mantuamakers, modistes and marchandes de mode, were skilled artisans, businesswomen and tradeswomen. During the eighteenth century, they commandeered the high-class sewing that set fashion and created stars of their most famous, like Rose Bertrand, milliner to Marie...

Building International Relations for Children through Sister Schools.

Science.gov (United States)

Pryor, Carolyn B.

1992-01-01

Inspired by Sister Cities International and the NASSP's school-to-school exchange program, "sister school" pairings have proved to be workable educational programs with long-range impact on participants. Some post-cold war efforts include U.S.-USSR High School Academic Partnerships, Project Harmony, and Center for U.S.-USSR Initiatives.…

Structure of the Pds5-Scc1 Complex and Implications for Cohesin Function

Directory of Open Access Journals (Sweden)

Kyle W. Muir

2016-03-01

Full Text Available Sister chromatid cohesion is a fundamental prerequisite to faithful genome segregation. Cohesion is precisely regulated by accessory factors that modulate the stability with which the cohesin complex embraces chromosomes. One of these factors, Pds5, engages cohesin through Scc1 and is both a facilitator of cohesion, and, conversely also mediates the release of cohesin from chromatin. We present here the crystal structure of a complex between budding yeast Pds5 and Scc1, thus elucidating the molecular basis of Pds5 function. Pds5 forms an elongated HEAT repeat that binds to Scc1 via a conserved surface patch. We demonstrate that the integrity of the Pds5-Scc1 interface is indispensable for the recruitment of Pds5 to cohesin, and that its abrogation results in loss of sister chromatid cohesion and cell viability.

[Two Dutch sisters in analysis with Freud].

Science.gov (United States)

Stroeken, Harry

2010-01-01

The author provides persuasive or at least plausible data for the identity of two patients recorded by Freud in his working season of 1910/11. They were two sisters, living in The Hague/Leiden, who came from a rich banker's family, the van der Lindens. Whereas the treatment does not seem to have led to any decisive improvement for the older of the two, it may have encouraged the younger sister to seek divorce.

New trends and techniques in chromosome aberration analysis

International Nuclear Information System (INIS)

Bender, M.A.

1978-01-01

The following topics are discussed: automation of chromosome analysis; storage of fixed cells from cultures of lymphocytes obtained routinely during periodic employee medical examinations; analysis of banded chromosomes; identification of first division metaphases; sister chromatid exchange; and patterns of aberration induction

Looping in on Ndc80 - how does a protein loop at the kinetochore control chromosome segregation?

DEFF Research Database (Denmark)

Nilsson, Jakob

2012-01-01

Segregation of chromosomes during mitosis requires the interaction of dynamic microtubules with the kinetochore, a large protein structure established on the centromere region of sister chromatids. The core microtubule-binding activity of the kinetochore resides in the KMN network, an outer...

BLM helicase suppresses recombination at G-quadruplex motifs in transcribed genes

NARCIS (Netherlands)

van Wietmarschen, Niek; Merzouk, Sarra; Halsema, Nancy; Spierings, Diana C J; Guryev, Victor; Lansdorp, Peter M

2018-01-01

Bloom syndrome is a cancer predisposition disorder caused by mutations in the BLM helicase gene. Cells from persons with Bloom syndrome exhibit striking genomic instability characterized by excessive sister chromatid exchange events (SCEs). We applied single-cell DNA template strand sequencing

Characterization of the NTPR and BD1 interacting domains of the human PICH-BEND3 complex

DEFF Research Database (Denmark)

Pitchai, Ganesha P; Hickson, Ian D; Streicher, Werner

2016-01-01

Chromosome integrity depends on DNA structure-specific processing complexes that resolve DNA entanglement between sister chromatids. If left unresolved, these entanglements can generate either chromatin bridging or ultrafine DNA bridging in the anaphase of mitosis. These bridge structures are def...

H4K20me0 marks post-replicative chromatin and recruits the TONSL–MMS22L DNA repair complex

DEFF Research Database (Denmark)

Saredi, Giulia; Huang, Hongda; Hammond, Colin M

2016-01-01

After DNA replication, chromosomal processes including DNA repair and transcription take place in the context of sister chromatids. While cell cycle regulation can guide these processes globally, mechanisms to distinguish pre- and post-replicative states locally remain unknown. Here we reveal...

High local carcinogenic activity of 1,3-dimethyl-3-phenyl-1-nitrosourea and its inactivation by intravenous application in rats: comparison of in vivo findings with the in vitro direct and a combined in vivo/in vitro sister chromatid exchange assay in V79-E cells.

Science.gov (United States)

Thust, R; Martin, J; Mendel, J; Schreiber, D

1987-02-01

1,3-Dimethyl-3-phenyl-1-nitrosourea (DMPNU) is a very potent local carcinogen in rats and induces a 100% frequency of forestomach carcinomas when applied i.g. in two different dosages (10 applications of 0.3 or 0.03 mmol/kg body wt, respectively, at 14-day intervals), but it is inactive upon i.v. administration (10 applications of 0.03 mmol/kg body wt at 14-day intervals). By means of the direct sister chromatid exchange (SCE) assay in V79-E cells in the presence of rat blood, serum or plasma, respectively, as well as by a 'host-mediated' SCE assay (in which the agent was given i.v. to rats, and blood taken from the animal was checked for the recovery of genotoxic activity in cell cultures), we tried to elucidate the unexpected lack of carcinogenic activity of i.v. DMPNU. The direct SCE assay revealed a drastic reduction of DMPNU genotoxicity by rat blood, serum or plasma, respectively, which is abolished by the esterase inhibitor diisopropylfluorophosphate. In the 'host-mediated' SCE assay a genotoxic activity of DMPNU was only recoverable after a very high i.v. dose and when the blood added to the cell cultures had been taken from the rat heart within 1 min after DMPNU administration in vivo. 1-Methyl-1-nitrosourea (MNU) and 1-methyl-3-phenyl-1-nitrosourea (MPNU) were used as positive controls in these experiments and also gave a lower response than theoretically expected, but the relative loss of activity with the latter compounds was much lower than with DMPNU. It is assumed that an esterase in rat blood effectively decomposes this trisubstituted nitrosourea. Problems of the novel 'host-mediated' SCE assay are discussed.

The frequency of chromatide aberrations as a function of radiation dose estimated by the number of dicentrics found by the cytogenetic analysis of lymphocytes in subjects affected by the Chernobyl accident

International Nuclear Information System (INIS)

Nugis, V.Yu.; Chirkov, A.A.

1990-01-01

A study was made of the frequency of chromatide aberrations in lymphocyte culture of subjects affected by the Chernobyl accident as a function of dose estimated by the incidence of dicentrics. The average number of chromatide aberrations was nearly the same within the dose range from 0 to 5 Gy exhibiting a tendency towards growth with dose. A high individual variability of the chromatide aberration frequency was observed

Sequence Classification: 890748 [

Lifescience Database Archive (English)

Full Text Available in, involved in maintaining sister chromatid cohesion during meiosis I as well as promoting proper attachmen...t of kinetochores to the spindle during meiosis I and meiosis II; Spo13p || http://www.ncbi.nlm.nih.gov/protein/6321802 ...

Terminalia catappa , an anticlastogenic agent against MMS induced ...

African Journals Online (AJOL)

Subjects: Anticarcinogenic potential of methanolic extract of T. catappa has been tested against the carcinogenicity induced by methyl methanesulfonate in the in vitro and in vivo models. Methods: The parameters for evaluation included chromosomal aberrations (CA), sister chromatid exchanges (SCEs) and replication ...

DNA template strand sequencing of single-cells maps genomic rearrangements at high resolution

NARCIS (Netherlands)

Falconer, Ester; Hills, Mark; Naumann, Ulrike; Poon, Steven S. S.; Chavez, Elizabeth A.; Sanders, Ashley D.; Zhao, Yongjun; Hirst, Martin; Lansdorp, Peter M.

DNA rearrangements such as sister chromatid exchanges (SCEs) are sensitive indicators of genomic stress and instability, but they are typically masked by single-cell sequencing techniques. We developed Strand-seq to independently sequence parental DNA template strands from single cells, making it

Roberts syndrome: clinical and cytogenetic aspects

OpenAIRE

Mann, N P; Fitzsimmons, J; Fitzsimmons, E; Cooke, P

1982-01-01

Roberts syndrome is reported in two sibs of consanguineous parents. Both infants had severe tetraphocomelia, facial clefting, and other serious malformations. In addition they were found to have an unusual cytogenetic abnormality with distortion of the normal sister chromatid relationship in many chromosomes.

Amphitelic orientation of centromeres at metaphase I is an important ...

Indian Academy of Sciences (India)

2014-07-31

Jul 31, 2014 ... sion of sister chromatids at AI without the second meiotic division (Matsuoka and .... level of chromosome pairing with 0.28 bivalents/PMC was seen in 20% of the ... The union of two such unreduced games could result in the ...

Biochemical evidence for deficient DNA repair leading to enhanced G2 chromatid radiosensitivity and susceptibility to cancer

International Nuclear Information System (INIS)

Gantt, R.; Parshad, R.; Price, F.M.; Sanford, K.K.

1986-01-01

Human tumor cells and cells from cancer-prone individuals, compared with those from normal individuals, show a significantly higher incidence of chromatid breaks and gaps seen in metaphase cells immediately after G2 X irradiation. Previous studies with DNA repair-deficient mutants and DNA repair inhibitors strongly indicate that the enhancement results from a G2 deficiency(ies) in DNA repair. We report here biochemical evidence for a DNA repair deficiency that correlates with the cytogenetic studies. In the alkaline elution technique, after a pulse label with radioactive thymidine in the presence of 3-acetylaminobenzamide (a G2-phase blocker) and X irradiation, DNA from tumor or cancer-prone cells elutes more rapidly during the postirradiation period than that from normal cells. These results indicate that the DNA of tumor and cancer-prone cells either repairs more slowly or acquires more breaks than that of normal cells; breaks can accumulate during incomplete or deficient repair processes. The kinetic difference between normal and tumor or cancer-prone cells in DNA strand-break repair reaches a maximum within 2 h, and this maximum corresponds to the kinetic difference in chromatid aberration incidence following X irradiation reported previously. These findings support the concept that cells showing enhanced G2 chromatid radiosensitivity are deficient in DNA repair. The findings could also lead to a biochemical assay for cancer susceptibility

Sister Mary Emil Penet, I.H.M.: Founder of the Sister Formation Conference

Science.gov (United States)

Glisky, Joan

2006-01-01

Mary Emil Penet, I.H.M., (1916-2001) used her talents and charisma to shape the first national organization of American women religious, the Sister Formation Conference (SFC; 1954-1964), facilitating the integrated intellectual, spiritual, psychological, and professional development of vowed women religious. In the decade preceding Vatican II, her…

Certain tryptophan photoproducts are inhibitors of cytochrome P450-dependent mutagenicity

International Nuclear Information System (INIS)

Rannug, U.; Agurell, E.; Cederberg, H.; Rannug, A.

1992-01-01

Two photoproducts, derived from UV-irradiation of the amino acid L-tryptophan and with high Ah (TCDD) receptor binding affinity, were tested for genotoxic and antimutagenic effects. The two indolo[3,2-b]carbazole derivatives, with the molecular weights of 284 and 312, respectively, were tested in Saccharomyces cerevisiae strain D7 for mitotic gene conversion and reverse mutation and in strain RS112 for sister chromatid conversion and gene conversion. No significant (P > 0.05) genotoxic effects were found in strain D7, while strain RS112 showed a small but significant increase in the frequency of sister chromatid conversions. In Chinese hamster ovary (CHO) cells the two compounds induced a statistically significant but less than twofold increase in the frequency of sister chromatid exchanges (SCE). No mutations were detected when the compounds were tested in Salmonella tphimurium strains TA98 and TA100. However, both 284 and 312 acted as antimutagens on strain TA100+S9 in the presence of benzo(a)pyrene. The decrease in mutagenicity by the most potent compound 284 was 20 revertants/nmol. This effect could be explained by an inhibitory effect on the cytochrome P450-dependent ethoxyresorufin O-deethylase (EROD) activity as seen in rat hepatocytes. The two compounds were also tested with hamster cells expressing rat cytochrome P-4501A1. The results support the conclusion that this cytochrome P-450 isozyme is inhibited by the tryptophan photoproducts. Similar results were also seen with two other high affinity Ah receptor ligands the quinazolinocarboline alkaloids rutaecapine and dehydrorutaecarpine. 20 refs., 3 figs., 4 tabs

Thrombopoietin-induced Polyploidization of Bone Marrow Megakaryocytes Is Due to a Unique Regulatory Mechanism in Late Mitosis

Science.gov (United States)

Nagata, Yuka; Muro, Yoshinao; Todokoro, Kazuo

1997-01-01

Megakaryocytes undergo a unique differentiation program, becoming polyploid through repeated cycles of DNA synthesis without concomitant cell division. However, the mechanism underlying this polyploidization remains totally unknown. It has been postulated that polyploidization is due to a skipping of mitosis after each round of DNA replication. We carried out immunohistochemical studies on mouse bone marrow megakaryocytes during thrombopoietin- induced polyploidization and found that during this process megakaryocytes indeed enter mitosis and progress through normal prophase, prometaphase, metaphase, and up to anaphase A, but not to anaphase B, telophase, or cytokinesis. It was clearly observed that multiple spindle poles were formed as the polyploid megakaryocytes entered mitosis; the nuclear membrane broke down during prophase; the sister chromatids were aligned on a multifaced plate, and the centrosomes were symmetrically located on either side of each face of the plate at metaphase; and a set of sister chromatids moved into the multiple centrosomes during anaphase A. We further noted that the pair of spindle poles in anaphase were located in close proximity to each other, probably because of the lack of outward movement of spindle poles during anaphase B. Thus, the reassembling nuclear envelope may enclose all the sister chromatids in a single nucleus at anaphase and then skip telophase and cytokinesis. These observations clearly indicate that polyploidization of megakaryocytes is not simply due to a skipping of mitosis, and that the megakaryocytes must have a unique regulatory mechanism in anaphase, e.g., factors regulating anaphase such as microtubule motor proteins might be involved in this polyploidization process. PMID:9334347

Three Sisters Dam modifications and performance

Energy Technology Data Exchange (ETDEWEB)

Courage, L.J.R. [Monenco AGRA Inc., Calgary, AB (Canada)

1995-12-31

Recent modifications and maintenance carried out at the Three Sisters Dam, in the Alberta Rockies south of the town of Canmore, were described. A detailed account was given of the dam`s geological setting, its abnormally high leakage through the foundation and its sinkhole activity. Results of studies aimed at finding the cause of leakage and sinkhole occurrences were reviewed. Modifications made to the dam since 1951 were detailed, as were modifications to handle probable maximum flood levels. Three approaches for estimating failure probabilities after identification of failure modes were described. The overall conclusion was that based on constant leakage, no settlement in the dam, penstocks, or the powerhouse since construction, the Three Sisters Dam was stable. 1 ref.

Reconstitution of Nucleosomes with Differentially Isotope-labeled Sister Histones.

Science.gov (United States)

Liokatis, Stamatios

2017-03-26

Asymmetrically modified nucleosomes contain the two copies of a histone (sister histones) decorated with distinct sets of Post-translational Modifications (PTMs). They are newly identified species with unknown means of establishment and functional implications. Current analytical methods are inadequate to detect the copy-specific occurrence of PTMs on the nucleosomal sister histones. This protocol presents a biochemical method for the in vitro reconstitution of nucleosomes containing differentially isotope-labeled sister histones. The generated complex can be also asymmetrically modified, after including a premodified histone pool during refolding of histone subcomplexes. These asymmetric nucleosome preparations can be readily reacted with histone-modifying enzymes to study modification cross-talk mechanisms imposed by the asymmetrically pre-incorporated PTM using nuclear magnetic resonance (NMR) spectroscopy. Particularly, the modification reactions in real-time can be mapped independently on the two sister histones by performing different types of NMR correlation experiments, tailored for the respective isotope type. This methodology provides the means to study crosstalk mechanisms that contribute to the formation and propagation of asymmetric PTM patterns on nucleosomal complexes.

GNE Myopathy in Turkish Sisters with a Novel Homozygous Mutation

Science.gov (United States)

Diniz, Gulden; Secil, Yaprak; Ceylaner, Serdar; Tokucoglu, Figen; Türe, Sabiha; Celebisoy, Mehmet; İncesu, Tülay Kurt; Akhan, Galip

2016-01-01

Background. Hereditary inclusion body myopathy is caused by biallelic defects in the GNE gene located on chromosome 9p13. It generally affects adults older than 20 years of age. Methods and Results. In this study, we present two Turkish sisters with progressive myopathy and describe a novel mutation in the GNE gene. Both sisters had slightly higher levels of creatine kinase (CK) and muscle weakness. The older sister presented at 38 years of age with an inability to climb steps, weakness, and a steppage gait. Her younger sister was 36 years old and had similar symptoms. The first symptoms of the disorder were seen when the sisters were 30 and 34 years old, respectively. The muscle biopsy showed primary myopathic features and presence of rimmed vacuoles. DNA analysis demonstrated the presence of previously unknown homozygous mutations [c.2152 G>A (p.A718T)] in the GNE genes. Conclusion. Based on our literature survey, we believe that ours is the first confirmed case of primary GNE myopathy with a novel missense mutation in Turkey. These patients illustrate that the muscle biopsy is still an important method for the differential diagnosis of vacuolar myopathies in that the detection of inclusions is required for the definitive diagnosis. PMID:27298745

Geographic variance of cardiovascular risk factors among community women: the national Sister to Sister campaign.

Science.gov (United States)

Jarvie, Jennifer L; Johnson, Caitlin E; Wang, Yun; Wan, Yun; Aslam, Farhan; Athanasopoulos, Leonidas V; Pollin, Irene; Foody, JoAnne M

2011-01-01

There are substantial variations in cardiovascular disease (CVD) risk and outcomes among women. We sought to determine geographic variation in risk factor prevalence in a contemporary sample of U.S. women. Using 2008-2009 Sister to Sister (STS) free heart screening data from 17 U.S. cities, we compared rates of obesity (body mass index [BMI] ≥30 kg/m(2)), hypertension (HTN ≥140/90 mm Hg), low high-density lipoprotein cholesterol (HDL-C cities had higher rates of hyperglycemia and low HDL-C. In a large, community-based sample of women nationwide, this comprehensive analysis shows remarkable geographic variation in risk factors, which provides opportunities to improve and reduce a woman's CVD risk. Further investigation is required to understand the reasons behind such variation, which will provide insight toward tailoring preventive interventions to narrow gaps in CVD risk reduction in women.

Terminalia arjuna, a herbal remedy against environmental ...

African Journals Online (AJOL)

... 429 due to AFB1 to 141 due to 5th concentration of Terminalia extracts at 32 h of exposure. Conclusion: The ameliorating potential of Terminalia extracts was dose and time dependant. Keywords: Ayurvedic medicine; Carcinogen; Chromosomal aberration; Sister chromatid exchange; Replication index; Terminalia arjuna ...

Phenotypic variability in 49 cases of ESCO2 mutations, including novel missense and codon deletion in the acetyltransferase domain, correlates with ESCO2 expression and establishes the clinical criteria for Roberts syndrome

DEFF Research Database (Denmark)

Vega, H; Trainer, A H; Gordillo, M

2010-01-01

Roberts syndrome (RBS) and SC phocomelia are caused by mutations in ESCO2, which codes for an acetyltransferase involved in the regulation of sister chromatid cohesion. Of 26 mutations described to date, only one missense mutation has been reported and all others are predicted to be truncating...

Phenotypic variability in 49 cases of ESCO2 mutations, including novel missense and codon deletion in the acetyltransferase domain, correlates with ESCO2 expression and establishes the clinical criteria for Roberts syndrome

NARCIS (Netherlands)

Vega, H.; Trainer, A.H.; Gordillo, M.; Crosier, M.; Kayserili, H.; Skovby, F.; Uzielli, M.L.G.; Schnur, R.E.; Manouvrier, S.; Blair, E.; Hurst, J.A.; Forzano, F.; Meins, M.; Simola, K.O.J.; Raas-Rothschild, A; Hennekam, R.C.M.; Jabs, E.W.

2010-01-01

Background Roberts syndrome (RBS) and SC phocomelia are caused by mutations in ESCO2, which codes for an acetyltransferase involved in the regulation of sister chromatid cohesion. Of 26 mutations described to date, only one missense mutation has been reported and all others are predicted to be

DNA Catenation Maintains Structure of Human Metaphase Chromosomes

DEFF Research Database (Denmark)

L. V. Bauer, David; Marie, Rodolphe; Rasmussen, Kristian Hagsted

2012-01-01

Mitotic chromosome structure is pivotal to cell division but difficult to observe in fine detail using conventional methods. DNA catenation has been implicated in both sister chromatid cohesion and chromosome condensation, but has never been observed directly. We have used a lab-on-a-chip microfl...

Assessment of drug induced genotoxicity in gastric cancer patients ...

African Journals Online (AJOL)

Cytogenetic studies were carried out in peripheral blood lymphocytes of study population by adopting standard cytogenetic protocols such as (a) chromosomal aberrations (CA) and (b) sister chromatid exchanges (SCE). Student t- test was adopted to analyze the statistical significance. An increased pattern in the frequency ...

Distinct roles of FANCO/RAD51C in DNA damage signaling and repair: implications for fanconi anemia and breast cancer susceptibility

International Nuclear Information System (INIS)

Nagaraju, G.; Somyajit, K.; Subramanya, S.

2012-01-01

Unrepaired or misrepaired chromosomal double-strand breaks (DSBs) can cause gross chromosomal rearrangements which eventually can lead to tumorigenesis through inactivation of tumor suppressor genes or activation of oncogenes. There are two major mechanisms of DSB repair: non-homologous end joining (NHEJ) and homologous recombination (HR). DSBs that are generated during S and G2 phase of the cell are preferentially repaired by sister chromatid recombination (SCR), an HR pathway that utilizes neighboring sister chromatid as a template. Since the copied information is accurate, SCR is potentially an error-free pathway. HR also plays a critical role in the repair of daughter strand gaps (DSGs) that arise as a result of replication fork stalling and facilitates replication fork recovery. Furthermore, in collaboration with nucleotide excision repair and translesion synthesis, HR is involved in the repair of DNA interstrand cross-links (ICLs). Thus, HR is important for the maintenance of genome integrity and its dysfunction can lead to various genetic disorders and cancer

Mutations in genes encoding condensin complex proteins cause microcephaly through decatenation failure at mitosis.

Science.gov (United States)

Martin, Carol-Anne; Murray, Jennie E; Carroll, Paula; Leitch, Andrea; Mackenzie, Karen J; Halachev, Mihail; Fetit, Ahmed E; Keith, Charlotte; Bicknell, Louise S; Fluteau, Adeline; Gautier, Philippe; Hall, Emma A; Joss, Shelagh; Soares, Gabriela; Silva, João; Bober, Michael B; Duker, Angela; Wise, Carol A; Quigley, Alan J; Phadke, Shubha R; Wood, Andrew J; Vagnarelli, Paola; Jackson, Andrew P

2016-10-01

Compaction of chromosomes is essential for accurate segregation of the genome during mitosis. In vertebrates, two condensin complexes ensure timely chromosome condensation, sister chromatid disentanglement, and maintenance of mitotic chromosome structure. Here, we report that biallelic mutations in NCAPD2, NCAPH, or NCAPD3, encoding subunits of these complexes, cause microcephaly. In addition, hypomorphic Ncaph2 mice have significantly reduced brain size, with frequent anaphase chromatin bridge formation observed in apical neural progenitors during neurogenesis. Such DNA bridges also arise in condensin-deficient patient cells, where they are the consequence of failed sister chromatid disentanglement during chromosome compaction. This results in chromosome segregation errors, leading to micronucleus formation and increased aneuploidy in daughter cells. These findings establish "condensinopathies" as microcephalic disorders, with decatenation failure as an additional disease mechanism for microcephaly, implicating mitotic chromosome condensation as a key process ensuring mammalian cerebral cortex size. © 2016 Martin et al.; Published by Cold Spring Harbor Laboratory Press.

Adaptive response induced by low concentrations of MMC in human peripheral lymphocytes

International Nuclear Information System (INIS)

Sun Shuqing; Wang Bin; Jiang Jie

1998-01-01

Samples of cultured human peripheral lymphocytes were pre-treated with mitomycin C (MMC) in concentrations of 0.01∼0.1 μg/mL at 34 h of incubation and then exposed to 1.5 Gy of X-rays. Chromosome aberrations, sister chromatid exchanges and micronuclei for these lymphocytes were observed. The results show that the chromosome aberration rates for lymphocytes pre-treated with MMC in concentrations of 0.5 and 0.075 μg/mL and the frequencies of sister chromatid exchanges for lymphocytes pre-treated with MMC in concentrations of 0.01 μg/mL were significantly lower than their own expected values but the rates of micronuclei for lymphocytes pre-treated with MMC in concentrations of 0.05, 0.075 and 0.1 μg/mL were significantly higher than the expected values. Such results suggest that for studying the cross resistance of lymphocytes to chemicals and ionizing radiation, inconsistent conclusions may be obtained if different endpoints are based on

Biomonitoring of genotoxic exposure among stainless steel welders

DEFF Research Database (Denmark)

Knudsen, Lisbeth E.; Boisen, T; Christensen, J M

1992-01-01

A biosurvey in the Danish metal industry measured the genotoxic exposure from stainless steel welding. The study comprised measurements of chromosomal aberrations (CA), sister-chromatid exchanges (SCE), unscheduled DNA synthesis (UDS) in peripheral lymphocytes and serum immunoglobulin G. Environm......A biosurvey in the Danish metal industry measured the genotoxic exposure from stainless steel welding. The study comprised measurements of chromosomal aberrations (CA), sister-chromatid exchanges (SCE), unscheduled DNA synthesis (UDS) in peripheral lymphocytes and serum immunoglobulin G....... A higher frequency of chromosomal aberrations, classified as translocations, double minutes, exchanges and rings, was observed in stainless steel welders than in non-welders. SCE was lower in welders working with both MMA and TIG welding than in reference persons. N-Acetoxy-N-acetylaminofluorene (NA...... lymphocytes in exposed persons compared with non-exposed are suggested. MMA welding gave the highest exposure to chromium, an increased number of chromosomal aberrations and a decrease in SCE when compared with TIG welding. Consequently improvements in the occupational practice of stainless steel welding...

Dam safety at Seven Sisters Generating Station

International Nuclear Information System (INIS)

Carson, R. W.; Gupta, R. C.

1996-01-01

A safety surveillance program for all hydraulic structures in Manitoba was first implemented in 1979, and updated in 1988. This contribution describes the current status of the program, and the nature of the issues that the program was designed to address. The Seven Sisters Station's dam on the Winnipeg River, about 90 km northeast of the City of Winnipeg, was used as an example. Extensive reviews of flood risks and downstream inundation potential at Seven Sisters' revealed a number of deficiencies; these findings will be incorporated into a corporate plan of overall remediation. Updating the program will also include efforts to ensure adherence to national dam safety guidelines. 5 figs

Geologic map of Three Sisters volcanic cluster, Cascade Range, Oregon

Science.gov (United States)

Hildreth, Wes; Fierstein, Judy; Calvert, Andrew T.

2012-01-01

The cluster of glaciated stratovolcanoes called the Three Sisters—South Sister, Middle Sister, and North Sister—forms a spectacular 20-km-long reach along the crest of the Cascade Range in Oregon. The three eponymous stratocones, though contiguous and conventionally lumped sororally, could hardly display less family resemblance. North Sister (10,085 ft), a monotonously mafic edifice at least as old as 120 ka, is a glacially ravaged stratocone that consists of hundreds of thin rubbly lava flows and intercalated falls that dip radially and steeply; remnants of two thick lava flows cap its summit. Middle Sister (10,047 ft), an andesite-basalt-dacite cone built between 48 and 14 ka, is capped by a thick stack of radially dipping, dark-gray, thin mafic lava flows; asymmetrically glaciated, its nearly intact west flank contrasts sharply with its steep east face. Snow and ice-filled South Sister is a bimodal rhyolitic-intermediate edifice that was constructed between 50 ka and 2 ka; its crater (rim at 10,358 ft) was created between 30 and 22 ka, during the most recent of several explosive summit eruptions; the thin oxidized agglutinate that mantles its current crater rim protects a 150-m-thick pyroclastic sequence that helped fill a much larger crater. For each of the three, the eruptive volume is likely to have been in the range of 15 to 25 km³, but such estimates are fairly uncertain, owing to glacial erosion. The map area consists exclusively of Quaternary volcanic rocks and derivative surficial deposits. Although most of the area has been modified by glaciation, the volcanoes are young enough that the landforms remain largely constructional. Furthermore, twelve of the 145 eruptive units on the map are postglacial, younger than the deglaciation that was underway by about 17 ka. The most recent eruptions were of rhyolite near South Sister, about 2,000 years ago, and of mafic magma near McKenzie Pass, about 1,500 years ago. As observed by trailblazing volcanologist

Sultana et al., Afr J Tradit Complement Altern Med. (2016) 13(2):185 ...

African Journals Online (AJOL)

Shahid Mahboob

broken anaphase bridges formed due to chromosome rearrangements such as dicentric chromatids, intermingled ring chromosomes or union of sister chromatids‖ (Albertini et al., 2000; Bouraoui et al., 2014). The objective of this study was to assess the indirect effect of radiation in the hospital workers of radiotherapy from ...

40 CFR 79.65 - In vivo sister chromatid exchange assay.

Science.gov (United States)

2010-07-01

... PROGRAMS (CONTINUED) REGISTRATION OF FUELS AND FUEL ADDITIVES Testing Requirements for Registration § 79.65... appropriate concentration level, a pilot or trial study may be advisable. Initially, one concentration of the...., “Cytogenetic Studies of Mice Exposed to Styrene by Inhalation.”, Mutation Research, 280:35-43, 1992. (7) Wolff...

The SUMO protease SENP1 is required for cohesion maintenance and mitotic arrest following spindle poison treatment

Energy Technology Data Exchange (ETDEWEB)

Era, Saho [Fondazione IFOM, Istituto FIRC di Oncologia Molecolare, IFOM-IEO campus, Via Adamello 16, 20139 Milan (Italy); Radiation Genetics, Graduate School of Medicine, Kyoto University, Yoshida-Konoe, Sakyo-ku, Kyoto 606-8501 (Japan); Abe, Takuya; Arakawa, Hiroshi [Fondazione IFOM, Istituto FIRC di Oncologia Molecolare, IFOM-IEO campus, Via Adamello 16, 20139 Milan (Italy); Kobayashi, Shunsuke [Radiation Genetics, Graduate School of Medicine, Kyoto University, Yoshida-Konoe, Sakyo-ku, Kyoto 606-8501 (Japan); Szakal, Barnabas [Fondazione IFOM, Istituto FIRC di Oncologia Molecolare, IFOM-IEO campus, Via Adamello 16, 20139 Milan (Italy); Yoshikawa, Yusuke; Motegi, Akira; Takeda, Shunichi [Radiation Genetics, Graduate School of Medicine, Kyoto University, Yoshida-Konoe, Sakyo-ku, Kyoto 606-8501 (Japan); Branzei, Dana, E-mail: dana.branzei@ifom.eu [Fondazione IFOM, Istituto FIRC di Oncologia Molecolare, IFOM-IEO campus, Via Adamello 16, 20139 Milan (Italy)

2012-09-28

Highlights: Black-Right-Pointing-Pointer SENP1 knockout chicken DT40 cells are hypersensitive to spindle poisons. Black-Right-Pointing-Pointer Spindle poison treatment of SENP1{sup -/-} cells leads to increased mitotic slippage. Black-Right-Pointing-Pointer Mitotic slippage in SENP1{sup -/-} cells associates with apoptosis and endoreplication. Black-Right-Pointing-Pointer SENP1 counteracts sister chromatid separation during mitotic arrest. Black-Right-Pointing-Pointer Plk1-mediated cohesion down-regulation is involved in colcemid cytotoxicity. -- Abstract: SUMO conjugation is a reversible posttranslational modification that regulates protein function. SENP1 is one of the six SUMO-specific proteases present in vertebrate cells and its altered expression is observed in several carcinomas. To characterize SENP1 role in genome integrity, we generated Senp1 knockout chicken DT40 cells. SENP1{sup -/-} cells show normal proliferation, but are sensitive to spindle poisons. This hypersensitivity correlates with increased sister chromatid separation, mitotic slippage, and apoptosis. To test whether the cohesion defect had a causal relationship with the observed mitotic events, we restored the cohesive status of sister chromatids by introducing the TOP2{alpha}{sup +/-} mutation, which leads to increased catenation, or by inhibiting Plk1 and Aurora B kinases that promote cohesin release from chromosomes during prolonged mitotic arrest. Although TOP2{alpha} is SUMOylated during mitosis, the TOP2{alpha}{sup +/-} mutation had no obvious effect. By contrast, inhibition of Plk1 or Aurora B rescued the hypersensitivity of SENP1{sup -/-} cells to colcemid. In conclusion, we identify SENP1 as a novel factor required for mitotic arrest and cohesion maintenance during prolonged mitotic arrest induced by spindle poisons.

Abnormally banded chromosomal regions in doxorubicin-resistant B16-BL6 murine melanoma cells.

Science.gov (United States)

Slovak, M L; Hoeltge, G A; Ganapathi, R

1986-08-01

B16-BL6 murine melanoma cells were selected for cytogenetic evaluation during the stepwise development of increasing resistance in vitro to the antitumor antibiotic, doxorubicin (DOX). Karyotypic studies demonstrated extensive heteroploidy with both numerical and structural abnormalities which were not present in the parental DOX-sensitive B16-BL6 cells. Trypsin-Giemsa banding revealed the presence of several marker chromosomes containing abnormally banding regions (ABRs) in the 44-fold B16-BL6 DOX-resistant subline. These ABRs appeared to be more homogeneously staining at the higher DOX concentrations. Length measurements (ABR index) in seven banded metaphases indicated a direct correlation with increasing DOX concentration. When the DOX-resistant cells were grown in drug-free medium for 1 yr, the drug-resistant phenotype gradually declined in parallel with the level of resistance and the ABR index. DOX-induced cytogenetic damage examined by sister chromatid exchange methodology in parental B16-BL6 cells indicated a linear sister chromatid exchange:DOX dose-response relationship. However, after continuous treatment of parental B16-BL6 cells with DOX (0.01 microgram/ml) for 30 days, sister chromatid exchange scores were found to return to base-line values. The B16-BL6 resistant cells demonstrated a cross-resistant phenotype with N-trifluoroacetyladriamycin-14-valerate, actinomycin D, and the Vinca alkaloids but not with 1-beta-D-arabinofuranosylcytosine. The results suggest that ABR-containing chromosomes in DOX-resistant sublines may represent cytogenetic alterations of specific amplified genes involved in the expression of DOX resistance. Further studies are required to identify and define the possible gene products and to correlate their relationship to the cytotoxic action of doxorubicin.

20 CFR 725.225 - Determination of dependency; parent, brother, or sister.

Science.gov (United States)

2010-04-01

... 20 Employees' Benefits 3 2010-04-01 2010-04-01 false Determination of dependency; parent, brother, or sister. 725.225 Section 725.225 Employees' Benefits EMPLOYMENT STANDARDS ADMINISTRATION... Benefits) § 725.225 Determination of dependency; parent, brother, or sister. An individual who is the miner...

Andrographia paniculata a Miracle Herbs for cancer treatment: In ...

African Journals Online (AJOL)

It is extensively used as home remedy for various diseases in Indian traditional system ... Aim: In our present work, extracts of these ayurvedic plants were tested for their ... and anticarcinogenic properties against Aflatoxin B1 induced toxicity. ... (CA), sister chromatid exchanges (SCEs) and cell growth kinetics (RI) both in the ...

Chromosome variant 1qh− and its influence on the 3D organization ...

Indian Academy of Sciences (India)

2014-04-21

Apr 21, 2014 ... protein for sister chromatid cohesion during S phase, is char- ... tansky in 1860, the mechanisms responsible for the disease ... the Ethics Review Committee on Human Research of the ... somes 1 with equal size of heterochromatic segments in a healthy control subject (A1) .... But, literature reports about the.

Kinetics of chromatid aberrations in G2 ataxia-telangiectasia cells exposed to X-rays and ara A

International Nuclear Information System (INIS)

Mozdarani, Hossein; Bryant, P.E.

1989-01-01

The cytogenetic effects of X-rays alone or in combination with 9-β-D-arabinofuranosyladenine (ara A) were studied in an immortalized fibroblastic line of ataxia-telangiectasia (A-T) cells. It is postulated that the kinetics of disappearance (rejoining) of chromatid deletions with postirradiation incubation time reflects the underlying repair of dsb, and is inhibited by ara A. The rejoining kinetics for deletions in A-T was similar to that found in a previous study of normal human fibroblasts (Mozdarani and Bryant 1987). The number of deletions in X-irradiated A-T cells at 1.5 h before fixation was found to be higher by a factor of approximately 2 than that found previously in normals, indicating that in A-T a higher rate of conversion of dsb into chromatid deletions occurs. The frequency of exchanges induced in G2 A-T cells was similarly enhanced but, unlike the situation in normal cells, ara A was found to cause only a slight increase in this frequency. (author)

[Florence Nightingale and charity sisters: revisiting the history].

Science.gov (United States)

Padilha, Maria Itayra Coelho de Souza; Mancia, Joel Rolim

2005-01-01

This study presents an historical analysis on the links between the nursing practice and the influence received from various religious orders/associations along the times, especially from Saint Vincent Paul's charity sisters. The professional nursing which was pioneered by Florence Nightingale in the XlXth century, was directly influenced by the teachings of love and fraternity. In addition, other contributions from the religious orders/associations were the concepts of altruism, valorization of an adequate environment for the care of patients, and the division of work in nursing. The study shows the influence of Charity Sisters on Florence Nightingale.

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.

Clouston′s Disease in Three Sisters

Directory of Open Access Journals (Sweden)

Jayakar Thomas

1988-01-01

Full Text Available In a family of four children, all females, three sisters presented with Clouston′s disease or hidrotic ectodermal dysplasia. The case is reported for the rarity of presentation in a single generation with no history of other family members affected.

Friel and his "sisters"

Directory of Open Access Journals (Sweden)

Nicholas Grene

2010-11-01

Full Text Available This essay, occasioned by a revival of Brian Friel's version of Chekhov's Three Sisters at the Abbey Theatre in 2008, considers the circumstances surrounding its first production by the Field Day Theatre Company in 1981, and the motivation behind the decision to translate Chekhov's text into a specifically Irish dialect of English. It also analyses how Friel's plays since that date, notably the award-winning Dancing at Lughnasa (1990, have changed our perspective on the play.

4. National Congress on Genetics. Memoirs

International Nuclear Information System (INIS)

1993-01-01

According to INIS coverage were analyzed four free works on Life and Environmental Sciences presented during the Congress which are treating over the effects of external irradiation on animals. Between the main aspects are the sister chromatid exchange, spermatogonia, somatic cells, genotoxicity, DNA, chlorophyll, gamma radiation, bone marrow cells and radiation injuries

Andrographia paniculata a Miracle Herbs for cancer treatment: In vivo and in vitro studies against Aflatoxin B1 Toxicity

Directory of Open Access Journals (Sweden)

Md. Sultan Ahmad

2014-04-01

Conclusion: In conclusion A. paniculata extracts significantly reduced the number of aberrant cells and frequencies of aberration per cell at each concentration and duration of exposure in vivo; similarly it reduced chromosomal aberrations and sister chromatid exchanges and replication index was enhanced in vitro that was statistically significant at <0.05 level.

Mammalian ChlR1 has a role in heterochromatin organization

International Nuclear Information System (INIS)

Inoue, Akira; Hyle, Judith; Lechner, Mark S.; Lahti, Jill M.

2011-01-01

The ChlR1 DNA helicase, encoded by DDX11 gene, which is responsible for Warsaw breakage syndrome (WABS), has a role in sister-chromatid cohesion. In this study, we show that human ChlR1 deficient cells exhibit abnormal heterochromatin organization. While constitutive heterochromatin is discretely localized at perinuclear and perinucleolar regions in control HeLa cells, ChlR1-depleted cells showed dispersed localization of constitutive heterochromatin accompanied by disrupted centromere clustering. Cells isolated from Ddx11 -/- embryos also exhibited diffuse localization of centromeres and heterochromatin foci. Similar abnormalities were found in HeLa cells depleted of combinations of HP1α and HP1β. Immunofluorescence and chromatin immunoprecipitation showed a decreased level of HP1α at pericentric regions in ChlR1-depleted cells. Trimethyl-histone H3 at lysine 9 (H3K9-me3) was also modestly decreased at pericentric sequences. The abnormality in pericentric heterochromatin was further supported by decreased DNA methylation within major satellite repeats of Ddx11 -/- embryos. Furthermore, micrococcal nuclease (MNase) assay revealed a decreased chromatin density at the telomeres. These data suggest that in addition to a role in sister-chromatid cohesion, ChlR1 is also involved in the proper formation of heterochromatin, which in turn contributes to global nuclear organization and pleiotropic effects. -- Highlights: → New role for ChlR1 (DDX11), a cohesinopathy gene, in heterochromatin organization. → Loss of ChlR1 altered heterochromatin localization and centromere clustering. → Reduced ChlR1 levels also reduced HP1α and H3K9-me3 binding to pericentric DNA. → Decreased DNA methylation was found in pericentric repeats of Ddx11 -/- embryos. → These findings will aid in understanding the pathogenesis of Warsaw breakage syndrome.

Chl1 DNA helicase regulates Scc2 deposition specifically during DNA-replication in Saccharomyces cerevisiae.

Directory of Open Access Journals (Sweden)

Soumya Rudra

Full Text Available The conserved family of cohesin proteins that mediate sister chromatid cohesion requires Scc2, Scc4 for chromatin-association and Eco1/Ctf7 for conversion to a tethering competent state. A popular model, based on the notion that cohesins form huge ring-like structures, is that Scc2, Scc4 function is essential only during G1 such that sister chromatid cohesion results simply from DNA replisome passage through pre-loaded cohesin rings. In such a scenario, cohesin deposition during G1 is temporally uncoupled from Eco1-dependent establishment reactions that occur during S-phase. Chl1 DNA helicase (homolog of human ChlR1/DDX11 and BACH1/BRIP1/FANCJ helicases implicated in Fanconi anemia, breast and ovarian cancer and Warsaw Breakage Syndrome plays a critical role in sister chromatid cohesion, however, the mechanism through which Chl1 promotes cohesion remains poorly understood. Here, we report that Chl1 promotes Scc2 loading unto DNA such that both Scc2 and cohesin enrichment to chromatin are defective in chl1 mutant cells. The results further show that both Chl1 expression and chromatin-recruitment are tightly regulated through the cell cycle, peaking during S-phase. Importantly, kinetic ChIP studies reveals that Chl1 is required for Scc2 chromatin-association specifically during S-phase, but not during G1. Despite normal chromatin enrichment of both Scc2 and cohesin during G1, chl1 mutant cells exhibit severe chromosome segregation and cohesion defects--revealing that G1-loaded cohesins is insufficient to promote cohesion. Based on these findings, we propose a new model wherein S-phase cohesin loading occurs during DNA replication and in concert with both cohesion establishment and chromatin assembly reactions--challenging the notion that DNA replication fork navigates through or around pre-loaded cohesin rings.

Mek1/Mre4 is a master regulator of meiotic recombination in budding yeast

Directory of Open Access Journals (Sweden)

Nancy M. Hollingsworth

2016-02-01

Full Text Available Sexually reproducing organisms create gametes with half the somatic cell chromosome number so that fusion of gametes at fertilization does not change the ploidy of the cell. This reduction in chromosome number occurs by the specialized cell division of meiosis in which two rounds of chromosome segregation follow a single round of chromosome duplication. Meiotic crossovers formed between the non-sister chromatids of homologous chromosomes, combined with sister chromatid cohesion, physically connect homologs, thereby allowing proper segregation at the first meiotic division. Meiotic recombination is initiated by programmed double strand breaks (DSBs whose repair is highly regulated such that (1 there is a bias for recombination with homologs rather than sister chromatids, (2 crossovers are distributed throughout the genome by a process called interference, (3 crossover homeostasis regulates the balance between crossover and non-crossover repair to maintain a critical number of crossovers and (4 each pair of homologs receives at least one crossover. It was previously known that the imposition of interhomolog bias in budding yeast requires meiosis-specific modifications to the DNA damage response and the local activation of the meiosis-specific Mek1/Mre4 (hereafter Mek1 kinase at DSBs. However, because inactivation of Mek1 results in intersister, rather than interhomolog DSB repair, whether Mek1 had a role in interhomolog pathway choice was unknown. A recent study by Chen et al. (2015 reveals that Mek1 indirectly regulates the crossover/non-crossover decision between homologs as well as genetic interference. It does this by enabling phosphorylation of Zip1, the meiosis-specific transverse filament protein of the synaptonemal complex (SC, by the conserved cell cycle kinase, Cdc7-Dbf4 (DDK. These results suggest that Mek1 is a “master regulator” of meiotic recombination in budding yeast.

Cell-stage-specific enhancement by caffeine of the frequency of chromatid aberrations induced by X-rays in neutral ganglia of Drosophila melanogaster

International Nuclear Information System (INIS)

De Marco, A.; Polani, S.

1981-01-01

Caffeine (10 -2 M) induced a high level of chromatid aberrations in neural ganglia of third-instar larvae of Drosophila melanogaster only when it was added to cells in late G 2 and mitotic prophase. No aberrations were observed after treatment in late S-middle G 2 or C-mitosis. We observed that, in these stages, caffeine strongly increased X-ray-induced damage (500 R). This potentiation was quantitatively similar. But it involved all types of aberration after treatment in C-mitosis, and essentially isochromatid deletions and chromatid exhanges after treatment in S-G 2 . Some hypotheses are put forth to explain the possible mechanism of action of caffeine in the potentiation of X-ray-induced damage. (orig.)

Sisters Hope - Protected by the Fiction

DEFF Research Database (Denmark)

Lawaetz, Anna; Hallberg, Gry Worre

2011-01-01

In this article we will introduce the fictional and art-pedagogical universe of Sisters Hope and describe how it in different ways transcends into contexts beyond the art world and thus functions as a tool to democratize the aesthetic dimension and mode of being within high schools, academia...

Interdependence of the rad50 hook and globular domain functions.

Science.gov (United States)

Hohl, Marcel; Kochańczyk, Tomasz; Tous, Cristina; Aguilera, Andrés; Krężel, Artur; Petrini, John H J

2015-02-05

Rad50 contains a conserved Zn(2+) coordination domain (the Rad50 hook) that functions as a homodimerization interface. Hook ablation phenocopies Rad50 deficiency in all respects. Here, we focused on rad50 mutations flanking the Zn(2+)-coordinating hook cysteines. These mutants impaired hook-mediated dimerization, but recombination between sister chromatids was largely unaffected. This may reflect that cohesin-mediated sister chromatid interactions are sufficient for double-strand break repair. However, Mre11 complex functions specified by the globular domain, including Tel1 (ATM) activation, nonhomologous end joining, and DNA double-strand break end resection were affected, suggesting that dimerization exerts a broad influence on Mre11 complex function. These phenotypes were suppressed by mutations within the coiled-coil and globular ATPase domains, suggesting a model in which conformational changes in the hook and globular domains are transmitted via the extended coils of Rad50. We propose that transmission of spatial information in this manner underlies the regulation of Mre11 complex functions. Copyright © 2015 Elsevier Inc. All rights reserved.

Bub1 autophosphorylation feeds back to regulate kinetochore docking and promote localized substrate phosphorylation.

Science.gov (United States)

Asghar, Adeel; Lajeunesse, Audrey; Dulla, Kalyan; Combes, Guillaume; Thebault, Philippe; Nigg, Erich A; Elowe, Sabine

2015-09-24

During mitosis, Bub1 kinase phosphorylates histone H2A-T120 to promote centromere sister chromatid cohesion through recruitment of shugoshin (Sgo) proteins. The regulation and dynamics of H2A-T120 phosphorylation are poorly understood. Using quantitative phosphoproteomics we show that Bub1 is autophosphorylated at numerous sites. We confirm mitosis-specific autophosphorylation of a several residues and show that Bub1 activation is primed in interphase but fully achieved only in mitosis. Mutation of a single autophosphorylation site T589 alters kinetochore turnover of Bub1 and results in uniform H2A-T120 phosphorylation and Sgo recruitment along chromosome arms. Consequently, improper sister chromatid resolution and chromosome segregation errors are observed. Kinetochore tethering of Bub1-T589A refocuses H2A-T120 phosphorylation and Sgo1 to centromeres. Recruitment of the Bub1-Bub3-BubR1 axis to kinetochores has recently been extensively studied. Our data provide novel insight into the regulation and kinetochore residency of Bub1 and indicate that its localization is dynamic and tightly controlled through feedback autophosphorylation.

Loss of heterozygosity in yeast can occur by ultraviolet irradiation during the S phase of the cell cycle

Energy Technology Data Exchange (ETDEWEB)

Daigaku, Yasukazu [Graduate School of Life Sciences, Tohoku University, Sendai 980-8577 (Japan); Mashiko, Satsuki [Graduate School of Life Sciences, Tohoku University, Sendai 980-8577 (Japan); Mishiba, Keiichiro [Iwate Biotechnology Research Center, Kitakami, Iwate 024-0003 (Japan); Yamamura, Saburo [Iwate Biotechnology Research Center, Kitakami, Iwate 024-0003 (Japan); Ui, Ayako [Graduate School of Pharmaceutical Sciences, Tohoku University, Sendai 980-8578 (Japan); Enomoto, Takemi [Graduate School of Pharmaceutical Sciences, Tohoku University, Sendai 980-8578 (Japan); Yamamoto, Kazuo [Graduate School of Life Sciences, Tohoku University, Sendai 980-8577 (Japan)]. E-mail: yamamot@mail.tains.tohoku.ac.jp

2006-08-30

A CAN1/can1{delta} heterozygous allele that determines loss of heterozygosity (LOH) was used to study recombination in Saccharomyces cerevisiae cells exposed to ultraviolet (UV) light at different points in the cell cycle. With this allele, recombination events can be detected as canavanine-resistant mutations after exposure of cells to UV radiation, since a significant fraction of LOH events appear to arise from recombination between homologous chromosomes. The radiation caused a higher level of LOH in cells that were in the S phase of the cell cycle relative to either cells at other points in the cell cycle or unsynchronized cells. In contrast, the inactivation of nucleotide excision repair abolished the cell cycle-specific induction by UV of LOH. We hypothesize that DNA lesions, if not repaired, were converted into double-strand breaks during stalled replication and these breaks could be repaired through recombination using a non-sister chromatid and probably also the sister chromatid. We argue that LOH may be an outcome used by yeast cells to recover from stalled replication at a lesion.

Loss of heterozygosity in yeast can occur by ultraviolet irradiation during the S phase of the cell cycle.

Science.gov (United States)

Daigaku, Yasukazu; Mashiko, Satsuki; Mishiba, Keiichiro; Yamamura, Saburo; Ui, Ayako; Enomoto, Takemi; Yamamoto, Kazuo

2006-08-30

A CAN1/can1Delta heterozygous allele that determines loss of heterozygosity (LOH) was used to study recombination in Saccharomyces cerevisiae cells exposed to ultraviolet (UV) light at different points in the cell cycle. With this allele, recombination events can be detected as canavanine-resistant mutations after exposure of cells to UV radiation, since a significant fraction of LOH events appear to arise from recombination between homologous chromosomes. The radiation caused a higher level of LOH in cells that were in the S phase of the cell cycle relative to either cells at other points in the cell cycle or unsynchronized cells. In contrast, the inactivation of nucleotide excision repair abolished the cell cycle-specific induction by UV of LOH. We hypothesize that DNA lesions, if not repaired, were converted into double-strand breaks during stalled replication and these breaks could be repaired through recombination using a non-sister chromatid and probably also the sister chromatid. We argue that LOH may be an outcome used by yeast cells to recover from stalled replication at a lesion.

Further environmental factors causing variations of SCE frequencies

International Nuclear Information System (INIS)

Tuschl, H.; Kovac, R.; Wottawa, A.

1986-12-01

The frequencies of spontaneously occurring sister chromatid exchanges (=SCE) were determined in control persons, persons exposed to very low doses of ionizing radiation and employees of a rubber factory. Besides smoking habits and the usage of oral contraceptives, background ultraviolet (=UV) radiation seems to exert the most pronounced effect on SCE levels in control persons. (Author)

Cancer predictive value of cytogenetic markers used in occupational health surveillance programs

DEFF Research Database (Denmark)

Hagmar, L; Bonassi, S; Strömberg, U

1998-01-01

It has not previously been clear whether cytogenetic biomarkers in healthy subjects will predict cancer. Earlier analyses of a Nordic and an Italian cohort indicated predictivity for chromosomal aberrations (CAS) but not for sister chromatid exchanges (SCES). A pooled analysis of the updated......, occupational exposures and smoking, will be assessed in a case-referent study within the study base....

Essential roles of BCCIP in mouse embryonic development and structural stability of chromosomes.

Directory of Open Access Journals (Sweden)

Huimei Lu

2011-09-01

Full Text Available BCCIP is a BRCA2- and CDKN1A(p21-interacting protein that has been implicated in the maintenance of genomic integrity. To understand the in vivo functions of BCCIP, we generated a conditional BCCIP knockdown transgenic mouse model using Cre-LoxP mediated RNA interference. The BCCIP knockdown embryos displayed impaired cellular proliferation and apoptosis at day E7.5. Consistent with these results, the in vitro proliferation of blastocysts and mouse embryonic fibroblasts (MEFs of BCCIP knockdown mice were impaired considerably. The BCCIP deficient mouse embryos die before E11.5 day. Deletion of the p53 gene could not rescue the embryonic lethality due to BCCIP deficiency, but partially rescues the growth delay of mouse embryonic fibroblasts in vitro. To further understand the cause of development and proliferation defects in BCCIP-deficient mice, MEFs were subjected to chromosome stability analysis. The BCCIP-deficient MEFs displayed significant spontaneous chromosome structural alterations associated with replication stress, including a 3.5-fold induction of chromatid breaks. Remarkably, the BCCIP-deficient MEFs had a ∼20-fold increase in sister chromatid union (SCU, yet the induction of sister chromatid exchanges (SCE was modestly at 1.5 fold. SCU is a unique type of chromatid aberration that may give rise to chromatin bridges between daughter nuclei in anaphase. In addition, the BCCIP-deficient MEFs have reduced repair of irradiation-induced DNA damage and reductions of Rad51 protein and nuclear foci. Our data suggest a unique function of BCCIP, not only in repair of DNA damage, but also in resolving stalled replication forks and prevention of replication stress. In addition, BCCIP deficiency causes excessive spontaneous chromatin bridges via the formation of SCU, which can subsequently impair chromosome segregations in mitosis and cell division.

Fanconi anaemia proteins are associated with sister chromatid bridging in mitosis

DEFF Research Database (Denmark)

Ying, Songmin; Hickson, Ian D

2011-01-01

exist in man where a breakdown in genome maintenance is associated with cancer predisposition. Amongst these are Bloom's syndrome (BS) and Fanconi anaemia (FA). The BS and FA gene products co-operate in the repair of damaged DNA. In this review, we focus on interactions between BS and FA proteins...

Homologous recombination, sister chromatid cohesion, and chromosome condensation in mammalian meiosis

NARCIS (Netherlands)

Eijpe, M.

2002-01-01

In the life cycle of sexually reproducing eukaryotes, haploid and diploid generations of cells alternate. Two types of cell division occur in such a life cycle: mitosis and meiosis. They are compared in chapter 1 . Haploid and

Food Yields and Nutrient Analyses of the Three Sisters: A Haudenosaunee Cropping System

Directory of Open Access Journals (Sweden)

Jane Mt.Pleasant

2016-11-01

Full Text Available Scholars have studied The Three Sisters, a traditional cropping system of the Haudenosaunee (Iroquois, from multiple perspectives. However, there is no research examining food yields, defined as the quantities of energy and protein produced per unit land area, from the cropping system within Iroquoia. This article compares food yields and other nutrient contributions from the Three Sisters, comprised of interplanted maize, bean and pumpkin, with monocultures of these same crops. The Three Sisters yields more energy (12.25 x 106 kcal/ha and more protein (349 kg/ha than any of the crop monocultures or mixtures of monocultures planted to the same area. The Three Sisters supplies 13.42 people/ha/yr. with energy and 15.86 people/ha/yr. with protein. Nutrient contents of the crops are further enhanced by nixtamalization, a traditional processing technique where maize is cooked in a high alkaline solution. This process increases calcium, protein quality, and niacin in maize.

[Analysis of genomic copy number variations in two sisters with primary amenorrhea and hyperandrogenism].

Science.gov (United States)

Zhang, Yanliang; Xu, Qiuyue; Cai, Xuemei; Li, Yixun; Song, Guibo; Wang, Juan; Zhang, Rongchen; Dai, Yong; Duan, Yong

2015-12-01

To analyze genomic copy number variations (CNVs) in two sisters with primary amenorrhea and hyperandrogenism. G-banding was performed for karyotype analysis. The whole genome of the two sisters were scanned and analyzed by array-based comparative genomic hybridization (array-CGH). The results were confirmed with real-time quantitative PCR (RT-qPCR). No abnormality was found by conventional G-banded chromosome analysis. Array-CGH has identified 11 identical CNVs from the sisters which, however, overlapped with CNVs reported by the Database of Genomic Variants (http://projects.tcag.ca/variation/). Therefore, they are likely to be benign. In addition, a -8.44 Mb 9p11.1-p13.1 duplication (38,561,587-47,002,387 bp, hg18) and a -80.9 kb 4q13.2 deletion (70,183,990-70,264,889 bp, hg18) were also detected in the elder and younger sister, respectively. The relationship between such CNVs and primary amenorrhea and hyperandrogenism was however uncertain. RT-qPCR results were in accordance with array-CGH. Two CNVs were detected in two sisters by array-CGH, for which further studies are needed to clarify their correlation with primary amenorrhea and hyperandrogenism.

Gay men with AIDS and their families of origin: an analysis of social support.

Science.gov (United States)

Kadushin, G

1996-05-01

This article reviews the literature on the relationships between gay men with AIDS and their families of origin to determine why the family is not a principal source of social support. Several reasons explain the absence of the family from the support network, including the family's lack of acceptance of homosexuality and the relationship with a male partner; the stigma associated with AIDS; the inability of family members to communicate openly about homosexuality and AIDS; the lack of competence among family members in dealing with HIV issues; and overprotective, infantilizing behavior by parents. A sibling, most often a sister, is the family member to whom the gay man with AIDS feels closest and from whom he is most likely to seek support. Implications for practice and research are discussed.

Three Sisters Dam: Investigations and monitoring

International Nuclear Information System (INIS)

Slopek, R.J.; Courage, L.J.R.; Keys, R.A.

1990-01-01

The geotechnical investigations, monitoring and interpretation of data associated with the evaluation of the Three Sisters Dam, which has been suffering from excessive seepage and is in need of enhancement, are outlined. The Three Sisters Dam is located in the continental ranges of the Rocky Mountains in Alberta, impounding the Spray Reservoir, and is founded on 60 m of interbedded sand, gravel, silt and clay layers. The computer code PC-SEEP was used to evaluate seepage. Details are provided of drilling, ground-penetrating radar surveys, seismic surveys, penstock inspection, sinkhole activity, piezometer monitoring, silt wells, settlement monuments, and tailrace monitoring. The intensive investigations of the foundations showed that they consist of a complex formation of interfingered stratified layers and leases of talus and glaciofluvial deposits. Due to the depth and nature of these materials drill hole penetration was limited to the use of the Becker hammer. This equipment successfully delineated the major soil horizons of the foundation. The continued information attained from inspection, drilling, testing, radar surveys, seismic work, monitoring of piezometers, leakage, silt wells and settlement monuments indicated that there are no large voids within the foundation of the dam. 2 refs., 12 figs

IMPLEMENTASI SISTER PROVINCE PROVINSI JAWA TENGAH DENGAN NEGARA BAGIAN QUEENSLAND AUSTRALIA DI BIDANG PERTANIAN

Directory of Open Access Journals (Sweden)

Reni Windiani

2016-02-01

Full Text Available Globalization on national context has insisted the central government to work together and share duties and rights with the local government in order to achieve the national interest.  In Indonesia, UU 32/2004 about local government provide the chance for them to become more active in foreign policy, such as doing the cooperation in sister province/sister city program. The Central Java Province had done many sister province/sister city program with some partners aboard, such as Fujian province (China, Chungchoeng buk-do province (South Korea and the Queensland province (Australia.  The cooperation cover many sectors such as agriculture, city and village development, transportation and tourism, industry, trade and infestation, education, science and technology, and other sectors that will be confer in advance. From all of the cooperation that have been done between Central Java Province and Queensland, the author, is interested to have research on farming, because central government has had many cows imported from Australia.  This research is become important because central java province is one of the major of national fresh meat distributors. This research is using a qualitative method, with descriptive type of research.  This research has three research questions: How effective is the Sister Province program in Central Java with the Queensland in farm sector? What is the obstacle that holds the Sister Province program in Central Java with the Queensland in farm sector? How is the prospect of Sister Province program in Central Java with the Queensland in farm sector? This result of this research is to prove that the implementation of Sister Province program in Central Java with the Queensland in farm sectors is not effective.  Some of the implementation variables of this program have not been fulfilled. Communication, financial resources and bureaucracy structure are some of the variables that have weakness on this program.  Act of

IVF for premature ovarian failure: first reported births using oocytes donated from a twin sister.

LENUS (Irish Health Repository)

Sills, Eric Scott

2010-01-01

BACKGROUND: Premature ovarian failure (POF) remains a clinically challenging entity because in vitro fertilisation (IVF) with donor oocytes is currently the only treatment known to be effective. METHODS: A 33 year-old nulligravid patient with a normal karyotype was diagnosed with POF; she had a history of failed fertility treatments and had an elevated serum FSH (42 mIU\\/ml). Oocytes donated by her dizygotic twin sister were used for IVF. The donor had already completed a successful pregnancy herself and subsequently produced a total of 10 oocytes after a combined FSH\\/LH superovulation regime. These eggs were fertilised with sperm from the recipient\\'s husband via intracytoplasmic injection and two fresh embryos were transferred to the recipient on day three. RESULTS: A healthy twin pregnancy resulted from IVF; two boys were delivered by caesarean section at 39 weeks\\' gestation. Additionally, four embryos were cryopreserved for the recipient\\'s future use. The sister-donor achieved another natural pregnancy six months after oocyte retrieval, resulting in a healthy singleton delivery. CONCLUSION: POF is believed to affect approximately 1% of reproductive age females, and POF patients with a sister who can be an oocyte donor for IVF are rare. Most such IVF patients will conceive from treatment using oocytes from an anonymous oocyte donor. This is the first report of births following sister-donor oocyte IVF in Ireland. Indeed, while sister-donor IVF has been successfully undertaken by IVF units elsewhere, this is the only known case where oocyte donation involved twin sisters. As with all types of donor gamete therapy, pre-treatment counselling is important in the circumstance of sister oocyte donation.

Catholic nursing sisters and brothers and racial justice in mid-20th-century America.

Science.gov (United States)

Wall, Barbra Mann

2009-01-01

This historical article considers nursing's work for social justice in the 1960s civil rights movement through the lens of religious sisters and brothers who advocated for racial equality. The article examines Catholic nurses' work with African Americans in the mid-20th century that took place amid the prevailing social conditions of poverty and racial disempowerment, conditions that were linked to serious health consequences. Historical methodology is used within the framework of "bearing witness," a term often used in relation to the civil rights movement and one the sisters themselves employed. Two situations involving nurses in the mid-20th century are examined: the civil rights movement in Selma, Alabama, and the actions for racial justice in Chicago, Illinois. The thoughts and actions of Catholic sister and brother nurses in the mid-20th century are chronicled, including those few sister nurses who stepped outside their ordinary roles in an attempt to change an unjust system entirely.

Living with a brother or sister with epilepsy: siblings' experiences.

Science.gov (United States)

Hames, Annette; Appleton, Richard

2009-12-01

There is conflicting evidence about the impact of disability upon siblings, and very little research on the siblings of children with epilepsy. There is some evidence that siblings who have less accurate information exhibit more distress. The aim of this study was to assess siblings' response to having a brother or sister with epilepsy and to begin to develop information for them. Parents of children attending paediatric neurology outpatient departments were invited to participate in a pilot study. Parents who consented to take part were asked if they had previously received information for siblings. Parents and siblings participated in a semi-structured interview and siblings were also invited to submit a personal account of living with a brother or sister who had epilepsy. Twenty-five families with a child with epilepsy aged 2.5-15 years initially agreed to take part. None of the families stated that they had ever seen or received any information specifically for siblings. Fourteen siblings from the 25 families, aged 8-25 years, provided a personal account of what it was like living with a brother or sister with epilepsy. Siblings' accounts included both negative and positive feelings, and specifically feelings of care and love for their sibling. This initial study suggests that siblings of children with epilepsy have many positive but also early negative feelings. The results are limited by the size of the study, the fact that most siblings were older sisters, and the mean time since diagnosis was 6 years. Finally, it is hoped that the personal accounts collected in this study will be published for the benefit of other siblings of children with epilepsy.

Spinal involvement in Camptodactyly Arthropathy Coxa-vara Pericarditis (CACP) syndrome in two Yemeni sisters

NARCIS (Netherlands)

Emad, Yasser; Ragab, Yasser; Ibrahim, Osama; Khalifa, Maher; Dawood, Ahmed; Rasker, Johannes J.

2017-01-01

Aim of the work The objective of this clinical report is to describe the detailed magnetic resonance imaging (MRI) findings of the spine, knee and hip joints in two young sisters with Camptodactyly Arthropathy Coxa-vara Pericarditis (CACP) syndrome. Cases report In two young sisters, both had normal

Brothers and Sisters of Adults with Mental Retardation: Gendered Nature of the Sibling Relationship.

Science.gov (United States)

Orsmond, Gael I.; Seltzer, Marsha Mailick

2000-01-01

Differences and similarities between 245 brothers and sisters of adults with mental retardation in the sibling relationship were examined. Sisters scored higher in the caregiving, companionship, and positive affect aspects of the sibling relationship. Sibling involvement increased over time, but was dependent upon changes in maternal health.…

Two Sisters with Idiopathic Pulmonary Hemosiderosis

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Mehmet Gencer

2007-01-01

Full Text Available Idiopathic pulmonary hemosiderosis (IPH is a rare cause of diffuse alveolar hemorrhage with unknown etiology. In the present report, the presentations of two sisters are described: one sister had IPH, eosinophilia and a high serum immunoglobulin E (IgE level; and the other had IPH, pneumothorax, eosinophilia and a high serum IgE level. Both cases had quite unusual presentations. The first patient was 23 years of age, and had suffered from dry cough and progressive dyspnea for four years. Her hemoglobin level was 60 g/L, total serum IgE level was 900 U/mL and eosinophilia was 9%. Her chest radiography revealed diffuse infiltration. She died due to respiratory failure. The second patient was 18 years of age. She had also suffered from dry cough and gradually increasing dyspnea for two years. She had partial pneumothorax in the right lung and diffuse infiltration in other pulmonary fields on chest radiography. Her hemoglobin level was 99 g/L, total serum IgE level was 1200 U/mL and eosinophilia was 8%. IPH was diagnosed by open lung biopsy. All these findings suggested that familial or allergic factors, as well as immunological factors, might have contributed to the etiology of IPH.

Identical Twin Primigravid Sisters -Spontaneous Labour and ...

African Journals Online (AJOL)

We report 2 cases of identical twin sisters, the older sibling getting married 14 months earlier but both got pregnant for their first child at about the same time and were managed by the same Obstetrician and fell into spontaneous labour within a few hours of each other. Both were delivered by emergency caesarean section ...

UDS and SCE in lymphocytes of persons occupationally exposed to low levels of ionizing radiation

International Nuclear Information System (INIS)

Tuschl, H.; Kovac, R.; Altmann, H.

1983-03-01

Unscheduled DNA synthesis induced by 'in vitro' UV-irradiation was investigated in lymphocytes of persons occupationally exposed to low doses of ionizing radiation (maximum registered radiation dose: 98 mrad/month). For radiation exposures >14 mrad/month, above background level, increased rates of UDS after in vitro UV-irradiation of lymphocytes were found. The bromodeoxyuridine differential chromatid labeling technique was applied to the examination of spontaneous and mytomycin C induced sister chromatid exchanges in the same population. No statistically significant difference could be determined in spontaneously occurring SCEs, while MMC induced SCEs were significantly reduced in persons exposed to radiation doses >14 mrad/month, thus indicating increased repair capability for DNA lesions inflicted by a second insult after protracted low dose irradiation. (Author) [de

Freud on Brothers and Sisters: A Neglected Topic

Science.gov (United States)

Sherwin-White, Susan

2007-01-01

This paper explores Freud's developing thought on brothers and sisters, and their importance in his psychoanalytical writings and clinical work. Freud's work on sibling psychology has been seriously undervalued. This paper aims to give due recognition to Freud's work in this area. (Contains 1 note.)

Genome-Wide Analysis of Heteroduplex DNA in Mismatch Repair–Deficient Yeast Cells Reveals Novel Properties of Meiotic Recombination Pathways

Science.gov (United States)

Martini, Emmanuelle; Borde, Valérie; Legendre, Matthieu; Audic, Stéphane; Regnault, Béatrice; Soubigou, Guillaume; Dujon, Bernard; Llorente, Bertrand

2011-01-01

Meiotic DNA double-strand breaks (DSBs) initiate crossover (CO) recombination, which is necessary for accurate chromosome segregation, but DSBs may also repair as non-crossovers (NCOs). Multiple recombination pathways with specific intermediates are expected to lead to COs and NCOs. We revisited the mechanisms of meiotic DSB repair and the regulation of CO formation, by conducting a genome-wide analysis of strand-transfer intermediates associated with recombination events. We performed this analysis in a SK1 × S288C Saccharomyces cerevisiae hybrid lacking the mismatch repair (MMR) protein Msh2, to allow efficient detection of heteroduplex DNAs (hDNAs). First, we observed that the anti-recombinogenic activity of MMR is responsible for a 20% drop in CO number, suggesting that in MMR–proficient cells some DSBs are repaired using the sister chromatid as a template when polymorphisms are present. Second, we observed that a large fraction of NCOs were associated with trans–hDNA tracts constrained to a single chromatid. This unexpected finding is compatible with dissolution of double Holliday junctions (dHJs) during repair, and it suggests the existence of a novel control point for CO formation at the level of the dHJ intermediate, in addition to the previously described control point before the dHJ formation step. Finally, we observed that COs are associated with complex hDNA patterns, confirming that the canonical double-strand break repair model is not sufficient to explain the formation of most COs. We propose that multiple factors contribute to the complexity of recombination intermediates. These factors include repair of nicks and double-stranded gaps, template switches between non-sister and sister chromatids, and HJ branch migration. Finally, the good correlation between the strand transfer properties observed in the absence of and in the presence of Msh2 suggests that the intermediates detected in the absence of Msh2 reflect normal intermediates. PMID

Genome-wide analysis of heteroduplex DNA in mismatch repair-deficient yeast cells reveals novel properties of meiotic recombination pathways.

Directory of Open Access Journals (Sweden)

Emmanuelle Martini

2011-09-01

Full Text Available Meiotic DNA double-strand breaks (DSBs initiate crossover (CO recombination, which is necessary for accurate chromosome segregation, but DSBs may also repair as non-crossovers (NCOs. Multiple recombination pathways with specific intermediates are expected to lead to COs and NCOs. We revisited the mechanisms of meiotic DSB repair and the regulation of CO formation, by conducting a genome-wide analysis of strand-transfer intermediates associated with recombination events. We performed this analysis in a SK1 × S288C Saccharomyces cerevisiae hybrid lacking the mismatch repair (MMR protein Msh2, to allow efficient detection of heteroduplex DNAs (hDNAs. First, we observed that the anti-recombinogenic activity of MMR is responsible for a 20% drop in CO number, suggesting that in MMR-proficient cells some DSBs are repaired using the sister chromatid as a template when polymorphisms are present. Second, we observed that a large fraction of NCOs were associated with trans-hDNA tracts constrained to a single chromatid. This unexpected finding is compatible with dissolution of double Holliday junctions (dHJs during repair, and it suggests the existence of a novel control point for CO formation at the level of the dHJ intermediate, in addition to the previously described control point before the dHJ formation step. Finally, we observed that COs are associated with complex hDNA patterns, confirming that the canonical double-strand break repair model is not sufficient to explain the formation of most COs. We propose that multiple factors contribute to the complexity of recombination intermediates. These factors include repair of nicks and double-stranded gaps, template switches between non-sister and sister chromatids, and HJ branch migration. Finally, the good correlation between the strand transfer properties observed in the absence of and in the presence of Msh2 suggests that the intermediates detected in the absence of Msh2 reflect normal intermediates.

Broad phylogenomic sampling and the sister lineage of land plants.

Directory of Open Access Journals (Sweden)

Ruth E Timme

Full Text Available The tremendous diversity of land plants all descended from a single charophyte green alga that colonized the land somewhere between 430 and 470 million years ago. Six orders of charophyte green algae, in addition to embryophytes, comprise the Streptophyta s.l. Previous studies have focused on reconstructing the phylogeny of organisms tied to this key colonization event, but wildly conflicting results have sparked a contentious debate over which lineage gave rise to land plants. The dominant view has been that 'stoneworts,' or Charales, are the sister lineage, but an alternative hypothesis supports the Zygnematales (often referred to as "pond scum" as the sister lineage. In this paper, we provide a well-supported, 160-nuclear-gene phylogenomic analysis supporting the Zygnematales as the closest living relative to land plants. Our study makes two key contributions to the field: 1 the use of an unbiased method to collect a large set of orthologs from deeply diverging species and 2 the use of these data in determining the sister lineage to land plants. We anticipate this updated phylogeny not only will hugely impact lesson plans in introductory biology courses, but also will provide a solid phylogenetic tree for future green-lineage research, whether it be related to plants or green algae.

Psychopathology, childhood trauma, and personality traits in patients with borderline personality disorder and their sisters.

Science.gov (United States)

Laporte, Lise; Paris, Joel; Guttman, Herta; Russell, Jennifer

2011-08-01

The aim of this study was to document and compare adverse childhood experiences, and personality profiles in women with borderline personality disorder (BPD) and their sisters, and to determine how these factors impact current psychopathology. Fifty-six patients with BPD and their sisters were compared on measures assessing psychopathology, personality traits, and childhood adversities. Most sisters showed little evidence of psychopathology. Both groups reported dysfunctional parent-child relationships and a high prevalence of childhood trauma. Subjects with BPD reported experiencing more emotional abuse and intrafamilial sexual abuse, but more similarities than differences between probands and sisters were found. In multilevel analyses, personality traits of affective instability and impulsivity predicted DIB-R scores and SCL-90-R scores, above and beyond trauma. There were few relationships between childhood adversities and other measures of psychopathology. Sensitivity to adverse experiences, as reflected in the development of psychopathology, appears to be influenced by personality trait profiles.

El naturalismo americano: Theodore Dreiser y Sister Carrie

Directory of Open Access Journals (Sweden)

Dolores G. ALONSO MULAS

2009-08-01

Full Text Available Para situar a un escritor, como Theodore Dreiser, y especialmente su novela Sister Carrie dentro de un movimiento literario y de una etapa determinada de la historia americana, es necesario dar un breve repaso al naturalismo, llegado a América a través de Stephen Crane

"If I only touch her cloak": the Sisters of Charity of St. Joseph in New Orleans hospital, 1834-1860.

Science.gov (United States)

Kong, Hyejung Grace; Kim, Ock-Joo

2015-04-01

This study is about the Sisters of Charity of St. Joseph in New Orleans' Charity Hospital during the years between 1834 and 1860. The Sisters of Charity of St. Joseph was founded in 1809 by Saint Elizabeth Ann Bailey Seton (first native-born North American canonized in 1975) in Emmitsburg, Maryland. Seton's Sisters of Charity was the first community for religious women to be established in the United States and was later incorporated with the French Daughters of Charity of St. Vincent de Paul in 1850. A call to work in New Orleans' Charity Hospital in the 1830s meant a significant achievement for the Sisters of Charity, since it was the second oldest continuously operating public hospitals in the United States until 2005, bearing the same name over the decades. In 1834, Sister Regina Smith and other sisters were officially called to Charity Hospital, in order to supersede the existing "nurses, attendants, and servants," and take a complete charge of the internal management of Charity Hospital. The existing scholarship on the history of hospitals and Catholic nursing has not integrated the concrete stories of the Sisters of Charity into the broader histories of institutionalized medicine, gender, and religion. Along with a variety of primary sources, this study primarily relies on the Charity Hospital History Folder stored at the Daughters of Charity West Center Province Archives. Located in the "Queen city of the South," Charity Hospital was the center of the southern medical profession and the world's fair of people and diseases. Charity Hospital provided the sisters with a unique situation that religion and medicine became intertwined. The Sisters, as nurses, constructed a new atmosphere of caring for patients and even their families inside and outside the hospital, and built their own separate space within the hospital walls. As hospital managers, the Sisters of Charity were put in complete charge of the hospital, which was never seen in other hospitals. By

Cytogenetic diagnosis of Roberts SC phocomelia syndrome: First report from Kashmir

OpenAIRE

Tahir M. Malla; Arshad A. Pandith; Fayaz A. Dar; Mahrukh H. Zargar

2016-01-01

There are several syndromes in which specific mitotic chromosomal abnormalities can be seen, like premature centromere separation, premature (sister) chromatid separation, and somatic aneuploidies. Identifications of such specific cytogenetic findings can be the key factor that leads towards the diagnosis of syndromes like Roberts SC phocomelia. The case presented here as Roberts SC phocomelia syndrome was identified as a child with multiple congenital anomalies and dysmorphic features. Conve...

Action of the poison of Apis mellifera bee and gamma radiation on bone marrow cells of Wistar rats and on lymphocytes of human peripheral blood

International Nuclear Information System (INIS)

Varanda, E.A.

1987-01-01

''In vivo'' and ''in vitro'' experiments are performed to determine the radioprotective action of the poison of Apis mellifera bees. The frequency of chromosome aberrations, induced by gamma radiation, is studied in two assays: ''in vivo'' in bone marrow cells from Wistar rats and ''in vitro'' in human peripheral blood lymphocyte cultures. The sister chromatid exchanges (SCE) are studied in the ''in vitro'' assays. (M.A.C.) [pt

Effect of cysteamine on sister chromatid exchange (SCE) induction by gamma rays

International Nuclear Information System (INIS)

Mendiola Cruz, M.T.

1987-01-01

The effect of different doses of cysteamine (3, 15 and 150 μg/g bw) on gamma ray-induced SCE was evaluated and compared with the responses obtained with regard to frequency of chromosomal aberrations, frequency of proliferating cells and the rate of cellular proliferating kinetics in mouse bone marrow cells in vivo. Groups of mice were either irradiated, treated with cysteamine and irradiated, only treated with cysteamine or left without treatment for determination of these parameters. The intraperitoneal administration of cysteamine preceding 1 Gy of gamma ray exposure, produces a dose dependent radioprotection on SCE-induction obtaining the greatest effect with 150 μg/g bw. However, this effect was not observed in the mitotic index nor in the average generation time. Chromosomic aberrations in animals irradiated after treatment with cysteamine were also detected. It was not observed any citotoxic or genotoxic effect produced by cysteamine per se. The results suggest that, under the experimental conditions of this study, the SCE are caused by free radicals produced by gamma radiation; not so, the additional damage indexes measured. (author)

Repairability during G1 of the inductor leisure of exchanges in the sister chromatid induced by alkylating agents in DNA substituted and no substituted with BUDR, in cells of the salivary gland of mouse In vivo; Reparabilidad durante G1 de las lesiones inductoras de intercambios en las cromatidas hermanas inducidos por agentes alquilantes en ADN sustituido y no sustituido con BrdU, en celulas de la glandula salival de raton In vivo

Energy Technology Data Exchange (ETDEWEB)

Gonzalez B, F

2004-07-01

In this work you determines the repair of the lesions inductoras of Sister chromatid exchange (ICHs) generated in the cells of the salivary gland of mouse, for the treatment with the N-Methyl-N-Nitrosourea (MNU), the N-Ethyl-N-Nitrosourea (ENU), the Methyl methanesulfonate (MMS) and the Ethyl methanesulfonate (EMS) in early and slow G1 of the first one and the second cellular division, that is to say before and after the cells incorporate 5-bromine-2 -Desoxyuridine (BrdU) in the DNA. Groups witness non treaties were included with mutagen. The cells of the salivary gland repaired the generated lesions partially by the MNU, the MMS and the EMS in the 1st division, and only the lesions induced by the ENU and MMS were repaired partially in the 2nd division. The ENU generates injure that they were not repaired in the 1st division and those taken place by the EMS were little repaired in the 2nd division. The methylating agents generated but ICHs that the ethylating. One observes that the BrdU makes to the molecule of the DNA but susceptible to the damage generated by the alkylating agents that induce the formation of the ICHs. This susceptibility was incremented around 150% for the treatment with the MNU, the ENU and the MMS, on the other hand for the EMS it was 3 times minor. It is proposed that the one electronegative atom of this analog of the timine would to work as a nucleophyllic center with which the electrophyllic compounds react. (Author)

Sisters in hereditary breast and ovarian cancer families: communal coping, social integration, and psychological well-being.

Science.gov (United States)

Koehly, Laura M; Peters, June A; Kuhn, Natalia; Hoskins, Lindsey; Letocha, Anne; Kenen, Regina; Loud, Jennifer; Greene, Mark H

2008-08-01

We investigated the association between psychological distress and indices of social integration and communal coping among sisters from hereditary breast and ovarian cancer (HBOC) families. Sixty-five sisters from 31 HBOC families completed the Brief Symptom Inventory-18 and the Colored Eco-Genetic Relationship Map, which identified members of participants' social support networks. Hierarchical linear models were used for all analyses to account for the clustering of sisters within families. Intra-family correlation coefficients suggested that sisters shared perceptions of breast cancer risk and worry, but not ovarian cancer risk and worry. Further, sisters demonstrated shared levels of anxiety and somatization, but not depressive symptoms. Communal coping indices quantifying shared support resources were negatively related to anxiety and somatization. The number of persons with whom cancer risk information was shared exhibited a positive trend with somatization. Social integration, as measured by the size of participants' emotional support network, was negatively associated with anxiety. Lower depression scores were observed among participants with more persons playing multiple support roles and fewer persons providing tangible assistance. Understanding how support relationships impact well-being among persons adjusting to HBOC risk, and the particular role of family in that process, will facilitate developing appropriate management approaches to help cancer-prone families adjust to their cancer risk.

Termini of human chromosomes display elevated rates of mitotic recombination.

Science.gov (United States)

Cornforth, M N; Eberle, R L

2001-01-01

The strand-specific in situ hybridization technique of CO-FISH was used to probe telomeres of human mitotic cells in order to determine the spontaneous frequency of crossover. This approach allowed the detection of recombinational crossovers occurring anywhere along the length of individual chromosomes, including reciprocal events taking place between sister chromatids. Although the process of sister chromatid exchange (SCE) is the most prominent type of recombination in somatic mammalian cells, our results show that SCEs accounted for less than a third of the recombinational events revealed by CO-FISH. It is concluded that chromosomal regions near the termini of chromosome arms undergo extraordinarily high rates of spontaneous recombination, producing terminal crossovers whose small size precludes detection by standard cytogenetic methods. That similar results were observed for transformed epithelial cells, as well as primary fibroblasts, suggests that the phenomenon is a common characteristic of human cells. These findings are noteworthy because, although telomeric and subtelomeric DNA is known to be preferentially involved in certain types of recombination, the tips of somatic mammalian chromosomes have not previously been identified as preferred sites for crossover. Implications of these results are discussed in terms of limitations imposed on CO-FISH for its proposed use in directional hybridization mapping.

Childhood obsessive-compulsive traits in anorexia nervosa patients, their unaffected sisters and healthy controls: a retrospective study.

Science.gov (United States)

Degortes, Daniela; Zanetti, Tatiana; Tenconi, Elena; Santonastaso, Paolo; Favaro, Angela

2014-07-01

Although there is evidence that childhood perfectionistic traits predate the onset of eating disorders, few studies to date have examined the prevalence and clinical correlates of these traits in patients with anorexia nervosa (AN) and their unaffected sisters. The aim of this work was to study the prevalence of childhood obsessive-compulsive traits in patients with lifetime AN, their unaffected sisters and healthy women. A total of 116 AN patients, 32 healthy sisters and 119 controls were assessed by the EATATE Interview to assess traits such as perfectionism, inflexibility, rule-bound traits, drive for order and symmetry, and excessive doubt and cautiousness. Both self-report and maternal reports were collected. AN patients reported more childhood obsessive-compulsive traits than their healthy sisters and controls. In contrast, no differences between healthy controls and unaffected sisters emerged. In patients with AN, a dose-response relationship was found between the number of childhood obsessive-compulsive traits and psychopathology, including body image distortion, thus indicating that these traits are an important feature to be considered in assessing and treating eating disorders. Copyright © 2014 John Wiley & Sons, Ltd and Eating Disorders Association.

Effects of Simultaneous Radiofrequency Radiation and Chemical Exposure of Mammalian Cells. Volume 2

Science.gov (United States)

1988-07-01

chromosome - - - - - - -I aberrations and sister chromatid exchanges (SCE). Yao (1982) exposed rat kangaroo RH5 and RH1l6 cells to 2.45 GHz radiation, and...control was reported in chromosome aberrations. Yac (1982) investigated the cytogenetic consequences of chronic microwave exposure on rat kangaroo RH5...was said to be 280C. The cells were exposed both as conidia, which are "rather inactive metabolically ," and also after DNA replication had been

Repair of O6-(2-chloroethyl)guanine mediates the biological effects of chloroethylnitrosoureas.

OpenAIRE

Bodell, W J; Aida, T; Berger, M S; Rosenblum, M L

1985-01-01

Chloroethylnitrosoureas (CENUs) are alkylating and crosslinking agents used for the treatment of human cancer; they are both mutagenic and carcinogenic. We compared the levels of induction of sister chromatid exchanges (SCEs) and the cytotoxicity of nitrosoureas that alkylate only with CENUs. CENUs are 200-fold more cytotoxic and induce SCEs with 45-fold greater efficiency than agents that do not crosslink; therefore, crosslinking is probably the most important molecular event that leads to c...

Imaging of DNA Ultrafine Bridges in Budding Yeast.

Science.gov (United States)

Quevedo, Oliver; Lisby, Michael

2018-01-01

DNA ultrafine bridges (UFBs) are a type of chromatin-free DNA bridges that connect sister chromatids in anaphase and pose a threat to genome stability. However, little is known about the origin of these structures, and how they are sensed and resolved by the cell. In this chapter, we review tools and methods for studying UFBs by fluorescence microscopy including chemical and genetic approaches to induce UFBs in the model organism Saccharomyces cerevisiae.

Imaging of DNA Ultrafine Bridges in Budding Yeast

DEFF Research Database (Denmark)

Quevedo Rodriguez, Oliver; Lisby, Michael

2018-01-01

DNA ultrafine bridges (UFBs) are a type of chromatin-free DNA bridges that connect sister chromatids in anaphase and pose a threat to genome stability. However, little is known about the origin of these structures, and how they are sensed and resolved by the cell. In this chapter, we review tools...... and methods for studying UFBs by fluorescence microscopy including chemical and genetic approaches to induce UFBs in the model organism Saccharomyces cerevisiae....

DNA template strand sequencing of single-cells maps genomic rearrangements at high resolution

OpenAIRE

Falconer, Ester; Hills, Mark; Naumann, Ulrike; Poon, Steven S. S.; Chavez, Elizabeth A.; Sanders, Ashley D.; Zhao, Yongjun; Hirst, Martin; Lansdorp, Peter M.

2012-01-01

DNA rearrangements such as sister chromatid exchanges (SCEs) are sensitive indicators of genomic stress and instability, but they are typically masked by single-cell sequencing techniques. We developed Strand-seq to independently sequence parental DNA template strands from single cells, making it possible to map SCEs at orders-of-magnitude greater resolution than was previously possible. On average, murine embryonic stem (mES) cells exhibit eight SCEs, which are detected at a resolution of up...

Synthesis and SAR studies of 5-(pyridin-4-yl)-1,3,4-thiadiazol-2-amine derivatives as potent inhibitors of Bloom helicase

DEFF Research Database (Denmark)

Rosenthal, Andrew S; Dexheimer, Thomas S; Gileadi, Opher

2013-01-01

complementary strands of duplex DNA as well as atypical DNA structures such as Holliday junctions. Mutations of the BLM gene can result in Bloom syndrome, an autosomal recessive disorder associated with cancer predisposition. BLM-deficient cells exhibit increased sensitivity to DNA damaging agents indicating...... and related analogs, which possess potent BLM inhibition and exhibit selectivity over related helicases. Moreover, these compounds demonstrated cellular activity by inducing sister chromatid exchanges, a hallmark of Bloom syndrome....

In vitro studies on chemoprotective effect of Purnark against benzo(a)pyrene-induced chromosomal damage in human lymphocytes.

Science.gov (United States)

Ghaisas, S D; Bhide, S V

1994-01-01

Human lymphocytes were used as an assay system to test chemopreventive activity of natural products. Purnark, a mixture of extracts of turmeric, betel leaf and catechu, was tested for its chemoprotective activity against BP induced DNA damage. Sister chromatid exchange and micronuclei were used as markers to assess the protective activity of Purnark. Purnark gave 50-60% protection against BP induced SCEs and micronuclei. Purnark at 100 micrograms dose did not show any genotoxicity.

Inhibition of repair activity induced by γ-radiation, UV-rays and radiomimetics in the in vitro cultured cells of patients wiyh schizophrenia

International Nuclear Information System (INIS)

Zasukhina, G.D.; Zharikov, N.M.; L'vova, G.N.; Vasil'eva, I.M.; Chekova, V.V.; Alekhina, N.I.; Ivanova, T.N.

1986-01-01

A study was made of the processes of repair, virus reactivation, and formation of sister chromatid exchages (SCE) in blood cells of patients with schizophrenia after the effect of γ-radiation and 4-nitroquinoline-1-oxide. These processes were estimated by 12 criteria. The mutagen-induced disturbances in the processes of repair and SCE formation were found in cells of patients with schizophrenia and were absent in the control cells of healthy donors

An illness in the family: Dr. Maude Abbott and her sister, Alice Abbott.

Science.gov (United States)

Brookes, Barbara

2011-01-01

This paper explores Maude Abbott's internationally significant career in medicine and her parallel commitment to caring for her sister, Alice Abbott. An examination of Abbott's life reveals the difficulties faced by an ambitious Canadian woman in medicine from the 1890s to the 1920s; difficulties compounded by caring for a sister with a mental illness. The Abbott archive suggests that it was far more difficult for a woman doctor to make the kind of sharp distinction between public and private life that might be expected of professional men.

Sister chromosome pairing maintains heterozygosity in parthenogenetic lizards.

Science.gov (United States)

Lutes, Aracely A; Neaves, William B; Baumann, Diana P; Wiegraebe, Winfried; Baumann, Peter

2010-03-11

Although bisexual reproduction has proven to be highly successful, parthenogenetic all-female populations occur frequently in certain taxa, including the whiptail lizards of the genus Aspidoscelis. Allozyme analysis revealed a high degree of fixed heterozygosity in these parthenogenetic species, supporting the view that they originated from hybridization events between related sexual species. It has remained unclear how the meiotic program is altered to produce diploid eggs while maintaining heterozygosity. Here we show that meiosis commences with twice the number of chromosomes in parthenogenetic versus sexual species, a mechanism that provides the basis for generating gametes with unreduced chromosome content without fundamental deviation from the classic meiotic program. Our observation of synaptonemal complexes and chiasmata demonstrate that a typical meiotic program occurs and that heterozygosity is not maintained by bypassing recombination. Instead, fluorescent in situ hybridization probes that distinguish between homologues reveal that bivalents form between sister chromosomes, the genetically identical products of the first of two premeiotic replication cycles. Sister chromosome pairing provides a mechanism for the maintenance of heterozygosity, which is critical for offsetting the reduced fitness associated with the lack of genetic diversity in parthenogenetic species.

Umbilical metastasis (Sister Mary Joseph's nodule diagnosed by fine-needle aspiration

Directory of Open Access Journals (Sweden)

Tatomirović Željka

2004-01-01

Full Text Available Sister Mary Joseph’s nodule is the eponym for metastatic involvement of the umbilicus. This less common entity is the sign of disseminated malignant disease, mainly of digestive and gynecologic origin, and is associated with a poor prognosis. A case of Sister Mary Joseph’s nodule in a 76-year-old woman in whom the umbilical metastasis was the first sign of malignant disease in presented. The diagnosis of metastatic adenocarcinoma was established by fine needle aspiration cytology of the umbilical nodule. Radiological and ultrasonographic investigation disclosed carcinoma of the gallbladder with pancreas, stomach, and colon invasion as well as peritoneal dissemination. The diagnosis was confirmed by exploratory laparatomy and histological examination of the excised umbilical nodule.

The Lehman Sisters Hypothesis: an exploration of literature and bankers

NARCIS (Netherlands)

I.P. van Staveren (Irene)

2012-01-01

textabstractAbstract This article tests the Lehman Sisters Hypothesis in two complementary, although incomplete ways. It reviews the diverse empirical literature in behavioral, experimental, and neuroeconomics as well as related fields of behavioral research. And it presents the findings from an

The Lehman Sisters Hypothesis: an exploration of literature and bankers

NARCIS (Netherlands)

I.P. van Staveren (Irene)

2012-01-01

textabstractThis article tests the Lehman Sisters Hypothesis in two complementary, although incomplete ways. It reviews the diverse empirical literature in behavioural, experimental, and neuroeconomics as well as related fields of behavioural research. And it presents the findings from an

Extensive range overlap between heliconiine sister species: evidence for sympatric speciation in butterflies?

Science.gov (United States)

Rosser, Neil; Kozak, Krzysztof M; Phillimore, Albert B; Mallet, James

2015-06-30

Sympatric speciation is today generally viewed as plausible, and some well-supported examples exist, but its relative contribution to biodiversity remains to be established. We here quantify geographic overlap of sister species of heliconiine butterflies, and use age-range correlations and spatial simulations of the geography of speciation to infer the frequency of sympatric speciation. We also test whether shifts in mimetic wing colour pattern, host plant use and climate niche play a role in speciation, and whether such shifts are associated with sympatry. Approximately a third of all heliconiine sister species pairs exhibit near complete range overlap, and analyses of the observed patterns of range overlap suggest that sympatric speciation contributes 32%-95% of speciation events. Müllerian mimicry colour patterns and host plant choice are highly labile traits that seem to be associated with speciation, but we find no association between shifts in these traits and range overlap. In contrast, climatic niches of sister species are more conserved. Unlike birds and mammals, sister species of heliconiines are often sympatric and our inferences using the most recent comparative methods suggest that sympatric speciation is common. However, if sister species spread rapidly into sympatry (e.g. due to their similar climatic niches), then assumptions underlying our methods would be violated. Furthermore, although we find some evidence for the role of ecology in speciation, ecological shifts did not show the associations with range overlap expected under sympatric speciation. We delimit species of heliconiines in three different ways, based on "strict and " "relaxed" biological species concepts (BSC), as well as on a surrogate for the widely-used "diagnostic" version of the phylogenetic species concept (PSC). We show that one reason why more sympatric speciation is inferred in heliconiines than in birds may be due to a different culture of species delimitation in the two

Ukrainian and European Baroque in the Context of “Sister Arts” Idea

Directory of Open Access Journals (Sweden)

Olga Shikirinskaya

2015-08-01

Full Text Available The article deals with the “Sister Arts” tradition as the interrelationship of various art forms (poetry, fiction, painting, theatre, music etc. relative to the Baroque period. “Sister Arts” criticism, based on E.G. Lessing essay “Laocoön…” uses the inter-art analogies to appreciate the importance of literature in the Arts, as well as to comprehend aspects of the modern approach to the synthesis of the arts. The article presents the aesthetic concept of Baroque art and its realization in architecture, sculpture, decorative and applied arts, music and literature on the background of the European and Ukrainian cultural tradition.

Sister chromatoid exchanges in atomic bomb survivors

International Nuclear Information System (INIS)

Nakano, Mimako; Awa, Akio

1980-01-01

Sister chromatoid exchange (SCE) frequencies in the peripheral lymphocyte with and without mitomycin-C (MMC) were studied, in the age of tens and thirties for an atomic-bomb survivor group and in thirties, fifties, and seventies for an unexposed group. The observation of 100 cells showed no statistically significant difference of SCE frequencies with aging or irradiation. The increasing rates of SCE frequencies by MMC showed no difference among the groups. The average increasing ratio by MMC was 3.6. (Nakanishi, T.)

High frequencies of chromatid aberrations produced during G/sub 2/ in human lymphocytes by very low doses (0. 025-0. 4 Gy) of X-rays in combination with inhibitors of DNA synthesis

Energy Technology Data Exchange (ETDEWEB)

Andersson, H.C.; Kihlman, B.A. (Uppsala Univ. (Sweden). Dept. of Genetics)

1984-09-01

Whole-blood cultures of human lymphocytes were exposed in the G/sub 2/-phase (3.5 h before harvesting) to various doses of X-rays and post-treated for 3 h with inhibitors of DNA synthesis. The inhibitors used were 2'-deoxyadenosine (dAdo), hydroxyurea (HU) and 1-..beta..-D-arabinofuranosylcytosine (ara-C). To prevent deamination of dAdo by adenosine deaminase (ADA), the dAdo treatments were carried out in the presence of the ADA inhibitor coformycin. HU and ara-C were used either alone or in combination. After the 3-h inhibitor treatments, the cultures were harvested and slides prepared and analyzed for chromatid aberrations in metaphase. When the inhibitors were used at concentrations high enough to cause marked chromosome damage by themselves, very low doses of X-rays (0.025-0.2 Gy) were sufficient to produce a dramatic increase in the frequency of chromatid aberrations. High frequencies of chromatid aberrations were also obtained when cultures that had received moderate doses of X-rays (0.4-0.8 Gy) were post-treated with low inhibitor concentrations that produce no or only a few aberrations by themselves.

Effect of SPL (Spent Pot Liner) and its main components on root growth, mitotic activity and phosphorylation of Histone H3 in Lactuca sativa L.

Science.gov (United States)

Freitas, Aline Silva; Fontes Cunha, Isabela Martinez; Andrade-Vieira, Larissa Fonseca; Techio, Vânia Helena

2016-02-01

Spent Pot Liner (SPL) is a solid waste from the aluminum industry frequently disposed of in industrial landfills; it can be leached and contaminate the soil, sources of drinking water and plantations, and thus may pose a risk to human health and to ecosystems. Its composition is high variable, including cyanide, fluoride and aluminum salts, which are highly toxic and environmental pollutants. This study evaluated the effect of SPL and its main components on root growth and the mitosis of Lactuca sativa, by investigating the mechanisms of cellular and chromosomal alterations with the aid of immunolocalization. To this end, newly emerged roots of L. sativa were exposed to SPL and its main components (solutions of cyanide, fluoride and aluminum) and to calcium chloride (control) for 48h. After this, root length was measured and cell cycle was examined by means of conventional cytogenetics and immunolocalization. Root growth was inhibited in the treatments with SPL and aluminum; chromosomal and nuclear alterations were observed in all treatments. The immunolocalization evidenced normal dividing cells with regular temporal and spatial distribution of histone H3 phosphorylation at serine 10 (H3S10ph). However, SPL and its main components inhibited the phosphorylation of histone H3 at serine 10, inactivated pericentromeric regions and affected the cohesion of sister chromatids, thus affecting the arrangement of chromosomes in the metaphase plate and separation of chromatids in anaphase. In addition, these substances induced breaks in pericentromeric regions, characterized as fragile sites. Copyright © 2015 Elsevier Inc. All rights reserved.

The development of SisterTalk: a cable TV-delivered weight control program for black women.

Science.gov (United States)

Gans, Kim M; Kumanyika, Shiriki K; Lovell, H Joan; Risica, Patricia M; Goldman, Roberta; Odoms-Young, Angela; Strolla, Leslie O; Decaille, Donna O; Caron, Colleen; Lasater, Thomas M

2003-12-01

Overweight and obesity have reached epidemic proportions in the United States, with black women disproportionately affected. SisterTalk is a weight control program designed specifically for delivery to black women via cable TV. The theoretical and conceptual frameworks and formative research that guided the development and cultural tailoring of SisterTalk are described. Social Action Theory was applied in the development of SisterTalk along with a detailed behavioral analysis of the way that black women view weight and weight loss within the context of their cultural and social realities. The entire intervention development process was framed using this information, rather than by changing only superficial aspects of program delivery. Community networking and both qualitative and quantitative interview techniques from the fields of social marketing and cultural anthropology were used to involve black women from Boston in the design and implementation of a program that would be practical, appealing, and culturally sensitive. Also discussed are strategies for evaluating the program, and lessons learned that might have broader applicability are highlighted. The development of the SisterTalk program could provide a useful starting point for development of successful weight control programs for black women in other parts of the United States as well as for other ethnic and racial groups.

Many functions of the meiotic cohesin.

Science.gov (United States)

Bardhan, Amit

2010-12-01

Sister chromatids are held together from the time of their formation in S phase until they segregate in anaphase by the cohesin complex. In meiosis of most organisms, the mitotic Mcd1/Scc1/Rad21 subunit of the cohesin complex is largely replaced by its paralog named Rec8. This article reviews the specialized functions of Rec8 that are crucial for diverse aspects of chromosome dynamics in meiosis, and presents some speculations relating to meiotic chromosome organization.

In Vivo Cytogenetic Studies on Aspartame

OpenAIRE

AlSuhaibani, Entissar S.

2010-01-01

Aspartame (a-Laspartyl-L-phenylalanine 1-methylester) is a dipeptide low-calorie artificial sweetener that is widely used as a nonnutritive sweetener in foods and drinks. The safety of aspartame and its metabolic breakdown products (phenylalanine, aspartic acid and methanol) was investigated in vivo using chromosomal aberration (CA) test and sister chromatid exchange (SCE) test in the bone marrow cells of mice. Swiss Albino male mice were exposed to aspartame (3.5, 35, 350 mg/kg body weight)....

Happiness matters : exploring the linkages between personality, personal happiness, and work-related psychological health among priests and sisters in Italy

OpenAIRE

Francis, Leslie J.; Crea, Giuseppe

2017-01-01

This study responds to the challenge posed by Rossetti’s work to explore the antecedents and consequences of individual differences in happiness among priests and religious sisters. The Oxford Happiness Questionnaire was completed together with measures of personality and work-related psychological health by 95 priests and 61 religious sisters. Overall the data demonstrated high levels of personal happiness among priests and religious sisters, but also significant signs of vulnerability. Pers...

Do brothers and sisters of siblings with intelectual disability need the support of social work?

OpenAIRE

Cardová, Michaela

2007-01-01

This thesis explores the experience and support needs of siblings with a brother or sister with intellectual disability. Through review of what is a quite limited literature and from original qualitative research, involving interviews with siblings, the author examines their social reality, focusing especially on their relationships with their disabled brother or sister and with the wider society. Particular attention is given to identifying to what extent the siblings' lives are influenced b...

PICH promotes sister chromatid disjunction and co-operates with topoisomerase II in mitosis

DEFF Research Database (Denmark)

Nielsen, Christian Thomas Friberg; Huttner, Diana; Bizard, Anna H

2015-01-01

PICH is a SNF2 family DNA translocase that binds to ultra-fine DNA bridges (UFBs) in mitosis. Numerous roles for PICH have been proposed from protein depletion experiments, but a consensus has failed to emerge. Here, we report that deletion of PICH in avian cells causes chromosome structural......-193-treated cells. We propose that PICH and Topo II cooperate to prevent chromosome missegregation events in mitosis....

Mouse RAD54 affects DNA double-strand break repair and sister chromatid exchange

NARCIS (Netherlands)

H.B. Beverloo (Berna); R.D. Johnson (Roger); M. Jasin (Maria); R. Kanaar (Roland); J.H.J. Hoeijmakers (Jan); M.L.G. Dronkert (Mies)

2000-01-01

textabstractCells can achieve error-free repair of DNA double-strand breaks (DSBs) by homologous recombination through gene conversion with or without crossover. In contrast, an alternative homology-dependent DSB repair pathway, single-strand annealing (SSA), results in deletions. In this study, we

Sister chromatid exchanges (SCEs) in lymphocytes of inhabitants in high background radiation area

International Nuclear Information System (INIS)

Li Jinsheng; Zheng Qiaoling

1985-01-01

Blood samples were taken from 126 students of 15-16 years old, living in the high background radiation area, and from 124 controls of the same age range, living in the normal background radiation area. All students were interviewed for evaluation of their health status. Whole blood cultures were done with RPMI 1640 medium supplemented with 20% fetal calf serum and antibiotics, The culture were incubated for 54-56 h in the presence of BrdU (10 μg/ml). Metaphases were stained for SCE using a modified techniqu of perry and Wolff. From each person 20 second division metaphases were analysed for SCEs. The average frequencies of SCEs observed in the high background group and the control group are presented. More SCEs were observed in the high background group than in the control with a statistically signigicant difference. In regard to the sex factor, it was found that the SCE frequencies in both sexes of the high background group were slightly higher than those in the control group. These findings suggest that continuous low-level irradiation by the high background radiation may induce increased frequency of SCEs

APC/C-Cdc20 mediates deprotection of centromeric cohesin at meiosis II in yeast.

Science.gov (United States)

Jonak, Katarzyna; Zagoriy, Ievgeniia; Oz, Tugce; Graf, Peter; Rojas, Julie; Mengoli, Valentina; Zachariae, Wolfgang

2017-06-18

Cells undergoing meiosis produce haploid gametes through one round of DNA replication followed by 2 rounds of chromosome segregation. This requires that cohesin complexes, which establish sister chromatid cohesion during S phase, are removed in a stepwise manner. At meiosis I, the separase protease triggers the segregation of homologous chromosomes by cleaving cohesin's Rec8 subunit on chromosome arms. Cohesin persists at centromeres because the PP2A phosphatase, recruited by the shugoshin protein, dephosphorylates Rec8 and thereby protects it from cleavage. While chromatids disjoin upon cleavage of centromeric Rec8 at meiosis II, it was unclear how and when centromeric Rec8 is liberated from its protector PP2A. One proposal is that bipolar spindle forces separate PP2A from Rec8 as cells enter metaphase II. We show here that sister centromere biorientation is not sufficient to "deprotect" Rec8 at meiosis II in yeast. Instead, our data suggest that the ubiquitin-ligase APC/C Cdc20 removes PP2A from centromeres by targeting for degradation the shugoshin Sgo1 and the kinase Mps1. This implies that Rec8 remains protected until entry into anaphase II when it is phosphorylated concurrently with the activation of separase. Here, we provide further support for this model and speculate on its relevance to mammalian oocytes.

The mitosis-regulating and protein-protein interaction activities of astrin are controlled by aurora-A-induced phosphorylation.

Science.gov (United States)

Chiu, Shao-Chih; Chen, Jo-Mei Maureen; Wei, Tong-You Wade; Cheng, Tai-Shan; Wang, Ya-Hui Candice; Ku, Chia-Feng; Lian, Chiao-Hsuan; Liu, Chun-Chih Jared; Kuo, Yi-Chun; Yu, Chang-Tze Ricky

2014-09-01

Cells display dramatic morphological changes in mitosis, where numerous factors form regulatory networks to orchestrate the complicated process, resulting in extreme fidelity of the segregation of duplicated chromosomes into two daughter cells. Astrin regulates several aspects of mitosis, such as maintaining the cohesion of sister chromatids by inactivating Separase and stabilizing spindle, aligning and segregating chromosomes, and silencing spindle assembly checkpoint by interacting with Src kinase-associated phosphoprotein (SKAP) and cytoplasmic linker-associated protein-1α (CLASP-1α). To understand how Astrin is regulated in mitosis, we report here that Astrin acts as a mitotic phosphoprotein, and Aurora-A phosphorylates Astrin at Ser(115). The phosphorylation-deficient mutant Astrin S115A abnormally activates spindle assembly checkpoint and delays mitosis progression, decreases spindle stability, and induces chromosome misalignment. Mechanistic analyses reveal that Astrin phosphorylation mimicking mutant S115D, instead of S115A, binds and induces ubiquitination and degradation of securin, which sequentially activates Separase, an enzyme required for the separation of sister chromatids. Moreover, S115A fails to bind mitosis regulators, including SKAP and CLASP-1α, which results in the mitotic defects observed in Astrin S115A-transfected cells. In conclusion, Aurora-A phosphorylates Astrin and guides the binding of Astrin to its cellular partners, which ensures proper progression of mitosis. Copyright © 2014 the American Physiological Society.

The kinetochore of the Lepidoptera, (2)

International Nuclear Information System (INIS)

Maeki, Kodo

1980-01-01

The chromosomes of Graphium Sarpedon (n, 20) and Eumeta variegata were examined by the acetoorcein squash method. In the equatorial plate of M-2 metaphase, two sister chromatids (rod-type) appeared in linear arrangement. The spindle fibers then gathered to the chromosomal part toward the cell pole, which condensed longwise on the other side. In the second anaphase, the two sister chromatids moved to the opposite poles, they appeared to move toward the pole ends-first. The M-2 metaphase and anaphase were identified only for the chromosomes equipped with the diffuse kinetochore structure. The male larvae of Graphium Sarpedon at the last-instar were irradiated with 800, 1000, 1500 or 2000 R of 60 Co to induce chromosome fragmentation, and killed 18, 21, 24, 27 and 30 hrs after the irradiation. The chromosomal aberration at the meitotic stage after the irradiation of 1500 R and 2000 R was pronounced. Although the normal haploid chromosome number of G. sarpedon is 20, it was found that the irradiated larvae had 21 or 19 chromosomes at the M-1 metaphase. The aberration resulted from chromosomal fusion as well as from fragmentation during meiosis. It was suggested that the induced fragment chromosomes each carry kinetochore. In general, it is considered that the chromosomes of lepidopteran insects were characterized by holokinetic organization. (Kaihara, S.)

Evaluation of cytogenetic and DNA damage in human lymphocytes treated with adrenaline in vitro.

Science.gov (United States)

Djelić, Ninoslav; Radaković, Milena; Spremo-Potparević, Biljana; Zivković, Lada; Bajić, Vladan; Stevanović, Jevrosima; Stanimirović, Zoran

2015-02-01

Catechol groups can be involved in redox cycling accompanied by generation of reactive oxygen species (ROS) which may lead to oxidative damage of cellular macromolecules including DNA. The objective of this investigation was to evaluate possible genotoxic effects of a natural catecholamine adrenaline in cultured human lymphocytes using cytogenetic (sister chromatid exchange and micronuclei) and the single cell gel electrophoresis (Comet) assay. In cytogenetic tests, six experimental concentrations of adrenaline were used in a range from 0.01-500 μM. There were no indications of genotoxic effects of adrenaline in sister chromatid exchange and micronucleus tests. However, at four highest concentrations of adrenaline (5 μM, 50 μM, 150 μM and 300 μM) we observed a decreased mitotic index and cell-cycle delay. In addition, in the Comet assay we used adrenaline in a range from 0.0005-500 μM, at two treatment times: 15 min or 60 min. In contrast to cytogenetic analysis, there was a dose-dependent increase of DNA damage detected in the Comet assay. These effects were significantly reduced by concomitant treatment with quercetin or catalase. Therefore, the obtained results indicate that adrenaline may exhibit genotoxic effects in cultured human lymphocytes, most likely due to production of reactive oxygen species. Copyright © 2014 Elsevier Ltd. All rights reserved.

20 CFR 410.340 - Determination of relationship; parent, brother, or sister.

Science.gov (United States)

2010-04-01

... domiciled (see § 410.392) at the time of his death would find, under the law they would apply in determining..., brother, or sister. Where, under such law, the individual does not bear the relationship to the miner of...

The centenary of Janssens's chiasmatype theory.

Science.gov (United States)

Koszul, Romain; Meselson, Matthew; Van Doninck, Karine; Vandenhaute, Jean; Zickler, Denise

2012-06-01

The segregation and random assortment of characters observed by Mendel have their basis in the behavior of chromosomes in meiosis. But showing this actually to be the case requires a correct understanding of the meiotic behavior of chromosomes. This was achieved only gradually, over several decades, with much dispute and confusion along the way. One crucial step in the understanding of meiosis was provided in 1909 by Frans Alfons Janssens who published in La Cellule an article entitled "La théorie de la Chiasmatypie. Nouvelle interprétation des cinèses de maturation," which contains the first description of the chiasma structure. He observed that, of the four chromatids present at the connection sites (chiasmata sites) at diplotene or anaphase of the first meiotic division, two crossed each other and two did not. He therefore postulated that the maternal and paternal chromatids that crossed penetrated the other until they broke and rejoined in maternal and paternal segments new ways; the other two chromatids remained free and thus intact. This allowed him also to propose that the chromatids distributed in the four nuclei issued from the second meiotic division had various combinations of maternal and paternal segments of each chromosome. And conversely, permitted the appreciation that the laws of Mendelian segregation required breakage and joining (crossing over) between homologous non-sister chromatids. Although Janssens's article found a broad appreciative audience and had a large influence on the chromosomal theory at that time, his theory was resisted by both geneticists and cytologists for several decades. This Perspectives aims to highlight the novelty of Janssens's chiasmatype theory by examining the historical background and our actual understanding of meiotic recombination.

An investigation of the genetic toxicology of irradiated foodstuffs using short-term test systems

International Nuclear Information System (INIS)

Phillips, B.J.; Kranz, E.; Elias, P.S.

1980-01-01

As part of a programme of short-term tests used to detect possible genetic toxicity in irradiated foodstuffs, cultured Chinese hamster ovary cells were exposed to extracts and digests of irradiated and unirradiated dates, fish and chicken and subjected to tests for cytotoxicity, sister chromatid exchange induction and mutation to thioguanine resistance. The results showed no evidence of genetic toxicity induced in food by irradiation. The general applicability of cell culture tests to the detection of mutagens in food is discussed. (author)

Bartter syndrome in two sisters with a novel mutation of the CLCNKB gene, one with deafness.

Science.gov (United States)

Robitaille, Pierre; Merouani, Aicha; He, Ning; Pei, York

2011-09-01

This article describes two sisters with type III Bartter syndrome (BS) due to a novel missense variant of the CLCNKB gene. The phenotypic expression of the disease was very different in these two siblings. In one sister, the disease followed a very severe course, especially in the neonatal period and as a toddler. Both the classic symptoms and the biochemical features of the syndrome were striking. In addition, she presented with sensorineural deafness, a complication yet unreported in this subtype of BS In contrast, the least affected sister was symptom free and the biochemical features of the disease although present remained discrete throughout the prolonged follow-up. It is suggested that such a difference in the phenotypic expression of the disease is possibly secondary to the modifier effect of a gene and/or results from environmental factor(s).

Adult Sibling Relationships with Brothers and Sisters with Severe Disabilities

Science.gov (United States)

Rossetti, Zach; Hall, Sarah

2015-01-01

The purpose of this qualitative study was to examine perceptions of adult sibling relationships with a brother or sister with severe disabilities and the contexts affecting the relationships. Adult siblings without disabilities (N = 79) from 19 to 72 years of age completed an online survey with four open-ended questions about their relationship…

High prevalence of metabolic syndrome in young Hispanic women: findings from the national Sister to Sister campaign.

Science.gov (United States)

Rodriguez, Fátima; Naderi, Sahar; Wang, Yun; Johnson, Caitlin E; Foody, JoAnne M

2013-04-01

Hispanics are the fastest growing segment of the U.S. population and have a higher prevalence of cardiometabolic risk factors as compared with non-Hispanic whites. Further data suggests that Hispanics have undiagnosed complications of metabolic syndrome, namely diabetes mellitus, at an earlier age. We sought to better understand the epidemiology of metabolic syndrome in Hispanic women using data from a large, community-based health screening program. Using data from the Sister to Sister: The Women's Heart Health Foundation community health fairs from 2008 to 2009 held in 17 U.S. cities, we sought to characterize how cardiometabolic risk profiles vary across age for women by race and ethnicity. Metabolic syndrome was defined using the updated National Cholesterol Education Program Adult Treatment Panel III (NCEP ATP III) guidelines, which included three or more of the following: Waist circumference ≥35 inches, triglycerides ≥150 mg/dL, high-density lipoprotein (HDL) <50 mg/dL, systolic blood pressure ≥130 mmHg or diastolic blood pressure ≥85 mmHg, or a fasting glucose ≥100 mg/dL. A total of 6843 community women were included in the analyses. Metabolic syndrome had a prevalence of 35%. The risk-adjusted odds ratio for metabolic syndrome in Hispanic women versus white women was 1.7 (95% confidence interval, 1.4, 2.0). Dyslipidemia was the strongest predictor of metabolic syndrome among Hispanic women. This disparity appeared most pronounced for younger women. Additional predictors of metabolic syndrome included black race, increasing age, and smoking. In a large, nationally representative sample of women, we found that metabolic syndrome was highly prevalent among young Hispanic women. Efforts specifically targeted to identifying these high-risk women are necessary to prevent the cardiovascular morbidity and mortality associated with metabolic syndrome.

Sister broods in the spruce bark beetle, Ips typographus (L.)

Czech Academy of Sciences Publication Activity Database

Davídková, Markéta; Doležal, Petr

2017-01-01

Roč. 405, DEC 01 (2017), s. 13-21 ISSN 0378-1127 Grant - others:Lesy ČR(CZ) 08/2009-2015 Institutional support: RVO:60077344 Keywords : re-emergence * sister broods * Ips typographus Subject RIV: EH - Ecology, Behaviour OBOR OECD: Zoology Impact factor: 3.064, year: 2016 http://www.sciencedirect.com/science/article/pii/S0378112717309507

Phylogenetic conservatism of thermal traits explains dispersal limitation and genomic differentiation of Streptomyces sister-taxa.

Science.gov (United States)

Choudoir, Mallory J; Buckley, Daniel H

2018-06-07

The latitudinal diversity gradient is a pattern of biogeography observed broadly in plants and animals but largely undocumented in terrestrial microbial systems. Although patterns of microbial biogeography across broad taxonomic scales have been described in a range of contexts, the mechanisms that generate biogeographic patterns between closely related taxa remain incompletely characterized. Adaptive processes are a major driver of microbial biogeography, but there is less understanding of how microbial biogeography and diversification are shaped by dispersal limitation and drift. We recently described a latitudinal diversity gradient of species richness and intraspecific genetic diversity in Streptomyces by using a geographically explicit culture collection. Within this geographically explicit culture collection, we have identified Streptomyces sister-taxa whose geographic distribution is delimited by latitude. These sister-taxa differ in geographic distribution, genomic diversity, and ecological traits despite having nearly identical SSU rRNA gene sequences. Comparative genomic analysis reveals genomic differentiation of these sister-taxa consistent with restricted gene flow across latitude. Furthermore, we show phylogenetic conservatism of thermal traits between the sister-taxa suggesting that thermal trait adaptation limits dispersal and gene flow across climate regimes as defined by latitude. Such phylogenetic conservatism of thermal traits is commonly associated with latitudinal diversity gradients for plants and animals. These data provide further support for the hypothesis that the Streptomyces latitudinal diversity gradient was formed as a result of historical demographic processes defined by dispersal limitation and driven by paleoclimate dynamics.

Metabolic syndrome, hypertension, and hyperlipidemia in mothers, fathers, sisters, and brothers of women with polycystic ovary syndrome: a systematic review and meta-analysis.

Science.gov (United States)

Yilmaz, Bulent; Vellanki, Priyathama; Ata, Baris; Yildiz, Bulent Okan

2018-02-01

To provide an evidence-based assessment of metabolic syndrome, hypertension, and hyperlipidemia in first-degree relatives of women with polycystic ovary syndrome (PCOS). Systematic review and meta-analysis. Not applicable. Mothers, fathers, sisters, and brothers of women with and without PCOS. An electronic-based search with the use of PubMed from 1960 to June 2015 and cross-checked references of relevant articles. Metabolic syndrome, hypertension and dyslipidemia, and surrogate markers, including systolic blood pressure (BP), diastolic BP, total cholesterol, low-density lipoprotein cholesterol, high-density lipoprotein cholesterol, and triglycerides. Fourteen of 3,346 studies were included in the meta-analysis. Prevalence of the following was significantly increased in relatives of women with PCOS: metabolic syndrome (risk ratio [RR] 1.78 [95% confidence interval 1.37, 2.30] in mothers, 1.43 [1.12, 1.81] in fathers, and 1.50 [1.12, 2.00] in sisters), hypertension (RR 1.93 [1.58, 2.35] in fathers, 2.92 [1.92, 4.45] in sisters), and dyslipidemia (RR 3.86 [2.54, 5.85] in brothers and 1.29 [1.11, 1.50] in fathers). Moreover, systolic BP (mothers, sisters, and brothers), total cholesterol (mothers and sisters), low-density lipoprotein cholesterol (sisters), and triglycerides (mothers and sisters) were significantly higher in first-degree relatives of PCOS probands than in controls. Our results show evidence of clustering for metabolic syndrome, hypertension, and dyslipidemia in mothers, fathers, sisters, and brothers of women with PCOS. PROSPERO 2016 CRD42016048557. Copyright © 2017 American Society for Reproductive Medicine. Published by Elsevier Inc. All rights reserved.

The use of convent archival records in medical research: the School Sisters of Notre Dame archives and the nun study.

Science.gov (United States)

Patzwald, Gari-Anne; Wildt, Sister Carol Marie

2004-01-01

The School Sisters of Notre Dame (SSND) archives program in a cooperative system for the arrangement and preservation of the records of the SSND provinces in North America, including records of individual sisters. Archival records include autobiographies, school and college transcripts, employment histories, and family socioeconomic data. The Nun Study, a longitudinal study of Alzheimer's disease and aging in 678 SSND sisters, compares data extracted from these records with data on late-life cognitive and physical function and postmortem brain neuropathology to explore early life factor that may affect late-life cognitive function and longevity.

20 CFR 410.380 - Determination of dependency; parent, brother, or sister.

Science.gov (United States)

2010-04-01

... 20 Employees' Benefits 2 2010-04-01 2010-04-01 false Determination of dependency; parent, brother... MINE HEALTH AND SAFETY ACT OF 1969, TITLE IV-BLACK LUNG BENEFITS (1969- ) Relationship and Dependency § 410.380 Determination of dependency; parent, brother, or sister. An individual who is the miner's...

The Physics of the Metaphase Spindle.

Science.gov (United States)

Oriola, David; Needleman, Daniel J; Brugués, Jan

2018-05-20

The assembly of the mitotic spindle and the subsequent segregation of sister chromatids are based on the self-organized action of microtubule filaments, motor proteins, and other microtubule-associated proteins, which constitute the fundamental force-generating elements in the system. Many of the components in the spindle have been identified, but until recently it remained unclear how their collective behaviors resulted in such a robust bipolar structure. Here, we review the current understanding of the physics of the metaphase spindle that is only now starting to emerge.

Very low dose and dose-rate X-ray induced adaptive response in human lymphocytes at various cell cycle stages against bleomycin induced chromatid aberrations

International Nuclear Information System (INIS)

Hossein Mozdarani; Moghadam, R.N.

2007-01-01

Complete text of publication follows. Objective: To study the adaptive response induced by very low doses of X-rays at very low dose rate in human lymphocytes at different cell cycle stages followed by a challenge dose of bleomycin sulphate at G2 phase. Materials and Methods: Human peripheral blood lymphocytes before (G0) and after PHA stimulation (G1 and G2) were exposed to 1 and 5 cGy X-rays generated by a fluoroscopy unit with a dose rate of 5.56 mGy/min and challenged with 5 μg/ml bleomycin sulphate (BLM) 48 hours after culture initiation. Mitotic cells were arrested at metaphase by addition of colcemid in cultures 1.5 h before harvesting. Harvesting and slide preparation was performed using standard method. 100 well spread metaphases were analyzed for the presence of chromatid type aberrations for each sample. Results: Results obtained indicate that there is a linear relationship between the dose of BLM and chromatid aberrations below 5 μg/ml (R=0.93, p<0.0001). The results also show that pretreatment of lymphocytes with low dose X-rays at G0, G1 and G2 phases of the cell cycle significantly reduced the sensitivity of lymphocytes to the clastogenic effects of BLM in G2. Much lower frequencies of chromatid aberrations were observed in X-ray irradiated lymphocytes following BLM treatment (p<0.05). The magnitudes of adaptation induced at different phases of the cell cycle were not significantly different. Furthermore, there was no a significant difference in the magnitude of adaptive response induced by either 1 or 5 cGy X-rays. Conclusion: These observations might indicate that resistance of pre-exposure of lymphocytes to very low doses of X-rays protects them from clastogenic effects of BLM. This effect might be due to initial DNA damage induced in these cells leading to provocation of an active DNA repair mechanism independent of cell cycle stage.

"Brothers and Sisters": A Novel Way to Teach Human Resources Management.

Science.gov (United States)

Bumpus, Minnette

2000-01-01

The novel "Brothers and Sisters" by Bebe Moore Campbell was used in a management course to explore human resource management issues, concepts, and theories. The course included prereading and postreading surveys, lecture, book review, and examination. Most of the students (92%) felt the novel was an appropriate way to meet course…

The Centenary of Janssens’s Chiasmatype Theory

Science.gov (United States)

Koszul, Romain; Meselson, Matthew; Van Doninck, Karine; Vandenhaute, Jean; Zickler, Denise

2012-01-01

The segregation and random assortment of characters observed by Mendel have their basis in the behavior of chromosomes in meiosis. But showing this actually to be the case requires a correct understanding of the meiotic behavior of chromosomes. This was achieved only gradually, over several decades, with much dispute and confusion along the way. One crucial step in the understanding of meiosis was provided in 1909 by Frans Alfons Janssens who published in La Cellule an article entitled “La théorie de la Chiasmatypie. Nouvelle interprétation des cinèses de maturation,” which contains the first description of the chiasma structure. He observed that, of the four chromatids present at the connection sites (chiasmata sites) at diplotene or anaphase of the first meiotic division, two crossed each other and two did not. He therefore postulated that the maternal and paternal chromatids that crossed penetrated the other until they broke and rejoined in maternal and paternal segments new ways; the other two chromatids remained free and thus intact. This allowed him also to propose that the chromatids distributed in the four nuclei issued from the second meiotic division had various combinations of maternal and paternal segments of each chromosome. And conversely, permitted the appreciation that the laws of Mendelian segregation required breakage and joining (crossing over) between homologous non-sister chromatids. Although Janssens’s article found a broad appreciative audience and had a large influence on the chromosomal theory at that time, his theory was resisted by both geneticists and cytologists for several decades. This Perspectives aims to highlight the novelty of Janssens’s chiasmatype theory by examining the historical background and our actual understanding of meiotic recombination. PMID:22701050

Cortical Pathology in RRMS: Taking a Cue from Four Sisters

Directory of Open Access Journals (Sweden)

Massimiliano Calabrese

2012-01-01

Full Text Available Background. Although grey matter pathology is a relevant aspect of multiple sclerosis (MS both with physical and cognitive rebounds, its pathogenesis is still under investigation. To what extent the familial and sporadic cases of MS differ in cortical pathology has not been elucidated yet. Here we present a multiple case report of four sisters affected by MS, all of them having a very high burden of cortical pathology. Methods. The clinical and grey matter MRI parameters of the patients were compared with those of twenty-five-aged matched healthy women and 25 women affected by sporadic MS (matched for age, disease duration, EDSS, and white matter lesion load. Results. Despite their short disease duration (<5 years, the four sisters showed a significant cortical thinning compared to healthy controls ( and sporadic MS ( and higher CLs number ( and volume ( compared to sporadic MS. Discussion. Although limited to a single family, our observation is worth of interest since it suggests that familial factors may account for a peculiar involvement of the cortex in MS pathology. This hypothesis should be further evaluated in a large number of multiplex MS families.

Constraining volcanic inflation at Three Sisters Volcanic Field in Oregon, USA, through microgravity and deformation modeling

Science.gov (United States)

Zurek, Jeffrey; William-Jones, Glyn; Johnson, Dan; Eggers, Al

2012-10-01

Microgravity data were collected between 2002 and 2009 at the Three Sisters Volcanic Complex, Oregon, to investigate the causes of an ongoing deformation event west of South Sister volcano. Three different conceptual models have been proposed as the causal mechanism for the deformation event: (1) hydraulic uplift due to continual injection of magma at depth, (2) pressurization of hydrothermal systems and (3) viscoelastic response to an initial pressurization at depth. The gravitational effect of continual magma injection was modeled to be 20 to 33 μGal at the center of the deformation field with volumes based on previous deformation studies. The gravity time series, however, did not detect a mass increase suggesting that a viscoelactic response of the crust is the most likely cause for the deformation from 2002 to 2009. The crust, deeper than 3 km, in the Three Sisters region was modeled as a Maxwell viscoelastic material and the results suggest a dynamic viscosity between 1018 to 5 × 1019 Pa s. This low crustal viscosity suggests that magma emplacement or stall depth is controlled by density and not the brittle ductile transition zone. Furthermore, these crustal properties and the observed geochemical composition gaps at Three Sisters can be best explained by different melt sources and limited magma mixing rather than fractional crystallization. More generally, low intrusion rates, low crustal viscosity, and multiple melt sources could also explain the whole rock compositional gaps observed at other arc volcanoes.

Psyche’s Sisters: Ambivalence of Sisterhood in Twentieth-century Irish Women’s Short Stories

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Ann Wan-lih Chang

2013-03-01

Full Text Available This paper examines and evaluates representations of problematic sisterly relationships in twentieth-century Irish women’s stories which display an emphasis on ambivalence and sibling rivalry.  The paper is based primarily on the literary output of Mary Lavin, Clare Boylan, Moy McCrory, Éilís Ní Dhuibhne, Jan Kennedy, Mary Morrissy and Claire Keegan.  The paper seeks, by reference both to feminist studies and Irish women’s short stories, to demonstrate the consequences and causes of a divided sisterhood which itself may be traced back to a suppression of expression of female solidarity embedded in western culture and manifested in western literary heritage.  Typically, such stories depict a conflict sourced in the need to develop self-identity and framed within the constraints imposed by separate social roles.  This kind of conflict results potentially in rivalry, antagonism, ambivalence, and the domination of one sibling by another.  Daughters/sisters are often depicted in these stories both as competing with each other for limited resources and also as seeking a sense of personal identity through mutual polarisation.  There are also stories into which are woven undertones of domination disguised as sisterly closeness, for which the actual motivation seems to be a repressed aspiration for intimacy.

[The work of Moscow communities of Sisters of Charity in own medical institutions].

Science.gov (United States)

Zorin, K V

2011-01-01

The article analyses the medical activities of Moscow communities of Sisters of Charity in curative and educational institutions organized by the communities themselves. The social ministration of communities on the territory of Moscow is considered.

Nanoceria have no genotoxic effect on human lens epithelial cells

Energy Technology Data Exchange (ETDEWEB)

Pierscionek, Barbara K; Yasseen, Akeel A [School of Biomedical Sciences, University of Ulster, Coleraine, BT52 1SA (United Kingdom); Li, Yuebin; Schachar, Ronald A; Chen, Wei [Department of Physics, University of Texas at Arlington, Arlington, TX 76019 (United States); Colhoun, Liza M, E-mail: b.pierscionek@ulster.ac.uk, E-mail: weichen@uta.edu [Centre for Vision and Vascular Sciences, School of Medicine, Dentistry and Biomedical Sciences, Queen' s University Belfast, Grosvenor Road, Belfast, BT12 6BA (United Kingdom)

2010-01-22

There are no treatments for reversing or halting cataract, a disease of the structural proteins in the eye lens, that has associations with other age-related degenerative conditions such as Alzheimer's disease. The incidence of cataract and associated conditions is increasing as the average age of the population rises. Protein folding diseases are difficult to assess in vivo as proteins and their age-related changes are assessed after extraction. Nanotechnology can be used to investigate protein changes in the intact lens as well as for a potential means of drug delivery. Nanoparticles, such as cerium oxide (CeO{sub 2}) which have antioxidant properties, may even be used as a means of treating cataract directly. Prior to use in treatments, nanoparticle genotoxicity must be tested to assess the extent of any DNA or chromosomal damage. Sister chromatid exchanges were measured and DNA damage investigated using the alkaline COMET assay on cultured human lens epithelial cells, exposed to 5 and 10 {mu}g ml{sup -1} of CeO{sub 2} nanoparticles (nanoceria). Nanoceria at these dosages did not cause any DNA damage or significant increases in the number of sister chromatid exchanges. The absence of genotoxic effects on lens cells suggests that nanoceria, in the doses and exposures tested in this study, are not deleterious to the eye lens and have the potential for use in studying structural alterations, in developing non-surgical cataract treatments and in investigating other protein folding diseases.

Arabidopsis thaliana WAPL is essential for the prophase removal of cohesin during meiosis.

Directory of Open Access Journals (Sweden)

Kuntal De

2014-07-01

Full Text Available Sister chromatid cohesion, which is mediated by the cohesin complex, is essential for the proper segregation of chromosomes in mitosis and meiosis. The establishment of stable sister chromatid cohesion occurs during DNA replication and involves acetylation of the complex by the acetyltransferase CTF7. In higher eukaryotes, the majority of cohesin complexes are removed from chromosomes during prophase. Studies in fly and human have shown that this process involves the WAPL mediated opening of the cohesin ring at the junction between the SMC3 ATPase domain and the N-terminal domain of cohesin's α-kleisin subunit. We report here the isolation and detailed characterization of WAPL in Arabidopsis thaliana. We show that Arabidopsis contains two WAPL genes, which share overlapping functions. Plants in which both WAPL genes contain T-DNA insertions show relatively normal growth and development but exhibit a significant reduction in male and female fertility. The removal of cohesin from chromosomes during meiotic prophase is blocked in Atwapl mutants resulting in chromosome bridges, broken chromosomes and uneven chromosome segregation. In contrast, while subtle mitotic alterations are observed in some somatic cells, cohesin complexes appear to be removed normally. Finally, we show that mutations in AtWAPL suppress the lethality associated with inactivation of AtCTF7. Taken together our results demonstrate that WAPL plays a critical role in meiosis and raises the possibility that mechanisms involved in the prophase removal of cohesin may vary between mitosis and meiosis in plants.

Maria Carolina and Marie Antoinette: Sisters and Queens in the mirror of Jacobin Public Opinion

Directory of Open Access Journals (Sweden)

Cinzia Recca

2014-09-01

Full Text Available Marie Antoinette of Franceand Maria Carolina of Naples, both consorts, contributed to a flourishing of matronage, reproducing conceptions of royal femininity that embraced both the private and public roles they were expected to fulfil. However, while the political role of the first Queen has been largely reconsidered, her sister Maria Carolina has not yet been adjudicated impartially. This is somewhat curious, because Maria Carolina inherited from her sister the same disregard towards the Revolution and this, as perceived by the Jacobins, was duly proposed in their acrimonious criticism of her political role. This paper aims to focus on this criticism, analysing how the charges against Maria Carolina in the post-French revolutionary period, were a political duplication of the Jacobin attacks on Marie Antoinette from 1791 onwards. From this point of view, the paper will focus on the portrait of Maria Carolina in 1793 revolutionary Parisby Giuseppe Gorani, an Italian Jacobin noble. His Mémoires Secrets – where Maria Carolina was represented as a wicked woman in the same terms previously employed to denounce her sister Marie Antoinette by the French Republicans – was well known across Italy. This subject dominated the main pamphlets and brochures published in Naples in 1799, during the brief duration of the Neapolitan Republic, because it legitimised the rebellion against the monarchy. After the fall of the Neapolitan Republic, the political attacks on Maria Carolina continued likewise in France, where many Neapolitan patriots were obliged to flee. Analysing  Giuseppe Gorani’s Mémoires we gather that the portrait of Marie Antoinette’s sister was painted according to the main stereotypes of  French revolutionary political culture.

Synergistic convergence and split pons in horizontal gaze palsy and progressive scoliosis in two sisters

Directory of Open Access Journals (Sweden)

Jain Nitin

2011-01-01

Full Text Available Synergistic convergence is an ocular motor anomaly where on attempted abduction or on attempted horizontal gaze, both the eyes converge. It has been related to peripheral causes such as congenital fibrosis of extraocular muscles (CFEOM, congenital cranial dysinnervation syndrome, ocular misinnervation or rarely central causes like horizontal gaze palsy with progressive scoliosis, brain stem dysplasia. We hereby report the occurrence of synergistic convergence in two sisters. Both of them also had kyphoscoliosis. Magnetic resonance imaging (MRI brain and spine in both the patients showed signs of brain stem dysplasia (split pons sign differing in degree (younger sister had more marked changes.

Empirical Psycho-Aesthetics and Her Sisters: Substantive and Methodological Issues--Part II

Science.gov (United States)

Konecni, Vladimir J.

2013-01-01

Empirical psycho-aesthetics is approached in this two-part article from two directions. Part I, which appeared in the Winter 2012 issue of "JAE," addressed definitional and organizational issues, including the field's origins, its relation to "sister" disciplines (experimental philosophy, cognitive neuroscience of art, and neuroaesthetics), and…

First-generation physical map of the Culicoides variipennis (Diptera: Ceratopogonidae) genome.

Science.gov (United States)

Nunamaker, R A; Brown, S E; McHolland, L E; Tabachnick, W J; Knudson, D L

1999-11-01

Recombinant cosmids labeled with biotin-11-dUTP or digoxigenin by nick translation were used as in situ hybridization probes to metaphase chromosomes of Culicoides variipennis (Coquillett). Paired fluorescent signals were detected on each arm of sister chromatids and were ordered along the 3 chromosomes. Thirty-three unique probes were mapped to the 3 chromosomes of C. variipennis (2n = 6): 7 to chromosome 1, 20 to chromosome 2, and 6 to chromosome 3. This work represents the first stage in generating a physical map of the genome of C. variipennis.

How unfinished business from S-phase affects mitosis and beyond

DEFF Research Database (Denmark)

Mankouri, H.W.; Huttner, D.; Hickson, I.D.

2013-01-01

The eukaryotic cell cycle is conventionally viewed as comprising several discrete steps, each of which must be completed before the next one is initiated. However, emerging evidence suggests that incompletely replicated, or unresolved, chromosomes from S-phase can persist into mitosis, where...... they present a potential threat to the faithful segregation of sister chromatids. In this review, we provide an overview of the different classes of loci where this 'unfinished S-phase business' can lead to a variety of cytogenetically distinct DNA structures throughout the various steps of mitosis...

STAG2 and Rad21 mammalian mitotic cohesins are implicated in meiosis

OpenAIRE

Prieto, Ignacio; Pezzi, Nieves; Buesa, José M.; Kremer, Leonor; Barthelemy, Isabel; Carreiro, Candelas; Roncal, Fernando; Martínez, Alicia; Gómez, Lucio; Fernández, Raúl; Martínez-A, Carlos; Barbero, José L.

2002-01-01

STAG/SA proteins are specific cohesin complex subunits that maintain sister chromatid cohesion in mitosis and meiosis. Two members of this family, STAG1/SA1 and STAG2/SA2,‡ are classified as mitotic cohesins, as they are found in human somatic cells and in Xenopus laevis as components of the cohesinSA1 and cohesinSA2 complexes, in which the shared subunits are Rad21/SCC1, SMC1 and SMC3 proteins. A recently reported third family member, STAG3, is germinal cell-specific and is a subunit of the ...

Review of the international symposium, sister chromatid exchanges: twenty-five years of experimental research

International Nuclear Information System (INIS)

Tice, R.R.; Lambert, B.; Morimoto, Kanehisa; Hollaender, A.

1983-01-01

The purpose of this symposium was to honor initial research at Brookhaven by bringing internationally recognized leaders in the fields of genetics, cytogenetics, carcinogenesis, mutagenesis, radiation biology, toxicology, and environmental health together into an open forum to present and discuss: (1) current knowledge of the induction and formation of SCEs and their relationship to other biological endpoints, including carcinogenesis, mutagenesis, transformation, clastogenesis, DNA damage and repair, and cellular toxicity; (2) the optimal strategies for the utilization of SCEs in genetic toxicology testing schemes involving in vitro and in vivo exposure situations; (3) the most valid statistical methods for analyzing SCE data obtained from cells in culture, from cells in intact organisms, and from cells in humans; (4) the relevance of SCEs as an indicator of human disease states, both inherited and acquired, and of progress in disease treatment; and (5) the use of SCEs as an indicator of human exposure to genotoxic agents and their relevance as a prognosticator of future adverse health outcomes. This report summarizes the presentations. 7 references

Probing the mechanism of sister chromatid exchange formation with the fluorescent plus Giemsa technique

International Nuclear Information System (INIS)

Yu, L.C.

1976-01-01

The effects of x rays and light flashes on the SCE formation in BrdUrd-substituted Chinese hamster ovary (CHO) cells are examined using the fluorescent plus Giemsa (FPG) technique, which allows SCE's to be visualized with greater precision than 3 H autoradiography does. Near-diploid cells are selected and scoring SCE from every chromosome of near-diploid cells or from chromosome no. 1 is found to give a more accurate measure of the SCE induction. Double synchronous cells are used for the x ray study and asynchronous cells are used for the light flash study. The results indicate that x rays can induce SCE's throughout the cell cycle with S the most sensitive stage and G 2 the least sensitive stage. Light flashes can induce an appreciable amount of SCE's while no appreciable amount of chromosomal aberrations can be detected under conditions used in this study. For x-ray-induced chromosomal aberrations, G 2 is the most sensitive stage with G 1 being slightly more sensitive than S, which is consistent with other observations. Additionally, aberration induction is shown to be a more sensitive indicator of x-ray-induced cell damage than SCE induction, but SCE induction is a potentially good indicator of mutation induction. This study also suggests that symmetrically reunited isochromatid breaks can not be the sole source of SCE's and SCE induction is a different but not independent radiobiological effect from chromosomal aberration induction. SCE formation is proposed to be a consequence of specific type(s) of single strand breaks in DNA

Effect of tritiated compounds on sister-chromatid exchanges (SCE) in human lymphocytes in vitro

International Nuclear Information System (INIS)

Gong Manli; Rao Yongqing; Chen Guanying; Wu Weiwei; Zhao Zilan; Shen Lei

1990-01-01

Human lymphocytes treated in vitro with various activities of 3 H-TdR and 3 H-UdR were cultured to understand the effects of tritium on the cell cycle and the frequency of SCE. The results of these experiments indicated that both tritiated compounds make the frequency of SCE increase and the cell cycle delay. The frequency of SCE increased markedly with activity of 3 H. With respect to delaying cell cycle, 3 H-UdR was more effective than 3 H-TdR. The average frequencies of SCE for 3 H-UdR were higher than those for 3 H-TdR. With the exception of 3.7 x 10 3 Bq/mL group and differences between other 3 H-UdR groups and corresponding 3 H-TdR group were significant (t test, p < 0.01). These results suggest that tritiated compounds may have the effect on the cell proliferating rate. The cell proliferating rate index (PRI) seems to be related with the frequency of SCE: the higher the frequency of SCE, the lower the PRI is

Review of the international symposium, sister chromatid exchanges: twenty-five years of experimental research

Energy Technology Data Exchange (ETDEWEB)

Tice, R.R.; Lambert, B.; Morimoto, Kanehisa; Hollaender, A.

1983-01-01

The purpose of this symposium was to honor initial research at Brookhaven by bringing internationally recognized leaders in the fields of genetics, cytogenetics, carcinogenesis, mutagenesis, radiation biology, toxicology, and environmental health together into an open forum to present and discuss: (1) current knowledge of the induction and formation of SCEs and their relationship to other biological endpoints, including carcinogenesis, mutagenesis, transformation, clastogenesis, DNA damage and repair, and cellular toxicity; (2) the optimal strategies for the utilization of SCEs in genetic toxicology testing schemes involving in vitro and in vivo exposure situations; (3) the most valid statistical methods for analyzing SCE data obtained from cells in culture, from cells in intact organisms, and from cells in humans; (4) the relevance of SCEs as an indicator of human disease states, both inherited and acquired, and of progress in disease treatment; and (5) the use of SCEs as an indicator of human exposure to genotoxic agents and their relevance as a prognosticator of future adverse health outcomes. This report summarizes the presentations. 7 references. (ACR)

Birth weight and fetal growth in infants born to female hairdressers and their sisters.

Science.gov (United States)

Axmon, A; Rylander, L

2009-03-01

To investigate birth weight and fetal growth in female hairdressers, while controlling for intergenerational effects and effects related to childhood exposures. A cohort of women who had attended vocational schools for hairdressers were compared to their sisters with respect to birth weight and fetal growth (measured as small for gestational age (SGA) or large for gestational age (LGA), respectively) in their infants. In total, 6223 infants born to 3137 hairdressers and 8388 infants born to 3952 hairdressers' sisters were studied. Among the infants born to the hairdressers' sisters, the distribution of birth weights were wider than that among the infants born to the hairdressers. This was also reflected in that hairdresser cohort affiliation tended to be protective against both SGA (odds ratio 0.80; 95% confidence interval 0.49 to 1.31) and LGA (0.77; 0.54 to 1.09). For LGA, this effect was even more pronounced among women who had actually worked as hairdressers during at least one pregnancy (0.60; 0.39 to 0.92). The infants born to these women also had a significantly lower mean birth weight (3387 g vs 3419 g; p = 0.033). The results from the present study suggest that infants born to hairdressers have a decreased risk of being LGA. This is most likely not caused by a shift in birth weight distribution or abnormal glucose metabolism.

Meiosis-specific cohesin component, Stag3 is essential for maintaining centromere chromatid cohesion, and required for DNA repair and synapsis between homologous chromosomes.

Science.gov (United States)

Hopkins, Jessica; Hwang, Grace; Jacob, Justin; Sapp, Nicklas; Bedigian, Rick; Oka, Kazuhiro; Overbeek, Paul; Murray, Steve; Jordan, Philip W

2014-07-01

Cohesins are important for chromosome structure and chromosome segregation during mitosis and meiosis. Cohesins are composed of two structural maintenance of chromosomes (SMC1-SMC3) proteins that form a V-shaped heterodimer structure, which is bridged by a α-kleisin protein and a stromal antigen (STAG) protein. Previous studies in mouse have shown that there is one SMC1 protein (SMC1β), two α-kleisins (RAD21L and REC8) and one STAG protein (STAG3) that are meiosis-specific. During meiosis, homologous chromosomes must recombine with one another in the context of a tripartite structure known as the synaptonemal complex (SC). From interaction studies, it has been shown that there are at least four meiosis-specific forms of cohesin, which together with the mitotic cohesin complex, are lateral components of the SC. STAG3 is the only meiosis-specific subunit that is represented within all four meiosis-specific cohesin complexes. In Stag3 mutant germ cells, the protein level of other meiosis-specific cohesin subunits (SMC1β, RAD21L and REC8) is reduced, and their localization to chromosome axes is disrupted. In contrast, the mitotic cohesin complex remains intact and localizes robustly to the meiotic chromosome axes. The instability of meiosis-specific cohesins observed in Stag3 mutants results in aberrant DNA repair processes, and disruption of synapsis between homologous chromosomes. Furthermore, mutation of Stag3 results in perturbation of pericentromeric heterochromatin clustering, and disruption of centromere cohesion between sister chromatids during meiotic prophase. These defects result in early prophase I arrest and apoptosis in both male and female germ cells. The meiotic defects observed in Stag3 mutants are more severe when compared to single mutants for Smc1β, Rec8 and Rad21l, however they are not as severe as the Rec8, Rad21l double mutants. Taken together, our study demonstrates that STAG3 is required for the stability of all meiosis-specific cohesin

Meiosis-specific cohesin component, Stag3 is essential for maintaining centromere chromatid cohesion, and required for DNA repair and synapsis between homologous chromosomes.

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Jessica Hopkins

2014-07-01

Full Text Available Cohesins are important for chromosome structure and chromosome segregation during mitosis and meiosis. Cohesins are composed of two structural maintenance of chromosomes (SMC1-SMC3 proteins that form a V-shaped heterodimer structure, which is bridged by a α-kleisin protein and a stromal antigen (STAG protein. Previous studies in mouse have shown that there is one SMC1 protein (SMC1β, two α-kleisins (RAD21L and REC8 and one STAG protein (STAG3 that are meiosis-specific. During meiosis, homologous chromosomes must recombine with one another in the context of a tripartite structure known as the synaptonemal complex (SC. From interaction studies, it has been shown that there are at least four meiosis-specific forms of cohesin, which together with the mitotic cohesin complex, are lateral components of the SC. STAG3 is the only meiosis-specific subunit that is represented within all four meiosis-specific cohesin complexes. In Stag3 mutant germ cells, the protein level of other meiosis-specific cohesin subunits (SMC1β, RAD21L and REC8 is reduced, and their localization to chromosome axes is disrupted. In contrast, the mitotic cohesin complex remains intact and localizes robustly to the meiotic chromosome axes. The instability of meiosis-specific cohesins observed in Stag3 mutants results in aberrant DNA repair processes, and disruption of synapsis between homologous chromosomes. Furthermore, mutation of Stag3 results in perturbation of pericentromeric heterochromatin clustering, and disruption of centromere cohesion between sister chromatids during meiotic prophase. These defects result in early prophase I arrest and apoptosis in both male and female germ cells. The meiotic defects observed in Stag3 mutants are more severe when compared to single mutants for Smc1β, Rec8 and Rad21l, however they are not as severe as the Rec8, Rad21l double mutants. Taken together, our study demonstrates that STAG3 is required for the stability of all meiosis

Exploring the transition from\\ud staff nurse to\\ud ward sister/manager –\\ud An exploratory case study

OpenAIRE

Enterkin, Judith

2016-01-01

Background\\ud The ward sister/manager figure has traditionally been considered the ward based\\ud clinical leader. This role has evolved over time in response to professional and\\ud political demands; despite or because of this, reports of role ambiguity exist and\\ud the ward sister/manager position has become increasingly difficult to recruit to,\\ud with nurses arguably looking to roles perceived to have greater influence and\\ud status, but less onerous managerial responsibility. Understandin...

Familial Churg-Strauss Syndrome in a Sister and Brother.

Science.gov (United States)

Alyasin, Soheyla; Khoshkhui, Maryam; Amin, Reza

2015-06-01

Churg-Strauss syndrome (CSS) is a granulomatous small vessel vasculitis. It is characterized by asthma, allergic granulomatosis and vasculitis. This syndrome is rare in children. A 5 years old boy was admitted with cough, fever and dyspnea for 2 weeks. On the basis of laboratory data (peripheral eosinophilia), associated with skin biopsy, and history of CSS in his sister, this disease was eventually diagnosed. The patient had good response to corticosteroid. In every asthmatic patient with prolonged fever, eosinophilia and multisystemic involvment, CSS should be considered.

Geodetic observations and modeling of magmatic inflation at the Three Sisters volcanic center, central Oregon Cascade Range, USA

Science.gov (United States)

Dzurisin, Daniel; Lisowski, Michael; Wicks, Charles W.; Poland, Michael P.; Endo, Elliot T.

2006-02-01

Tumescence at the Three Sisters volcanic center began sometime between summer 1996 and summer 1998 and was discovered in April 2001 using interferometric synthetic aperture radar (InSAR). Swelling is centered about 5 km west of the summit of South Sister, a composite basaltic-andesite to rhyolite volcano that last erupted between 2200 and 2000 yr ago, and it affects an area ˜20 km in diameter within the Three Sisters Wilderness. Yearly InSAR observations show that the average maximum displacement rate was 3-5 cm/yr through summer 2001, and the velocity of a continuous GPS station within the deforming area was essentially constant from June 2001 to June 2004. The background level of seismic activity has been low, suggesting that temperatures in the source region are high enough or the strain rate has been low enough to favor plastic deformation over brittle failure. A swarm of about 300 small earthquakes ( Mmax = 1.9) in the northeast quadrant of the deforming area on March 23-26, 2004, was the first notable seismicity in the area for at least two decades. The U.S. Geological Survey (USGS) established tilt-leveling and EDM networks at South Sister in 1985-1986, resurveyed them in 2001, the latter with GPS, and extended them to cover more of the deforming area. The 2001 tilt-leveling results are consistent with the inference drawn from InSAR that the current deformation episode did not start before 1996, i.e., the amount of deformation during 1995-2001 from InSAR fully accounts for the net tilt at South Sister during 1985-2001 from tilt-leveling. Subsequent InSAR, GPS, and leveling observations constrain the source location, geometry, and inflation rate as a function of time. A best-fit source model derived from simultaneous inversion of all three datasets is a dipping sill located 6.5 ± 2.5 km below the surface with a volume increase of 5.0 × 10 6 ± 1.5 × 10 6 m 3/yr (95% confidence limits). The most likely cause of tumescence is a pulse of basaltic magma

The first record of a trans-oceanic sister-group relationship between obligate vertebrate troglobites.

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Prosanta Chakrabarty

Full Text Available We show using the most complete phylogeny of one of the most species-rich orders of vertebrates (Gobiiformes, and calibrations from the rich fossil record of teleost fishes, that the genus Typhleotris, endemic to subterranean karst habitats in southwestern Madagascar, is the sister group to Milyeringa, endemic to similar subterranean systems in northwestern Australia. Both groups are eyeless, and our phylogenetic and biogeographic results show that these obligate cave fishes now found on opposite ends of the Indian Ocean (separated by nearly 7,000 km are each others closest relatives and owe their origins to the break up of the southern supercontinent, Gondwana, at the end of the Cretaceous period. Trans-oceanic sister-group relationships are otherwise unknown between blind, cave-adapted vertebrates and our results provide an extraordinary case of Gondwanan vicariance.

X-ray- and TEM-induced mitotic recombination in Drosophila melanogaster: Unequal and sister-strand recombination

International Nuclear Information System (INIS)

Becker, H.J.

1975-01-01

Twin mosaic spots of dark-apricot and light-apricot ommatidia were found in the eyes of wsup(a)/wsup(a) females, of wsup(a) males, of females homozygous for In(1)sc 4 , wsup(a) and of attached-X females homozygous for wsup(a). The flies were raised from larvae which had been treated with 1,630 R of X-rays at the age of 48-52 hours. An additional group of wsup(a)/wsup(a) females and wsup(a) males came from larvae that had been fed with triethylene melamine (TEM) at the age of 22-24 hours. The twin spots apparently were the result of induced unequal mitotic recombination, i.e. from unequal sister-strand recombination in the males and from unequal sister-strand recombination as well as, possibly, unequal recombination between homologous strands in the females. That is, a duplication resulted in wsup(a)Dpwsup(a)/wsup(a) dark-apricto ommatidia and the corresponding deficiency in an adjacent area of wsup(a)/Dfwsup(a) light-apricot ommatidia. In an additional experiment sister-strand mitotic recombination in the ring-X chromosome of ring-X/rod-X females heterozygous for w and wsup(co) is believed to be the cause for X-ray induced single mosaic spots that show the phenotype of the rod-X marker. (orig.) [de

Non-SMC condensin I complex proteins control chromosome segregation and survival of proliferating cells in the zebrafish neural retina

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Harris William A

2009-07-01

Full Text Available Abstract Background The condensation of chromosomes and correct sister chromatid segregation during cell division is an essential feature of all proliferative cells. Structural maintenance of chromosomes (SMC and non-SMC proteins form the condensin I complex and regulate chromosome condensation and segregation during mitosis. However, due to the lack of appropriate mutants, the function of the condensin I complex during vertebrate development has not been described. Results Here, we report the positional cloning and detailed characterization of retinal phenotypes of a zebrafish mutation at the cap-g locus. High resolution live imaging reveals that the progression of mitosis between prometa- to telophase is delayed and that sister chromatid segregation is impaired upon loss of CAP-G. CAP-G associates with chromosomes between prometa- and telophase of the cell cycle. Loss of the interaction partners CAP-H and CAP-D2 causes cytoplasmic mislocalization of CAP-G throughout mitosis. DNA content analysis reveals increased genomic imbalances upon loss of non-SMC condensin I subunits. Within the retina, loss of condensin I function causes increased rates of apoptosis among cells within the proliferative ciliary marginal zone (CMZ whereas postmitotic retinal cells are viable. Inhibition of p53-mediated apoptosis partially rescues cell numbers in cap-g mutant retinae and allows normal layering of retinal cell types without alleviating their aberrant nuclear sizes. Conclusion Our findings indicate that the condensin I complex is particularly important within rapidly amplifying progenitor cell populations to ensure faithful chromosome segregation. In contrast, differentiation of postmitotic retinal cells is not impaired upon polyploidization.

[THE INFLUENCE OF THE PREPARATION PRETREATMENT ON IN SITU DETECTION OF 5-METHYLCYTOSINE IN METAPHASE CHROMOSOMES AND IN INTERPHASE NUCLEI].

Science.gov (United States)

Grudinina, N A; Sasina, L K; Noniashvili, E M; Neronova, E G; Pavlinova, L I; Suchkova, I O; Sofronov, G A; Patkin, E L

2015-01-01

Qualitative and quantitate analysis of DNA methylation in situ at the level of cells, chromosomes and chromosomal domains is extremely important for the diagnosis and treatment of various diseases, the study of ageing and the consequences of environmental impacts. An important question arises, whether the revealed in situ methylation pattern reflects DNA methylation per se and (or) availability of the DNA for antibodies, which in turn depends on the peculiarities of chromatin structure and chromosome condensation. These events can lead to an incorrect evaluation of the actual pattern of DNA methylation. To avoid this shortcoming as far as possible, we have modified the most widely used method of revealing 5-methylcytosine in situ with monoclonal antibodies. Here we have shown that the detection of DNA methylation staining of chromosomes including C-heterochromatin, chromosomal arms and sister chromatids is drastically dependent on pretreatment of chromosomal preparations for immunocytochemical study using fluorescent antibodies. Using undifferentiated stem cells of mouse embryonal carcinoma line F9, it has been found that change in preparations storage results in a sharp fluorescence decrease up to complete disappearance of the signal in centromeric heterochromatin. With the help of the method described in the work, we have first revealed the asymmetry of sister chromatids methylation in metaphase chromosomes of F9 cell and lymphocytes of human periphery blood. This may lead to asymmetry of transcriptional signature of daughter cells after division. The proposed here modification of 5-methylcytosine detection in situ provides a more complete characterization of methylation of chromosomes and chromosomal domains, compared to previously published methods.

[Wolfram syndrome: clinical and genetic analysis in two sisters].

Science.gov (United States)

Conart, J-B; Maalouf, T; Jonveaux, P; Guerci, B; Angioi, K

2011-10-01

Wolfram syndrome is a severe genetic disorder defined by the association of diabetes mellitus, optic atrophy, deafness, and diabetes insipidus. Two sisters complained of progressive visual loss. Fundus examination evidenced optic atrophy. Their past medical history revealed diabetes mellitus and deafness since childhood. The association of these symptoms made the diagnosis of Wolfram syndrome possible. It was confirmed by molecular analysis, which evidenced composite WFS1 heterozygous mutations inherited from both their mother and father. Ophthalmologists should be aware of the possibility of Wolfram syndrome when diagnosing optic atrophy in diabetic children. Copyright © 2011 Elsevier Masson SAS. All rights reserved.

Social Functioning among Girls with Fragile X or Turner Syndrome and Their Sisters.

Science.gov (United States)

Mazzocco, Michele M. M.; Baumgardner, Thomas; Freund, Lisa S.; Reiss, Allan L.

1998-01-01

Social behaviors among girls (ages 6-16) with fragile X (n=8) or Turner syndrome (n=9) were examined to address the role of family environment versus biological determinants of social dysfunction. Compared to their sisters, subjects had lower IQS and higher rating of social and attention problems. (Author/CR)

Climate niches of milkweeds with plesiomorphic traits (Secamonoideae; Apocynaceae) and the milkweed sister group link ancient African climates and floral evolution.

Science.gov (United States)

Livshultz, Tatyana; Mead, Jerry V; Goyder, David J; Brannin, Michelle

2011-12-01

Climate change that increases mortality of plants and pollinators can create mate-finding Allee effects and thus act as a strong selective force on floral morphology. Milkweeds (Secamonoideae and Asclepiadoideae; Apocynaceae) are typically small plants of seasonally dry habitats, with pollinia and high pollen-transfer efficiency. Their sister group (tribe Baisseeae and Dewevrella) is mostly comprised of giant lianas of African rainforests, with pollen in monads. Comparison of the two groups motivated a new hypothesis: milkweeds evolved in the context of African aridification and the shifting of rainforest to dry forest. Pollinia and high pollen-transfer efficiency may have been adaptations that alleviated mate-finding Allee effects generated by high mortality during droughts. We formally tested whether milkweeds have a drier climate niche by comparing milkweeds with plesiomorphic traits (Secamonoideae) and the milkweed sister group in continental Africa. We georeferenced specimens of the milkweed sister group and Secamonoideae in continental Africa, extracted 19 climatic variables from the Worldclim model, conducted factor analysis to identify correlated suites of variables, and compared the frequency distributions of the two lineages relative to each factor. The distributions of Secamonoideae and the milkweed sister group differed significantly relative to four factors, each correlated with a distinct suite of climate parameters: (1) air temperature (Secamonoideae: cooler), (2) total and (3) summer precipitation (Secamonoideae: drier), and (4) temperature seasonality and isothermality (Secamonoideae: more seasonal and less isothermal). Secamonoideae in continental Africa inhabit drier, cooler sites than do the milkweed sister group, consistent with a shift from rainforests to dry forests in a cooling climate.

Effect of pretreatment with venom of Apis mellifera bees on the yield of gamma-ray induced chromosome aberrations in human blood lymphocytes

International Nuclear Information System (INIS)

Varanda, E.A.; Takahashi, C.S.

1993-01-01

Venom of the honey bee Apis mellifera induced a protective effect against the induction of dicentric chromosomes by gamma radiation (2.0 Gy) in human peripheral blood lymphocytes when the cultures were treated with 0.00015 μl venom/1 ml medium 6 h before irradiation. In cultures to which the venom was added immediately before irradiation with 0.25, 1.0 and 2.0 Gy, no significant differences in number of dicentric chromosomes induced was observed when compared to cultures submitted to irradiation only. The venom did not induce clastogenic effects nor did it increase the frequency of sister chromatid exchanges. (author)

The roles of the Saccharomyces cerevisiae RecQ helicase SGS1 in meiotic genome surveillance.

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Amit Dipak Amin

2010-11-01

Full Text Available The Saccharomyces cerevisiae RecQ helicase Sgs1 is essential for mitotic and meiotic genome stability. The stage at which Sgs1 acts during meiosis is subject to debate. Cytological experiments showed that a deletion of SGS1 leads to an increase in synapsis initiation complexes and axial associations leading to the proposal that it has an early role in unwinding surplus strand invasion events. Physical studies of recombination intermediates implicate it in the dissolution of double Holliday junctions between sister chromatids.In this work, we observed an increase in meiotic recombination between diverged sequences (homeologous recombination and an increase in unequal sister chromatid events when SGS1 is deleted. The first of these observations is most consistent with an early role of Sgs1 in unwinding inappropriate strand invasion events while the second is consistent with unwinding or dissolution of recombination intermediates in an Mlh1- and Top3-dependent manner. We also provide data that suggest that Sgs1 is involved in the rejection of 'second strand capture' when sequence divergence is present. Finally, we have identified a novel class of tetrads where non-sister spores (pairs of spores where each contains a centromere marker from a different parent are inviable. We propose a model for this unusual pattern of viability based on the inability of sgs1 mutants to untangle intertwined chromosomes. Our data suggest that this role of Sgs1 is not dependent on its interaction with Top3. We propose that in the absence of SGS1 chromosomes may sometimes remain entangled at the end of pre-meiotic replication. This, combined with reciprocal crossing over, could lead to physical destruction of the recombined and entangled chromosomes. We hypothesise that Sgs1, acting in concert with the topoisomerase Top2, resolves these structures.This work provides evidence that Sgs1 interacts with various partner proteins to maintain genome stability throughout

Living with a Brother Who Has an Autism Spectrum Disorder: A Sister's Perspective

Science.gov (United States)

Connell, Zara O.; Halloran, Maeve O.; Doody, Owen

2016-01-01

People with Autism Spectrum Disorder (ASD) are born into families and influence family functioning both positively and negatively. One of the most enduring relationships a person with ASD will have is their relationship with a brother or sister. Services for people with ASD should provide effective support to families, which include brothers,…

Arts, Crafts, and Rural Rehabilitation: the Sisters of Charity, Halifax, and Vocational Education in Terence Bay, Nova Scotia, 1938-1942

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Sasha MULLALLY

2018-01-01

Full Text Available Responding to rural poverty associated with the declining fishery, the rise of industrial capitalism, and the impact of the Great Depression, the Sisters of Charity, Halifax, implemented a vocational training program in weaving and carpentry in the small community of Terence Bay, Nova Scotia in 1938. Senator William Dennis, a proponent of the New Democracy Movement, financed the program. Because the Sisters based their claims to success on observed behavioural changes among the residents of Terence Bay, the program can be seen as an example of liberal therapeutics in education, a model that placed emphasis on achieving social goals rather than transferring discrete skills and capacities to pupils. Focusing on the years 1938-43, this paper outlines the rehabilitation efforts at Terence Bay, describes the programs the Sisters implemented, and evaluates the definitions of success ascribed to their training school just a few years later.

Meiosis I chromosome segregation is established through regulation of microtubule–kinetochore interactions

Science.gov (United States)

Miller, Matthew P; Ünal, Elçin; Brar, Gloria A; Amon, Angelika

2012-01-01

During meiosis, a single round of DNA replication is followed by two consecutive rounds of nuclear divisions called meiosis I and meiosis II. In meiosis I, homologous chromosomes segregate, while sister chromatids remain together. Determining how this unusual chromosome segregation behavior is established is central to understanding germ cell development. Here we show that preventing microtubule–kinetochore interactions during premeiotic S phase and prophase I is essential for establishing the meiosis I chromosome segregation pattern. Premature interactions of kinetochores with microtubules transform meiosis I into a mitosis-like division by disrupting two key meiosis I events: coorientation of sister kinetochores and protection of centromeric cohesin removal from chromosomes. Furthermore we find that restricting outer kinetochore assembly contributes to preventing premature engagement of microtubules with kinetochores. We propose that inhibition of microtubule–kinetochore interactions during premeiotic S phase and prophase I is central to establishing the unique meiosis I chromosome segregation pattern. DOI: http://dx.doi.org/10.7554/eLife.00117.001 PMID:23275833

Subcortical laminar heterotopia in two sisters and their mother : MRI, clinical findings and pathogenesis

NARCIS (Netherlands)

van der Valk, PHM; Snoeck, [No Value; Meiners, LC; des Portes, [No Value; Chelly, J; Pinard, JM; Ippel, PF; van Nieuwenhuizen, O

MR imaging, clinical data and underlying pathogenesis of subcortical laminar heterotopia (SCLH), also known as band heterotopia, in two sisters and their mother are presented. On MR imaging a different degree of SCLH was found in all three affected family-members. The inversion recovery sequence was

Teaching Sisters and Transnational Networks: Recruitment and Education Expansion in the Long Nineteenth Century

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Raftery, Deirdre

2015-01-01

This article examines the management of the education enterprise of teaching Sisters, with reference to their transnational networking. The article suggests that orders of women religious were the first all-female transnational networks, engaged constantly in work that was characterised by "movement, ebb and circulation". The mobility of…

Live and let die - the B(sister MADS-box gene OsMADS29 controls the degeneration of cells in maternal tissues during seed development of rice (Oryza sativa.

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Xuelian Yang

Full Text Available B(sister genes have been identified as the closest relatives of class B floral homeotic genes. Previous studies have shown that B(sister genes from eudicots are involved in cell differentiation during ovule and seed development. However, the complete function of B(sister genes in eudicots is masked by redundancy with other genes and little is known about the function of B(sister genes in monocots, and about the evolution of B(sister gene functions. Here we characterize OsMADS29, one of three MADS-box B(sister genes in rice. Our analyses show that OsMADS29 is expressed in female reproductive organs including the ovule, ovule vasculature, and the whole seed except for the outer layer cells of the pericarp. Knock-down of OsMADS29 by double-stranded RNA-mediated interference (RNAi results in shriveled and/or aborted seeds. Histological analyses of the abnormal seeds at 7 days after pollination (DAP indicate that the symplastic continuity, including the ovular vascular trace and the nucellar projection, which is the nutrient source for the filial tissue at early development stages, is affected. Moreover, degeneration of all the maternal tissues in the transgenic seeds, including the pericarp, ovular vascular trace, integuments, nucellar epidermis and nucellar projection, is blocked as compared to control plants. Our results suggest that OsMADS29 has important functions in seed development of rice by regulating cell degeneration of maternal tissues. Our findings provide important insights into the ancestral function of B(sister genes.

A role for the budding yeast separase, Esp1, in Ty1 element retrotransposition.

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Krystina L Ho

2015-03-01

Full Text Available Separase/Esp1 is a protease required at the onset of anaphase to cleave cohesin and thereby enable sister chromatid separation. Esp1 also promotes release of the Cdc14 phosphatase from the nucleolus to enable mitotic exit. To uncover other potential roles for separase, we performed two complementary genome-wide genetic interaction screens with a strain carrying the budding yeast esp1-1 separase mutation. We identified 161 genes that when mutated aggravate esp1-1 growth and 44 genes that upon increased dosage are detrimental to esp1-1 viability. In addition to the expected cell cycle and sister chromatid segregation genes that were identified, 24% of the genes identified in the esp1-1 genetic screens have a role in Ty1 element retrotransposition. Retrotransposons, like retroviruses, replicate through reverse transcription of an mRNA intermediate and the resultant cDNA product is integrated into the genome by a conserved transposon or retrovirus encoded integrase protein. We purified Esp1 from yeast and identified an interaction between Esp1 and Ty1 integrase using mass spectrometry that was subsequently confirmed by co-immunoprecipitation analysis. Ty1 transposon mobility and insertion upstream of the SUF16 tRNA gene are both reduced in an esp1-1 strain but increased in cohesin mutant strains. Securin/Pds1, which is required for efficient localization of Esp1 to the nucleus, is also required for efficient Ty1 transposition. We propose that Esp1 serves two roles to mediate Ty1 transposition - one to remove cohesin and the second to target Ty1-IN to chromatin.

99mTc-DMSA Uptake in a Sister Mary Joseph's Nodule From Ovarian Cancer.

Science.gov (United States)

Naddaf, Sleiman; Azzumeea, Fahad; Fahad Alzayed, Mohammed

2016-12-01

A 50-year-old woman with ovarian cancer underwent Tc-DMSA scan to evaluate the functional status of the right hydronephrotic kidney. The images incidentally revealed a well-defined focus of mild radiotracer uptake at the midanterior abdominal wall, which correlated with a metastatic Sister Mary Joseph's nodule seen on CT performed a week earlier.

[Sense of coherence and ways of coping in the relationship with brother or sister in healthy siblings of mentally ill persons].

Science.gov (United States)

Osuchowska-Kościjańska, Anna; Charzyńska, Katarzyna; Chadzyńska, Małgorzata; Drozdzyńska, Anna; Kasperek-Zimowska, Beata; Bednarek, Agata; Sawicka, Maryla

2014-01-01

The aim of the present study was to investigate sense of coherence in healthy siblings of persons suffering from schizophrenia as well as their ways of coping in the relationship with ill brother or sister. 40 healthy brothers and sisters of persons with ICD- 10 diagnosis of F20 to F29 participated in the present study. Orientation to Life Scale (SOC- 29) was used to assess sense of coherence and Ways of Coping with Stress questionnaire (SRSS) was used to examine stress coping strategies. Mean global score of siblings of persons with schizophrenia was 111 points. Subjects used coping strategies focused on problem significantly more often than those focused on emotions. Therapeutic work with healthy siblings should focus on strengthening sense of personal competence, development of personal resources and different ways of coping with stress, investigation of emotions that healthy siblings experience in the relationship with ill brother or sister as well as supporting the process of accepting changes in the relationship with the ill sibling.

On Brothers and Sisters: South Asian and Japanese Idea Systems and their Consequences

OpenAIRE

Lyon, Stephen M.

2017-01-01

The role expectations of cross siblings varies across culture. Such expectations, while not rigidly prescribing actual behaviors nevertheless influences relations between brothers and sisters in observable ways. In South Asia, a cultural rhetoric of sororal sacrifice and support coupled with fraternal protection are commonplace. While such noble sibling roles are regularly transgressed they remain powerful idioms of the relationship and transgressions require appropriate cultural justificatio...

Mentoring in Schools: An Impact Study of Big Brothers Big Sisters School-Based Mentoring

Science.gov (United States)

Herrera, Carla; Grossman, Jean Baldwin; Kauh, Tina J.; McMaken, Jennifer

2011-01-01

This random assignment impact study of Big Brothers Big Sisters School-Based Mentoring involved 1,139 9- to 16-year-old students in 10 cities nationwide. Youth were randomly assigned to either a treatment group (receiving mentoring) or a control group (receiving no mentoring) and were followed for 1.5 school years. At the end of the first school…

From equator to pole: splitting chromosomes in mitosis and meiosis

Science.gov (United States)

Duro, Eris

2015-01-01

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

Cytogenetic effects of near ultraviolet radiation in normal and systemic lupus erythematosus lymphocytes

Energy Technology Data Exchange (ETDEWEB)

Caporossi, D.; Sebastiani, G.; Nicoletti, B. (Rome 2 University (Italy). Department of Public Health and Cellular Biology); Masala, C. (' La Sapienza' University, rome (Italy). Institute of Infectious and Tropical Diseases)

1990-03-01

The authors conducted a study on the spontaneous and UV-A induced frequency of chromosomal breaks and sister-chromatid exchanges (SCE) in purified lymphocytes from normal donors and from systemic lupus erythematosus (SLE) patients who were in clinical remission at the time of the study. Our results show that although SLE lymphocytes exhibit a higher frequency of spontaneous SCEs than controls, the rate of chromosomal breakage is comparable in the 2-groups. In both controls and patients, irradiation with UV-A (320-400 nm) increases the SCE values but does not significantly affect the frequency of chromosomal aberrations. (author). 14 refs.; 1 fig.; 3 tabs.

Evaluation of chemopreventive effects of betel leaf on the genotoxicity of pan masala.

Science.gov (United States)

Trivedi, A H; Patel, R K; Rawal, U M; Adhvaryu, S G; Balar, D B

1994-01-01

The antigenotoxic effect of the aqueous extract of betel leaf (BL-ext.) against the pan masala was tested with the help of cytogenetic endpoints like chromosome aberration (CA) and sister chromatid exchange (SCE) utilizing Chinese hamster ovary (CHO) cells. Compared to the cultures treated with aqueous extract of pan masala alone, a reduction in CA and SCE frequencies in CHO cells was observed following a combined treatment with pan masala (with or without tobacco) extract and BL-ext. The protective effect of BL-ext. against the genomic damage caused by pan masala was statistically significant only after treating the cells for a longer period.

Cytogenetic effects of near ultraviolet radiation in normal and systemic lupus erythematosus lymphocytes

International Nuclear Information System (INIS)

Caporossi, D.; Sebastiani, G.; Nicoletti, B.; Masala, C.

1990-01-01

The authors conducted a study on the spontaneous and UV-A induced frequency of chromosomal breaks and sister-chromatid exchanges (SCE) in purified lymphocytes from normal donors and from systemic lupus erythematosus (SLE) patients who were in clinical remission at the time of the study. Our results show that although SLE lymphocytes exhibit a higher frequency of spontaneous SCEs than controls, the rate of chromosomal breakage is comparable in the 2-groups. In both controls and patients, irradiation with UV-A (320-400 nm) increases the SCE values but does not significantly affect the frequency of chromosomal aberrations. (author). 14 refs.; 1 fig.; 3 tabs

Two Cases of Endometrial Cancer in Twin Sisters with Myotonic Dystrophy

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Ezra Y. Koh

2016-01-01

Full Text Available We describe two cases of endometrial cancer (EC occurring in nulligravid twin sisters with myotonic dystrophy. Both tested negative for Lynch syndrome and both were treated with laparoscopic hysterectomy with bilateral salpingooophorectomy and adjuvant radiotherapy. Although EC tends to run in families, the diagnosis in itself is not considered sufficient cause for screening or prophylactic measures in close relatives. However, the presence of additional risk factors, such as nulligravidity and myotonic dystrophy in the underlying cases, may call for extra vigilance in first-degree family members.

Getting SaaS-y. Why the sisters of Mercy Health System opted for on-demand portfolio management.

Science.gov (United States)

Carter, Jay

2011-03-01

Sisters of Mercy Health System chose the SaaS model as a simpler way to plan, execute, and monitor strategic business initiatives. It also provided something that was easy to use and offered quick time to value.

Linking Shorebird Conservation and Education Along Flyways: An Overview of the Shorebird Sister Schools Program

Science.gov (United States)

Hillary Chapman; Heather Johnson

2005-01-01

The Shorebird Sister Schools Program (SSSP) is an internet-based environmental education program that provides a forum for students, biologists, and shorebird enthusiasts to track shorebird migration and share observations along flyways. The program?s vision is to engage public participation in the conservation of shorebirds and their wetland, grassland, and shoreline...

Genome-wide high-resolution mapping of UV-induced mitotic recombination events in Saccharomyces cerevisiae.

Directory of Open Access Journals (Sweden)

Yi Yin

2013-10-01

Full Text Available In the yeast Saccharomyces cerevisiae and most other eukaryotes, mitotic recombination is important for the repair of double-stranded DNA breaks (DSBs. Mitotic recombination between homologous chromosomes can result in loss of heterozygosity (LOH. In this study, LOH events induced by ultraviolet (UV light are mapped throughout the genome to a resolution of about 1 kb using single-nucleotide polymorphism (SNP microarrays. UV doses that have little effect on the viability of diploid cells stimulate crossovers more than 1000-fold in wild-type cells. In addition, UV stimulates recombination in G1-synchronized cells about 10-fold more efficiently than in G2-synchronized cells. Importantly, at high doses of UV, most conversion events reflect the repair of two sister chromatids that are broken at approximately the same position whereas at low doses, most conversion events reflect the repair of a single broken chromatid. Genome-wide mapping of about 380 unselected crossovers, break-induced replication (BIR events, and gene conversions shows that UV-induced recombination events occur throughout the genome without pronounced hotspots, although the ribosomal RNA gene cluster has a significantly lower frequency of crossovers.

Love as harm reduction: fighting AIDS and stigma in Vietnam

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Small Dan

2009-12-01

Full Text Available Abstract In the summer of 2009, I visited a humble orphanage for children with HIV/AIDS in Vietnam. Here, like many parts in the world, the very existence of marginalized people with stigmatized illness is hidden away. Relegated to the shadows of society, these children lacked something more fundamental than housing, shelter, nutrition and medications. They lacked families to love and care for them unconditionally. One might think it self-evident that a visit to an orphanage for children with HIV would be profound, but the profundity wasn't where I expected to find it. It was in how the children had created their own family, loving each other like brothers and sisters, and the way the priest who operated the shelters was more than a Father, he was a dad to dozens of children. This is an account of love as harm reduction in the Mai Tam orphanage in Ho Chi Minh City.

20 CFR 222.40 - When determinations of relationship are made for parent, grandchild, brother or sister.

Science.gov (United States)

2010-04-01

... 20 Employees' Benefits 1 2010-04-01 2010-04-01 false When determinations of relationship are made... RETIREMENT BOARD REGULATIONS UNDER THE RAILROAD RETIREMENT ACT FAMILY RELATIONSHIPS Relationship as Parent..., brother or sister. (a) Parent. The claimant's relationship as a parent of the employee is determined when...

'For Good, God, and the Empire': French Franciscan Sisters in Ethiopia 1896-1937

Science.gov (United States)

Guidi, Pierre

2018-01-01

In 1897, four French Franciscan sisters arrived in Ethiopia, having been summoned there by the Capuchin missionaries. In 1925, they ran an orphanage, a dispensary, a leper colony and 10 schools with 350 girl students. The students were freed slaves, orphans and upper-class Ethiopian and European girls. After providing a brief background to the…

Discovering non-random segregation of sister chromatids: The naïve treatment of a premature discovery

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Karl G. Lark

2013-02-01

Full Text Available The discovery of non-random chromosome segregation is discussed from the perspective of what was known in1965 and1966. The distinction between daughter, parent or grandparent strands of DNA was developed in a bacterial system and led to the discovery that multiple copies of DNA elements of bacteria are not distributed randomly with respect to the age of the template strand. Experiments with higher eukaryotic cells demonstrated that during mitosis Mendel’s laws were violated; and the initial serendipitous choice of eukaryotic cell system led to the striking example of non-random segregation of parent and grand-parent DNA template strands in primary cultures of cells derived from mouse embryos. Attempts to extrapolate these findings to established TC lines demonstrated that the property could be lost. Experiments using plant root tips demonstrated that the phenomenon exists in plants and that it was, at some level, under genetic control. Despite publication in major journals and symposia (Lark et al. (1966a; Lark (1967a; 1967b; 1969, 1969a; 1969b the potential implications of these findings were ignored for several decades. Here we explore possible reasons for the pre-maturity (Stent, 1972 of this discovery.

Crystal Structure of the Cohesin Gatekeeper Pds5 and in Complex with Kleisin Scc1

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Byung-Gil Lee

2016-03-01

Full Text Available Sister chromatid cohesion is mediated by cohesin, whose Smc1, Smc3, and kleisin (Scc1 subunits form a ring structure that entraps sister DNAs. The ring is opened either by separase, which cleaves Scc1 during anaphase, or by a releasing activity involving Wapl, Scc3, and Pds5, which bind to Scc1 and open its interface with Smc3. We present crystal structures of Pds5 from the yeast L. thermotolerans in the presence and absence of the conserved Scc1 region that interacts with Pds5. Scc1 binds along the spine of the Pds5 HEAT repeat fold and is wedged between the spine and C-terminal hook of Pds5. We have isolated mutants that confirm the observed binding mode of Scc1 and verified their effect on cohesin by immunoprecipitation and calibrated ChIP-seq. The Pds5 structure also reveals architectural similarities to Scc3, the other large HEAT repeat protein of cohesin and, most likely, Scc2.

Improving Emotion Regulation and Sibling Relationship Quality: The More Fun with Sisters and Brothers Program

Science.gov (United States)

Kennedy, Denise E.; Kramer, Laurie

2008-01-01

We examined the role of emotion regulation (ER) in improving sibling relationship quality (SRQ) by evaluating the More Fun With Sisters and Brothers Program where 4- to 8-year-old siblings from 95 families were taught emotional and social competencies. Parents reported on SRQ and ER, and sibling interactions were observed in homes. SRQ and ER…

Pyrimidine Pool Disequilibrium Induced by a Cytidine Deaminase Deficiency Inhibits PARP-1 Activity, Leading to the Under Replication of DNA.

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Simon Gemble

2015-07-01

Full Text Available Genome stability is jeopardized by imbalances of the dNTP pool; such imbalances affect the rate of fork progression. For example, cytidine deaminase (CDA deficiency leads to an excess of dCTP, slowing the replication fork. We describe here a novel mechanism by which pyrimidine pool disequilibrium compromises the completion of replication and chromosome segregation: the intracellular accumulation of dCTP inhibits PARP-1 activity. CDA deficiency results in incomplete DNA replication when cells enter mitosis, leading to the formation of ultrafine anaphase bridges between sister-chromatids at "difficult-to-replicate" sites such as centromeres and fragile sites. Using molecular combing, electron microscopy and a sensitive assay involving cell imaging to quantify steady-state PAR levels, we found that DNA replication was unsuccessful due to the partial inhibition of basal PARP-1 activity, rather than slower fork speed. The stimulation of PARP-1 activity in CDA-deficient cells restores replication and, thus, chromosome segregation. Moreover, increasing intracellular dCTP levels generates under-replication-induced sister-chromatid bridges as efficiently as PARP-1 knockdown. These results have direct implications for Bloom syndrome (BS, a rare genetic disease combining susceptibility to cancer and genomic instability. BS results from mutation of the BLM gene, encoding BLM, a RecQ 3'-5' DNA helicase, a deficiency of which leads to CDA downregulation. BS cells thus have a CDA defect, resulting in a high frequency of ultrafine anaphase bridges due entirely to dCTP-dependent PARP-1 inhibition and independent of BLM status. Our study describes previously unknown pathological consequences of the distortion of dNTP pools and reveals an unexpected role for PARP-1 in preventing DNA under-replication and chromosome segregation defects.

When the genome plays dice: circumvention of the spindle assembly checkpoint and near-random chromosome segregation in multipolar cancer cell mitoses.

Science.gov (United States)

Gisselsson, David; Håkanson, Ulf; Stoller, Patrick; Marti, Dominik; Jin, Yuesheng; Rosengren, Anders H; Stewénius, Ylva; Kahl, Fredrik; Panagopoulos, Ioannis

2008-04-02

Normal cell division is coordinated by a bipolar mitotic spindle, ensuring symmetrical segregation of chromosomes. Cancer cells, however, occasionally divide into three or more directions. Such multipolar mitoses have been proposed to generate genetic diversity and thereby contribute to clonal evolution. However, this notion has been little validated experimentally. Chromosome segregation and DNA content in daughter cells from multipolar mitoses were assessed by multiphoton cross sectioning and fluorescence in situ hybridization in cancer cells and non-neoplastic transformed cells. The DNA distribution resulting from multipolar cell division was found to be highly variable, with frequent nullisomies in the daughter cells. Time-lapse imaging of H2B/GFP-labelled multipolar mitoses revealed that the time from the initiation of metaphase to the beginning of anaphase was prolonged and that the metaphase plates often switched polarity several times before metaphase-anaphase transition. The multipolar metaphase-anaphase transition was accompanied by a normal reduction of cellular cyclin B levels, but typically occurred before completion of the normal separase activity cycle. Centromeric AURKB and MAD2 foci were observed frequently to remain on the centromeres of multipolar ana-telophase chromosomes, indicating that multipolar mitoses were able to circumvent the spindle assembly checkpoint with some sister chromatids remaining unseparated after anaphase. Accordingly, scoring the distribution of individual chromosomes in multipolar daughter nuclei revealed a high frequency of nondisjunction events, resulting in a near-binomial allotment of sister chromatids to the daughter cells. The capability of multipolar mitoses to circumvent the spindle assembly checkpoint system typically results in a near-random distribution of chromosomes to daughter cells. Spindle multipolarity could thus be a highly efficient generator of genetically diverse minority clones in transformed cell

When the genome plays dice: circumvention of the spindle assembly checkpoint and near-random chromosome segregation in multipolar cancer cell mitoses.

Directory of Open Access Journals (Sweden)

David Gisselsson

Full Text Available BACKGROUND: Normal cell division is coordinated by a bipolar mitotic spindle, ensuring symmetrical segregation of chromosomes. Cancer cells, however, occasionally divide into three or more directions. Such multipolar mitoses have been proposed to generate genetic diversity and thereby contribute to clonal evolution. However, this notion has been little validated experimentally. PRINCIPAL FINDINGS: Chromosome segregation and DNA content in daughter cells from multipolar mitoses were assessed by multiphoton cross sectioning and fluorescence in situ hybridization in cancer cells and non-neoplastic transformed cells. The DNA distribution resulting from multipolar cell division was found to be highly variable, with frequent nullisomies in the daughter cells. Time-lapse imaging of H2B/GFP-labelled multipolar mitoses revealed that the time from the initiation of metaphase to the beginning of anaphase was prolonged and that the metaphase plates often switched polarity several times before metaphase-anaphase transition. The multipolar metaphase-anaphase transition was accompanied by a normal reduction of cellular cyclin B levels, but typically occurred before completion of the normal separase activity cycle. Centromeric AURKB and MAD2 foci were observed frequently to remain on the centromeres of multipolar ana-telophase chromosomes, indicating that multipolar mitoses were able to circumvent the spindle assembly checkpoint with some sister chromatids remaining unseparated after anaphase. Accordingly, scoring the distribution of individual chromosomes in multipolar daughter nuclei revealed a high frequency of nondisjunction events, resulting in a near-binomial allotment of sister chromatids to the daughter cells. CONCLUSION: The capability of multipolar mitoses to circumvent the spindle assembly checkpoint system typically results in a near-random distribution of chromosomes to daughter cells. Spindle multipolarity could thus be a highly efficient

Evaluation of the genotoxic effects of a folk medicine, Petiveria alliacea (Anamu).

Science.gov (United States)

Hoyos, L S; Au, W W; Heo, M Y; Morris, D L; Legator, M S

1992-07-01

Crude extract from a plant known as Petiveria alliacea (Anamu) is used extensively as folk medicine in developing countries like Colombia, South America. Although the plant is known to contain toxic ingredients potential adverse health effects from its use have not been adequately evaluated. We investigated its genotoxic activities by conducting a sister chromatid exchange (SCE) assay using cells in vitro and in vivo. Lymphocytes from humans were treated at 24 h after initiation of culture for 6 h with alcohol extract from the folk medicine. Concentrations of 0, 10, 100, 250, 275, 500, 750, and 1000 micrograms/ml of the extract were used. Significant dose-dependent increase of SCE (3.7-7.4 SCE per cell) were observed (analysis of variances, p less than 0.01). Delay in cell proliferation but not inhibition of mitosis was also observed. In another experiment, mice were exposed once orally to 1x, 200x, 300x and 400x the human daily consumption dose of Anamu. The induction of sister chromatid exchanges in bone marrow cells were investigated. We observed a significant dose dependent increase of SCE compared with the saline control (2.15-4.53; p less than 0.01) and compared with the solvent control (3.04-4.53; p less than 0.01). Our data suggest, therefore, that the folk medicine contains mutagenic and potentially carcinogenic agents although the medicine is not a potent mutagen. Individuals who consume large amounts of this drug may be at risk for development of health problems. Further studies with cells from exposed individuals and from experimental animals should be conducted to provide a better evaluation of health risk from the use of this drug.

77 FR 48993 - Proposed Collection; Comment Request; The Sister Study: A Prospective Study of the Genetic and...

Science.gov (United States)

2012-08-15

... Genetic and Environmental Risk Factors for Breast Cancer SUMMARY: In compliance with the requirement of... proposed data collection projects, the National Institute of Environmental Health Sciences (NIEHS), the... Sister Study: A Prospective Study of the Genetic and Environmental Risk Factors for Breast Cancer. Type...

Differences in mycorrhizal communities between Epipactis palustris, E. helleborine and its presumed sister species E. neerlandica

OpenAIRE

Jacquemyn, Hans; Waud, Michael; Lievens, Bart; Brys, Rein

2016-01-01

Background and Aims In orchid species that have populations occurring in strongly contrasting habitats, mycorrhizal divergence and other habitat-specific adaptations may lead to the formation of reproductively isolated taxa and ultimately to species formation. However, little is known about the mycorrhizal communities associated with recently diverged sister taxa that occupy different habitats.

Mercury poisoning in two 13-year-old twin sisters

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Ezzat Khodashenas

2015-01-01

Full Text Available Mercury (Hg is a toxic agent that evaporates in room temperature and its inhalation may cause poisoning. Due to the nonspecific symptoms, diagnosis is difficult in special circumstances with no initial history of Hg exposure. We report two such cases of Hg poisoning. The patients were two sisters, presenting with pain in extremities, itchy rashes, sweating, salivation, weakness, and mood changes. They have used a compound that contains mercury, for treatment of pedicullosis three months before admission. This compound was purchased from a herbal shop and was applied locally on the scalps for 2 days. Their urinary mercury concentrations were 50 and 70 mg/L. They were successfully treated by D-penicillamine and gabapentin. In a patient with any kind of bone and joint pain, skin rash erythema and peripheral neuropathy, mercury poisoning should be considered as a differential diagnosis.

Antigenotoxic Effect of Curcumin and Carvacrol against Parathion Induced DNA Damage in Cultured Human Peripheral Blood Lymphocytes and Its Relation to GSTM1 and GSTT1 Polymorphism

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Neeraj Kumar

2014-01-01

Full Text Available In recent years, the use of organophosphorus pesticides has been extensively increased and these compounds signify a major class of agricultural pesticides today. We studied antigenotoxic potential of curcumin and carvacrol against the parathion induced DNA damage in cultured peripheral blood lymphocytes using sister chromatid exchanges as a biomarker of genotoxicity. Heparinised fresh blood from healthy individuals was treated with 2.5 μg/mL concentration of parathion in presence of curcumin and carvacrol in order to observe the antigenotoxic potential of both curcumin and carvacrol. Significant reduction (P0.05 of GSTT1 and GSTM1 polymorphism on genotoxicity of parathion and antigenotoxic potential of curcumin and carvacrol.

The bystander effect: is reactive oxygen species the driver?

International Nuclear Information System (INIS)

Szumiel, I.

2003-01-01

The paper reviews selected examples of the bystander effect, such as clonogenic survival decrease, chromosomal aberrations and mutations. The similarities and differences between the biological effects in directly targeted and bystander cells are briefly discussed. Also reviewed are the experimental data which support the role of reactive oxygen species (ROS), especially *O 2 - , as mediators of the bystander effect. Endogenously generated ROS, due to activation of NAD(P)H oxidases, play a kay role in the introduction of DNA damage in bystander cells. All the observed effects in bystander cells, such as alteration in gene expression patterns, chromosomal aberrations, sister chromatid exchanges, mutations, genome instability and neoplastic transformation are the consequence of DNA damage. (author)

Chromosome damage and clinical manifestation in a fetus and the mother after accidental 60Co exposure in Xinzhou

International Nuclear Information System (INIS)

Wang Jiajing; Mu Ying; Wang Shanmi

1995-01-01

The authors present the clinical effect and chromosome damage sustained by a fetus and the four months pregnant mother in an accidental 60 Co exposure in November of 1992 in Xinzhou, Shanxi Province. The mother suffered from a moderate acute radiation sickness with ratardation of fetal development. After delivery, the infant's body length, body weight and head circumference were all lowered by three percentiles compared with the normals. Four months after the exposure, the assay of the mother's peripheral lymphocytes showed a chromosome aberration rate of 36%, while concomitant examination of the baby failed to reveal any chromosome abnormality although the sister chromatid exchange rate was remarkably higher than that of the mother and the normal control

Chromosome analyses of nurses handling cytostatic agents

International Nuclear Information System (INIS)

Waksvik, H.; Klepp, O.; Brogger, A.

1981-01-01

A cytogenetic study of ten nurses handling cytostatic agents (average exposure, 2150 hours) and ten female hospital clerks revealed an increased frequency of chromosome gaps and a slight increase in sister chromatid exchange frequency among the nurses. The increase may be due to exposure to cytostatic drugs and points to these agents as a possible occupational health hazard. A second group of 11 nurses handling cytostatic agents for a shorter period of time (average exposure, 1078 hours), and three other groups (eight nurses engaged in therapeutic and diagnostic radiology, nine nurses engaged in anesthesiology, and seven nurses in postoperative ward) did not differ from the office personnel, except for an increased frequency of chromosome gaps in the radiology group

DNA repair in Bloom's syndrome skin fibroblasts after ultraviolet light irradiation

International Nuclear Information System (INIS)

Kurihara, Takayuki; Inoue, Masao; Kawashima, Hiroko; Yagi, Takashi; Takebe, Hiraku.

1981-01-01

Skin fibroblasts from a patient with Bloom's syndrome (86NoKi) were assayed for various DNA repair activities after ultraviolet light (UV) irradiation. Cultured fibroblasts as well as lymphocytes obtained from this patient showed a high frequency of spontaneous sister chromatid exchanges (SCEs). There was no significant difference between 86NoKi fibroblasts and skin fibroblasts from normal donors in the sensitivity to UV as measured by inactivation of colony forming activity, the capacity of host-cell reactivation (HCR) of UV-irradiated virus, and the amount of unscheduled DNA synthesis (UDS) after UV irradiation. However, the yield of UV-induced SCEs in 86NoKi cells was significantly higher than that in normal cells. (author)

Historical biogeography and diversification of truffles in the Tuberaceae and their newly identified Southern hemisphere sister lineage

Science.gov (United States)

Gregory Bonito; Matthew E. Smith; Michael Nowak; Rosanne A. Healy; Gonzalo Guevara; Efren Cazares; Akihiko Kinoshita; Eduardo R. Nouhra; Laura S. Dominguez; Leho Tedersoo; Claude Murat; Yun Wang; Baldomero Arroyo Moreno; Donald H. Pfister; Kazuhide Nara; Alessandra Zambonelli; James M. Trappe; Rytas. Vilgalys

2013-01-01

In this study we reassessed the biogeography and origin of the Tuberaceae and their relatives using multiple loci and a global sampling of taxa. Multiple independent transitions from an aboveground to a belowground truffie fruiting body form have occurred in the Tuberaceae and in its newly recognized sister lineage...

Genotoxic monitoring of nurses handling cytotoxic drugs

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Anna Tompa

2016-01-01

Full Text Available Objective: Several biomarkers may be used to detect harmful exposure and individual susceptibility to cancer. Monitoring of biomarkers related to exposure may have a significant effect on early detection of cell transformation, thereby aiding the primary prevention of various chronic and malignant diseases. Nurses who handle cytotoxic drugs are exposed to carcinogenic agents, which have the potential to interrupt the cell cycle and to induce chromosomal aberrations. The presence of high chromosomal aberrations indicates the need for intervention even when exposure to these carcinogens is low. Methods: Nationally representative samples of 552 nurses were investigated by a follow-up monitoring system. The measured biomarkers were clinical laboratory routine tests, completed with genotoxicological (chromosome aberrations [CAs] and sister chromatid exchanges [SCEs] and immunotoxicological monitoring (ratio of lymphocyte subpopulations and lymphocyte activation markers measured on peripheral blood lymphocytes. Results were compared to the data of 140 healthy, age-matched controls. Results: In nurses exposed to cytostatics, we observed a significantly increased frequency of CAs and SCEs compared with those in the controls. Cytostatic drug exposure also manifested itself in an increased frequency of helper T lymphocytes. Genotoxicological and immunotoxicological changes, as well as negative health effects (i.e., iron deficiency, anemia, and thyroid diseases, increased among cytostatic exposed subjects. Conclusions: These results raised concerns about the protection of nursing staff from chemical carcinogens in the working environment.

NURSING AND ITS PROBLEMS*

African Journals Online (AJOL)

1971-07-10

Jul 10, 1971 ... not enough stress was laid on the exceedingly importa~t part played by the nursing staff .... trained to take more of the load off the sister, and on the other hand the sister should .... a world problem. Employment of Nurse Aides.

Novel Familial Variant of the Desert Hedgehog Gene: Clinical Findings in Two Sisters with 46,XY Gonadal Dysgenesis or 46,XX Karyotype and Literature Review.

Science.gov (United States)

Baldinotti, Fulvia; Cavallaro, Tiziana; Dati, Eleonora; Baroncelli, Giampiero I; Bertini, Veronica; Valetto, Angelo; Massart, Francesco; Fabrizi, Gian Maria; Zanette, Giampietro; Peroni, Diego; Bertelloni, Silvano

2018-01-01

In humans, Desert Hedgehog (DHH) gene mutations are a very rare cause of 46,XY gonadal dysgenesis (GD), eventually associated with peripheral neuropathy. Clinical records of 12 patients with 46,XY GD and unknown genetic background were reviewed and a 46,XY woman with peripheral neuropathy was individuated. Her 46,XX sister affected by similar neuropathy was also investigated. Genomic DNA was extracted and DHH exons sequenced and analyzed. A comparative genomic hybridization array was also performed. In both the 46,XY and 46,XX sisters, a homozygous c.554C>A mutation in exon 2 of the DHH gene was found, determining a premature termination codon (p.Ser 185*). Heterozygous consanguineous carrier parents showed neither reproductive problems nor peripheral neuropathy. In the proband and her sister, a 499-kb duplication in 9p22.1 was also found. A 46,XY European woman with 46,XY GD and a novel homozygous DHH pathogenic variant is reported, confirming that this gene plays a key role in male gonadal development. Her 46,XX sister, harboring the same mutation, showed normal internal and external female phenotype. Thus, DHH seems not to be involved in the ovarian development pathway or its postpubertal function. Homozygous DHH mutations cause a specific peripheral neuropathy in humans with both 46,XY and 46,XX karyotypes. © 2018 S. Karger AG, Basel.

Basalt Weathering in a Cold and Icy Climate: Three Sisters, Oregon as an Analog for Early Mars

Science.gov (United States)

Rampe, E. B.; Horgan, B.; Smith, R. J.; Scudder, N. A.; Rutledge, A. M.; Bamber, E.; Morris, R. V.

2017-01-01

There is abundant evidence for liquid water on early Mars, but the debate remains whether early Mars was warm and wet or cold and icy with punctuated periods of melting. To further investigate the hypothesis of a cold and icy early Mars, we collected rocks and sediments from the Collier and Diller glacial valleys in the Three Sisters volcanic complex in Oregon. We analyzed rocks and sediments with X-ray diffraction (XRD), scanning and transmission electron microscopies with energy dispersive spectroscopy (SEM, TEM, EDS), and visible, short-wave infrared (VSWIR) and thermal-IR (TIR) spectroscopies to characterize chemical weathering and sediment transport through the valleys. Here, we focus on the composition and mineralogy of the weathering products and how they compare to those identified on the martian surface. Phyllosilicates (smectite), zeolites, and poorly crystalline phases were discovered in pro- and supra-glacial sediments, whereas Si-rich regelation films were found on hand samples and boulders in the proglacial valleys. Most phyllosilicates and zeolites are likely detrital, originating from hydrothermally altered units on North Sister. TEM-EDS analyses of the flour samples demonstrate a variety of poorly crystalline (i.e., no long-range crystallographic order) phases: iron oxides, devitrified volcanic glass, and Fe-Si-Al phases. The CheMin XRD on the Curiosity rover in Gale crater has identified significant amounts of X-ray amorphous materials in all samples measured to date. The amorphous component is likely a combination of silicates, iron oxides, and sulfates. Although we have not yet observed amorphous sulfate in the samples from Three Sisters, the variety of poorly crystalline weathering products found at this site is consistent with the variable composition of the X-ray amorphous component identified by CheMin. We suggest that these amorphous phases on Mars could have formed in a similarly cold and icy environment.

EPRI/DOE High Burnup Fuel Sister Pin Test Plan Simplification and Visualization

Energy Technology Data Exchange (ETDEWEB)

Saltzstein, Sylvia J. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Sorenson, Ken B. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Hanson, Brady [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Billone, Mike [Argonne National Lab. (ANL), Argonne, IL (United States); Scaglione, John [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Montgomery, Rose [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Bevard, Bruce [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)

2017-07-01

The EPRI/DOE High Burnup Confirmatory Data Project (herein called the "Demo") is a multi-year, multi-entity confirmation demonstration test with the purpose of providing quantitative and qualitative data to show how high-burnup fuel ages in dry storage over a ten-year period. The Demo involves obtaining 32 assemblies of high-burnup PWR fuel of four common cladding alloys from the North Anna Nuclear Power Plant, drying them according to standard plant procedures, and then storing them in an NRC-licensed TN-3 2B cask on the North Anna dry storage pad for ten years. After the ten-year storage time, the cask will be opened and the rods will be examined for signs of aging. Twenty-five rods from assemblies of similar claddings, in-reactor placement, and burnup histories (herein called "sister rods") have been shipped from the North Anna Nuclear Power Plant and are currently being nondestructively tested at Oak Ridge National Laboratory. After the non-destructive testing has been completed for each of the twenty-five rods, destructive analysis will be performed at ORNL, PNNL, and ANL to obtain mechanical data. Opinions gathered from the expert interviews, ORNL and PNNL Sister Rod Test Plans, and numerous meetings has resulted in the Simplified Test Plan described in this document. Some of the opinions and discussions leading to the simplified test plan are included here. Detailed descriptions and background are in the ORNL and PNNL plans in the appendices . After the testing described in this simplified test plan h as been completed , the community will review all the collected data and determine if additional testing is needed.

Selective accumulation of 147Pm in organism on induction of PCE's micronucleus and SCE of bone marrow cells as well as the chromosome aberrations on fetal liver and spleen

International Nuclear Information System (INIS)

Zhu Shoupeng; Zheng Siying; Wang Liuyi; Lu Zhongyan; Yang Shuqin

1989-01-01

Study of accumulation peculiarity of 147 Pm showed that I.V. different doses of 147 Pm were the same selectively localized in skeleton and liver. Retention of 147 Pm in skeleton and liver was elevated when the radioactive doses of 147 Pm were increased. At the same time absorption does of 147 Pm radiation was heightened. The ability of 147 Pm to induce sister chromatid exchanges (SCEs) has been investigated by IdU labelling methods. A statistically significant elevation of SCEs was observed after 147 Pm intake.In mice the number of SCEs per cell in bone marrow cells was always higher when the animals were maintained on the doses of 37 Bq/g. The injurious effects of 147 Pm, using PCE's micronucleus rates in bone marrow cells were observed. 147 Pm was dominantly deposited on maternal liver. Deposition of 147 Pm in maternal spleen was about quandrantal of the maternal liver. Studies indicated that maternal contamination of 147 Pm could induced chromosome aberrations in fetal liver and spleen cells. Among the type of aberrations induced by 147 Pm, chromatid breakage were predominant. The incidence of chromosome aberrations on fetal liver cells induced by 147 Pm was higher on fetal spleen cells

Studies on mutagenic activity of 60Co γ-ray irradiated rape pollen

International Nuclear Information System (INIS)

He Weishun; Liu Aihua; Lin Shiying; Xiong Xikun

1989-01-01

In the present study on disinfection, the rape pollen was irradiated with 2.5 kGy 60 Co γ-ray. Micronuclei, sister chromatid exchanges (SCE) of bone marrow cells and chromosomal aberrations of meiotic cells in mice were used as an indicater of chromosomal damage to study the mutagenicity of irradiated rape pollen. The results are as follows: (1) The frequency of micronuclei in polychromatic erythrocytes is 2.00 per mille; nucleated cells is 0.8 per mille in control group. In the numbers of polychromatic erythrocytes and nucleated cells with micronuclei, there is no obviously difference in irradiated and unirradiated groups. (2) SCE incidence of control group is 2.01 ± 0.12/cell. No significant difference in the frequency of SCE exists between non-irradiated rape pollen and the control groups. But the frequency of SCE in irradiated rape pollen group (3000 mg/kg/day x 7) is 2.36 ± 0.12/cell; high dose group (6000 mg/kg/day x 7) is 2.96 ± 0.14/cell. In comparison with control group, there is a significant difference. (3) The chromatid breaks, fragments, and univalents in primary spermatocytes have been obseved. The frequencies of chromosomal aberration showed no obviously difference among irradiated and non-irradiated rape pollen groups

Microcystin-LR and Cylindrospermopsin Induced Alterations in Chromatin Organization of Plant Cells

Science.gov (United States)

Máthé, Csaba; M-Hamvas, Márta; Vasas, Gábor

2013-01-01

Cyanobacteria produce metabolites with diverse bioactivities, structures and pharmacological properties. The effects of microcystins (MCYs), a family of peptide type protein-phosphatase inhibitors and cylindrospermopsin (CYN), an alkaloid type of protein synthesis blocker will be discussed in this review. We are focusing mainly on cyanotoxin-induced changes of chromatin organization and their possible cellular mechanisms. The particularities of plant cells explain the importance of such studies. Preprophase bands (PPBs) are premitotic cytoskeletal structures important in the determination of plant cell division plane. Phragmoplasts are cytoskeletal structures involved in plant cytokinesis. Both cyanotoxins induce the formation of multipolar spindles and disrupted phragmoplasts, leading to abnormal sister chromatid segregation during mitosis. Thus, MCY and CYN are probably inducing alterations of chromosome number. MCY induces programmed cell death: chromatin condensation, nucleus fragmentation, necrosis, alterations of nuclease and protease enzyme activities and patterns. The above effects may be related to elevated reactive oxygen species (ROS) and/or disfunctioning of microtubule associated proteins. Specific effects: MCY-LR induces histone H3 hyperphosphorylation leading to incomplete chromatid segregation and the formation of micronuclei. CYN induces the formation of split or double PPB directly related to protein synthesis inhibition. Cyanotoxins are powerful tools in the study of plant cell organization. PMID:24084787

Microcystin-LR and Cylindrospermopsin Induced Alterations in Chromatin Organization of Plant Cells

Directory of Open Access Journals (Sweden)

Gábor Vasas

2013-09-01

Full Text Available Cyanobacteria produce metabolites with diverse bioactivities, structures and pharmacological properties. The effects of microcystins (MCYs, a family of peptide type protein-phosphatase inhibitors and cylindrospermopsin (CYN, an alkaloid type of protein synthesis blocker will be discussed in this review. We are focusing mainly on cyanotoxin-induced changes of chromatin organization and their possible cellular mechanisms. The particularities of plant cells explain the importance of such studies. Preprophase bands (PPBs are premitotic cytoskeletal structures important in the determination of plant cell division plane. Phragmoplasts are cytoskeletal structures involved in plant cytokinesis. Both cyanotoxins induce the formation of multipolar spindles and disrupted phragmoplasts, leading to abnormal sister chromatid segregation during mitosis. Thus, MCY and CYN are probably inducing alterations of chromosome number. MCY induces programmed cell death: chromatin condensation, nucleus fragmentation, necrosis, alterations of nuclease and protease enzyme activities and patterns. The above effects may be related to elevated reactive oxygen species (ROS and/or disfunctioning of microtubule associated proteins. Specific effects: MCY-LR induces histone H3 hyperphosphorylation leading to incomplete chromatid segregation and the formation of micronuclei. CYN induces the formation of split or double PPB directly related to protein synthesis inhibition. Cyanotoxins are powerful tools in the study of plant cell organization.

Three Sisters Mountain Village development transformation of old coal mine properties into modern day use

International Nuclear Information System (INIS)

Fox, B.

2006-01-01

This paper discussed the development of the Three Sisters Mountain Village, located close to Canmore, Alberta. The paper provided the history and background of the mining and development of the site. It discussed underground mining methodology and planned housing and industrial development. The village included plans for 10,000 residential homes, 2 golf courses, a wellness centre, a school, commercial buildings and wildlife corridors. Environmental concerns were also addressed, as Canmore contains a series of natural wildlife corridors, which act as migration and travelling routes for elk and deer as well as cougars, grizzly bears, and other animals. These routes are essential for the survival of the different herds and animal species. The development progress strategy was discussed. The Three Sisters Mountain Village Development commissioned Golder Associates Ltd. to study and address the environmental concerns of the stakeholders regarding the migrating routes of wildlife. Mining works mitigation, including mapping of the constraint zones, knowledge of subsidence issues and the effects of subsidence on structural stress and the ability to analysis field data to predict potential problems was also presented along with a methodology for mitigation and choice of backfill material to be used to fill the mine workings. The advantages of using concrete paste backfill were also identified

Three Sisters Mountain Village development transformation of old coal mine properties into modern day use

Energy Technology Data Exchange (ETDEWEB)

Fox, B. [Golder Paste Technology Ltd., Sudbury, ON (Canada)

2006-07-01

This paper discussed the development of the Three Sisters Mountain Village, located close to Canmore, Alberta. The paper provided the history and background of the mining and development of the site. It discussed underground mining methodology and planned housing and industrial development. The village included plans for 10,000 residential homes, 2 golf courses, a wellness centre, a school, commercial buildings and wildlife corridors. Environmental concerns were also addressed, as Canmore contains a series of natural wildlife corridors, which act as migration and travelling routes for elk and deer as well as cougars, grizzly bears, and other animals. These routes are essential for the survival of the different herds and animal species. The development progress strategy was discussed. The Three Sisters Mountain Village Development commissioned Golder Associates Ltd. to study and address the environmental concerns of the stakeholders regarding the migrating routes of wildlife. Mining works mitigation, including mapping of the constraint zones, knowledge of subsidence issues and the effects of subsidence on structural stress and the ability to analysis field data to predict potential problems was also presented along with a methodology for mitigation and choice of backfill material to be used to fill the mine workings. The advantages of using concrete paste backfill were also identified.

Cis-Acting Determinants Affecting Centromere Function, Sister-Chromatid Cohesion and Reciprocal Recombination during Meiosis in Saccharomyces Cerevisiae

OpenAIRE

Sears, D. D.; Hegemann, J. H.; Shero, J. H.; Hieter, P.

1995-01-01

We have employed a system that utilizes homologous pairs of human DNA-derived yeast artificial chromosomes (YACs) as marker chromosomes to assess the specific role (s) of conserved centromere DNA elements (CDEI, CDEII and CDEIII) in meiotic chromosome disjunction fidelity. Thirteen different centromere (CEN) mutations were tested for their effects on meiotic centromere function. YACs containing a wild-type CEN DNA sequence segregate with high fidelity in meiosis I (99% normal segregation) and...

Parallel increases in sister chromatid exchanges at base level and with UV treatment in human opiate users

International Nuclear Information System (INIS)

Shafer, D.A.; Falek, A.; Madden, J.J.; Tadayon, F.; Pline, M.; Kuehnle, J.C.; Mendelson, J.

1983-01-01

The SCE base level frequency and SCE levels induced by far-UV (254 nm) treatment of cells in early G 1 and early S phases of the cell cycle were significantly higher in leukocytes from heroin addicts as compared to controls. The increased SCE levels in addicts was greatest at base level and smallest after UV irradiation of cells in S phase. These results corrobate and extend our previous findings of increased chromosome damage and reduced DNA-repair synthesis in heroin users. Since opiates do not directly damage DNA, the elevated cytogenetic effects associated with opiate use probably arise from secondary promotional effects related to opiate-mediated alterations in leukocyte metabolism. (orig.)

Sister Chromatid Exchanges (=SCEs) in Lymphocytes of persons working at Shlobin (USSR), 150km north of Chernobyl

International Nuclear Information System (INIS)

Tuschl, H.; Kovac, R.

1988-08-01

SCEs are considered to be a sensitive indicator for the DNA damaging effects of mutagenic and carcinogenic agents. In 1986, during the Chernobyl accident, employees of an Austrian company worked at Shlobin, 150km north of Chernobyl. At their return to Austria blood as taken and spontaneously occurring and MMC induced SCEs were studied. Spontaneously occurring SCEs in lymphocytes of 'exposed' and 'unexposed' persons were only insignificantly different when results were summarized for all test persons. A significant influence of smoking could be established. When results were correlated with the time interval between the Chernobyl accident and the date of blood sampling, the increased rate of spontaneous SCEs observed soon after the accident decreased to the normal range during the following months. Irrespective of the molecular mechanism that might be the rationale for the observed decreased induction of SCEs in lymphocytes of exposed persons, the estimation of MMC induced SCEs proved to be the most sensitive test to demonstrate population exposure to low doses of ionizing radiation. 7 refs., 1 fig., 5 tabs. (Author)

Phylogenetic analysis of seven WRKY genes across the palm subtribe Attaleinae (Areceaceae) identifies Syagrus as sister to the coconut

Science.gov (United States)

The origins of the coconut (Cocos nucifera) have been one of the "abominable mysteries" of palm systematics for decades. Previous studies with predominantly plastid genes have indicated an American ancestry for the coconut but with weak support and ambiguous sister relationships. We used primers d...

The importance of chromosome studies in Roberts syndrome/SC phocomelia and other cohesinopathies.

Science.gov (United States)

Gerkes, Erica H; van der Kevie-Kersemaekers, Anne-Marie F; Yakin, Mariam; Smeets, Dominique F C M; van Ravenswaaij-Arts, Conny M A

2010-01-01

Roberts syndrome/SC phocomelia is a rare, autosomal recessive syndrome characterised by pre- and postnatal growth retardation, microcephaly, craniofacial anomalies, mental retardation, and tetraphocomelia in varying degrees of severity. The clinical diagnosis can be challenging in phenotypically mild cases. In the extremely mild case presented here, specific mitotic abnormalities were detected and proved to be very helpful, since Roberts syndrome/SC phocomelia could be diagnosed after finding premature centromere separation and somatic aneuploidy at routine karyotyping. We discuss these and other mitotic cytogenetic abnormalities that can be of significant diagnostic importance, but which will be missed if only array studies are performed. We also discuss the difference between premature centromere separation and premature (sister) chromatid separation. Copyright (c) 2009 Elsevier Masson SAS. All rights reserved.

Biomonitoring human exposure to environmental carcinogenic chemicals

DEFF Research Database (Denmark)

Farmer, P.B.; Sepai, O.; Lawrence, R.

1996-01-01

A coordinated study was carried out on the development, evaluation and application of biomonitoring procedures for populations exposed to environmental genotoxic pollutants. The procedures used involved both direct measurement of DNA or protein damage (adducts) and assessment of second biological...... spectrometry). The measurement of adducts was focused on those from genotoxicants that result from petrochemical combustion or processing, e.g. low-molecular-weight alkylating agents, PAHs and compounds that cause oxidative DNA damage. Cytogenetic analysis of lymphocytes was undertaken (micronuclei, chromosome...... aberrations and sister chromatid exchanges) and mutation frequency was estimated at a number of loci including the hprt gene and genes involving in cancer development. Blood and urine samples from individuals exposed to urban pollution were collected. Populations exposed through occupational or medical...

Phonic and induced level of mutations and mutagenicity in bioorganisms habitating in the environs of Ignalina APP

International Nuclear Information System (INIS)

Lekevichius, R.; Morkunas, V.; Knabikas, A.

1992-01-01

The investigation of the extracts from the water, mud and hydrobionts of the lake Drukshiai before the construction of the Ignalina atomic power plant (1982-1984) and after its construction enabled to detect the moment of the build-up of mutagens in the hydrobionts (in 1986), when the extracts began to induce spot mutations in Salmonella typhimurium and exchanges of sister chromatids in human leukocytes in vitro. The mutagenicity of rain water, sewerage water and water from the cooler of the atomic power plant to drosophila and Salmonella typhimurium has been detected. The increments of mutations in the populations of Larus ridibundus and Microtus arvalis inhabiting the surroundings of the atomic power plant has not been noticed. (author). 4 figs., 4 refs

The expanding universe of cohesin functions: a new genome stability caretaker involved in human disease and cancer.

Science.gov (United States)

Mannini, Linda; Menga, Stefania; Musio, Antonio

2010-06-01

Cohesin is responsible for sister chromatid cohesion, ensuring the correct chromosome segregation. Beyond this role, cohesin and regulatory cohesin genes seem to play a role in preserving genome stability and gene transcription regulation. DNA damage is thought to be a major culprit for many human diseases, including cancer. Our present knowledge of the molecular basis underlying genome instability is extremely limited. Mutations in cohesin genes cause human diseases such as Cornelia de Lange syndrome and Roberts syndrome/SC phocomelia, and all the cell lines derived from affected patients show genome instability. Cohesin mutations have also been identified in colorectal cancer. Here, we will discuss the human disorders caused by alterations of cohesin function, with emphasis on the emerging role of cohesin as a genome stability caretaker.

Emergence of ethnochoreology internationally: The Janković sisters, Maud Karpeles, and Gertrude Kurath

Directory of Open Access Journals (Sweden)

Dunin Elsie Ivancich

2014-01-01

Full Text Available A fifty-year (1962-2012 period has been shown as a history of ethnochoreology supported by living memories of members of the International Council for Traditional Music (ICTM Study Group on Ethnochoreology. Recently uncovered and juxtapositioned correspondence of three predecessors within earlier years of the International Folk Music Council (IFMC broadens the history. This article reveals the emergence of ethnochoreology during the 1950s with publications of the two Janković sisters in Serbia with that of Gertrude Kurath in the United States, alongside correspondence with Maud Karpeles, the unheralded founder of the IFMC.

The yield of fission neutron-induced chromatid aberrations in G[sub 2]-stage human lymphocytes: effect of caffeine, hydroxyurea and cytosine arabinoside post-irradiation

Energy Technology Data Exchange (ETDEWEB)

Antoccia, A.; Tanzarella, C. (La Sapienza Univ., Rome (Italy)); Palitti, F. (Tuscia Univ., Viterbo (Italy) La Sapienza Univ., Rome (Italy)); Raggi, T. (Tuscia Univ., Viterbo (Italy)); Catena, C. (ENEA, Casaccia (Italy). Centro Ricerche Energia)

1992-11-01

To evaluate the influence of inhibitors of DNA synthesis/repair on the yield of chromosomal aberrations in the G[sub 2] phase of the cell cycle, whole-blood cultures of human lymphocytes were exposed to various doses of fission neutrons or X-rays and treated post-irradiation during the last 2.45 h before harvesting, with 5mM hydroxyurea (HU) and 0.05 mM cytosine arabinoside (ara-C). The presence of caffeine and HU strongly potentiated the yield of chromatid-type aberrations induced by both neutrons and X-rays. No potentiating effect, except at the highest dose of neutrons, was observed when irradiated cells were subsequently treated with ara-C. In addition, neutron-induced mitotic delay was shortened by treatment with caffeine, mainly within the first 2 h after irradiation. (Author).

Aid and AIDS: a delicate cocktail

NARCIS (Netherlands)

van Dalen, H.P.; Reuser, M.

2008-01-01

Development assistance targeting health overwhelmingly concentrates on HIV/AIDS. This column argues that that focus neglects critical demographic issues and degrades health infrastructure, particularly in Sub-Saharan Africa. The prime rule for AIDS aid should be “First, do no harm”.

Cytological and cytochemical effects of sodium benzoate and gamma irradiation on human peripheral lymphocytes

International Nuclear Information System (INIS)

Mohamed, N.A.F.

1981-01-01

In vitro studies of human peripheral lymphocytes were conducted to elucidate and compare the effects of a suspected chemical clastogen, sodium benzoate, widely used in the food industry as an antimicrobial food additive, to that of a well-known physical mutagen, gamma rays. Blood from ten normal donors, five males and five females, was collected and treated with various doses of the two agents independently and in combination during G 0 or G 1 phase. Induction of structural chromosomal aberrations, sister chromatid exchanges (SCEs) and unscheduled DNA synthesis were used as parameters to monitor the effects of the two agents. Sodium benzoate at the same concentrations used in the food industry (0.05% and 0.10%) caused inhibition of mitosis and induced chromatid-type aberrations (gaps and breaks). The frequency of aberrations increased as the concentration of sodium benzoate increased. No increase in SCEs over the control level was observed as either concentration tested. The relative amount of DNA damage inflicted in the treated lymphocytes estimated as 3 H-tritiated thymidine incorporation (unscheduled DNA synthesis) was highly significant. In contrast, blood irradiated with 300, 600, or 900 rad 60 Co gamma rays produced chromatid and chromosome aberrations in cultured lymphocytes, dicentrics being the most frequent exchange event. The aberration yield was found to be dose-dependent and to fit the quadratic model. Unscheduled DNA synthesis as measured by lymphocyte 3 H-TdR incorporation following gamma irradiation was highly significantly increased with the largest uptake occurring during the first hour of incubation. The combined treatment of gamma irradiation plus 0.05% sodium benzoate did not increase the aberration frequencies over the independent irradiation treatments and had no effect on SCEs frequencies

The unforgotten sisters female astronomers and scientists before Caroline Herschel

CERN Document Server

Bernardi, Gabriella

2016-01-01

Taking inspiration from Siv Cedering’s poem in the form of a fictional letter from Caroline Herschel that refers to “my long, lost sisters, forgotten in the books that record our science”, this book tells the lives of twenty-five female scientists, with specific attention to astronomers and mathematicians. Each of the presented biographies is organized as a kind of "personal file" which sets the biographee’s life in its historical context, documents her main works, highlights some curious facts, and records citations about her. The selected figures are among the most representative of this neglected world, including such luminaries as Hypatia of Alexandra, Hildegard of Bingen, Elisabetha Hevelius, and Maria Gaetana Agnesi. They span a period of about 4000 years, from En HeduAnna, the Akkadian princess, who was one of the first recognized female astronomers, to the dawn of the era of modern astronomy with Caroline Herschel and Mary Somerville. The book will be of interest to all who wish to learn more ...

Emplacement of Holocene silicic lava flows and domes at Newberry, South Sister, and Medicine Lake volcanoes, California and Oregon

Science.gov (United States)

Fink, Jonathan H.; Anderson, Steven W.

2017-07-19

This field guide for the International Association of Volcanology and Chemistry of the Earth’s Interior (IAVCEI) Scientific Assembly 2017 focuses on Holocene glassy silicic lava flows and domes on three volcanoes in the Cascade Range in Oregon and California: Newberry, South Sister, and Medicine Lake volcanoes. Although obsidian-rich lava flows have been of interest to geologists, archaeologists, pumice miners, and rock hounds for more than a century, many of their emplacement characteristics had not been scientifically observed until two very recent eruptions in Chile. Even with the new observations, several eruptive processes discussed in this field trip guide can only be inferred from their final products. This makes for lively debates at outcrops, just as there have been in the literature for the past 30 years.Of the three volcanoes discussed in this field guide, one (South Sister) lies along the main axis defined by major peaks of the Cascade Range, whereas the other two lie in extensional tectonic settings east of the axis. These two tectonic environments influence volcano morphology and the magmatic and volcanic processes that form silicic lava flows and domes. The geomorphic and textural features of glass-rich extrusions provide many clues about their emplacement and the magma bodies that fed them.The scope of this field guide does not include a full geologic history or comprehensive explanation of hazards associated with a particular volcano or volcanic field. The geochemistry, petrology, tectonics, and eruption history of Newberry, South Sister, and Medicine Lake volcanic centers have been extensively studied and are discussed on other field excursions. Instead, we seek to explore the structural, textural, and geochemical evolution of well-preserved individual lava flows—the goal is to understand the geologic processes, rather than the development, of a specific volcano.

Creating Sister Cities: An Exchange Across Hemispheres

Science.gov (United States)

Adams, M. T.; Cabezon, S. A.; Hardy, E.; Harrison, R. J.

2008-06-01

Sponsored by Associated Universities, Inc. (AUI) and the National Radio Astronomy Observatory (NRAO), this project creates a cultural and educational exchange program between communities in South and North America, linking San Pedro de Atacama in Chile and Magdalena, New Mexico in the United States. Both communities have similar demographics, are in relatively undeveloped regions of high-elevation desert, and are located near major international radio astronomy research facilities. The Atacama Large Millimeter/submillimeter Array (ALMA) is just 40 km east of San Pedro; the Very Large Array (VLA) is just 40 km west of Magdalena. In February 2007, the Mayor of San Pedro and two teachers visited Magdalena for two weeks; in July 2007 three teachers from Magdalena will visit San Pedro. These visits enable the communities to lay the foundation for a permanent, unique partnership. The teachers are sharing expertise and teaching methodologies for physics and astronomy. In addition to creating science education opportunities, this project offers students linguistic and cultural connections. The town of San Pedro, Chile, hosts nearly 100,000 tourists per year, and English language skills are highly valued by local students. Through exchanges enabled by email and distance conferencing, San Pedro and Magdalena students will improve English and Spanish language skills while teaching each other about science and their respective cultures. This poster describes the AUI/NRAO Sister Cities program, including the challenges of cross-cultural communication and the rewards of interpersonal exchanges between continents and cultures.

Reducing HIV risk among transgender women in Thailand: a quasi-experimental evaluation of the sisters program.

Directory of Open Access Journals (Sweden)

Duangta Pawa

Full Text Available Transgender women are particularly at risk of HIV infection, but little evidence exists on effective HIV prevention strategies with this population. We evaluated whether Sisters, a peer-led program for transgender women, could reduce HIV risks in Pattaya, Thailand. The study used time-location sampling to recruit 308 transgender women in Pattaya into a behavioral survey in 2011. Coarsened exact matching was used to create statistically equivalent groups of program participants and non-participants, based on factors influencing likelihood of program participation. Using multivariable logistic regression, we estimated effects of any program participation and participation by delivery channel on: condom use at last sex; consistent condom and condom/water-based lubricant use in the past 3 months with commercial, casual, and regular partners; and receipt of HIV testing in the past 6 months. Program coverage reached 75% of the population. In a matched sub-sample (n = 238, participation in outreach was associated with consistent condom/water-based lubricant use with commercial partners (AOR 3.22, 95% CI 1.64-6.31. Attendance at the Sisters drop-in center was associated with receiving an HIV test (AOR 2.58, 95% CI 1.47-4.52. Dedicated transgender-friendly programs are effective at reducing HIV risks and require expansion to better serve this key population and improve HIV prevention strategies.

A cytogenetic study of personnel of the Kozloduy NPP with a view to the hazards of late effects

Energy Technology Data Exchange (ETDEWEB)

Bulanova, M; Benova, D; Georgieva, I; Georgieva, V; Yagova, A; Rupova, I; Kusheva, R; Khadzhidekova, V; Topalova, S; Nikolova, T [National Centre of Radiobiology and Radiation Protection, Sofia (Bulgaria)

1996-12-31

Chromosomal analysis of 40 Kozloduy NPP workers has been carried out. Three cytogenetic end-points have been considered: chromosomal aberrations (CA), sister-chromatid exchanges and micro nuclear assays in peripheral blood lymphocytes. A higher incidence of CA has been detected in the investigated group in comparison with a control group. This is attributed to the radiation factor taking into consideration that the highest occurrence is that of dicentric chromosomes induced by radiation exposure. 95% of the workers have been employed for more than 5 years and 60% have received a dose of more than 30 cSv. However no direct relation of CA incidence to the accumulated dose has been observed. Tobacco smoking potentiates additionally the damage of the chromosome structures caused by ionizing radiation. 15 refs., 3 tabs.

Radio-adaptive response

International Nuclear Information System (INIS)

Ikushima, T.

1992-01-01

Knowledge about cellular events in mammalian cells exposed to low doses of ionizing radiation is meager. Recent works showed that human lymphocytes become resistant to radiation-induced chromosomal damage after exposure to low doses of ionizing radiation. Experimental evidence for radio-adaptive response (RAR) in cultured mammalian cells was obtained. Exposure to very low doses of gamma-rays or tritium beta-rays make cells less susceptible to the induction of micronuclei and sister chromatid exchanges by subsequent higher doses. Many important characteristics of the novel response suggest that RAR is a stress response resulting in the enhanced repair of chromosomal DNA damage in cell under restricted conditions. Experiments are still in progress in order to elucidate the molecular basis for RAR processes. (author). 13 refs.; 2 figs., 1 tab

The roles of cohesins in mitosis, meiosis, and human health and disease

Science.gov (United States)

Brooker, Amanda S.; Berkowitz, Karen M.

2015-01-01

Summary Mitosis and meiosis are essential processes that occur during development. Throughout these processes, cohesion is required to keep the sister chromatids together until their separation at anaphase. Cohesion is created by multi-protein subunit complexes called cohesins. Although the subunits differ slightly in mitosis and meiosis, the canonical cohesin complex is composed of four subunits that are quite diverse. The cohesin complexes are also important for DNA repair, gene expression, development, and genome integrity. Here we provide an overview of the roles of cohesins during these different events, as well as their roles in human health and disease, including the cohesinopathies. Although the exact roles and mechanisms of these proteins are still being elucidated, this review will serve as a guide for the current knowledge of cohesins. PMID:24906316

Experimental verification for in vitro technique confirmation of bystander effect induced by gamma radiation in CHO-K1 cell line

International Nuclear Information System (INIS)

Viana, P.H.L.; Goes, A.M.; Gomes, D.A.

2013-01-01

The bystander effect refers to biological responses detected in cells not directly irradiated but influenced, somehow, by signals transmitted from neighboring irradiated cells. These biological responses include sister chromatid exchange, mutations, micronucleus formation, chromosomal aberrations, carcinogenesis, apoptosis and necrosis. Although its existence is unquestionable, the mechanisms involved on triggering the bystander effect are not yet completely elucidated. Previous studies have shown that the bystander effect depends on a large variety of parameters including the radiation dose, the dose rate, the type of radiation and type of cells or tissue. This study aims to confirm the technique previously used in the literature in human cell lines for the bystander effect verification. The results suggest that the working conditions adopted by the group show technical efficiency and enables the reproduction of the bystander effect. (author)

Stem cell identity and template DNA strand segregation.

Science.gov (United States)

Tajbakhsh, Shahragim

2008-12-01

The quest for stem cell properties to distinguish their identity from that of committed daughters has led to a re-investigation of the notion that DNA strands are not equivalent, and 'immortal' DNA strands are retained in stem cells whereas newly replicated DNA strands segregate to the differentiating daughter cell during mitosis. Whether this process occurs only in stem cells, and also in all tissues, remains unclear. That individual chromosomes can be also partitioned non-randomly raises the question if this phenomenon is related to the immortal DNA hypothesis, and it underscores the need for high-resolution techniques to observe these events empirically. Although initially postulated as a mechanism to avoid DNA replication errors, alternative views including epigenetic regulation and sister chromatid silencing may provide insights into this process.

Proteomic analysis of human metaphase chromosomes reveals Topoisomerase II alpha as an Aurora B substrate

DEFF Research Database (Denmark)

Morrison, Ciaran; Henzing, Alexander J; Jensen, Ole Nørregaard

2002-01-01

B in the presence of radioactive ATP. Immunoblot analysis confirmed the HeLa scaffold fraction to be enriched for known chromosomal proteins including CENP-A, CENP-B, CENP-C, ScII and INCENP. Mass spectrometry of bands excised from one-dimensional polyacrylamide gels further defined the protein......The essential Aurora B kinase is a chromosomal passenger protein that is required for mitotic chromosome alignment and segregation. Aurora B function is dependent on the chromosome passenger, INCENP. INCENP, in turn, requires sister chromatid cohesion for its appropriate behaviour. Relatively few...... composition of the extracted chromosome fraction. Cloning, fluorescent tagging and expression in HeLa cells of the putative GTP-binding protein NGB/CRFG demonstrated it to be a novel mitotic chromosome protein, with a perichromosomal localisation. Identi fication of the protein bands corresponding to those...

Experimental verification for in vitro technique confirmation of bystander effect induced by gamma radiation in CHO-K1 cell line; Verificacao experimental para confirmacao da tecnica in vitro do efeito bystander induzido por radiacao gama na linhagem celular CHO-K1

Energy Technology Data Exchange (ETDEWEB)

Viana, P.H.L.; Goes, A.M.; Gomes, D.A., E-mail: pedroleroybio@hotmail.com [Universidade Federal de Minas Gerais (UFMG), Belo Horizonte, MG (Brazil). Departamento Bioquimica e Imunologia. Lab. de Imunologia Celular e Molecular; Grynberg, S.E., E-mail: seg@cdtn.br [Centro de Desenvolvimento da Tecnologia Nuclear (CDTN/CNEN-MG), Belo Horizonte, MG (Brazil)

2013-08-15

The bystander effect refers to biological responses detected in cells not directly irradiated but influenced, somehow, by signals transmitted from neighboring irradiated cells. These biological responses include sister chromatid exchange, mutations, micronucleus formation, chromosomal aberrations, carcinogenesis, apoptosis and necrosis. Although its existence is unquestionable, the mechanisms involved on triggering the bystander effect are not yet completely elucidated. Previous studies have shown that the bystander effect depends on a large variety of parameters including the radiation dose, the dose rate, the type of radiation and type of cells or tissue. This study aims to confirm the technique previously used in the literature in human cell lines for the bystander effect verification. The results suggest that the working conditions adopted by the group show technical efficiency and enables the reproduction of the bystander effect. (author)

Macrocephaly, epilepsy, autism, dysmorphic features, and mental retardation in two sisters: a new autosomal recessive syndrome?

OpenAIRE

Orstavik, K H; Strømme, P; Ek, J; Torvik, A; Skjeldal, O H

1997-01-01

We report two sisters with macrocephaly, epilepsy, and severe mental retardation. The first child was a 14 year old girl born at term after a normal pregnancy, with birth weight 3600 g and occipitofrontal circumference (OFC) 36 cm (75th centile). Her head size increased markedly during the first six months of life, and was later stable at 2-3 cm above the 97.5th centile. Her development was characterised by psychomotor delay, epilepsy, and autistic features. Her face appeared mildly dysmorphi...

Study of cell cycle parameters of man lymphocytes irradiated at various stages using differential coloring of sister chromatides

International Nuclear Information System (INIS)

Poryadkova, N.A.

1984-01-01

Parameters of the cell cycle of human lymphocytes are specified, radiation effect applied at various stages of mitotic cycle on the kinetics of cell advance in the cycle is also investigated. It is shown that increasing mitotic index occurs only due to the introduction of cells into the first mitosis. It is not excluded that cells ready to enter the second mitosis died with greater probability as after second synthesis they contained two-fold amount of BDU (5-brominedesoxiuridine) than cells of the first mitosis. In all cases with irradiation of cells of the third mitosis were not found

Evolutionary comparison of prenylation pathway in kinetoplastid Leishmania and its sister Leptomonas.

Science.gov (United States)

Chauhan, Indira Singh; Kaur, Jaspreet; Krishna, Shagun; Ghosh, Arpita; Singh, Prashant; Siddiqi, Mohammad Imran; Singh, Neeloo

2015-11-21

Leptomonas is monogenetic kinetoplastid parasite of insects and is primitive in comparison to Leishmania. Comparative studies of these two kinetoplastid may share light on the evolutionary transition to dixenous parasitism in Leishmania. In order to adapt and survive within two hosts, Leishmania species must have acquired virulence factors in addition to mechanisms that mediate susceptibility/resistance to infection in the pathology associated with disease. Rab proteins are key mediators of vesicle transport and contribute greatly to the evolution of complexity of membrane transport system. In this study we used our whole genome sequence data of these two divergent kinetoplastids to analyze the orthologues/paralogues of Rab proteins. During change of lifestyle from monogenetic (Leptomonas) to digenetic (Leishmania), we found that the prenyl machinery remained unchanged. Geranylgeranyl transferase-I (GGTase-I) was absent in both Leishmania and its sister Leptomonas. Farnesyltransferase (FTase) and geranylgeranyl transferase-II (GGTase-II) were identified for protein prenylation. We predict that activity of the missing alpha-subunit (α-subunit) of GGTase-II in Leptomonas was probably contributed by the α-subunit of FTase, while beta-subunit (β-subunit) of GGTase-II was conserved and indicated functional conservation in the evolution of these two kinetoplastids. Therefore the β-subunit emerges as an excellent target for compounds inhibiting parasite activity in clinical cases of co-infections. We also confirmed that during the evolution to digenetic life style in Leishmania, the parasite acquired capabilities to evade drug action and maintain parasite virulence in the host with the incorporation of short-chain dehydrogenase/reductase (SDR/MDR) superfamily in Rab genes. Our study based on whole genome sequences is the first to build comparative evolutionary analysis and identification of prenylation proteins in Leishmania and its sister Leptomonas. The information

SisterTalk: final results of a culturally tailored cable television delivered weight control program for Black women

OpenAIRE

Risica, Patricia Markham; Gans, Kim M; Kumanyika, Shiriki; Kirtania, Usree; Lasater, Thomas M

2013-01-01

Background Obesity among Black women continues to exceed that of other women. Most weight loss programs created without reference to specific cultural contexts are less effective for Black than White women. Weight control approaches accessible to Black women and adapted to relevant cultural contexts are important for addressing this problem. This paper reports the final results of SisterTalk, the randomized controlled trial of a cable TV weight control program oriented toward Black women. Met...

AID SELECTIVITY PRACTICE AND AID EFFECTIVENESS IN SUB-SAHARAN AFRICA

Directory of Open Access Journals (Sweden)

Adeniyi Jimmy Adedokun

2017-09-01

Full Text Available Foreign aid strategies have undergone restructuring as donors adopt aid selectivity practice to improve aid effectiveness. This study investigates the impact of aid selectivity practice on aid effectiveness (aid-growth relationship in Sub-Saharan Africa (SSA and several groups of countries within SSA from 1980 to 2012. Employing system generalized methods of moments (system GMM technique; the study produces strong evidence that there is significant improvement in aid effectiveness due to aid selectivity practice.

Chromatid repulsion associated with Roberts/SC phocomelia syndrome is reduced in malignant cells and not expressed in interspecies somatic-cell hybrids.

Science.gov (United States)

Krassikoff, N E; Cowan, J M; Parry, D M; Francke, U

1986-01-01

Different cell types from a female patient with Roberts/SC phocomelia syndrome were evaluated quantitatively for the presence of repulsion of heterochromatin and satellite regions of mitotic chromosomes. Whereas EBV-transformed lymphoblasts from an established cell line revealed these phenomena at frequencies equal to those in PHA-stimulated lymphocytes and cultured skin fibroblasts, aneuploid cells from a metastatic melanoma displayed them at 50% lower frequency. Cocultivation of the patient's fibroblasts with either an immortal Chinese hamster cell line or with a human male fibroblast strain carrying a t(4;6)(p14;q21) translocation showed that the phenomenon was not corrected or induced by a diffusible factor or by cell-to-cell contact. In each experiment, only the patient's metaphase spreads revealed chromatid repulsion. In fusion hybrids between the patient's fibroblasts and an established Chinese hamster cell line, the human chromosomes behaved perfectly normally, suggesting that the gene product which is missing or mutant in Roberts/SC phocomelia syndrome is supplied by the Chinese hamster genome. Images Fig. 1 Fig. 2 Fig. 3 PMID:3788975

Foreign aid

DEFF Research Database (Denmark)

Tarp, Finn

2008-01-01

Foreign aid has evolved significantly since the Second World War in response to a dramatically changing global political and economic context. This article (a) reviews this process and associated trends in the volume and distribution of foreign aid; (b) reviews the goals, principles and instituti......Foreign aid has evolved significantly since the Second World War in response to a dramatically changing global political and economic context. This article (a) reviews this process and associated trends in the volume and distribution of foreign aid; (b) reviews the goals, principles...... and institutions of the aid system; and (c) discusses whether aid has been effective. While much of the original optimism about the impact of foreign aid needed modification, there is solid evidence that aid has indeed helped further growth and poverty reduction...

Narrative research on mental health recovery: two sister paradigms.

Science.gov (United States)

Spector-Mersel, Gabriela; Knaifel, Evgeny

2017-06-24

Despite the breadth of narrative studies on individuals with severe mental illness, the suitability of narrative inquiry to exploring mental health recovery (MHR) has not been examined. (1) Examining the appropriateness of narrative inquiry to studying MHR; (2) assessing the extent to which narrative studies on MHR conform to the unique features of narrative research, as a distinctive form of qualitative inquiry. Review of empirical, theoretical and methodological literature on recovery and narrative inquiry. Considering the perspectives of recovery and narrative as paradigms, the similarity between their ontology and epistemology is shown, evident in 10 common emphases: meaning, identity, change and development, agency, holism, culture, uniqueness, context, language and giving voice. The resemblance between these "sister" paradigms makes narrative methodology especially fruitful for accessing the experiences of individuals in recovery. Reviewing narrative studies on MHR suggests that, currently, narrative research's uniqueness, centered on the holistic principle, is blurred on the philosophical, methodological and textual levels. Well-established narrative research has major implications for practice and policy in recovery-oriented mental health care. The narrative inquiry paradigm offers a possible path to enhancing the distinctive virtues of this research, realizing its potential in understanding and promoting MHR.

Educational aids

International Nuclear Information System (INIS)

Lenkeit, S.

1989-01-01

Educational aids include printed matter, aural media, visual media, audiovisual media and objects. A distinction is made between learning aids, which include blackboards, overhead projectors, flipcharts, wallcharts and pinboards, and learning aids, which include textbooks, worksheets, documentation and experimental equipment. The various aids are described and their use explained. The aids available at the School for Nuclear Technology of the Karlsruhe Nuclear Research Centre are described

AID SELECTIVITY PRACTICE AND AID EFFECTIVENESS IN SUB-SAHARAN AFRICA

OpenAIRE

Adedokun, Adeniyi Jimmy; Abiodun O. Folawewo, Abiodun O.

2017-01-01

Foreign aid strategies have undergone restructuring as donors adopt aid selectivity practice to improve aid effectiveness. This study investigates the impact of aid selectivity practice on aid effectiveness (aid-growth relationship) in Sub-Saharan Africa (SSA) and several groups of countries within SSA from 1980 to 2012. Employing system generalized methods of moments (system GMM) technique; the study produces strong evidence that there is significant improvement in aid effectiveness due to a...

Sister Mary Theresa Brentano, OSB's Innovative Use of Magnetic Audio Tapes: An Overlooked Story in the History of Educational Technology.

Science.gov (United States)

Herndon, Linda

This paper tells the story of Sister Mary Theresa Brentano, O.S.B's (1902-1987) innovative use of magnetic audiotapes to provide instruction for students in grades K-12. From 1952 to approximately 1968, Brentano implemented, refined, and tested her tape teaching methods with special emphasis on individualizing instruction in the elementary school.…

Changes in Siblings Over Time After the Death of a Brother or Sister From Cancer.

Science.gov (United States)

Akard, Terrah Foster; Skeens, Micah A; Fortney, Christine A; Dietrich, Mary S; Gilmer, Mary Jo; Vannatta, Kathryn; Barrera, Maru; Davies, Betty; Wray, Sarah; Gerhardt, Cynthia A

2018-02-27

Limited research has examined the impact of a child's death from cancer on siblings. Even less is known about how these siblings change over time. This study compared changes in siblings 1 (T1) and 2 (T2) years after the death of a brother or sister from cancer based on bereaved parent and sibling interviews. Participants across 3 institutions represented 27 families and included bereaved mothers (n = 21), fathers (n = 15), and siblings (n = 26) ranging from 8 to 17 years old. Participants completed semistructured interviews. Content analysis identified emerging themes and included frequency counts of participant responses. McNemar tests examined differences in the frequency of responses between T1 and T2 data. Participants reported similar types of changes in bereaved siblings at both time points, including changes in sibling relationships, life perspectives, their personal lives, and school performance. A new theme of "openness" emerged at T2. Frequencies of responses differed according to mother, father, or sibling informant. Overall, participants less frequently reported changes at T2 versus T1. Compared with findings in the first year, participants reported greater sibling maturity at follow-up. Overall changes in bereaved siblings continued over 2 years with less frequency over time, with the exception of increases in maturity and openness. Providers can educate parents regarding the impact of death of a brother or sister over time. Nurses can foster open communication in surviving grieving siblings and parents as potential protective factors in families going through their grief.

Estudo comparativo do LCR de pacientes com neurocriptococose sem AIDS e com AIDS Comparison between CSF samples from AIDS and non-AIDS patients with neurocryptococcosis

Directory of Open Access Journals (Sweden)

João Baptista dos Reis-Filho

1994-06-01

Full Text Available Até a década de 80, antes do surgimento da AIDS, a criptococose era relativamente rara. Verificou-se que esta doença afeta muito frequentemente os pacientes com AIDS e pode ser a primeira manifestação desta síndrome. O objetivo deste trabalho é o de comparar o resultado dos exames das amostras do LCR inicial na meningencefalite por criptococo entre pacientes com e sem AIDS. Este trabalho é baseado no estudo de 41 pacientes com neurocriptococose sem AIDS e de 23 pacientes com neurocriptococose e AIDS. Este estudo permitiu verificar que a reação inflamatória, no sistema nervoso, quando presente, foi de menor intensidade nos pacientes com AIDS; a reação inflamatória esteve presente em todos os pacientes sem AIDS e ausente em 21,7% dos pacientes com AIDS; o quadro inflamatório crônico, semelhante ao da meningencefalite tuberculosa, clássico nas meningencefalites por criptococo, ocorreu raramente nos pacientes com AIDS; em média, o número de criptococos no LCR foi maior nos pacientes com AIDS; pode ser feito diagnóstico presuntivo da AIDS quando o criptococo estiver presente no LCR que não apresenta alterações citológicas e bioquímicas.Neurocryptococcosis was a rare nervous system infection. With the rising number of patients with AIDS it became a very frequent disease. This infection is supposed to infect patients with some kind of immunodeficiency and the CSF alterations often simulate tuberculous meningitis. The purpose of this research was to compare the CSF changes in AIDS and non-AIDS patients with meningoencephalitis caused by Cr. neoformans. There were analysed 41 CSF samples from non-AIDS patients with neurocryptococcosis and 23 CSF samples from AIDS patients with neurocryptococcosis. The results of this research allowed to conclude that the inflammatory changes in the CSF from AIDS patients showed a lower intensity compared to those non-AIDS patients. These results showed as well, that the CSF samples from non-AIDS

Aid Effectiveness

DEFF Research Database (Denmark)

Arndt, Channing; Jones, Edward Samuel; Tarp, Finn

of the main relationships; (ii) estimating the impact of aid on a range of final and intermediate outcomes; and (iii) quantifying a simplied representation of the full structural form, where aid impacts on growth through key intermediate outcomes. A coherent picture emerges: aid stimulates growth and reduces......Controversy over the aggregate impact of foreign aid has focused on reduced form estimates of the aid-growth link. The causal chain, through which aid affects developmental outcomes including growth, has received much less attention. We address this gap by: (i) specifying a structural model...... poverty through physical capital investment and improvements in health....

The Politics of Exile: Ama Ata Aidoo's Our Sister Killjoy

Directory of Open Access Journals (Sweden)

Gay Wilentz

1991-01-01

Full Text Available Ama Ata Aidoo's Our Sister Killjoy or Reflections from a Black-Eyed Squint is a relentless attack on the notions of exile as relief from the societal constraints of national development and freedom to live in a cultural environment conducive to creativity. In this personalized prose/poem, Aidoo questions certain prescribed theories of exile (including the reasons for exile—particularly among African men. The novel exposes a rarely heard viewpoint in literature in English—that of the African woman exile. Aidoo's protagonist Sissie, as the "eye" of her people, is a sojourner in the "civilized" world of the colonizers. In this article, I examine Aidoo's challenge to prevailing theories of exile, her questioning of the supposed superiority of European culture for the colonial subject, and her exposé of the politics of exile for African self-exile. Through a combination of prose, poetry, oral voicing and letter writing, Aidoo's Sissie reports back to her home community what she sees in the land of the colonizers and confronts those exiles who have forgotten their duty to their native land.

Longitudinal pathways linking family factors and sibling relationship qualities to adolescent substance use and sexual risk behaviors.

Science.gov (United States)

East, Patricia L; Khoo, Siek Toon

2005-12-01

This 3-wave, 5-year longitudinal study tested the contributions of family contextual factors and sibling relationship qualities to younger siblings' substance use, sexual risk behaviors, pregnancy, and sexually transmitted disease. More than 220 non-White families participated (67% Latino and 33% African American), all of which involved a younger sibling (133 girls and 89 boys; mean age = 13.6 years at Time 1) and an older sister (mean age = 17 years at Time 1). Results from structural equation latent growth curve modeling indicated that qualities of the sibling relationship (high older sister power, low warmth/closeness, and low conflict) mediated effects from several family risks (mothers' single parenting, older sisters' teen parenting, and family's receipt of aid) to younger sibling outcomes. Model results were generally stronger for sister-sister pairs than for sister-brother pairs. Findings add to theoretical models that emphasize the role of family and parenting processes in shaping sibling relationships, which, in turn, influence adolescent outcomes. Copyright 2006 APA, all rights reserved).

The roles of WRN and BLM RecQ helicases in the Alternative Lengthening of Telomeres.

Science.gov (United States)

Mendez-Bermudez, Aaron; Hidalgo-Bravo, Alberto; Cotton, Victoria E; Gravani, Athanasia; Jeyapalan, Jennie N; Royle, Nicola J

2012-11-01

Approximately 10% of all cancers, but a higher proportion of sarcomas, use the recombination-based alternative lengthening of telomeres (ALT) to maintain telomeres. Two RecQ helicase genes, BLM and WRN, play important roles in homologous recombination repair and they have been implicated in telomeric recombination activity, but their precise roles in ALT are unclear. Using analysis of sequence variation present in human telomeres, we found that a WRN- ALT+ cell line lacks the class of complex telomere mutations attributed to inter-telomeric recombination in other ALT+ cell lines. This suggests that WRN facilitates inter-telomeric recombination when there are sequence differences between the donor and recipient molecules or that sister-telomere interactions are suppressed in the presence of WRN and this promotes inter-telomeric recombination. Depleting BLM in the WRN- ALT+ cell line increased the mutation frequency at telomeres and at the MS32 minisatellite, which is a marker of ALT. The absence of complex telomere mutations persisted in BLM-depleted clones, and there was a clear increase in sequence homogenization across the telomere and MS32 repeat arrays. These data indicate that BLM suppresses unequal sister chromatid interactions that result in excessive homogenization at MS32 and at telomeres in ALT+ cells.

Adolescent Siblings of Individuals with and without Intellectual and Developmental Disabilities: Self-Reported Empathy and Feelings about Their Brothers and Sisters

Science.gov (United States)

Shivers, Carolyn M.; Dykens, Elisabeth M.

2017-01-01

Siblings of brothers or sisters with intellectual and developmental disabilities (IDD) are important but understudied family members. As many previous studies have relied on parent report of sibling outcomes, the use of sibling self-report is an important addition to the research. This study assessed the feelings of adolescent siblings toward…

The SISTA pilot project: understanding the training and technical assistance needs of community-based organizations implementing HIV prevention interventions for African American women--implications for a capacity building strategy.

Science.gov (United States)

Fuller, Taleria R; Brown, Mari; King, Winifred; Prather, Cynthia; Cazaubon, Janine; Mack, Justin; Russell, Brandi

2007-01-01

The disproportionate rates of HIV/AIDS among African American women in the U.S. signify the ongoing need for targeted HIV prevention interventions. Additionally, building the capacity of service providers to sustain prevention efforts is a major concern. The Centers for Disease Control and Prevention (CDC) conducted a pilot project to disseminate the Sisters Informing Sisters about Topics on AIDS (SISTA), an HIV prevention intervention designed for African American women. The project was to inform the diffusion process and examine the training and technical assistance needs of participating community-based organizations. Results demonstrated a need for extensive pre-planning and skills-building prior to implementation.

Introgression and selection shaped the evolutionary history of sympatric sister-species of coral reef fishes (genus: Haemulon)

KAUST Repository

Bernal, Moisés A.

2016-11-22

Closely related marine species with large overlapping ranges provide opportunities to study mechanisms of speciation, particularly when there is evidence of gene flow between such lineages. Here, we focus on a case of hybridization between the sympatric sister-species Haemulon maculicauda and H. flaviguttatum, using Sanger sequencing of mitochondrial and nuclear loci, as well as 2422 single nucleotide polymorphisms (SNPs) obtained via restriction site-associated DNA sequencing (RADSeq). Mitochondrial markers revealed a shared haplotype for COI and low divergence for CytB and CR between the sister-species. On the other hand, complete lineage sorting was observed at the nuclear loci and most of the SNPs. Under neutral expectations, the smaller effective population size of mtDNA should lead to fixation of mutations faster than nDNA. Thus, these results suggest that hybridization in the recent past (0.174-0.263Ma) led to introgression of the mtDNA, with little effect on the nuclear genome. Analyses of the SNP data revealed 28 loci potentially under divergent selection between the two species. The combination of mtDNA introgression and limited nuclear DNA introgression provides a mechanism for the evolution of independent lineages despite recurrent hybridization events. This study adds to the growing body of research that exemplifies how genetic divergence can be maintained in the presence of gene flow between closely related species.

Introgression and selection shaped the evolutionary history of sympatric sister-species of coral reef fishes (genus: Haemulon)

KAUST Repository

Bernal, Moisé s A.; Gaither, Michelle R.; Simison, W. Brian; Rocha, Luiz A.

2016-01-01

Closely related marine species with large overlapping ranges provide opportunities to study mechanisms of speciation, particularly when there is evidence of gene flow between such lineages. Here, we focus on a case of hybridization between the sympatric sister-species Haemulon maculicauda and H. flaviguttatum, using Sanger sequencing of mitochondrial and nuclear loci, as well as 2422 single nucleotide polymorphisms (SNPs) obtained via restriction site-associated DNA sequencing (RADSeq). Mitochondrial markers revealed a shared haplotype for COI and low divergence for CytB and CR between the sister-species. On the other hand, complete lineage sorting was observed at the nuclear loci and most of the SNPs. Under neutral expectations, the smaller effective population size of mtDNA should lead to fixation of mutations faster than nDNA. Thus, these results suggest that hybridization in the recent past (0.174-0.263Ma) led to introgression of the mtDNA, with little effect on the nuclear genome. Analyses of the SNP data revealed 28 loci potentially under divergent selection between the two species. The combination of mtDNA introgression and limited nuclear DNA introgression provides a mechanism for the evolution of independent lineages despite recurrent hybridization events. This study adds to the growing body of research that exemplifies how genetic divergence can be maintained in the presence of gene flow between closely related species.

Magmatic Activity Beneath the Quiescent Three Sisters Volcanic Center, Central Oregon Cascade Range, USA, Inferred from Satellite InSAR

Science.gov (United States)

Wicks, C. W.; Dzurisin, D.; Ingebritsen, S.; Thatcher, W.; Lu, Z.; Iverson, J.

2001-12-01

Images from satellite interferometric synthetic aperture radar (InSAR) reveal uplift of a broad ~10 km by 20 km area in the Three Sisters volcanic center of the central Oregon Cascade Range, ~130 km south of Mt. St. Helens. The uplift is centered ~5 km west of South Sister volcano, the youngest stratovolcano in the volcanic center. The center has been volcanically inactive since the last eruption ~1500 years ago. Multiple European Space Agency ERS-1 and 2 satellite images from 1992 through 2000, used in this study, were selected based on orbital separation and time of year. Summer and early autumn scenes were necessary to avoid decorrelation from snow cover. Interferograms generated from these images indicate that most if not all of ~100 mm of observed uplift occurred between September 1998 and October 2000. We interpret the uplift as inflation caused by an apparently ongoing episode of magma intrusion at a depth of ~6.5 km. Geochemical (water chemistry) anomalies, first noted ~1990, coincide with the area of uplift and suggest the existence of a magma reservoir prior to the uplift. High chloride and sulfate concentrations, and a positive correlation between chloride concentration and spring temperature were found within the uplift area, with larger SO4/Cl ratios in springs at higher elevations. These findings are indicative of a high-temperature hydrothermal system driven by magma intrusions. The current inflation episode observed with InSAR may lead to an eruption, but the more persistent geochemical evidence suggests that the episode is likely the latest in a series of hitherto undetected magma intrusions. We do not yet know if the inflation has abated, is continuing, or has accelerated since October 2000--we only know that the highest rate of uplift occurred in the last year for which ERS-2 data was available (1999- 2000). In May of 2001, a continuous GPS receiver and seismometer were installed by the USGS within the Three Sisters Wilderness to monitor the

AIDS Myths and Myths about AIDS Myths : A Study about AIDS-related Perceptions in South Africa

OpenAIRE

Sivelä, Jonas

2016-01-01

This doctoral thesis, consisting of four separate articles and a summarizing report, discusses so-called South African AIDS myths also called AIDS beliefs, rumours, misconceptions and legends. AIDS myths have been put forth as an outcome of and a major reason behind the severe HIV/AIDS situation in South Africa. They are proposed to flourish among black South Africans living in impoverished townships and villages. In previous studies, the reasons and mechanisms behind AIDS myths have be...

HIV/AIDS - resources

Science.gov (United States)

Resources - HIV/AIDS ... information on AIDS : AIDS.gov -- www.aids.gov AIDS Info -- aidsinfo.nih.gov The Henry J. Kaiser Family Foundation -- www.kff.org/hivaids US Centers for Disease Control and Prevention -- www.cdc.gov/hiv

A critical view to explanations for the maximal value of 50 % of genetic recombination Críticas a las explicaciones del máximo de 50 % de recombinación genética

Directory of Open Access Journals (Sweden)

CARLOS Y VALENZUELA

2001-03-01

Full Text Available The maximal value of 50 % of genetic recombination (RF = recombination fraction between two linked gene loci has been explained by two models: (i the restriction of crossovers to only two of the four chromatids of a tetrad (tetrad model; (ii the limit of the occurrence of an odd number of crossovers between two loci, when the expected number of crossovers tends to infinite (odd-even model. This article shows that (i is wrong. If tetrads were responsible for the maximal 50 % RF, sister chromatid exchanges (SCE should display a maximal 100 % RF. In mammalian CHO cells we found that SCE yield a maximal 50 % recombination. Also, we demonstrated that the maximal 50 % RF for tetrads occurs because the sum of odd order coefficients in the binomial distribution is equal to the sum of even order coefficients. At the end of meiosis the two chromatids of a chromosome that receives K crossovers are separated. Then K breaks should distribute into two chromatids. Thus, the expected number of breaks per chromatid distributes, when K is large, in 50 % of chromatids having an even number of breaks (RF = 0 and 50 % having an odd number (RF = 1, irrespective of tetrads, hexads, octads or more complex meiotic chromosome configurationsEl máximo de 50 % de recombinación genética (RF entre dos loci ligados ha sido explicado por dos modelos. (i la restricción de los entrecruzamientos a dos de las cuatro cromátidas de una tétrada (modelo de tétrada; (ii el límite de la ocurrencia de un número impar de entrecruzamientos entre los dos loci, cuando el número esperado de entrecruzamientos tiende a infinito (modelo par-impar. Este artículo muestra que (i es erróneo, ya que, si la tétrada fuera responsable del máximo de 50 % de RF, el intercambio de cromátidas hermanas (SCE debería alcazar el 100 % de recombinación y esto no se da en células CHO, en las que encontramos un máximo de 50 %. Además, demostramos que el máximo de 50 % RF para las t

In vivo mutagenicity studies in rats mice and Chinese hamsters fed irradiated foodstuffs - chicken, fish, dates, pulses, mangoes and cocoa beans

International Nuclear Information System (INIS)

Renner, H.W.

1982-01-01

Three in vivo genetic toxicity tests were performed in rats, mice and Chinese hamsters to detect possible mutagenic effects of irradiated chicken, dried dates, fish, cocoa beans, pulses and mangoes. The tests employed were the micronucleus test and sister-chromatid exchange (SCE) test for irradiated and unirradiated samples of all foodstuffs listed, and the spermatogonia test, (including SCE technique) in mice for irradiated and unirradiated chicken, fish and dates only. In the case of cocoa beans, the mutagenicity tests were performed on an additional test group fed beans fumigated with ethylene oxide. The different mammalian species used for the various experiments are given below. None of the tests provided any evidence of mutagenicity induced by irradiation in any of the foodstuffs studied. Moreover, these tests are currently considered to be the most sensitive in vivo mutagenicity tests in mammals. (orig.)

The phenotype of FancB-mutant mouse embryonic stem cells

International Nuclear Information System (INIS)

Kim, Tae Moon; Ko, Jun Ho; Choi, Yong Jun; Hu Lingchuan; Hasty, Paul

2011-01-01

Fanconi anemia (FA) is a rare autosomal recessive disease characterized by bone marrow failure, developmental defects and cancer. There are multiple FA genes that enable the repair of interstrand crosslinks (ICLs) in coordination with a variety of other DNA repair pathways in a way that is poorly understood. Here we present the phenotype of mouse embryonic stem (ES) cells mutated for FancB. We found FancB-mutant cells exhibited reduced cellular proliferation, hypersensitivity to the crosslinking agent mitomycin C (MMC), increased spontaneous and MMC-induced chromosomal abnormalities, reduced spontaneous sister chromatid exchanges (SCEs), reduced gene targeting, reduced MMC-induced Rad51 foci and absent MMC-induced FancD2 foci. Since FancB is on the X chromosome and since ES cells are typically XY, FancB is an excellent target for an epistatic analysis to elucidate FA's role in ICL repair.

Cancer risk in humans predicted by increased levels of chromosomal aberrations in lymphocytes: Nordic study group on the health risk of chromosome damage

DEFF Research Database (Denmark)

Hagmar, L; Brøgger, A; Hansteen, I L

1994-01-01

Cytogenetic assays in peripheral blood lymphocytes (PBL) have been used extensively to survey the exposure of humans to genotoxic agents. The conceptual basis for this has been the hypothesis that the extent of genetic damage in PBL reflects critical events for carcinogenic processes in target...... tissues. Until now, no follow-up studies have been performed to assess the predictive value of these methods for subsequent cancer risk. In an ongoing Nordic cohort study of cancer incidence, 3182 subjects were examined between 1970 and 1988 for chromosomal aberrations (CA), sister chromatid exchange.......0009) in CA strata with regard to subsequent cancer risk. The point estimates of the standardized incidence ratio in the three CA strata were 0.9, 0.7, and 2.1, respectively. Thus, an increased level of chromosome breakage appears to be a relevant biomarker of future cancer risk....

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...

Antioxidant and antigenotoxic potencies of Sempervivum armenum on human lymphocytes in vitro.

Science.gov (United States)

Sunar, Serap; Anar, Mustafa; Sengul, Meryem; Agar, Guleray

2016-12-01

In this research, the genotoxic and antigenotoxic effects of methanol extract of Sempervivum armenum (MSA) were studied using micronucleus (MN) test and sister chromatid exchange (SCE) test systems in cultured human peripheral blood cells. According to the SCE and MN tests results, MSA reduced the genotoxic effects of aflatoxin B 1 . In order to explain the reason for the antigenotoxic effects of MSA, antioxidants levels were determined. Cotreatments of 5, 10, 20 mg/mL concentrations of MSA with aflatoxin B 1 decreased the frequencies of SCE, MN and the malondialdehyde level and increased the amount of superoxide dismutase, glutathione and glutathione peroxidase which were decreased by aflatoxin. The results of this experiment showed that MSA has strong antioxidative and antigenotoxic effects and this antigenotoxic activities of MSA can be due to the antioxidant activities.

Tricky typhus ticks two: A report of two sisters from North India presenting with acute respiratory distress syndrome due to scrub typhus

Directory of Open Access Journals (Sweden)

R Pai

2016-01-01

Full Text Available Scrub typhus is emerging as an important cause of acute febrile illness in Northern India. This is a report of two sisters presenting concurrently with acute respiratory distress syndrome. A diagnosis of scrub typhus was made in both the patients, and they were successfully treated with doxycycline.

Aid Policy and the Macroeconomic Management of Aid

DEFF Research Database (Denmark)

Addison, Tony; Tarp, Finn

2015-01-01

This is an introduction to the UNU-WIDER special issue of World Development on aid policy and the macroeconomic management of aid. We provide an overview of the 10 studies, grouping them under three sub-themes: the aid–growth relationship; the supply-side of aid (including its level, volatility......, and coordination of donors); and the macroeconomic framework around aid. The studies in the special issue demonstrate the centrality of research methodology, the importance of disaggregation, and the need to account for country-specific situations and problems. This introduction concludes that the sometimes “over...

Aid is dead. Long live aid!

Directory of Open Access Journals (Sweden)

Jean-Michel Severino

2012-06-01

Full Text Available The concepts, targets, tools, institutions and modes of operation of official development assistance have been overtaken by the pace of change in a world marked by the combined momentum of demography, technology and economic growth.Aid can however recover, as social consequences of the globalization call for new forms of regulation. It will then be necessary to modify and diversify our target-setting processes, to update operating procedures, and to find better ways of measuring policy implementation. Aid volumes will certainly continue to grow, and we must transform the way aid is financed. Public and private aid stakeholders must recognize the importance of these transformations and be ready to support them, by questioning the methods as well as the objectives of the policies they are implementing. Otherwise, they will severely impede the emergence of the policies we need if we are to build a better world.

Detection of sister-species in invasive populations of the fall armyworm Spodoptera frugiperda (Lepidoptera: Noctuidae) from Uganda

Science.gov (United States)

Tay, Wee Tek; Walsh, Thomas K.; Kanyesigye, Dalton; Adumo, Stella; Abongosi, Joseph; Ochen, Stephen; Sserumaga, Julius; Alibu, Simon; Abalo, Grace; Asea, Godfrey; Agona, Ambrose

2018-01-01

The fall armyworm (FAW) Spodoptera frugiperda (J. E. Smith) is a species native to the Americas. This polyphagous lepidopteran pest was first reported in Nigeria and the Democratic Republic of São Tomé and Principe in 2016, but its presence in eastern Africa has not been confirmed via molecular characterisation. In this study, FAW specimens from western and central Uganda were identified based on the partial mtDNA COI gene sequences, with mtDNA COI haplotypes matching those identified in Nigeria and São Tomé. In this study, we sequence an additional partial mtDNA Cyt b gene and also the partial mtDNA COIII gene in Ugandan FAW samples. We detected identical mitochondrial DNA haplotypes for both the mtDNA Cyt b and COI partial genes, while combining the mtDNA COI/Cyt b haplotypes and mtDNA COIII haplotypes enabled a new maternal lineage in the Ugandan corn-preferred FAW samples to be identified. Our results suggested that the African incursions of S. frugiperda involved at least three maternal lineages. Recent full genome, phylogenetic and microsatellite analyses provided evidence to support S. frugiperda as likely consisted of two sympatric sister species known as the corn-preferred and rice-preferred strains. In our Ugandan FAW populations, we identified the presence of mtDNA haplotypes representative of both sister species. It is not known if both FAW sister species were originally introduced together or separately, and whether they have since spread as a single population. Further analyses of additional specimens originally collected from São Tomé, Nigeria and throughout Africa would be required to clarify this issue. Importantly, our finding showed that the genetic diversity of the African corn-preferred FAW species is higher than previously reported. This potentially contributed to the success of FAW establishment in Africa. Furthermore, with the additional maternal lineages detected, there is likely an increase in paternal lineages, thereby increasing

Project THANKS: Examining HIV/AIDS-Related Barriers and Facilitators to Care in African American Women: A Community Perspective.

Science.gov (United States)

Amutah-Onukagha, Ndidiamaka; Mahadevan, Meena; Opara, Ijeoma; Rodriguez, Monica; Trusdell, Megan; Kelly, Jessica

2018-04-01

Project THANKS, (Turning HIV/AIDS into Knowledge for Sisters), is an evidence-based intervention that utilizes a community-based participatory and empowerment building approach for African American female substance abusers living with HIV and other chronic diseases. This qualitative study sought to gain insight from women living with HIV on how to improve Project THANKS. African American women living with substance abuse disorders, HIV, and other comorbidities were recruited from three community based health centers in New Jersey (N = 31). Ninety minute focus group sessions were implemented in each health center. The focus group sessions were designed to understand the perceived factors influencing the participants' ability to self-manage their health conditions and challenges they are currently facing regarding their diagnoses. The barriers and suggestions presented by participants included addressing stigmatization, managing mental health symptoms, improving physician-patient trust, accessing health education, educating community members, and proper nutrition. In addition, an engaged and trusting relationship with their healthcare provider and having positive sources of support were cited as motivators to adhering to their HIV treatment regimen. Participants living with HIV/AIDS also expressed more concern with difficulty treating their comorbidities than participants with only HIV/AIDS. Receiving input from African American women living with HIV related comorbidities was essential in improving the intervention to include a behavioral and primary health approach. Future programmatic interventions of Project THANKS will include a targeted focus on addressing mental health needs in women by offering meditation services and mental health referrals. In addition, Project THANKS will incorporate activities to improve communication with physicians, families, and media outlets to empower women to take an active role in their primary and social support needs.

Sister mary joseph′s nodule: A case of umbilical cutaneous metastasis with signet ring cell histology

Directory of Open Access Journals (Sweden)

Zadeh Valid

2009-01-01

Full Text Available The metastasis of a visceral malignancy to the umbilicus is known as "Sister Mary Joseph′s nodule". It is a rare clinical sign indicating advanced, metastasizing intraabdominal cancer. We report a 50-year-old man who developed metastatic skin cancer in the form of semicircular indurated plaque on top of which was a firm mobile rounded nodule at the umbilical area. Histopathological examination demonstrated diastase-resistant periodic acid-Schiff and mucicarmine positive signet ring cells, suggesting gastric carcinoma. Immunohistochemical staining showed that these cells were positive for cytokeratins and epithelial membrane antigen, suggesting epithelial origin.

AIDS

Science.gov (United States)

... page: //medlineplus.gov/ency/article/000594.htm HIV/AIDS To use the sharing features on this page, ... immunodeficiency virus (HIV) is the virus that causes AIDS. When a person becomes infected with HIV, the ...

Phylogenetic Analysis of Seven WRKY Genes across the Palm Subtribe Attaleinae (Arecaceae) Identifies Syagrus as Sister Group of the Coconut

Science.gov (United States)

Meerow, Alan W.; Noblick, Larry; Borrone, James W.; Couvreur, Thomas L. P.; Mauro-Herrera, Margarita; Hahn, William J.; Kuhn, David N.; Nakamura, Kyoko; Oleas, Nora H.; Schnell, Raymond J.

2009-01-01

Background The Cocoseae is one of 13 tribes of Arecaceae subfam. Arecoideae, and contains a number of palms with significant economic importance, including the monotypic and pantropical Cocos nucifera L., the coconut, the origins of which have been one of the “abominable mysteries” of palm systematics for decades. Previous studies with predominantly plastid genes weakly supported American ancestry for the coconut but ambiguous sister relationships. In this paper, we use multiple single copy nuclear loci to address the phylogeny of the Cocoseae subtribe Attaleinae, and resolve the closest extant relative of the coconut. Methodology/Principal Findings We present the results of combined analysis of DNA sequences of seven WRKY transcription factor loci across 72 samples of Arecaceae tribe Cocoseae subtribe Attaleinae, representing all genera classified within the subtribe, and three outgroup taxa with maximum parsimony, maximum likelihood, and Bayesian approaches, producing highly congruent and well-resolved trees that robustly identify the genus Syagrus as sister to Cocos and resolve novel and well-supported relationships among the other genera of the Attaleinae. We also address incongruence among the gene trees with gene tree reconciliation analysis, and assign estimated ages to the nodes of our tree. Conclusions/Significance This study represents the as yet most extensive phylogenetic analyses of Cocoseae subtribe Attaleinae. We present a well-resolved and supported phylogeny of the subtribe that robustly indicates a sister relationship between Cocos and Syagrus. This is not only of biogeographic interest, but will also open fruitful avenues of inquiry regarding evolution of functional genes useful for crop improvement. Establishment of two major clades of American Attaleinae occurred in the Oligocene (ca. 37 MYBP) in Eastern Brazil. The divergence of Cocos from Syagrus is estimated at 35 MYBP. The biogeographic and morphological congruence that we see for

Magmatic activity beneath the quiescent Three Sisters volcanic center, central Oregon Cascade Range, USA

Science.gov (United States)

Wicks, Charles W.; Dzurisin, Daniel; Ingebritsen, Steven; Thatcher, Wayne; Lu, Zhong; Iverson, Justin

2002-04-01

Images from satellite interferometric synthetic aperture radar (InSAR) reveal uplift of a broad ~10 km by 20 km area in the Three Sisters volcanic center of the central Oregon Cascade Range, ~130 km south of Mt. St. Helens. The last eruption in the volcanic center occurred ~1500 years ago. Multiple satellite images from 1992 through 2000 indicate that most if not all of ~100 mm of observed uplift occurred between September 1998 and October 2000. Geochemical (water chemistry) anomalies, first noted during 1990, coincide with the area of uplift and suggest the existence of a crustal magma reservoir prior to the uplift. We interpret the uplift as inflation caused by an ongoing episode of magma intrusion at a depth of ~6.5 km.

The hsSsu72 phosphatase is a cohesin-binding protein that regulates the resolution of sister chromatid arm cohesion

OpenAIRE

Kim, Hyun-Soo; Baek, Kwan-Hyuck; Ha, Geun-Hyoung; Lee, Jae-Chul; Kim, Yu-Na; Lee, Janet; Park, Hye-Young; Lee, Noo Ri; Lee, Ho; Cho, Yunje; Lee, Chang-Woo

2010-01-01

An interplay of phosphorylation, dephosphorylation and protecting factors controls proteolysis-independent cohesin dissociation from chromosomes. The identification of a new phosphatase protecting arm cohesin now adds further complexity to this regulation.

Resistance to radiation, recombination, repair of DNA and chromosome organisation

Energy Technology Data Exchange (ETDEWEB)

Fletcher, H L [East Anglia Univ., Norwich (UK). School of Biological Sciences

1981-01-01

The model advanced here proposes that death is caused by destructive lesions, mainly double-strand breaks, in all the inter-repairable copies so close together that recombination repair cannot function. Death is related to the exponential of dose where r is the number of copies of the genome. A graph of ln(-ln survival) against ln dose is used to produce a linear dose-survival relationship, the slope of which gives the number of inter-repairable copies of the genome (= number of hits per lethal event). In Ustilago maydis it seems that unless all the chromatids are broken within a few thousand base pairs all ds breaks are repaired. The size of this critical target is similar to the size of a gene. Meiotic pairing in fungi starts outside the genes, and it is therefore suggested that specific pairing sites between genes define the ends of the targets. The model also describes the radiation-induced death of Micrococcus radiodurans and Sacchromyces cerevisiae. Cultured mammalian cells also show a linear ln(-ln survival)/ln dose relationship with a slope of 1.5 showing that both 1st and 2nd order killing occured. Sublethal radiation induces recombination in heterozygous diploid U. maydis proportional to the square of the dose. Sister-chromatid repair is preferred. Polyploid yeast can only use pairs of chromosomes for repair, showing that chromosome pairing is required for recombination repair, and mitotic pairing is restricted to bivalents in the same way that meiotic pairing is.

Vicia cytogenetic tests for environmental mutagens. A report of the US Environmental Protection Agency gene-tox program

Energy Technology Data Exchange (ETDEWEB)

Ma, T H

1982-01-01

Vicia root-tip mitotic and pollen mother-cell meiotic tests are two major kinds of cytogenetic tests for environmental mutagens. According to the present review, 81 of 85 earlier studies used mitotic tests to determine the frequencies of chromosome or chromatid aberrations and/or sister-chromatid exchange from root-tip meristematic cells; only 4 used meiotic tests to determine the frequencies of chromosome aberration from pollen mother cells. Treatment of root-tip meristem can be done by allowing the newly germinated roots to absorb the chemical mutagens from a water solution. Pollen mother cells can be treated by spraying the solution or pipetting the liquid over the flower buds. After an appropriate recovery time, the samples are fixed and stained, and the slides are prepared for metaphase or anaphase figures for scoring aberration frequencies. Slides for meiotic tests are prepared for metaphase I and/or Anaphase I stages for scoring chromosome aberration frequencies. Results of both cytogenetic tests should be expressed in terms of number of breaks per cell or per 100 cells. Test results of 76 chemicals from 32 classes in this review indicate that the Vicia root-tip mitotic test is reliable, efficient, and relatively inexpensive. These results also reveal that antibiotics are most frequently studied, followed by alkyl sulfones, pyrimidine, and purine derivatives. Of all the agents studied through root-tip mitotic tests, about 90% gave positive responses; antibiotics (phyleomycin and bleomycin) had very high mutagenicity (less than 1 ppM gave positive response).

The FANC pathway and BLM collaborate during mitosis to prevent micro-nucleation and chromosome abnormalities.

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Naim, Valeria; Rosselli, Filippo

2009-06-01

Loss-of-function of caretaker genes characterizes a group of cancer predisposition diseases that feature cellular hypersensitivity to DNA damage and chromosome fragility; this group includes Fanconi anaemia and Bloom syndrome. The products of the 13 FANC genes (mutated in Fanconi anaemia), which constitute the 'FANC' pathway, and BLM (the RecQ helicase mutated in Bloom syndrome) are thought to collaborate during the S phase of the cell cycle, preventing chromosome instability. Recently, BLM has been implicated in the completion of sister chromatid separation during mitosis, a complex process in which precise regulation and execution is crucial to preserve genomic stability. Here we show for the first time a role for the FANC pathway in chromosome segregation during mitotic cell division. FANCD2, a key component of the pathway, localizes to discrete spots on mitotic chromosomes. FANCD2 chromosomal localization is responsive to replicative stress and specifically targets aphidicolin (APH)-induced chromatid gaps and breaks. Our data indicate that the FANC pathway is involved in rescuing abnormal anaphase and telophase (ana-telophase) cells, limiting aneuploidy and reducing chromosome instability in daughter cells. We further address a cooperative role for the FANC pathway and BLM in preventing micronucleation, through FANC-dependent targeting of BLM to non-centromeric abnormal structures induced by replicative stress. We reveal new crosstalk between FANC and BLM proteins, extending their interaction beyond the S-phase rescue of damaged DNA to the safeguarding of chromosome stability during mitosis.

Assessment of adaptability of zebu cattle (Bos indicus) breeds in two different climatic conditions: using cytogenetic techniques on genome integrity.

Science.gov (United States)

Kumar, Anil; Waiz, Syma Ashraf; Sridhar Goud, T; Tonk, R K; Grewal, Anita; Singh, S V; Yadav, B R; Upadhyay, R C

2016-06-01

The aim of this study was to evaluate the genome integrity so as to assess the adaptability of three breeds of indigenous cattle reared under arid and semi-arid regions of Rajasthan (Bikaner) and Haryana (Karnal) India. The cattle were of homogenous group (same age and sex) of indigenous breeds viz. Sahiwal, Tharparkar and Kankrej. A total of 100 animals were selected for this study from both climatic conditions. The sister chromatid exchanges (SCE's), chromosomal gaps and chromatid breaks were observed in metaphase plates of chromosome preparations obtained from in vitro culture of peripheral blood lymphocytes. The mean number of breaks and gaps in Sahiwal and Tharparkar of semi-arid zone were 8.56 ± 3.16, 6.4 ± 3.39 and 8.72 ± 2.04, 3.52 ± 6.29, respectively. Similarly, the mean number of breaks and gaps in Tharparkar and Kankrej cattle of arid zone were 5.26 ± 1.76, 2.74 ± 1.76 and 5.24 ± 1.84, 2.5 ± 1.26, respectively. The frequency of SCEs in chromosomes was found significantly higher (P  0.05) was observed in the same zone. The analysis of frequency of CAs and SCEs revealed significant effects of environmental conditions on the genome integrity of animals, thereby indicating an association with their adaptability.

Aid and good governance: Examining aggregate unintended effects of aid.

Science.gov (United States)

Dijkstra, Geske

2018-06-01

Although donors generally aim to improve governance in recipient countries by various means, critics claim that the aggregate effect of large aid flows is the deterioration of governance. Aid is said to weaken domestic accountability, sustain authoritarian regimes, increase political instability, weaken government capacities, and increase corruption. Conducting a systematic search in Web of Science, this paper reviews the empirical evidence for these unintended aggregate effects of aid on the political, administrative, and judicial dimensions of good governance. It finds that the negative effects of aid on governance are much exaggerated. The aggregate effect of aid on democracy has become more positive after the Cold War, and the effect of aid on government capacity and on reducing corruption has also improved over time. Furthermore, most studies show a positive effect of aid on political stability. These findings imply that donor intentions matter: donors that are serious about their intended effects on governance are able to mitigate the possible negative unintended effects of their aid. Copyright © 2017 Elsevier Ltd. All rights reserved.

Challenging stereotypes? The older woman in the TV series Brothers & Sisters.

Science.gov (United States)

Oró-Piqueras, Maricel

2014-12-01

The TV series, Brothers & Sisters, broadcast from 2006 to 2011 by ABC (USA) and a year later by Channel 4 (UK) with quite high audience rates, starts when the patriarchal figure, William Walker, dies of a heart attack and two female figures around their sixties come center stage: his wife, Nora Walker, and his long-term lover, Holly Harper. Once the patriarchal figure disappears, the female characters regain visibility by entering the labor market and starting relationships with other men. In that sense, both protagonists experience aging as a time in which they are increasingly freed from social and family constraints. However, their roles as nurturers keep on bringing them back to the domestic space in which they are safe from being involved in uncomfortable and unsuitable situations. Drawing on previous studies on the representation of the older woman in fictional media, this article intends to discern to what extent stereotypes related to the older woman are challenged through the two main protagonists of a contemporary TV series. Copyright © 2014 Elsevier Inc. All rights reserved.

TurbinAID

International Nuclear Information System (INIS)

Moradian, M.A.; Chow, M.P.; Osborne, R.L.; Jenkins, M.A.

1991-01-01

The Westinghouse Turbine Artificial Intelligence Diagnostics system or TurbinAID, can diagnose both thermodynamic and mechanical component anomalies within the turbine, and around the turbine cycle. any monitoring system can detect that a variable is in an abnormal state, but TurbinAID can also indicate the cause, and provide recommended corrective action(s). The TurbinAID Expert Systems utilize multiple sensor and variable inputs, and their interdependencies in the generation of a diagnosis. The system performs sensor validation as part of the data acquisition scheme. The TurbinAID system has been in operation for several years. This paper describes the monitoring and diagnostic functions provided by TurbinAID, and how the utility industry both nuclear and fossil, can utilize the system to enhance unit operation

Early Development of Squamous Cell Carsinoma in Two Sister Cases with pidermodysplasia Verruciformis

Directory of Open Access Journals (Sweden)

Ömer Çalka

2010-06-01

Full Text Available Epidermodysplasia verruciformis (Lewandowsky-Lutz syndrome is an uncommon disease characterized by multiple plane warts, pityriasis versicolor-like lesions, defects of cell-mediated immunity, and tendency to develop skin malignancies, primarily on sun-exposed areas. Most commonly it is inherited as an autosomal recessive trait. Squamous cell carcinoma is the most common type of skin cancer found in patient with epidermodysplasia verruciformis. Human papilloma virus 5, 8, and 47 are found in more than 90% of epidermodysplasia verruciformis skin cancers. Treatment for epidermodysplasia verruciformis consists largely of preventive measures. Photoprotection remains essential for management. In this report, two sister case of epidermodisplasia verruciformis with plane warts, pityriasis versicolor-like lesions, and squamous cell carcinomas on sun-exposed areas of skin was presented for it is a rarely encountered disease and associated with early development of malignancy.

Fear and loathing in Mississippi: the attack on cAMP sister spirit.

Science.gov (United States)

Greene, Kate

2003-01-01

SUMMARY In 1993, the small rural community of Ovett, Miss., and a group of self-described radical lesbian feminists clashed over the establishment by the women of a feminist educational retreat known as Camp Sister Spirit. This dispute took the form of physical and psychological harassment of the women, wide-open public debate in the community, in the press, and on television, federal mediation efforts, and two lawsuits. This article analyzes this dispute using Mary Daly's seven patterns of the sado-ritual syndrome (Daly, 1978). The analysis examines the ideological and moral standpoints of the participants, the issues of "blaming the victim" and scapegoating, the development of the conflict from a dispute between neighbors to the involvement of international media, national activists and the Clinton Administration, the transformation of the conflict from a political to legal dispute, the representations of the groups within the community and the media, the effect of public opinion on the dispute, and the politics of the media in the dispute.

Benign multicystic mesothelioma: a case report of three sisters

Directory of Open Access Journals (Sweden)

Thomas Rutherford

2009-12-01

Full Text Available Benign multicystic mesothelioma (BMCM is a rare tumor of the abdomen-peritoneum of unknown etiology. This benign tumor was initially described by Plaut in 1928 when he observed loose cysts in the pelvis during a surgery for a uterine leiomyoma.2 The mesothelial origin was later confirmed by electron micro-scopy by Mennemeyer and Smith in 1979.3 To date, there are approximately 140 cases of BMCM reported in the literature.4 This disease primarily occurs in pre-menopausal women and is associated with a history of pelvic inflammatory disease, prior abdominal surgery, and endometriosis.4,5 The pathogenesis of this disease remains controversial, with possible etiologies including a neoplastic versus a reactive process.5 In the literature, a few case reports discuss a possible genetic or familial association with BMCM.6 Specifically, one report describes a man with familial Mediterranean fever who developed BMCM. Although familial Mediter-ranean fever is associated with malignant mesothelioma, he had only BMCM, and did not suffer from malignant mesothelioma.6 A genetic evaluation and chromosomal analysis were not able to identify a specific genetic cause of the family’s pattern of disease. This case report describes two female siblings diagnosed with BMCM. In addition, a third sister also had findings consistent with BMCM, however, the discrete histological diagnosis was never confirmed.

Psychological first-aid: a practical aide-memoire.

Science.gov (United States)

Leach, J

1995-07-01

Despite advances made in recent years in medical first aid, psychiatric intervention, survival training and equipment design, many people still perish quickly during and immediately following a disastrous event. In this study, individuals and groups of survivors of life-threatening events were debriefed and the behavior of those who coped well during such a threat to life were compared with those who did not. The behaviors of those who coped well were distilled into a set of principles for psychological first aid; that is, a series of simple actions for use within a disaster which serves to recover victims to functional behavior as quickly as possible, thus increasing their chance for survival. These principles of psychological first aid have recently been introduced into basic first aid and survival training courses for both military and civilian units.

Ancient fossil specimens of extinct species are genetically more distant to an outgroup than extant sister species are

Science.gov (United States)

Huang, Shi

2009-01-01

There exists a remarkable correlation between genetic distance as measured by protein or DNA dissimilarity and time of species divergence as inferred from fossil records. This observation has provoked the molecular clock hypothesis. However, data inconsistent with the hypothesis have steadily accumulated in recent years from studies of extant organisms. Here the published DNA and protein sequences from ancient fossil specimens were examined to see if they would support the molecular clock hypothesis. The hypothesis predicts that ancient specimens cannot be genetically more distant to an outgroup than extant sister species are. Also, two distinct ancient specimens cannot be genetically more distant than their extant sister species are. The findings here do not conform to these predictions. Neanderthals are more distant to chimpanzees and gorillas than modern humans are. Dinosaurs are more distant to frogs than extant birds are. Mastodons are more distant to opossums than other placental mammals are. The genetic distance between dinosaurs and mastodons is greater than that between extant birds and mammals. Therefore, while the molecular clock hypothesis is consistent with some data from extant organisms, it has yet to find support from ancient fossils. Far more damaging to the hypothesis than data from extant organisms, which merely question the constancy of mutation rate, the study of ancient fossil organisms here challenges for the first time the fundamental premise of modern evolution theory that genetic distances had always increased with time in the past history of life on Earth. PMID:18600632

Genetic damage in human cells exposed to non-ionizing radiofrequency fields: a meta-analysis of the data from 88 publications (1990-2011).

Science.gov (United States)

Vijayalaxmi; Prihoda, Thomas J

2012-12-12

Based on the 'limited' evidence suggesting an association between exposure to radiofrequency fields (RF) emitted from mobile phones and two types of brain cancer, glioma and acoustic neuroma, the International Agency for Research on Cancer has classified RF as 'possibly carcinogenic to humans' in group 2B. In view of this classification and the positive correlation between increased genetic damage and carcinogenesis, a meta-analysis was conducted to determine whether a significant increase in genetic damage in human cells exposed to RF provides a potential mechanism for its carcinogenic potential. The extent of genetic damage in human cells, assessed from various end-points, viz., single-/double-strand breaks in the DNA, incidence of chromosomal aberrations, micronuclei and sister chromatid exchanges, reported in a total of 88 peer-reviewed scientific publications during 1990-2011 was considered in the meta-analysis. Among the several variables in the experimental protocols used, the influence of five specific variables related to RF exposure characteristics was investigated: (i) frequency, (ii) specific absorption rate, (iii) exposure as continuous wave, pulsed wave and occupationally exposed/mobile phone users, (iv) duration of exposure, and (v) different cell types. The data indicated the following. (1) The magnitude of difference between RF-exposed and sham-/un-exposed controls was small with some exceptions. (2) In certain RF exposure conditions there was a statistically significant increase in genotoxicity assessed from some end-points: the effect was observed in studies with small sample size and was largely influenced by publication bias. Studies conducted within the generally recommended RF exposure guidelines showed a smaller effect. (3) The multiple regression analyses and heterogeneity goodness of fit data indicated that factors other than the above five variables as well as the quality of publications have contributed to the overall results. (4) More

AIDS guidelines.

Science.gov (United States)

Berger, R

1986-04-30

The Sun article, "Employers finding that AIDS in the workplace is a managerial nightmare" (April 3), did not accurately portray the status of AIDS in the workplace. The AIDS virus, HTLV III, is transmitted by body fluids, primarily semen and blood, and there is no known risk of transmitting the virus by casual contact in the workplace. The Center for Disease Control (CDC) released guidelines for child care workers last August. Guidelines on preventing transmission of AIDS in the workplace were issued by CDC in November 1985. These guidelines specifically discussed health care, personal service, and food service workers. The recommendations were against routine screening. Furthermore, employment should not be restricted on the basis of a positive HTLV III antibody test. A person with HTLV III infection should be exempt from the workplace only if there are circumstances interfering with job performance. In Maryland, the Governor's Task Force on AIDS has gone on record as endorsing CDC guidelines related to employment. Furthermore, the task force condemns discrimination based on the disease AIDS, AIDS Related Complex (ARC), or HTLV III infection. Increasingly AIDS patients are being considered legally disabled and therefore are protected by federal and state laws prohibiting discrimination on the basis of a handicap. Marylanders who are subjected to mandatory HTLV III screening in the workplace, or if discriminated against on the basis of HTLV III inefction, should contact the Maryland Commission on Human Relations, the Maryland Department of Health and Mental Hygiene, or the Health Education Resource Organization (HERO). All 3 of these resources guarantee confidentiality. It is only by employees reporting incidents that a nightmare in the workplace can be avoided in Maryland. full text

Gastroenteritis: First Aid

Science.gov (United States)

First aid Gastroenteritis: First aid Gastroenteritis: First aid By Mayo Clinic Staff Gastroenteritis is an inflammation of your stomach and intestines. Common causes are: Viruses. Food or water contaminated by ...

Snakebites: First Aid

Science.gov (United States)

First aid Snakebites: First aid Snakebites: First aid By Mayo Clinic Staff Most North American snakes aren't dangerous to humans. Some exceptions include the rattlesnake, coral snake, water moccasin ...

The Master Hearing Aid

Science.gov (United States)

Curran, James R.

2013-01-01

As early as the 1930s the term Master Hearing Aid (MHA) described a device used in the fitting of hearing aids. In their original form, the MHA was a desktop system that allowed for simulated or actual adjustment of hearing aid components that resulted in a changed hearing aid response. Over the years the MHA saw many embodiments and contributed to a number of rationales for the fitting of hearing aids. During these same years, the MHA was viewed by many as an inappropriate means of demonstrating hearing aids; the audio quality of the desktop systems was often superior to the hearing aids themselves. These opinions and the evolution of the MHA have molded the modern perception of hearing aids and the techniques used in the fitting of hearing aids. This article reports on a history of the MHA and its influence on the fitting of hearing aids. PMID:23686682

Chest Pain: First Aid

Science.gov (United States)

First aid Chest pain: First aid Chest pain: First aid By Mayo Clinic Staff Causes of chest pain can vary from minor problems, such as indigestion ... 26, 2018 Original article: http://www.mayoclinic.org/first-aid/first-aid-chest-pain/basics/ART-20056705 . Mayo ...

Head Trauma: First Aid

Science.gov (United States)

First aid Head trauma: First aid Head trauma: First aid By Mayo Clinic Staff Most head trauma involves injuries that are minor and don't require ... 21, 2015 Original article: http://www.mayoclinic.org/first-aid/first-aid-head-trauma/basics/ART-20056626 . Mayo ...

Animal Bites: First Aid

Science.gov (United States)

First aid Animal bites: First aid Animal bites: First aid By Mayo Clinic Staff These guidelines can help you care for a minor animal bite, such ... 26, 2017 Original article: http://www.mayoclinic.org/first-aid/first-aid-animal-bites/basics/ART-20056591 . Mayo ...

Sensitivity to ultraviolet radiation in a dominantly inherited form of xeroderma pigmentosum

International Nuclear Information System (INIS)

Imray, F.P.; Relf, W.; Ramsay, R.G.; Kidson, C.; Hockey, A.

1986-01-01

An Australian family is described in which a mild form of xeroderma pigmentosum (XP) is inherited as an autosomal dominant trait. Studies of lymphoblastoid cells and fibroblasts from affected person demonstrated sensitivity to ultraviolet (UV) light as judged by diminished clonogenicity and higher frequencies of UV induced chromosome aberrations compared to normal controls. After UV irradiation of dominant XP cells, replicative DNA synthesis was depressed to a greater extent than normal and the level of UV induced DNA repair synthesis was lower than that in normal cells. The level of sister chromatid exchanges and the numbers of 6-thioguanine resistant mutants induced by UV irradiation were equal to those found in normal controls. Although two subjects in the family had skin cancers, this dominant form of XP is not apparently associated with high risk, or large numbers of skin cancers in affected persons. (author)

Assessment of in vitro genotoxic and cytotoxic effects of flurbiprofen on human cultured lymphocytes.

Science.gov (United States)

Timocin, Taygun; Ila, Hasan Basri; Dordu, Tuba; Husunet, Mehmet Tahir; Tazehkand, Mostafa Norizadeh; Valipour, Ebrahim; Topaktas, Mehmet

2016-01-01

Flurbiprofen is non-steroidal anti-inflammatory drug which is commonly used for its analgesic, antipyretic, and anti-inflammatory effects. The purpose of the study was to explore the genotoxic and cytotoxic effects of flurbiprofen in human cultured lymphocytes by sister chromatid exchange, chromosome aberration, and cytokinesis-blocked micronucleus tests. 10, 20, 30, and 40 μg/mL concentrations of flurbiprofen (solvent is DMSO) were used to treatment of human cultured lymphocytes at two different treatment periods (24 and 48 h). Flurbiprofen had no significant genotoxic effect in any of these tests. But exposing to flurbiprofen for 24 and 48 h led to significant decrease on proliferation index, mitotic index, and nuclear division index (NDI). Also, all decreases were concentration-dependent (except NDI at 24 h treatment period). Consequently, the findings of this research showed that flurbiprofen had cytotoxic effects in human blood lymphocytes.

Male meiosis in Crustacea: synapsis, recombination, epigenetics and fertility in Daphnia magna.

Science.gov (United States)

Gómez, Rocío; Van Damme, Kay; Gosálvez, Jaime; Morán, Eugenio Sánchez; Colbourne, John K

2016-09-01

We present the first detailed cytological study of male meiosis in Daphnia (Crustacea: Branchiopoda: Cladocera)-an aquatic microcrustacean with a cyclical parthenogenetic life cycle. Using immunostaining of the testes in Daphnia magna for baseline knowledge, we characterized the different stages of meiotic division and spermiogenesis in relation to the distribution of proteins involved in synapsis, early recombination events and sister chromatid cohesion. We also studied post-translational histone modifications in male spermatocytes, in relation to the dynamic chromatin progression of meiosis. Finally, we applied a DNA fragmentation test to measure sperm quality of D. magna, with respect to levels of inbreeding. As a proxy for fertility, this technique may be used to assess the reproductive health of a sentinel species of aquatic ecosystems. Daphnia proves to be a model species for comparative studies of meiosis that is poised to improve our understanding of the cytological basis of sexual and asexual reproduction.

Familial melanoma associated with dominant ultraviolet radiation sensitivity

International Nuclear Information System (INIS)

Ramsay, R.G.; Chen, P.; Imray, F.P.; Kidson, C.; Lavin, M.F.; Hockey, A.

1982-01-01

Sensitivity to ultraviolet radiation was studied in lymphoblastoid cell lines derived from 32 members of two families with histories of multiple primary melanomas in several generations. As assayed by colony formation in agar or by trypan blue exclusion following irradiation, cellular sensitivity showed a bimodal distribution. All persons with melanoma or multiple moles were in the sensitive group, while some family members exhibited responses similar to those of controls. Cells from four cases of sporadic melanoma showed normal levels of sensitivity. The data are consistent with a dominantly inherited ultraviolet light sensitivity associated with these examples of familial melanoma. Spontaneous and ultraviolet light-induced sister chromatid exchange frequencies were similar to those in control cell lines. No defect in excision repair was detected in any of the above cell lines, but the sensitive group showed postirradiation inhibition of DNA replication intermediate between controls and an excision-deficient xeroderma pigmentosum cell line

Chromosome aberration analysis in peripheral lymphocytes of Gulf war and Balkans war veterans

Energy Technology Data Exchange (ETDEWEB)

Schroeder, H.; Heimers, A.; Frentzel-Beyme, R.; Schott, A.; Hoffmann, W

2003-07-01

Chromosome aberrations and sister chromatid exchanges (SCEs) were determined in standard peripheral lymphocyte metaphase preparations of 13 British Gulf War veterans, two veterans of the recent war in the Balkans, and one veteran of both wars. All 16 volunteers suspect exposures to depleted uranium while deployed at the two different theatres of war in 1990 and later on. The Bremen laboratory control served as a reference in this study. Compared with this control there was a statistically significant increase in the frequency of dicentric chromosomes (dic) and centric ring chromosomes (cR) in the veterans' group, indicating a previous exposure to ionising radiation. The statistically significant overdispersion of dic and cR indicates non-uniform irradiation as would be expected after non-uniform exposure and/or exposure to radiation with a high linear energy transfer. The frequency of SCEs was decreased when compared with the laboratory control. (author)

Chromosome aberration analysis in peripheral lymphocytes of Gulf war and Balkans war veterans

International Nuclear Information System (INIS)

Schroeder, H.; Heimers, A.; Frentzel-Beyme, R.; Schott, A.; Hoffmann, W.

2003-01-01

Chromosome aberrations and sister chromatid exchanges (SCEs) were determined in standard peripheral lymphocyte metaphase preparations of 13 British Gulf War veterans, two veterans of the recent war in the Balkans, and one veteran of both wars. All 16 volunteers suspect exposures to depleted uranium while deployed at the two different theatres of war in 1990 and later on. The Bremen laboratory control served as a reference in this study. Compared with this control there was a statistically significant increase in the frequency of dicentric chromosomes (dic) and centric ring chromosomes (cR) in the veterans' group, indicating a previous exposure to ionising radiation. The statistically significant overdispersion of dic and cR indicates non-uniform irradiation as would be expected after non-uniform exposure and/or exposure to radiation with a high linear energy transfer. The frequency of SCEs was decreased when compared with the laboratory control. (author)

The phenotype of FancB-mutant mouse embryonic stem cells

Energy Technology Data Exchange (ETDEWEB)

Kim, Tae Moon; Ko, Jun Ho; Choi, Yong Jun; Hu Lingchuan [Department of Molecular Medicine and Institute of Biotechnology, University of Texas Health Science Center at San Antonio, 15355 Lambda Drive, San Antonio, TX 78245 (United States); Hasty, Paul, E-mail: hastye@uthscsa.edu [Department of Molecular Medicine and Institute of Biotechnology, University of Texas Health Science Center at San Antonio, 15355 Lambda Drive, San Antonio, TX 78245 (United States)

2011-07-01

Fanconi anemia (FA) is a rare autosomal recessive disease characterized by bone marrow failure, developmental defects and cancer. There are multiple FA genes that enable the repair of interstrand crosslinks (ICLs) in coordination with a variety of other DNA repair pathways in a way that is poorly understood. Here we present the phenotype of mouse embryonic stem (ES) cells mutated for FancB. We found FancB-mutant cells exhibited reduced cellular proliferation, hypersensitivity to the crosslinking agent mitomycin C (MMC), increased spontaneous and MMC-induced chromosomal abnormalities, reduced spontaneous sister chromatid exchanges (SCEs), reduced gene targeting, reduced MMC-induced Rad51 foci and absent MMC-induced FancD2 foci. Since FancB is on the X chromosome and since ES cells are typically XY, FancB is an excellent target for an epistatic analysis to elucidate FA's role in ICL repair.

Aid and development

DEFF Research Database (Denmark)

Tarp, Finn

2006-01-01

evolved since World War II in response to a dramatically changing global political and economic context. I review the aid process and associated trends in the volume and distribution of aid and categorize some of the key goals, principles and institutions of the aid system. The evidence on whether aid has...... been effective in furthering economic growth and development is discussed in some detail. I add perspective and identify some critical unresolved issues. I finally turn to the current development debate and discuss some key concerns, I believe should be kept in mind in formulating any agenda for aid...

HIV/AIDS Coinfection

Science.gov (United States)

... Coinfection Hepatitis C Coinfection HIV/AIDS Coinfection HIV/AIDS Coinfection Approximately 10% of the HIV-infected population ... Control and Prevention website to learn about HIV/AIDS and Viral Hepatitis guidelines and resources. Home About ...

Ter um irmão especial: convivendo com a Síndrome de Down Having a special brother/sister: living together with the Down Syndrome

Directory of Open Access Journals (Sweden)

Eucia Beatriz Lopes Petean

2005-12-01

Full Text Available O presente estudo teve por objetivos conhecer como é a relação entre irmãos mais velhos de pessoas com diagnóstico de Síndrome de Down (SD; que informações e sentimentos possuem sobre o diagnóstico; se houve ou não modificações na dinâmica familiar e em suas próprias vidas. Foram entrevistadas 11 pessoas, de ambos os sexos, com idade superior a dez anos, sendo, cada uma, o irmão mais velho de criança com diagnóstico de SD, sendo realizada análise quantitativa de dados da amostra e análise quantitativa-interpretativa e qualitativa para os dados da entrevista. Os dados mostram que a maioria dos sujeitos (90,9% sabe o nome da Síndrome e foram informados pela mãe logo após o nascimento do irmão, seis deles consideram que reagiram normalmente à notícia. Quanto às responsabilidades adquiridas, a maioria, 90,9%, são responsáveis pelas atividades de vida diária; 27,27% deles consideram que houve acréscimo de responsabilidade em suas vidas em decorrência do nascimento do irmão com SD. Em relação ao sentimento que apresentam por terem um irmão especial, 54,54% consideram como positivo, ou seja, disseram que também sentem-se especiais. Na falta (morte dos pais, a metade dos participantes informa que eles serão os responsáveis legais deste irmão. Pode-se concluir que o nascimento de um irmão com SD tem conseqüências na rotina de vida dos irmãos mais velhos, trazendo modificações e responsabilidades para eles. Entretanto, parece ter um efeito menos dirigido para a desestrutura psicológica, sendo poucas as manifestações de sentimentos extremos, ficando apenas no nível da tristeza, quando são expressos.The present study intended to know about the relation among older brothers/sisters of people with a diagnosis of Down Syndrome (DS, regarding to information and feelings they have about this diagnosis, and if changes have occurred within family dynamics and their own lives. Eleven people were interviewed, from

Gauging Change in Australian Aid: Stakeholder Perceptions of the Government Aid Program.

Science.gov (United States)

Wood, Terence; Burkot, Camilla; Howes, Stephen

2017-05-01

In this article, we use data from the 2013 and 2015 Australian Aid Stakeholder Surveys to gauge the extent of the changes to the Australian Government Aid Program since the 2013 federal election. The two surveys targeted the same set of stakeholders of the aid program, and both gathered data on a wide range of aspects of its functioning. As we assess the findings that emerged from the surveys, we situate our work amongst recent academic studies that have looked at the post-2013 aid changes in Australia. Our key findings are that the post-2013 changes to Australian aid have had wide-ranging impacts and have led to deteriorating overall aid quality. However, changes have not affected all aspects of the aid program equally, and some changes are starting to be reversed. In discussion, we examine what these developments mean for the future of Australian aid.

Extracting phylogenetic signal and accounting for bias in whole-genome data sets supports the Ctenophora as sister to remaining Metazoa.

Science.gov (United States)

Borowiec, Marek L; Lee, Ernest K; Chiu, Joanna C; Plachetzki, David C

2015-11-23

Understanding the phylogenetic relationships among major lineages of multicellular animals (the Metazoa) is a prerequisite for studying the evolution of complex traits such as nervous systems, muscle tissue, or sensory organs. Transcriptome-based phylogenies have dramatically improved our understanding of metazoan relationships in recent years, although several important questions remain. The branching order near the base of the tree, in particular the placement of the poriferan (sponges, phylum Porifera) and ctenophore (comb jellies, phylum Ctenophora) lineages is one outstanding issue. Recent analyses have suggested that the comb jellies are sister to all remaining metazoan phyla including sponges. This finding is surprising because it suggests that neurons and other complex traits, present in ctenophores and eumetazoans but absent in sponges or placozoans, either evolved twice in Metazoa or were independently, secondarily lost in the lineages leading to sponges and placozoans. To address the question of basal metazoan relationships we assembled a novel dataset comprised of 1080 orthologous loci derived from 36 publicly available genomes representing major lineages of animals. From this large dataset we procured an optimized set of partitions with high phylogenetic signal for resolving metazoan relationships. This optimized data set is amenable to the most appropriate and computationally intensive analyses using site-heterogeneous models of sequence evolution. We also employed several strategies to examine the potential for long-branch attraction to bias our inferences. Our analyses strongly support the Ctenophora as the sister lineage to other Metazoa. We find no support for the traditional view uniting the ctenophores and Cnidaria. Our findings are supported by Bayesian comparisons of topological hypotheses and we find no evidence that they are biased by long-branch attraction. Our study further clarifies relationships among early branching metazoan lineages

Chromosomal aberration

International Nuclear Information System (INIS)

Ishii, Yutaka

1988-01-01

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

Differences in mycorrhizal communities between Epipactis palustris, E. helleborine and its presumed sister species E. neerlandica.

Science.gov (United States)

Jacquemyn, Hans; Waud, Michael; Lievens, Bart; Brys, Rein

2016-07-01

In orchid species that have populations occurring in strongly contrasting habitats, mycorrhizal divergence and other habitat-specific adaptations may lead to the formation of reproductively isolated taxa and ultimately to species formation. However, little is known about the mycorrhizal communities associated with recently diverged sister taxa that occupy different habitats. In this study, 454 amplicon pyrosequencing was used to investigate mycorrhizal communities associating with Epipactis helleborine in its typical forest habitat and with its presumed sister species E. neerlandica that almost exclusively occurs in coastal dune habitats. Samples of the phylogenetically more distant E. palustris, which co-occurred with E. neerlandica, were also included to investigate the role of habitat-specific conditions on mycorrhizal communities. A total of 105 operational taxonomic units (OTUs) of putative orchid mycorrhizal fungi were observed in the three studied species. The majority of these fungi were endophytic fungi of Helotiales and ectomycorrhizal fungi belonging to Thelephoraceae, Sebacinaceae and Inocybaceae. In addition, a large number of other ectomycorrhizal taxa were detected, including Cortinarius, Cenococcum, Tuber, Geopora, Wilcoxina, Meliniomyces, Hebeloma, Tricholoma, Russula and Peziza Mycorrhizal communities differed significantly between the three species, but differences were most pronounced between the forest species (E. helleborine) and the two dune slack species (E. neerlandica and E. palustris). The results clearly showed that recently diverged orchid species that occupy different habitats were characterized by significantly different mycorrhizal communities and call for more detailed experiments that aim at elucidating the contribution of habitat-specific adaptations in general and mycorrhizal divergence in particular to the process of speciation in orchids. © The Author 2016. Published by Oxford University Press on behalf of the Annals of Botany

HIV and AIDS

Science.gov (United States)

... Staying Safe Videos for Educators Search English Español HIV and AIDS KidsHealth / For Kids / HIV and AIDS ... actually the virus that causes the disease AIDS. HIV Hurts the Immune System People who are HIV ...

Mobilising Mother Cabrini's Educational Practice: The Transnational Context of the London School of the Missionary Sisters of the Sacred Heart of Jesus 1898-1911

Science.gov (United States)

Williams, Maria Patricia

2015-01-01

A schoolteacher from Lombardy, Saint Frances Xavier Cabrini (1850-1917), founded the Institute of Missionary Sisters of the Sacred Heart of Jesus (MSC) in 1880. It was one of the 185 female religious institutes established in Italy in the nineteenth century. In the newly unified Italy, Cabrini found opportunities to formulate progressive Catholic…

Macroeconomic Issues in Foreign Aid

DEFF Research Database (Denmark)

Hjertholm, Peter; Laursen, Jytte; White, Howard

foreign aid, macroeconomics of aid, gap models, aid fungibility, fiscal response models, foreign debt,......foreign aid, macroeconomics of aid, gap models, aid fungibility, fiscal response models, foreign debt,...

Aid and Growth

DEFF Research Database (Denmark)

Arndt, Channing; Jones, Edward Samuel; Tarp, Finn

, are being drawn on the basis of fragile evidence. This paper first assesses the aid-growth literature with a focus on recent contributions. The aid-growth literature is then framed, for the first time, in terms of the Rubin Causal Model, applied at the macroeconomic level. Our results show that aid has......The micro-macro paradox has been revived. Despite broadly positive evaluations at the micro and meso-levels, recent literature has turned decidedly pessimistic with respect to the ability of foreign aid to foster economic growth. Policy implications, such as the complete cessation of aid to Africa...... a positive and statistically significant causal effect on growth over the long run with point estimates at levels suggested by growth theory. We conclude that aid remains an important tool for enhancing the development prospects of poor nations....

JPRS Report, Epidemiology, AIDS

National Research Council Canada - National Science Library

1993-01-01

Partial Contents: AIDS in Burundi, Rwanda AIDS Situation in Country Examined, Estimated Over 750,000 HIV Positive, In 3 Years 4 Million May Be AIDS Carriers, Events at National AIDS Convention Analyzed, Senior Army...

Shakespeare’s Weird Sisters – In Between Outlandish Womanhood and Prophesing Moirae

Directory of Open Access Journals (Sweden)

Avarvarei Simona Catrinel

2017-12-01

Full Text Available This study intends to map the meandering expression of otherness when womanhood constructs an epiphanic encounter with time and fortune. Hereinafter, hegemonic, oppressive masculinity meets peripheral, prophesying femininity in an intricate exercise of doing and becoming Shakespeare‘s Weird Sisters, forming a complex mythological construction, whose uniqueness arises from the duality of their personae, reflection of displaced femininity, somewhat grotesque, peripheral within the realm of marginality itself. They are not only weird expressions of the Other, they are the other self of themselves, as alter ego expressions. There is a constant, minutely woven border crossing that does not only (redefine the geometry of becoming, but it also permeates gender constructions, making femaleness look androgynous and ruthless. Foretelling dreams of glory, mightiness or summoning lost humanity, these three Parcae rewrite the myth of the androgynous and its story about the quest of the Other. It is this Other that will be explored from a variety of angles that speak of masculinity, femininity, sanity, irrationality, consciousness, unconsciousness, freewill and fate.

Aid Allocation across Sectors: Does aid fit well with recipients' development priorities?

OpenAIRE

KASUGA Hidefumi

2008-01-01

This paper investigates whether aid flows to developing countries fit well with their development priorities. In particular, we examine aid allocation across sectors in a given recipient country by using sectoral data on aid and indicators that measure the recipient's need for aid in each sector. The data show that inter-recipient aid allocation reflects the recipient's need. However, we found no evidence that inter-sectoral allocation fits with national priorities except in high- and middle-...

UV-sensitivity of bromodeoxyuridine (BUdR)-substituted chromosomes in Chinese hamster cells

International Nuclear Information System (INIS)

Antoshchina, M.M.; Luchnik, N.V.

1990-01-01

Chinese hamster cells with chromosomes differently substituted for BUdR (TT-TT, TT-TB, TB-TB, TB-BB, where T is thymidine containing chromatid and B is BUdR substituted chromatid) were exposed to UV-light in phase G 2 and chromosome aberrations (mainly chromatid breaks) were analysed. Breaks frequency per chromosome was proportional to BUdR content. No breaks were found in TT-TT chromosomes. The frequency of breaks per TB chromatid was similar with TT-TB and TB-BB chromosomes. In TB-BB chromosomes, however, virtually no breaks occured in TB chromatids whereas in BB chromatids, their frequency was much higher than was expected