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Sample records for embryo dormancy final

  1. Genetic analysis of embryo dormancy. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Galau, G.

    1998-09-01

    Primary dormancy is the inability of mature seed to immediately germinate until specific environmental stimuli are perceived that predict that future conditions will support plant growth and seed set. The analysis of abscisic acid deficient and insensitive mutants, in particular in Arabidopsis, suggests that embryo abscisic acid may be directly involved in the development of primary dormancy. Other studies implicate the continued accumulation of LEA proteins as inhibiting germination in dormant embryos. The results of these physiological, molecular and genetic approaches are complex and equivocal. There is a real need for approaches that test the separate nature of vivipary inhibition and primary dormancy and deliberately seed to decouple and dissect them. These approaches should be of help in understanding both late embryo development and primary dormancy. The approach taken here is to directly isolate mutants of Arabidopsis that appear to be deficient only in primary dormancy, that is fresh seed that germinate rapidly without the normally-required cold-stratification. The authors have isolated at least 8 independent, rapidly germinating RGM mutants of Arabidopsis. All others aspects of plant growth and development appear normal in these lines, suggesting that the rgm mutants are defective only in the establishment or maintenance of primary dormancy. At least one of these may be tagged with T-DNA. In addition, about 50 RGM isolates have been recovered from EMS-treated seed.

  2. Dependency of seed dormancy types on embryo traits and environmental conditions in Ribes species.

    Science.gov (United States)

    Mattana, E; Stuppy, W H; Fraser, R; Waller, J; Pritchard, H W

    2014-07-01

    The hypothesis that seed dormancy may be dependent on environmental conditions and seed morphological traits was tested for six Ribes species, across an altitudinal gradient of 1300 m and a longitudinal separation of 120°. Embryo measurements and seed germination experiments were conducted for R. alpinum L., R. hudsonianum Richardson var. petiolare (Douglas) Jancz., R. nevadaense Kellogg, R. roezlii Regel var. cruentum (Greene) Rehder and R. speciosum Pursh, and data taken from the literature for R. multiflorum Kit. ex Schult. ssp. sandalioticum Arrigoni. Germination was compared with seed viability to reveal proportional seed dormancy, which was then correlated to seed/embryo morphological traits and these traits related to the seed provenance environment. The embryos of all the investigated species are linear underdeveloped and all had a morphological component of seed dormancy (MD). Seeds of R. roezlii, R. hudsonianum and R. nevadaense required a temperature and/or hormone pre-treatment in order to germinate, highlighting morphophysiological seed dormancy (MPD). Seed dormancy was found to be strongly negatively correlated with embryo length, but not with embryo to seed (E:S) ratio or seed mass. Initial embryo length was positively related to mean annual temperature. Seed dormancy in the investigated Ribes species could be quantified and predicted by the interaction of embryo traits and environmental conditions. This approach may be helpful in assessing and predicting seed dormancy in the Ribes genus and in other genera and families with underdeveloped embryos. © 2013 German Botanical Society and The Royal Botanical Society of the Netherlands.

  3. Effects of dormancy-breaking chemicals on ABA levels in barley grain embryos

    NARCIS (Netherlands)

    Wang, M.; Meulen, R.M. van der; Visser, K.; Schalk, H.P. van; Duijn, B. van; Boer, A.H. de

    1998-01-01

    The endogenous ABA contents of dormant and nondormant barley grains were determined following application of different compounds to break dormancy. The chemicals used for breaking of dormancy in intact dormant grains were weak and strong acids, alcohols,. hydrogen peroxide, cyanide, nitrate,

  4. Gibberellin-like effects of KAR1 on dormancy release of Avena fatua caryopses include participation of non-enzymatic antioxidants and cell cycle activation in embryos.

    Science.gov (United States)

    Cembrowska-Lech, Danuta; Kępczyński, Jan

    2016-02-01

    The induction of dormancy release and germination of Avena fatua caryopses by KAR 1 involves ABA degradation to phaseic acid. Both, KAR 1 and GA 3 , control the AsA-GSH cycle, DNA replication and accumulation of β-tubulin in embryos before caryopses germination. Avena fatua caryopses cannot germinate in darkness at 20 °C because of dormancy, but karrikinolide-1 (KAR1), a compound in plant-derived smoke, and gibberellic acid (GA3) induced an almost complete germination. The radicle protrusion through the coleorhiza was preceded by increased water uptake, rupture of coat, increased embryo size and coleorhiza length as well as coleorhiza protrusion through covering structures. The stimulatory effect of KAR1 was correlated with the reduced content of abscisic acid (ABA) and an increase in phaseic acid (PA) in embryos from caryopses before coleorhiza protrusion. Two non-enzymatic antioxidants, ascorbate (AsA) and reduced glutathione (GSH), did not affect the germination of dormant caryopses, but in the presence of KAR1 or GA3 they only slightly delayed the germination. The stimulatory effect of KAR1 or GA3 on the final germination percentage was markedly antagonized by lycorine, an AsA biosynthesis inhibitor. KAR1 and GA3 applied during caryopses imbibition resulted in increases of AsA, dehydroascorbate (DHA) and GSH, but reduced the embryos' oxidized glutathione (GSSG) content. Furthermore, both KAR1 and GA3 induced an additional ascorbate peroxidase (APX) isoenzyme and increased the glutathione reductase (GR) activity. Both compounds stimulated β-tubulin accumulation in radicle+coleorhiza (RC) and plumule+coleoptile (PC), and enhanced the transition from G1 to S and also from S to G2 phases. The comparison of the effects produced by KAR1 and GA3  shows a similar action; thus the KAR1 effect may not be specific. The study provides new data regarding the mechanism with which KAR1, a representative of a novel class of plant growth regulators, regulates dormancy and

  5. Germination ecology of the endemic Iberian daffodil Narcissus radinganorum (Amaryllidaceae. Dormancy induction by cold stratification or desiccation in late stages of embryo growth

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    José María Herranz

    2015-04-01

    Full Text Available Aim of study: We studied the germination ecology of a threatened daffodil in order to develop a protocol to produce plants ex-situ from seeds, a key tool for population reinforcement. Area of study: Experiments were carried out both outdoors and in the laboratory in Albacete (Spain. Material and methods: Embryo length, radicle and shoot emergence were analyzed to determine the level of morphophysiological dormancy (MPD. Effects on germination of cold stratification or desiccation in late stages of embryo growth were also studied. Main results: Mean embryo length in fresh seeds was 1.36 mm, needing to grow up to 2.20 mm to be able to germinate. In the laboratory, embryo growth occurred during warm stratification (28/14, 25/10 ºC, and then radicle emerged when temperatures went down (15/4 ºC in darkness. Phenology study in outdoors conditions revealed that embryo grew during summer-early autumn, short time after seed dispersal in nature (i.e., May; radicle emerged in autumn. The shoot however did not emerge until late winter-early spring, because it was physiologically dormant and required a cold (5 ºC period of 30 days to break dormancy. Early cold temperatures interrupted the embryo growth and induced dormancy in seeds whose embryo had grown 30% with respect to the initial length. Desiccation in seeds whose embryo had grown 30% did not induce dormancy, but did it when the embryo growth reached 70%. Research highlights: Seeds of Narcissus radinganorum have deep simple epicotyl MPD.

  6. Seed dormancy and germination.

    Science.gov (United States)

    Penfield, Steven

    2017-09-11

    Reproduction is a critical time in plant life history. Therefore, genes affecting seed dormancy and germination are among those under strongest selection in natural plant populations. Germination terminates seed dispersal and thus influences the location and timing of plant growth. After seed shedding, germination can be prevented by a property known as seed dormancy. In practise, seeds are rarely either dormant or non-dormant, but seeds whose dormancy-inducing pathways are activated to higher levels will germinate in an ever-narrower range of environments. Thus, measurements of dormancy must always be accompanied by analysis of environmental contexts in which phenotypes or behaviours are described. At its simplest, dormancy can be imposed by the formation of a simple physical barrier around the seed through which gas exchange and the passage of water are prevented. Seeds featuring this so-called 'physical dormancy' often require either scarification or passage through an animal gut (replete with its associated digestive enzymes) to disrupt the barrier and permit germination. In other types of seeds with 'morphological dormancy' the embryo remains under-developed at maturity and a dormant phase exists as the embryo continues its growth post-shedding, eventually breaking through the surrounding tissues. By far, the majority of seeds exhibit 'physiological dormancy' - a quiescence program initiated by either the embryo or the surrounding endosperm tissues. Physiological dormancy uses germination-inhibiting hormones to prevent germination in the absence of the specific environmental triggers that promote germination. During and after germination, early seedling growth is supported by catabolism of stored reserves of protein, oil or starch accumulated during seed maturation. These reserves support cell expansion, chloroplast development and root growth until photoauxotrophic growth can be resumed. Crown Copyright © 2017. Published by Elsevier Ltd. All rights reserved.

  7. Exogenous auxin regulates multi-metabolic network and embryo development, controlling seed secondary dormancy and germination in Nicotiana tabacum L.

    Science.gov (United States)

    Li, Zhenhua; Zhang, Jie; Liu, Yiling; Zhao, Jiehong; Fu, Junjie; Ren, Xueliang; Wang, Guoying; Wang, Jianhua

    2016-02-09

    Auxin was recognized as a secondary dormancy phytohormone, controlling seed dormancy and germination. However, the exogenous auxin-controlled seed dormancy and germination remain unclear in physiological process and gene network. Tobacco seeds soaked in 1000 mg/l auxin solution showed markedly decreased germination compared with that in low concentration of auxin solutions and ddH2O. Using an electron microscope, observations were made on the seeds which did not unfold properly in comparison to those submerged in ddH2O. The radicle traits measured by WinRHIZO, were found to be also weaker than the other treatment groups. Quantified by ELISA, there was no significant difference found in β-1,3glucanase activity and abscisic acid (ABA) content between the seeds imbibed in gradient concentration of auxin solution and those soaked in ddH2O. However, gibberellic acid (GA) and auxin contents were significantly higher at the time of exogenous auxin imbibition and were gradually reduced at germination. RNA sequencing (RNA-seq), revealed that the transcriptome of auxin-responsive dormancy seeds were more similar to that of the imbibed seeds when compared with primary dormancy seeds by principal component analysis. The results of gene differential expression analysis revealed that auxin-controlled seed secondary dormancy was associated with flavonol biosynthetic process, gibberellin metabolic process, adenylyl-sulfate reductase activity, thioredoxin activity, glutamate synthase (NADH) activity and chromatin regulation. In addition, auxin-responsive germination responded to ABA, auxin, jasmonic acid (JA) and salicylic acid (SA) mediated signaling pathway (red, far red and blue light), glutathione and methionine (Met) metabolism. In this study, exogenous auxin-mediated seed secondary dormancy is an environmental model that prevents seed germination in an unfavorable condition. Seeds of which could not imbibe normally, and radicles of which also could not develop normally and

  8. Unraveling Key Metabolomic Alterations in Wheat Embryos Derived from Freshly Harvested and Water-Imbibed Seeds of Two Wheat Cultivars with Contrasting Dormancy Status

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    Aayudh Das

    2017-07-01

    Full Text Available Untimely rains in wheat fields during harvest season can cause pre-harvest sprouting (PHS, which deteriorates the yield and quality of wheat crop. Metabolic homeostasis of the embryo plays a role in seed dormancy, determining the status of the maturing grains either as dormant (PHS-tolerant or non-dormant (PHS-susceptible. Very little is known for direct measurements of global metabolites in embryonic tissues of dormant and non-dormant wheat seeds. In this study, physiologically matured and freshly harvested wheat seeds of PHS-tolerant (cv. Sukang, dormant and PHS-susceptible (cv. Baegjoong, non-dormant cultivars were water-imbibed, and the isolated embryos were subjected to high-throughput, global non-targeted metabolomic profiling. A careful comparison of identified metabolites between Sukang and Baegjoong embryos at 0 and 48 h after imbibition revealed that several key metabolic pathways [such as: lipids, fatty acids, oxalate, hormones, the raffinose family of oligosaccharides (RFOs, and amino acids] and phytochemicals were differentially regulated between dormant and non-dormant varieties. Most of the membrane lipids were highly reduced in Baegjoong compared to Sukang, which indicates that the cell membrane instability in response to imbibition could also be a key factor in non-dormant wheat varieties for their untimely germination. This study revealed that several key marker metabolites (e.g., RFOs: glucose, fructose, maltose, and verbascose, were highly expressed in Baegjoong after imbibition. Furthermore, the data showed that the key secondary metabolites and phytochemicals (vitexin, chrysoeriol, ferulate, salidroside and gentisic acid, with known antioxidant properties, were comparatively low at basal levels in PHS-susceptible, non-dormant cultivar, Baegjoong. In conclusion, the results of this investigation revealed that after imbibition the metabolic homeostasis of dormant wheat is significantly less affected compared to non

  9. physiological mechanisms for potato dormancy release and ...

    African Journals Online (AJOL)

    ACSS

    Potato (Solanum tuberosum L.) tubers undergo a period of dormancy, during which visible bud growth is inhibited. The length of the dormancy is determined by environmental, physiological and hormonal control mechanisms. Dormancy is the final stage of tuber life, which serves to preserve tubers as organs of vegetative.

  10. Transcriptome and Degradome Sequencing Reveals Dormancy Mechanisms of Cunninghamia lanceolata Seeds.

    Science.gov (United States)

    Cao, Dechang; Xu, Huimin; Zhao, Yuanyuan; Deng, Xin; Liu, Yongxiu; Soppe, Wim J J; Lin, Jinxing

    2016-12-01

    Seeds with physiological dormancy usually experience primary and secondary dormancy in the nature; however, little is known about the differential regulation of primary and secondary dormancy. We combined multiple approaches to investigate cytological changes, hormonal levels, and gene expression dynamics in Cunninghamia lanceolata seeds during primary dormancy release and secondary dormancy induction. Light microscopy and transmission electron microscopy revealed that protein bodies in the embryo cells coalesced during primary dormancy release and then separated during secondary dormancy induction. Transcriptomic profiling demonstrated that expression of genes negatively regulating gibberellic acid (GA) sensitivity reduced specifically during primary dormancy release, whereas the expression of genes positively regulating abscisic acid (ABA) biosynthesis increased during secondary dormancy induction. Parallel analysis of RNA ends revealed uncapped transcripts for ∼55% of all unigenes. A negative correlation between fold changes in expression levels of uncapped versus capped mRNAs was observed during primary dormancy release. However, this correlation was loose during secondary dormancy induction. Our analyses suggest that the reversible changes in cytology and gene expression during dormancy release and induction are related to ABA/GA balance. Moreover, mRNA degradation functions as a critical posttranscriptional regulator during primary dormancy release. These findings provide a mechanistic framework for understanding physiological dormancy in seeds. © 2016 American Society of Plant Biologists. All Rights Reserved.

  11. Short day transcriptomic programming during induction of dormancy in grapevine

    Science.gov (United States)

    Fennell, Anne Y.; Schlauch, Karen A.; Gouthu, Satyanarayana; Deluc, Laurent G.; Khadka, Vedbar; Sreekantan, Lekha; Grimplet, Jerome; Cramer, Grant R.; Mathiason, Katherine L.

    2015-01-01

    Bud dormancy in grapevine is an adaptive strategy for the survival of drought, high and low temperatures and freeze dehydration stress that limit the range of cultivar adaptation. Therefore, development of a comprehensive understanding of the biological mechanisms involved in bud dormancy is needed to promote advances in selection and breeding, and to develop improved cultural practices for existing grape cultivars. The seasonally indeterminate grapevine, which continuously develops compound axillary buds during the growing season, provides an excellent system for dissecting dormancy, because the grapevine does not transition through terminal bud development prior to dormancy. This study used gene expression patterns and targeted metabolite analysis of two grapevine genotypes that are short photoperiod responsive (Vitis riparia) and non-responsive (V. hybrid, Seyval) for dormancy development to determine differences between bud maturation and dormancy commitment. Grapevine gene expression and metabolites were monitored at seven time points under long (LD, 15 h) and short (SD, 13 h) day treatments. The use of age-matched buds and a small (2 h) photoperiod difference minimized developmental differences and allowed us to separate general photoperiod from dormancy specific gene responses. Gene expression profiles indicated three distinct phases (perception, induction and dormancy) in SD-induced dormancy development in V. riparia. Different genes from the NAC DOMAIN CONTAINING PROTEIN 19 and WRKY families of transcription factors were differentially expressed in each phase of dormancy. Metabolite and transcriptome analyses indicated ABA, trehalose, raffinose and resveratrol compounds have a potential role in dormancy commitment. Finally, a comparison between V. riparia compound axillary bud dormancy and dormancy responses in other species emphasized the relationship between dormancy and the expression of RESVERATROL SYNTHASE and genes associated with C3HC4-TYPE RING

  12. Short day transcriptomic programming during induction of dormancy in grapevine.

    Science.gov (United States)

    Fennell, Anne Y; Schlauch, Karen A; Gouthu, Satyanarayana; Deluc, Laurent G; Khadka, Vedbar; Sreekantan, Lekha; Grimplet, Jerome; Cramer, Grant R; Mathiason, Katherine L

    2015-01-01

    Bud dormancy in grapevine is an adaptive strategy for the survival of drought, high and low temperatures and freeze dehydration stress that limit the range of cultivar adaptation. Therefore, development of a comprehensive understanding of the biological mechanisms involved in bud dormancy is needed to promote advances in selection and breeding, and to develop improved cultural practices for existing grape cultivars. The seasonally indeterminate grapevine, which continuously develops compound axillary buds during the growing season, provides an excellent system for dissecting dormancy, because the grapevine does not transition through terminal bud development prior to dormancy. This study used gene expression patterns and targeted metabolite analysis of two grapevine genotypes that are short photoperiod responsive (Vitis riparia) and non-responsive (V. hybrid, Seyval) for dormancy development to determine differences between bud maturation and dormancy commitment. Grapevine gene expression and metabolites were monitored at seven time points under long (LD, 15 h) and short (SD, 13 h) day treatments. The use of age-matched buds and a small (2 h) photoperiod difference minimized developmental differences and allowed us to separate general photoperiod from dormancy specific gene responses. Gene expression profiles indicated three distinct phases (perception, induction and dormancy) in SD-induced dormancy development in V. riparia. Different genes from the NAC DOMAIN CONTAINING PROTEIN 19 and WRKY families of transcription factors were differentially expressed in each phase of dormancy. Metabolite and transcriptome analyses indicated ABA, trehalose, raffinose and resveratrol compounds have a potential role in dormancy commitment. Finally, a comparison between V. riparia compound axillary bud dormancy and dormancy responses in other species emphasized the relationship between dormancy and the expression of RESVERATROL SYNTHASE and genes associated with C3HC4-TYPE RING

  13. Seed dormancy and germination - Emerging mechanisms and new hypotheses

    Directory of Open Access Journals (Sweden)

    Hiroyuki eNonogaki

    2014-05-01

    Full Text Available Seed dormancy has played a significant role in adaptation and evolution of seed plants. While its biological significance is clear, molecular mechanisms underlying seed dormancy induction, maintenance and alleviation still remain elusive. Intensive efforts have been made to investigate gibberellin and abscisic acid metabolism in seeds, which greatly contributed to the current understanding of seed dormancy mechanisms. Other mechanisms, which might be independent of hormones, or specific to the seed dormancy pathway, are also emerging from genetic analysis of seed dormancy mutants. These studies suggest that chromatin remodeling through histone ubiquitination, methylation and acetylation, which could lead to transcription elongation or gene silencing, may play a significant role in seed dormancy regulation. Small interfering RNA and/or long non-coding RNA might be a trigger of epigenetic changes at the seed dormancy or germination loci, such as DELAY OF GERMINATION1. While new mechanisms are emerging from genetic studies of seed dormancy, novel hypotheses are also generated from seed germination study with high throughput gene expression analysis. Recent studies on tissue-specific gene expression in tomato and Arabidopsis seeds, which suggested possible mechanosensing in the regulatory mechanisms, advanced our understanding of embryo-endosperm interaction and have potential to re-draw the traditional hypotheses or integrate them into a comprehensive scheme. The progress in basic seed science will enable knowledge translation, another frontier of research to be expanded for food and fuel production.

  14. Chilling-dependent release of seed and bud dormancy in peach associates to common changes in gene expression.

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    Carmen Leida

    Full Text Available Reproductive meristems and embryos display dormancy mechanisms in specialized structures named respectively buds and seeds that arrest the growth of perennial plants until environmental conditions are optimal for survival. Dormancy shows common physiological features in buds and seeds. A genotype-specific period of chilling is usually required to release dormancy by molecular mechanisms that are still poorly understood. In order to find common transcriptional pathways associated to dormancy release, we analyzed the chilling-dependent expression in embryos of certain genes that were previously found related to dormancy in flower buds of peach. We propose the presence of short and long-term dormancy events affecting respectively the germination rate and seedling development by independent mechanisms. Short periods of chilling seem to improve germination in an abscisic acid-dependent manner, whereas the positive effect of longer cold treatments on physiological dwarfing coincides with the accumulation of phenylpropanoids in the seed.

  15. Chilling-Dependent Release of Seed and Bud Dormancy in Peach Associates to Common Changes in Gene Expression

    Science.gov (United States)

    Arbona, Vicent; Gómez-Cadenas, Aurelio; Llácer, Gerardo; Badenes, María Luisa; Ríos, Gabino

    2012-01-01

    Reproductive meristems and embryos display dormancy mechanisms in specialized structures named respectively buds and seeds that arrest the growth of perennial plants until environmental conditions are optimal for survival. Dormancy shows common physiological features in buds and seeds. A genotype-specific period of chilling is usually required to release dormancy by molecular mechanisms that are still poorly understood. In order to find common transcriptional pathways associated to dormancy release, we analyzed the chilling-dependent expression in embryos of certain genes that were previously found related to dormancy in flower buds of peach. We propose the presence of short and long-term dormancy events affecting respectively the germination rate and seedling development by independent mechanisms. Short periods of chilling seem to improve germination in an abscisic acid-dependent manner, whereas the positive effect of longer cold treatments on physiological dwarfing coincides with the accumulation of phenylpropanoids in the seed. PMID:22590512

  16. Physiology, morphology and phenology of seed dormancy break and germination in the endemic Iberian species Narcissus hispanicus (Amaryllidaceae)

    Science.gov (United States)

    Copete, Elena; Herranz, José M.; Ferrandis, Pablo; Baskin, Carol C.; Baskin, Jerry M.

    2011-01-01

    Background and Aims Only very few studies have been carried out on seed dormancy/germination in the large monocot genus Narcissus. A primary aim of this study was to determine the kind of seed dormancy in Narcissus hispanicus and relate the dormancy breaking and germination requirements to the field situation. Methods Embryo growth, radicle emergence and shoot growth were studied by subjecting seeds with and without an emerged radicle to different periods of warm, cold or warm plus cold in natural temperatures outdoors and under controlled laboratory conditions. Key Results Mean embryo length in fresh seeds was approx. 1·31 mm, and embryos had to grow to 2·21 mm before radicle emergence. Embryos grew to full size and seeds germinated (radicles emerged) when they were warm stratified for 90 d and then incubated at cool temperatures for 30 d. However, the embryos grew only a little and no seeds germinated when they were incubated at 9/5, 10 or 15/4 °C for 30 d following a moist cold pre-treatment at 5, 9/5 or 10 °C. In the natural habitat of N. hispanicus, seeds are dispersed in late May, the embryo elongates in autumn and radicles emerge (seeds germinate) in early November; however, if the seeds are exposed to low temperatures before embryo growth is completed, they re-enter dormancy (secondary dormancy). The shoot does not emerge until March, after germinated seeds are cold stratified in winter. Conclusion Seeds of N. hispanicus have deep simple epicotyl morphophysiological dormancy (MPD), with the dormancy formula C1bB(root) – C3(epicotyl). This is the first study on seeds with simple MPD to show that embryos in advanced stages of growth can re-enter dormancy (secondary dormancy). PMID:21335326

  17. Physiology, morphology and phenology of seed dormancy break and germination in the endemic Iberian species Narcissus hispanicus (Amaryllidaceae).

    Science.gov (United States)

    Copete, Elena; Herranz, José M; Ferrandis, Pablo; Baskin, Carol C; Baskin, Jerry M

    2011-05-01

    Only very few studies have been carried out on seed dormancy/germination in the large monocot genus Narcissus. A primary aim of this study was to determine the kind of seed dormancy in Narcissus hispanicus and relate the dormancy breaking and germination requirements to the field situation. Embryo growth, radicle emergence and shoot growth were studied by subjecting seeds with and without an emerged radicle to different periods of warm, cold or warm plus cold in natural temperatures outdoors and under controlled laboratory conditions. Mean embryo length in fresh seeds was approx. 1·31 mm, and embryos had to grow to 2·21 mm before radicle emergence. Embryos grew to full size and seeds germinated (radicles emerged) when they were warm stratified for 90 d and then incubated at cool temperatures for 30 d. However, the embryos grew only a little and no seeds germinated when they were incubated at 9/5, 10 or 15/4 °C for 30 d following a moist cold pre-treatment at 5, 9/5 or 10 °C. In the natural habitat of N. hispanicus, seeds are dispersed in late May, the embryo elongates in autumn and radicles emerge (seeds germinate) in early November; however, if the seeds are exposed to low temperatures before embryo growth is completed, they re-enter dormancy (secondary dormancy). The shoot does not emerge until March, after germinated seeds are cold stratified in winter. Seeds of N. hispanicus have deep simple epicotyl morphophysiological dormancy (MPD), with the dormancy formula C(1b)B(root) - C(3)(epicotyl). This is the first study on seeds with simple MPD to show that embryos in advanced stages of growth can re-enter dormancy (secondary dormancy).

  18. Dormancy induction by summer temperatures and/or desiccation in imbibed seeds of trumpet daffodils Narcissus alcaracensis and N. longispathus (Amaryllidaceae).

    Science.gov (United States)

    Herranz, J M; Copete, E; Copete, M A; Márquez, J; Ferrandis, P

    2017-01-01

    We analysed the effects of summer temperatures (28/14 °C) and/or desiccation (from 48% to 8% humidity) on imbibed Narcissus alcaracensis and N. longispathus seeds with an elongating embryo. In the N. alcaracensis seeds that overcame dormancy (embryo elongation = 27.14%), exposure to high temperatures induced secondary dormancy and reduced subsequent embryo growth. A further 3-month cold stratification (5 °C) was required to break secondary dormancy. Desiccation in early embryo growth stages (elongation = 11.42%) also reduced germination. Desiccation in the seeds in a more advanced growth stage (i.e. embryo elongation = 27.14%) induced secondary dormancy, which the further 3-month cold stratification did not overcome. When desiccation was preceded by high temperatures, seeds better overcame secondary dormancy (i.e. longer embryo elongation and seed germination). Treatments did not affect seed viability. In the N. longispathus seeds that overcame dormancy (embryo elongation = 59.21%), exposure to high temperatures induced secondary dormancy and they needed a further 1-month stratification at 15/4 °C + 2 months at 5 °C to reactivate the germination process. When embryo elongation was 42.10%, seed desiccation totally impeded subsequent germination. When embryo elongation reached 59.21%, desiccation induced secondary dormancy, which was not overcome by the above-described stratification treatment. When desiccation was preceded by high temperatures, seeds better overcame dormancy. Stress treatments killed 5-10% of seeds. This study suggests that the seeds of species with complex morphophysiological dormancy (MPD) levels are sensitive to desiccation in early embryo development stages, as opposed to the seeds of species with deep simple epicotyl MPD, which better tolerate water stress. © 2016 German Botanical Society and The Royal Botanical Society of the Netherlands.

  19. Fruit maturation and in vitro germination of macaw palm embryos ...

    African Journals Online (AJOL)

    -industrial potential. Seed dormancy in palm species may be due to embryo immaturity, which could result from delayed embryogenesis. We evaluated the correspondence between the visual characteristics of maturing fruits and their ...

  20. The morphophysiological dormancy in Amborella trichopoda seeds is a pleisiomorphic trait in angiosperms.

    Science.gov (United States)

    Fogliani, Bruno; Gâteblé, Gildas; Villegente, Matthieu; Fabre, Isabelle; Klein, Nicolas; Anger, Nicolas; Baskin, Carol C; Scutt, Charlie P

    2017-03-01

    Recent parsimony-based reconstructions suggest that seeds of early angiosperms had either morphophysiological or physiological dormancy, with the former considered as more probable. The aim of this study was to determine the class of seed dormancy present in Amborella trichopoda , the sole living representative of the most basal angiosperm lineage Amborellales, with a view to resolving fully the class of dormancy present at the base of the angiosperm clade. Drupes of A. trichopoda without fleshy parts were germinated and dissected to observe their structure and embryo growth. Pre-treatments including acid scarification, gibberellin treatment and seed excision were tested to determine their influence on dormancy breakage and germination. Character-state mapping by maximum parsimony, incorporating data from the present work and published sources, was then used to determine the likely class of dormancy present in early angiosperms. Germination in A. trichopoda requires a warm stratification period of at least approx. 90 d, which is followed by endosperm swelling, causing the water-permeable pericarp-mesocarp envelope to split open. The embryo then grows rapidly within the seed, to radicle emergence some 17 d later and cotyledon emergence after an additional 24 d. Gibberellin treatment, acid scarification and excision of seeds from the surrounding drupe tissues all promoted germination by shortening the initial phase of dormancy, prior to embryo growth. Seeds of A. trichopoda have non-deep simple morphophysiological dormancy, in which mechanical resistance of the pericarp-mesocarp envelope plays a key role in the initial physiological phase. Maximum parsimony analyses, including data obtained in the present work, indicate that morphophysiological dormancy is likely to be a pleisiomorphic trait in flowering plants. The significance of this conclusion for studies of early angiosperm evolution is discussed.

  1. Metastatic Tumor Dormancy in Cutaneous Melanoma: Does Surgery Induce Escape?

    Energy Technology Data Exchange (ETDEWEB)

    Tseng, William W. [Department of Surgery, University of California at San Francisco, 513 Parnassus Avenue, Room S-321, San Francisco, CA 94143 (United States); Fadaki, Niloofar; Leong, Stanley P., E-mail: leongsx@cpmcri.org [Department of Surgery and Center for Melanoma Research and Treatment, California Pacific Medical Center and Research Institute, 2340 Clay Street, 2nd floor, San Francisco, CA 94115 (United States)

    2011-02-21

    According to the concept of tumor dormancy, tumor cells may exist as single cells or microscopic clusters of cells that are clinically undetectable, but remain viable and have the potential for malignant outgrowth. At metastatic sites, escape from tumor dormancy under more favorable local microenvironmental conditions or through other, yet undefined stimuli, may account for distant recurrence after supposed “cure” following surgical treatment of the primary tumor. The vast majority of evidence to date in support of the concept of tumor dormancy originates from animal studies; however, extensive epidemiologic data from breast cancer strongly suggests that this process does occur in human disease. In this review, we aim to demonstrate that metastatic tumor dormancy does exist in cutaneous melanoma based on evidence from mouse models and clinical observations of late recurrence and occult transmission by organ transplantation. Experimental data underscores the critical role of impaired angiogenesis and immune regulation as major mechanisms for maintenance of tumor dormancy. Finally, we examine evidence for the role of surgery in promoting escape from tumor dormancy at metastatic sites in cutaneous melanoma.

  2. Metastatic Tumor Dormancy in Cutaneous Melanoma: Does Surgery Induce Escape?

    Directory of Open Access Journals (Sweden)

    William W. Tseng

    2011-02-01

    Full Text Available According to the concept of tumor dormancy, tumor cells may exist as single cells or microscopic clusters of cells that are clinically undetectable, but remain viable and have the potential for malignant outgrowth. At metastatic sites, escape from tumor dormancy under more favorable local microenvironmental conditions or through other, yet undefined stimuli, may account for distant recurrence after supposed “cure” following surgical treatment of the primary tumor. The vast majority of evidence to date in support of the concept of tumor dormancy originates from animal studies; however, extensive epidemiologic data from breast cancer strongly suggests that this process does occur in human disease. In this review, we aim to demonstrate that metastatic tumor dormancy does exist in cutaneous melanoma based on evidence from mouse models and clinical observations of late recurrence and occult transmission by organ transplantation. Experimental data underscores the critical role of impaired angiogenesis and immune regulation as major mechanisms for maintenance of tumor dormancy. Finally, we examine evidence for the role of surgery in promoting escape from tumor dormancy at metastatic sites in cutaneous melanoma.

  3. Characterization of embryo-specific genes. Final report, April 1, 1987--March 31, 1992

    Energy Technology Data Exchange (ETDEWEB)

    Sung, R.

    1992-06-12

    The objective of the proposed research is to characterize the function and regulation of a set of embryonic genes which are expressed in the embryos, not in the plants. 22 cDNA clones were isolated from a cDNA library we constructed using mRNAS of -carrot somatic embryos. These cDNA clones identified mRNA species that are present in the somatic and zygotic embryos, but not in adult plants. The sequence of all 22cDNA clones were determined; genomic clones for three cDNA clones, DC8, DC59, and DC49 were isolated and gene sequences determined. DC8, DC49, and several other genes identified by the cDNA sequences belong to the category of late embryogenesis abundant protein genes, Lea. The function of these gens have not yet been determined, but they share common structural features, are regulated by ABA and are speculated to play a role in seed desiccation.

  4. The qSD12 locus controls offspring tissue-imposed seed dormancy in rice

    Science.gov (United States)

    Seed component structures were grouped into maternal and offspring (embryo and endosperm) tissues to characterize a dormancy quantitative trait locus (QTL) for tissue-specific function using a marker-assisted genetic approach. The approach is devised to test if genotypic/allelic frequencies of a mar...

  5. Morphophysiological dormancy in seeds of three eastern North American Sanicula species (Apiaceae subf

    Science.gov (United States)

    Tracy S. Hawkins; Carol C. Baskin; Jerry M Baskin

    2010-01-01

    Dormancy breaking and germination requirements were determined for seeds of the eastern North American (eNA) species Sanicula canadensis, Sanicula gregaria and Sanicula trifoliata, and the data compared to those available for the European–Asian (EurA) congener Sanicula europaea. Seeds of the three eNA species had underdeveloped embryos that were physiologically dormant...

  6. Computer-Assisted Recovery of Threatened Plants: Keys for Breaking Seed Dormancy of Eryngium viviparum

    Directory of Open Access Journals (Sweden)

    Manuel Ayuso

    2017-12-01

    Full Text Available Many endangered plants such as Eryngium viviparum (Apiaceae present a poor germination rate. This fact could be due to intrinsic and extrinsic seed variability influencing germination and dormancy of seeds. The objective of this study is to better understand the physiological mechanism of seed latency and, through artificial intelligence models, to determine the factors that stimulate germination rates of E. viviparum seeds. This description could be essential to prevent the disappearance of endangered plants. Germination in vitro was carried out under different dormancy breaking and incubation procedures. Percentages of germination, viability and E:S ratio were calculated and seeds were dissected at the end of each assay to describe embryo development. The database obtained was modeled using neurofuzzy logic technology. We have found that the most of Eryngium seeds (62.6% were non-viable seeds (fully empty or without embryos. Excluding those, we have established the germination conditions to break seed dormancy that allow obtaining a real germination rate of 100%. Advantageously, the best conditions pointed out by neurofuzzy logic model for embryo growth were the combination of 1 mg L−1 GA3 (Gibberellic Acid and high incubation temperature and for germination the combination of long incubation and short warm stratification periods. Our results suggest that E. viviparum seeds present morphophysiological dormancy, which reduce the rate of germination. The knowledge provided by the neurofuzzy logic model makes possible not just break the physiological component of dormancy, but stimulate the embryo development increasing the rate of germination. Undoubtedly, the strategy developed in this work can be useful to recover other endangered plants by improving their germination rate and uniformity favoring their ex vitro conservation.

  7. A potential role for endogenous microflora in dormancy release, cytokinin metabolism and the response to fluridone in Lolium rigidum seeds

    Science.gov (United States)

    Goggin, Danica E.; Emery, R. J. Neil; Kurepin, Leonid V.; Powles, Stephen B.

    2015-01-01

    Background and Aims Dormancy in Lolium rigidum (annual ryegrass) seeds can be alleviated by warm stratification in the dark or by application of fluridone, an inhibitor of plant abscisic acid (ABA) biosynthesis via phytoene desaturase. However, germination and absolute ABA concentration are not particularly strongly correlated. The aim of this study was to determine if cytokinins of both plant and bacterial origin are involved in mediating dormancy status and in the response to fluridone. Methods Seeds with normal or greatly decreased (by dry heat pre-treatment) bacterial populations were stratified in the light or dark and in the presence or absence of fluridone in order to modify their dormancy status. Germination was assessed and seed cytokinin concentration and composition were measured in embryo-containing or embryo-free seed portions. Key Results Seeds lacking bacteria were no longer able to lose dormancy in the dark unless supplied with exogenous gibberellin or fluridone. Although these seeds showed a dramatic switch from active cytokinin free bases to O-glucosylated storage forms, the concentrations of individual cytokinin species were only weakly correlated to dormancy status. However, cytokinins of apparently bacterial origin were affected by fluridone and light treatment of the seeds. Conclusions It is probable that resident microflora contribute to dormancy status in L. rigidum seeds via a complex interaction between hormones of both plant and bacterial origin. This interaction needs to be taken into account in studies on endogenous seed hormones or the response of seeds to plant growth regulators. PMID:25471097

  8. Seed dormancy and ABA metabolism in Arabidopsis and barley: the role of ABA 8'-hydroxylase.

    Science.gov (United States)

    Millar, Anthony A; Jacobsen, John V; Ross, John J; Helliwell, Chris A; Poole, Andrew T; Scofield, Graham; Reid, James B; Gubler, Frank

    2006-03-01

    We have investigated the relationship between seed dormancy and abscisic acid (ABA) metabolism in the monocot barley and the dicot Arabidopsis. Whether dormant (D) or non-dormant (ND), dry seed of Arabidopsis and embryos of dry barley grains all had similarly high levels of ABA. ABA levels decreased rapidly upon imbibition, although they fell further in ND than in D. Gene expression profiles were determined in Arabidopsis for key ABA biosynthetic [the 9-cis epoxycarotenoid dioxygenasegene family] and ABA catabolic [the ABA 8'-hydroxylase gene family (CYP707A)] genes. Of these, only the AtCYP707A2 gene was differentially expressed between D and ND seeds, being expressed to a much higher level in ND seeds. Similarly, a barley CYP707 homologue, (HvABA8'OH-1) was expressed to a much higher level in embryos from ND grains than from D grains. Consistent with this, in situ hybridization studies showed HvABA8'OH-1 mRNA expression was stronger in embryos from ND grains. Surprisingly, the signal was confined in the coleorhiza, suggesting that this tissue plays a key role in dormancy release. Constitutive expression of a CYP707A gene in transgenic Arabidopsis resulted in decreased ABA content in mature dry seeds and a much shorter after-ripening period to overcome dormancy. Conversely, mutating the CYP707A2 gene resulted in seeds that required longer after-ripening to break dormancy. Our results point to a pivotal role for the ABA 8'-hydroxylase gene in controlling dormancy and that the action of this enzyme may be confined to a particular organ as in the coleorhiza of cereals.

  9. Blackout cloth for dormancy induction

    Science.gov (United States)

    Tom Jopson

    2007-01-01

    The use of blackout cloth to create long night photoperiods for the induction of dormancy in certain conifer species has been an established practice for a long time. Its use was suggested by Tinus and McDonald (1979) as an effective technique, and the practice has been commonly used in Canadian forest nurseries for a number of years. Cal-Forest Nursery installed its...

  10. In-vitro propagation of Picralima nitida (Stapf) through embryo culture

    African Journals Online (AJOL)

    Embryo abortion in wide crosses and seed dormancy has hampered the mass propagation of selected tree germplasm from the wild. An in vitro plant regeneration protocol was successfully established in Picralima nitida (Stapf), a medicinal tropical plant, by culturing excised embryo from mature seeds collected from the ...

  11. Embryo rescue as a method to develop and multiply a backcross ...

    African Journals Online (AJOL)

    Jane

    2010-10-18

    Oct 18, 2010 ... growing as a food security crop in sub Saharan Africa, where malnutrition is a menace. ... seeds in embryo culture was high (66%). ... Embryo culture provides a simple technique for breaking seed dormancy and ensuring a fairly uniform germination rate (Biggs et al., 1986). Raising cassava plantlets in a ...

  12. Embryo splitting

    Directory of Open Access Journals (Sweden)

    Karl Illmensee

    2010-04-01

    Full Text Available Mammalian embryo splitting has successfully been established in farm animals. Embryo splitting is safely and efficiently used for assisted reproduction in several livestock species. In the mouse, efficient embryo splitting as well as single blastomere cloning have been developed in this animal system. In nonhuman primates embryo splitting has resulted in several pregnancies. Human embryo splitting has been reported recently. Microsurgical embryo splitting under Institutional Review Board approval has been carried out to determine its efficiency for blastocyst development. Embryo splitting at the 6–8 cell stage provided a much higher developmental efficiency compared to splitting at the 2–5 cell stage. Embryo splitting may be advantageous for providing additional embryos to be cryopreserved and for patients with low response to hormonal stimulation in assisted reproduction programs. Social and ethical issues concerning embryo splitting are included regarding ethics committee guidelines. Prognostic perspectives are presented for human embryo splitting in reproductive medicine.

  13. Identification of genes associated with bud dormancy release in Prunus persica by suppression subtractive hybridization.

    Science.gov (United States)

    Leida, Carmen; Terol, Javier; Martí, Gracia; Agustí, Manuel; Llácer, Gerardo; Badenes, María Luisa; Ríos, Gabino

    2010-05-01

    To better understand the molecular and physiological mechanisms underlying maintenance and release of seasonal bud dormancy in perennial trees, we identified differentially expressed genes during dormancy progression in reproductive buds from peach (Prunus persica [L.] Batsch) by suppression subtractive hybridization (SSH) and microarray hybridization. Four SSH libraries were constructed, which were respectively enriched in cDNA highly expressed in dormant buds (named DR), in dormancy-released buds (RD) and in the cultivars with different chilling requirement, 'Zincal 5' (ZS) and 'Springlady' (SZ), sampled after dormancy release. About 2500 clones picked from the four libraries were loaded on a glass microarray. Hybridization of microarrays with the final products of SSH procedure was performed in order to validate the selected clones that were effectively enriched in their respective sample. Nearly 400 positive clones were sequenced, which corresponded to 101 different unigenes with diverse functional annotation. We obtained DAM4, 5 and 6 genes coding for MADS-box transcription factors previously related to growth cessation and terminal bud formation in the evergrowing mutant of peach. Several other cDNAs are similar to dormancy factors described in other species, and others have been related to bud dormancy for the first time in this study. Quantitative reverse transcription polymerase chain reaction analysis confirmed differential expression of cDNAs coding for a Zn-finger transcription factor, a GRAS-like regulator, a DNA-binding protein and proteins similar to forisome subunits involved in the reversible occlusion of sieve elements in Fabaceae, among others.

  14. Wheat ABA-insensitive mutants result in reduced grain dormancy

    Science.gov (United States)

    Schramm, Elizabeth C.; Nelson, Sven K.

    2014-01-01

    This paper describes the isolation of wheat mutants in the hard red spring Scarlet resulting in reduced sensitivity to the plant hormone abscisic acid (ABA) during seed germination. ABA induces seed dormancy during embryo maturation and inhibits the germination of mature seeds. Wheat sensitivity to ABA gradually decreases with dry after-ripening. Scarlet grain normally fails to germinate when fully dormant, shows ABA sensitive germination when partially after-ripened, and becomes ABA insensitive when after-ripened for 8–12 months. Scarlet ABA-insensitive (ScABI) mutants were isolated based on the ability to germinate on 5 µM ABA after only 3 weeks of after-ripening, a condition under which Scarlet would fail to germinate. Six independent seed-specific mutants were recovered. ScABI 1, ScABI2, ScABI3 and ScABI4 are able to germinate more efficiently than Scarlet at up to 25 µM ABA. The two strongest ABA insensitive lines, ScABI3 and ScABI4, both proved to be partly dominant suggesting that they result from gain-of-function mutations. The ScABI1, ScABI2, ScABI3, ScABI4, and ScABI5 mutants after-ripen more rapidly than Scarlet. Thus, ABA insensi-tivity is associated with decreased grain dormancy in Scarlet wheat. This suggests that ABA sensitivity is an important factor controlling grain dormancy in wheat, a trait that impacts seedling emergence and pre-harvest sprouting resistance. PMID:25431501

  15. Crosstalk between reactive oxygen species and hormonal signalling pathways regulates grain dormancy in barley.

    Science.gov (United States)

    Bahin, Emilie; Bailly, Christophe; Sotta, Bruno; Kranner, Ilse; Corbineau, Françoise; Leymarie, Juliette

    2011-06-01

    Seed dormancy, defined as the inability to germinate under favourable conditions, is controlled by abscisic acid (ABA) and gibberellins (GAs). Phytohormone signalling interacts with reactive oxygen species (ROS) signalling regarding diverse aspects of plant physiology and is assumed to be important in dormancy alleviation. Using dormant barley grains that do not germinate at 30 °C in darkness, we analysed ROS content and ROS-processing systems, ABA content and metabolism, GA-responsive genes and genes involved in GA metabolism in response to hydrogen peroxide (H₂O₂) treatment. During after-ripening, the ROS content in the embryo was not affected, while the antioxidant glutathione (GSH) was gradually converted to glutathione disulphide (GSSG). ABA treatment up-regulated catalase activity through transcriptional activation of HvCAT2. Exogenous H₂O₂ partially alleviated dormancy although it was associated with a small increase in embryonic ABA content related to a slight induction of HvNCED transcripts. H₂O₂ treatment did not affect ABA sensitivity but up-regulated the expression of HvExpA11 (GA-induced gene), inhibited the expression of HvGA2ox3 involved in GA catabolism and enhanced the expression of HvGA20ox1 implicated in GA synthesis. In barley, H₂O₂ could be implicated in dormancy alleviation through activation of GA signalling and synthesis rather than repression of ABA signalling. © 2011 Blackwell Publishing Ltd.

  16. Experiences with dormancy in tardigrades

    Directory of Open Access Journals (Sweden)

    Deborah BOSCHINI

    2004-09-01

    Full Text Available Tardigrades often colonise extreme habitats, in which they survive using both types of dormancy: quiescence and diapause. Together with nematodes and bdelloid rotifers, tardigrades are known to enter quiescence (with several forms of cryptobiosis: anhydrobiosis, cryobiosis, anoxybiosis, osmobiosis at any stage of their life cycle, from egg to adult. Entering anhydrobiosis, tardigrades contract their body into a so-called tun, loosing most of their free and bound water (>95%, synthesizing cell protectants (e.g., trehalose, glycerol, heat shock proteins and strongly reducing or suspending their metabolism. Our research on cryptobiosis focused on some ecological and evolutionary aspects. We evaluated: i the long-term anhydrobiotic survival by comparing quantitative data on recovery from naturally induced desiccation in several species of tardigrades; ii differences in survival patterns between species and populations by experimentally inducing anhydrobiosis and cryobiosis; iii phenotypic factors affecting anhydrobiotic survival. As regards diapause, we considered encystment and eggs. Encystment involves at least the synthesis of new cuticular structures. Morphological changes during cyst formation are more complex than those involved in tun formation. We analyzed more in detail encystment processes, comparing a semiterrestrial with a limnic species. Several inter-specific differences have been identified, other than the production of two types of cysts in the semiterrestrial species. Our analysis of life history traits of a laboratory reared strain of a soil tardigrade revealed a particular hatching phenology that involved the production of both subitaneous and resting eggs. The latter need a cue to hatch (dehydration followed by re-hydration. In addition, the evolutionary meaning of dormancy in tardigrades is discussed.

  17. Regulation of Metastatic Breast Cancer Dormancy

    Science.gov (United States)

    2015-09-01

    to begin to unravel the complex resistance seen with metastatic breast cancer , particularly the fear of recurrence 5-10 years after apparent cure...AWARD NUMBER: W81XWH-14-1-0062 TITLE: Regulation of Metastatic Breast Cancer Dormancy PRINCIPAL INVESTIGATOR: Sarah Wheeler CONTRACTING...Metastatic Breast Cancer Dormancy 5a. CONTRACT NUMBER 5b. GRANT NUMBER W81XWH-14-1-0062 5c. PROGRAM ELEMENT NUMBER 6. AUTHOR(S) Sarah Wheeler 5d

  18. Dormancy programs as emerging antimetastasis therapeutic alternatives

    Science.gov (United States)

    Sosa, Maria Soledad

    2016-01-01

    We recently published that the retinoid-responsive gene NR2F1 (nuclear receptor subfamily 2, group F, member 1) mediates postsurgical dormancy of local residual tumor cells and disseminated tumor cells. Importantly, the combination of azacytidine with retinoids induces dormancy of malignant tumor cells by reinstating the NR2F1-regulated gene program. These findings open the door to the development of strategies that may stop minimal residual disease from becoming life-threatening metastases. PMID:27308542

  19. Regulation of dormancy in barley by blue light and after-ripening: effects on abscisic acid and gibberellin metabolism.

    Science.gov (United States)

    Gubler, Frank; Hughes, Trijntje; Waterhouse, Peter; Jacobsen, John

    2008-06-01

    White light strongly promotes dormancy in freshly harvested cereal grains, whereas dark and after-ripening have the opposite effect. We have analyzed the interaction of light and after-ripening on abscisic acid (ABA) and gibberellin (GA) metabolism genes and dormancy in barley (Hordeum vulgare 'Betzes'). Analysis of gene expression in imbibed barley grains shows that different ABA metabolism genes are targeted by white light and after-ripening. Of the genes examined, white light promotes the expression of an ABA biosynthetic gene, HvNCED1, in embryos. Consistent with this result, enzyme-linked immunosorbent assays show that dormant grains imbibed under white light have higher embryo ABA content than grains imbibed in the dark. After-ripening has no effect on expression of ABA biosynthesis genes, but promotes expression of an ABA catabolism gene (HvABA8'OH1), a GA biosynthetic gene (HvGA3ox2), and a GA catabolic gene (HvGA2ox3) following imbibition. Blue light mimics the effects of white light on germination, ABA levels, and expression of GA and ABA metabolism genes. Red and far-red light have no effect on germination, ABA levels, or HvNCED1. RNA interference experiments in transgenic barley plants support a role of HvABA8'OH1 in dormancy release. Reduced HvABA8'OH1 expression in transgenic HvABA8'OH1 RNAi grains results in higher levels of ABA and increased dormancy compared to nontransgenic grains.

  20. Intermediate complex morphophysiological dormancy in seeds of the cold desert sand dune geophyte Eremurus anisopterus (Xanthorrhoeaceae; Liliaceae s.l.).

    Science.gov (United States)

    Mamut, Jannathan; Tan, Dun Yan; Baskin, Carol C; Baskin, Jerry M

    2014-10-01

    Little is known about morphological (MD) or morphophysiological (MPD) dormancy in cold desert species and in particular those in Liliaceae sensu lato, an important floristic element in the cold deserts of Central Asia with underdeveloped embyos. The primary aim of this study was to determine if seeds of the cold desert liliaceous perennial ephemeral Eremurus anisopterus has MD or MPD, and, if it is MPD, then at what level. Embryo growth and germination was monitored in seeds subjected to natural and simulated natural temperature regimes and the effects of after-ripening and GA3 on dormancy break were tested. In addition, the temperature requirements for embryo growth and dormancy break were investigated. At the time of seed dispersal in summer, the embryo length:seed length (E:S) ratio was 0·73, but it increased to 0·87 before germination. Fresh seeds did not germinate during 1 month of incubation in either light or darkness over a range of temperatures. Thus, seeds have MPD, and, after >12 weeks incubation at 5/2 °C, both embryo growth and germination occurred, showing that they have a complex level of MPD. Since both after-ripening and GA3 increase the germination percentage, seeds have intermediate complex MPD. Embryos in after-ripened seeds of E. anisopterus can grow at low temperatures in late autumn, but if the soil is dry in autumn then growth is delayed until snowmelt wets the soil in early spring. The ecological advantage of embryo growth phenology is that seeds can germinate at a time (spring) when sand moisture conditions in the desert are suitable for seedling establishment. © The Author 2014. Published by Oxford University Press on behalf of the Annals of Botany Company. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  1. Intermediate complex morphophysiological dormancy in seeds of the cold desert sand dune geophyte Eremurus anisopterus (Xanthorrhoeaceae; Liliaceae s.l.)

    Science.gov (United States)

    Mamut, Jannathan; Tan, Dun Yan; Baskin, Carol C.; Baskin, Jerry M.

    2014-01-01

    Background and Aims Little is known about morphological (MD) or morphophysiological (MPD) dormancy in cold desert species and in particular those in Liliaceae sensu lato, an important floristic element in the cold deserts of Central Asia with underdeveloped embyos. The primary aim of this study was to determine if seeds of the cold desert liliaceous perennial ephemeral Eremurus anisopterus has MD or MPD, and, if it is MPD, then at what level. Methods Embryo growth and germination was monitored in seeds subjected to natural and simulated natural temperature regimes and the effects of after-ripening and GA3 on dormancy break were tested. In addition, the temperature requirements for embryo growth and dormancy break were investigated. Key Results At the time of seed dispersal in summer, the embryo length:seed length (E:S) ratio was 0·73, but it increased to 0·87 before germination. Fresh seeds did not germinate during 1 month of incubation in either light or darkness over a range of temperatures. Thus, seeds have MPD, and, after >12 weeks incubation at 5/2 °C, both embryo growth and germination occurred, showing that they have a complex level of MPD. Since both after-ripening and GA3 increase the germination percentage, seeds have intermediate complex MPD. Conclusions Embryos in after-ripened seeds of E. anisopterus can grow at low temperatures in late autumn, but if the soil is dry in autumn then growth is delayed until snowmelt wets the soil in early spring. The ecological advantage of embryo growth phenology is that seeds can germinate at a time (spring) when sand moisture conditions in the desert are suitable for seedling establishment. PMID:25180288

  2. Are seed dormancy and persistence in soil related?

    NARCIS (Netherlands)

    Thompson, K; Ceriani, RM; Bakker, JP; Bekker, RM

    There is confusion in the ecological literature between seed dormancy and persistence in soil. Some ecologists seem to assume that dormancy is necessary for persistence, while others imply that dormancy and persistence are virtually synonymous. Here, we show that there is no close relationship

  3. Dormancy removal of apple seeds by cold stratification is associated with fluctuation in H2O2, NO production and protein carbonylation level.

    Science.gov (United States)

    Dębska, Karolina; Krasuska, Urszula; Budnicka, Katarzyna; Bogatek, Renata; Gniazdowska, Agnieszka

    2013-03-15

    Reactive oxygen (ROS) and nitrogen (RNS) species play a signaling role in seed dormancy alleviation and germination. Their action may be described by the oxidative/nitrosative "window/door". ROS accumulation in embryos could lead to oxidative modification of protein through carbonylation. Mature apple (Malus domestica Borkh.) seeds are dormant and do not germinate. Their dormancy may be overcome by 70-90 days long cold stratification. The aim of this work was to analyze the relationship between germinability of embryos isolated from cold (5°C) or warm (25°C) stratified apple seeds and ROS or nitric oxide (NO) production and accumulation of protein carbonyl groups. A biphasic pattern of variation in H2O2 concentration in the embryos during cold stratification was detected. H2O2 content increased markedly after 7 days of seeds imbibition at 5°C. After an additional two months of cold stratification, the H2O2 concentration in embryos reached the maximum. NO production by the embryos was low during entire period of stratification, but increased significantly in germination sensu stricto (i.e. phase II of the germination process). The highest content of protein carbonyl groups was detected after 6 weeks of cold stratification treatment. Fluctuation of H2O2 and protein carbonylation seems to play a pivotal role in seed dormancy alleviation by cold stratification, while NO appears to be necessary for seed germination. Copyright © 2012 Elsevier GmbH. All rights reserved.

  4. physiological mechanisms for potato dormancy release and ...

    African Journals Online (AJOL)

    ACSS

    in carbohydrate status, increase in respiration rate, additional weight loss, and storage management issues like impeded .... Dormancy period depends also on soil and weather conditions during growth, tuber maturity, ... Soil conditions after haulm destruction but before harvest, probably have the largest effect on tuber ...

  5. The human embryo: ethical and legal aspects.

    Science.gov (United States)

    Knoppers, Bartha Maria; Bordet, Sylvie; Isasi, Rosario

    2009-01-01

    This paper analyses the status of the embryo in Canadian law. First, a brief overview of some ethical issues raised by research with embryos, focusing on the moral status of the embryo, is presented. A survey of the regulatory framework applicable to embryo research in Canada follows, so as to delineate the legal status of the embryo in Canada and its ethical underpinnings. A summary of applicable regulation in Germany, the United Kingdom, and the United States is also undertaken, illustrating the lack of consensus on this issue in Western countries. Finally, recent developments in stem cell research are considered, focusing on current alternatives to embryo destruction.

  6. Effects of moist cold stratification on germination, plant growth regulators, metabolites and embryo ultrastructure in seeds of Acer morrisonense (Sapindaceae).

    Science.gov (United States)

    Chen, Shun-Ying; Chou, Shih-Han; Tsai, Ching-Chu; Hsu, Wen-Yu; Baskin, Carol C; Baskin, Jerry M; Chien, Ching-Te; Kuo-Huang, Ling-Long

    2015-09-01

    Breaking of seed dormancy by moist cold stratification involves complex interactions in cells. To assess the effect of moist cold stratification on dormancy break in seeds of Acer morrisonense, we monitored percentages and rates of germination and changes in plant growth regulators, sugars, amino acids and embryo ultrastructure after various periods of cold stratification. Fresh seeds incubated at 25/15 °C for 24 weeks germinated to 61%, while those cold stratified at 5 °C for 12 weeks germinated to 87% in 1 week. Neither exogenous GA3 nor GA4 pretreatment significantly increased final seed germination percentage. Total ABA content of seeds cold stratified for 12 weeks was reduced about 3.3-fold, to a concentration similar to that in germinated seeds (radicle emergence). Endogenous GA3 and GA7 were detected in 8-week and 12-week cold stratified seeds but not in fresh seeds. Numerous protein and lipid bodies were present in the plumule, first true leaves and cotyledons of fresh seeds. Protein and lipid bodies decreased greatly during cold stratification, and concentrations of total soluble sugars and amino acids increased. The major non-polar sugars in fresh seeds were sucrose and fructose, but sucrose increased and fructose decreased significantly during cold stratification. The major free amino acids were proline and tryptophan in fresh seeds, and proline increased and tryptophan decreased during cold stratification. Thus, as dormancy break occurs during cold stratification seeds of A. morrisonense undergo changes in plant growth regulators, proteins, lipids, sugars, amino acids and cell ultrastructure. Copyright © 2015 Elsevier Masson SAS. All rights reserved.

  7. Pre- and post-harvest influences on seed dormancy status of an Australian Goodeniaceae species, Goodenia fascicularis.

    Science.gov (United States)

    Hoyle, Gemma L; Steadman, Kathryn J; Daws, Matthew I; Adkins, Steve W

    2008-07-01

    The period during which seeds develop on the parent plant has been found to affect many seed characteristics, including dormancy, through interactions with the environment. Goodenia fascicularis (Goodeniaceae) seeds were used to investigate whether seeds of an Australian native forb, harvested from different environments and produced at different stages of the reproductive period, differ in dormancy status. During the reproductive phase, plants were grown ex situ in warm (39/21 degrees C) or cool (26/13 degrees C) conditions, with adequate or limited water availability. The physiological dormancy of resulting seeds was measured in terms of the germination response to warm stratification (34/20 degrees C, 100 % RH, darkness). Plants in the cool environment were tall and had high above-ground biomass, yet yielded fewer seeds over a shorter, later harvest period when compared with plants in the warm environment. Seeds from the cool environment also had higher viability and greater mass, despite a significant proportion (7 % from the cool-wet environment) containing no obvious embryo. In the warm environment, the reproductive phase was accelerated and plants produced more seeds despite being shorter and having lower above-ground biomass than those in the cool environment. Ten weeks of warm stratification alleviated physiological dormancy in seeds from all treatments resulting in 80-100 % germination. Seeds that developed at warm temperatures were less dormant (i.e. germination percentages were higher) than seeds from the cool environment. Water availability had less effect on plant and seed traits than air temperature, although plants with reduced soil moisture were shorter, had lower biomass and produced fewer, less dormant seeds than plants watered regularly. Goodenia fascicularis seeds are likely to exhibit physiological dormancy regardless of the maternal environment. However, seeds collected from warm, dry environments are likely to be more responsive to warm

  8. Dormancy Breaking in Ormosia arborea Seeds

    Directory of Open Access Journals (Sweden)

    Edilma Pereira Gonçalves

    2011-01-01

    Full Text Available Ormosia arborea is a tree species planted in urban areas and used to restore degraded areas. Its seeds are dormant and propagation is difficult. This study compares different dormancy breaking methods and physiological seed quality and seedling production. The seeds were germinated in sand in the laboratory of the Universidade Estadual de Santa Cruz, Ilhéus, Bahia, Brazil. The following dormancy breaking treatments were applied: control (intact seeds, 100°C water immersion; boiling water immersion followed by 24 hours of soaking; scarification with number 100 and number 50 sandpaper opposite from root emergence; sulfuric acid immersion for 1 hour, 50, 45, and 30 minutes. Seed immersion in 100°C and boiling water did not break the dormancy. The study species showed a greater vigor of seedling when its seeds were submitted to treatments associated with tegument rupturing by sandpaper or sulfuric acid. On the other hand, seed scarification with sulfuric acid for 1 hour, 50, 45, and 30 minutes or sandpaper favored seed germination and vigor.

  9. Seed dormancy and germination of the medicinal holoparasitic plant Cistanche deserticola from the cold desert of northwest China.

    Science.gov (United States)

    Wang, Jia; Baskin, Jerry M; Baskin, Carol C; Liu, Guofang; Yang, Xuejun; Huang, Zhenying

    2017-06-01

    Cistanche deserticola is a holoparasitic plant with high medicinal value that reproduces only by seeds. However, the requirements for seed dormancy break and germination of this species remain unclear. The freshly matured dust-like seeds consist of a water-permeable seed coat and an undifferentiated oval-shaped embryo embedded in endosperm. No fresh seeds germinated in water or a 10 -5  M fluridone solution at any incubation temperature within 60 days. Length of embryos in seeds incubated in warm- and cold-started stratification sequences had increased 10.4 and 11.7% after 50 and 40 weeks, respectively. After 6 months, length of embryos in seeds stratified at 5 °C had increased by 12%. Germination of fresh seeds and of seeds stratified at 5 °C for 6 months and then incubated in mixed fluridone/gibberellic acid 3 (GA 3 ) solutions at 30/20 °C germinated to only 2.6 and 11.7%, respectively. Embryos of fresh seeds and of cold-stratified seeds had increased 29.4 and 15.8% in length, respectively, at the time of germination, but they never differentiated into organs. The highest germination (54.4%) was for seeds incubated in a 10 -5  M solution of fluridone in darkness in spring that had overwinter on the soil surface in the natural habitat. Our study indicates that breaking of physiological dormancy (PD) occurs first and then the embryo grows to a critical length (0.44 mm) without differentiation into organs prior to seed germination. Seeds for which PD had been broken were induced to germinate by fluridone and GA 3 at high temperature. Taken together, these results suggest that C. deserticola seeds have a specialized kind of morphophysiological dormancy. This study reveals possible ways to release seed dormancy that will be useful in propagating this medicinal species. Copyright © 2017 Elsevier Masson SAS. All rights reserved.

  10. Identification of the seasonal conditions required for dormancy break of Persoonia longifolia (Proteaceae), a species with a woody indehiscent endocarp.

    Science.gov (United States)

    Chia, K A; Sadler, R; Turner, S R; Baskin, C C

    2016-08-01

    The mechanisms involved in breaking seed dormancy in species with woody endocarps are poorly understood. In a landmark study examining the role of endocarps in regulating germination, our aim was to investigate the effects of the natural sequence of environmental conditions on dormancy break of a species with a woody endocarp (Persoonia longifolia). The role of the endocarp in germination was investigated through imbibition and endocarp removal germination tests. The use of burial to break dormancy was examined and results from these experiments were used to guide laboratory investigations into the use of wet/dry cycling and stratification to break dormancy. Endocarps were water-permeable. Germination increased from 0 to 92·5 % when endocarps were removed. During burial in the field and nursery, 41·6 and 63·7 % of the endocarps germinated, respectively, after 36 months. Ex situ post-burial germination was cyclical and highest after 30 months of burial (45·4 % nursery and 31·8 % field). Highest germination occurred in wet/dry trials when the dry summer was long (20 weeks), had fluctuating temperatures (30/50 °C) and two long (7 d) wet cycles and was followed by moist winters at 10/20 °C. A stratification trial found that highest germination occurred following incubation for 12 weeks at 30 °C (including 2 weeks moist) + 6 weeks moist at 8 °C then placement at 20/10 °C for germination. Summer conditions break physiological dormancy of the embryo and promote opening of the endocarp, allowing seeds to germinate during winter conditions. By closely monitoring the environment that endocarps are exposed to in nature, dormancy breaking mechanisms can be identified and used to improve germination. These results outline for the first time how dormancy and germination are regulated in a species with a hard woody endocarp, insights which will significantly improve our understanding of other species with similar reproductive features. © The Author 2016

  11. An analysis of dormancy, ABA responsiveness, after-ripening and pre-harvest sprouting in hexaploid wheat (Triticum aestivum L.) caryopses

    Science.gov (United States)

    Gerjets, Tanja; Scholefield, Duncan; Foulkes, M. John; Lenton, John R.; Holdsworth, Michael J.

    2010-01-01

    Embryo and caryopsis dormancy, abscisic acid (ABA) responsiveness, after-ripening (AR), and the disorder pre-harvest sprouting (PHS) were investigated in six genetically related wheat varieties previously characterized as resistant, intermediate, or susceptible to PHS. Timing of caryopsis AR differed between varieties; AR occurred before harvest ripeness in the most PHS-susceptible, whereas AR was slowest in the most PHS-resistant. Whole caryopses of all varieties showed little ABA-responsiveness during AR; PHS-susceptible varieties were responsive at the beginning of the AR period whereas PHS-resistant showed some responsiveness throughout. Isolated embryos showed relatively little dormancy during grain-filling and most varieties exhibited a window of decreased ABA-responsiveness around the period of maximum dry matter accumulation (physiological maturity). Susceptibility to PHS was assessed by overhead misting of either isolated ears or whole plants during AR; varieties were clearly distinguished using both methods. These analyses allowed an investigation of the interactions between the different components of seed development, compartments, and environment for the six varieties. There was no direct relationship between speed of caryopsis AR and embryo dormancy or ABA-responsiveness during seed maturation. However, the velocity of AR of a variety was closely associated with the degree of susceptibility to PHS during AR suggesting that these characters are developmentally linked. Investigation of genetic components of AR may therefore aid breeding approaches to reduce susceptibility to PHS. PMID:19923197

  12. Evaluation of different methods to overcome in vitro seed dormancy ...

    African Journals Online (AJOL)

    Seeds from yellow passion fruit (Passiflora edulis Sims) present dormancy imposed by the seed-coat. The present study aimed to evaluate some methods to overcome dormancy of seeds from P. edulis grown under in vitro conditions. The experimental design was completely randomized in factorial scheme (15 scarification ...

  13. Effects of different methods of breaking dormancy and seed ...

    African Journals Online (AJOL)

    Seed dormancy in palms, date palm inclusive have continued to be challenging especially when cultivating through seeds. This study evaluated different methods of breaking dormancy and seed germination rate in P. dactylifera. Using Completely Randomize Design, two varieties of P. dactylifera were treated with three ...

  14. Dormancy, activation and viability of Rhizopus oligosporus sporangiospores

    NARCIS (Netherlands)

    Thanh, N.V.; Nout, M.J.R.

    2004-01-01

    Interruption of dormancy to improve viability of Rhizopus oligosporus sporangiospores is crucial for the application of stored starter cultures for fungal (tempe) production. We aimed to assess the extent of dormancy and factors that could result in activation. Whereas heat treatments were

  15. genetics and inheritance of seed dormancy inflicted by seed

    African Journals Online (AJOL)

    Mgina

    reference to its genetic factors. Bull. Inst. Res. Tohoku University 14:1-. 879 (J). Takahashi T 1997 Inheritance of seed germination and dormancy. In. Science of the Rice Plant Genetics. Vol. 3. Eds. T Matsao et al (1997). FAO Policy Center, Tokyo. Tomar JB 1984 Genetics of grain dormancy in rice (Oryza sativa L.) Genetica.

  16. REDUCED DORMANCY5 Encodes a Protein Phosphatase 2C That Is Required for Seed Dormancy in Arabidopsis

    NARCIS (Netherlands)

    Xiang, Y.; Nakabayashi, K.; Ding, J.; He, F.; Bentsink, L.; Soppe, W.J.J.

    2014-01-01

    Seed dormancy determines germination timing and contributes to crop production and the adaptation of natural populations to their environment. Our knowledge about its regulation is limited. In a mutagenesis screen of a highly dormant Arabidopsis thaliana line, the reduced dormancy5 (rdo5) mutant was

  17. Dormancy models for Mycobacterium tuberculosis: A minireview.

    Science.gov (United States)

    Alnimr, Amani M

    2015-01-01

    Dormancy models for Mycobacterium tuberculosis play important roles in understanding various aspects of tuberculosis pathogenesis and in the testing of novel therapeutic regimens. By simulating the latent tuberculosis infection, in which the bacteria exist in a non-replicative state, the models demonstrate reduced susceptibility to antimycobacterial agents. This minireview outlines the models available for simulating latent tuberculosis both in vitro and in several animal species. Additionally, this minireview discusses the advantages and disadvantages of these models for investigating the bacterial subpopulations and susceptibilities to sterilization by various antituberculosis drugs.

  18. Dormancy models for Mycobacterium tuberculosis: A minireview

    Directory of Open Access Journals (Sweden)

    Amani M. Alnimr

    2015-09-01

    Full Text Available Dormancy models for Mycobacterium tuberculosis play important roles in understanding various aspects of tuberculosis pathogenesis and in the testing of novel therapeutic regimens. By simulating the latent tuberculosis infection, in which the bacteria exist in a non-replicative state, the models demonstrate reduced susceptibility to antimycobacterial agents. This minireview outlines the models available for simulating latent tuberculosis both in vitro and in several animal species. Additionally, this minireview discusses the advantages and disadvantages of these models for investigating the bacterial subpopulations and susceptibilities to sterilization by various antituberculosis drugs.

  19. Increased ABA sensitivity results in higher seed dormancy in soft white spring wheat cultivar ‘Zak’

    Science.gov (United States)

    Schramm, Elizabeth C.; Nelson, Sven K.; Kidwell, Kimberlee K.

    2014-01-01

    As a strategy to increase the seed dormancy of soft white wheat, mutants with increased sensitivity to the plant hormone abscisic acid (ABA) were identified in mutagenized grain of soft white spring wheat “Zak”. Lack of seed dormancy is correlated with increased susceptibility to preharvest sprouting in wheat, especially those cultivars with white kernels. ABA induces seed dormancy during embryo maturation and inhibits the germination of mature grain. Three mutant lines called Zak ERA8, Zak ERA19A, and Zak ERA19B (Zak ENHANCED RESPONSE to ABA) were recovered based on failure to germinate on 5 µM ABA. All three mutants resulted in increased ABA sensitivity over a wide range of concentrations such that a phenotype can be detected at very low ABA concentrations. Wheat loses sensitivity to ABA inhibition of germination with extended periods of dry after-ripening. All three mutants recovered required more time to after-ripen sufficiently to germinate in the absence of ABA and to lose sensitivity to 5 µM ABA. However, an increase in ABA sensitivity could be detected after as long as 3 years of after-ripening using high ABA concentrations. The Zak ERA8 line showed the strongest phenotype and segregated as a single semi-dominant mutation. This mutation resulted in no obvious decrease in yield and is a good candidate gene for breeding preharvest sprouting tolerance. PMID:23212773

  20. Functional genomics of seed dormancy in wheat: advances and prospects

    Science.gov (United States)

    Gao, Feng; Ayele, Belay T.

    2014-01-01

    Seed dormancy is a mechanism underlying the inability of viable seeds to germinate under optimal environmental conditions. To achieve rapid and uniform germination, wheat and other cereal crops have been selected against dormancy. As a result, most of the modern commercial cultivars have low level of seed dormancy and are susceptible to preharvest sprouting when wet and moist conditions occur prior to harvest. As it causes substantial loss in grain yield and quality, preharvest sprouting is an ever-present major constraint to the production of wheat. The significance of the problem emphasizes the need to incorporate an intermediate level of dormancy into elite wheat cultivars, and this requires detailed dissection of the mechanisms underlying the regulation of seed dormancy and preharvest sprouting. Seed dormancy research in wheat often involves after-ripening, a period of dry storage during which seeds lose dormancy, or comparative analysis of seeds derived from dormant and non-dormant cultivars. The increasing development in wheat genomic resources along with the application of transcriptomics, proteomics, and metabolomics approaches in studying wheat seed dormancy have extended our knowledge of the mechanisms acting at transcriptional and post-transcriptional levels. Recent progresses indicate that some of the molecular mechanisms are associated with hormonal pathways, epigenetic regulations, targeted oxidative modifications of seed mRNAs and proteins, redox regulation of seed protein thiols, and modulation of translational activities. Given that preharvest sprouting is closely associated with seed dormancy, these findings will significantly contribute to the designing of efficient strategies for breeding preharvest sprouting tolerant wheat. PMID:25309557

  1. Functional genomics of seed dormancy in wheat: advances and prospects

    Directory of Open Access Journals (Sweden)

    Feng eGao

    2014-09-01

    Full Text Available Seed dormancy is a mechanism underlying the inability of viable seeds to germinate under optimal environmental conditions. To achieve rapid and uniform germination, wheat and other cereal crops have been selected against dormancy. As a result, most of the modern commercial cultivars have low level of seed dormancy and are susceptible to preharvest sprouting when wet and moist conditions occur prior to harvest. As it causes substantial loss in grain yield and quality, preharvest sprouting is an ever-present major constraint to the production of wheat. The significance of the problem emphasizes the need to incorporate an intermediate level of dormancy into elite wheat cultivars, and this requires detailed dissection of the mechanisms underlying the regulation of seed dormancy and preharvest sprouting. Seed dormancy research in wheat often involves after-ripening, a period of dry storage during which seeds lose dormancy, or comparative analysis of seeds derived from dormant and non-dormant cultivars. The increasing development in wheat genomic resources along with the application of transcriptomics, proteomics and metabolomics approaches in studying wheat seed dormancy have extended our knowledge of the underlying mechanisms acting at transcriptional and post-transcriptional levels. Recent progresses indicate that some of the molecular mechanisms are associated with hormonal pathways, epigenetic regulations, targeted oxidative modifications of seed mRNAs and proteins, redox regulation of seed protein thiols and modulation of translational activities. Given that preharvest sprouting is closely associated with seed dormancy, these findings will significantly contribute to the designing of efficient strategies for breeding preharvest sprouting tolerant wheat.

  2. Embryo selection in IVF

    National Research Council Canada - National Science Library

    Mastenbroek, Sebastiaan; van der Veen, Fulco; Aflatoonian, Abbas; Shapiro, Bruce; Bossuyt, Patrick; Repping, Sjoerd

    2011-01-01

    To optimize success rates of IVF, selection of the most viable embryo(s) for transfer has always been essential, as embryos that are cryopreserved are thought to have a reduced chance of implanting after thawing...

  3. Transcriptional mechanisms associated with seed dormancy and dormancy loss in the gibberellin-insensitive sly1-2 mutant of Arabidopsis thaliana

    Science.gov (United States)

    While widespread transcriptome changes have been previously observed with seed dormancy loss, this study specifically characterized transcriptional changes associated with the increased seed dormancy and dormancy loss of the gibberellin (GA) hormone-insensitive sleepy1-2 (sly1-2) mutant. The SLY1 g...

  4. Expression of ABA Metabolism-Related Genes Suggests Similarities and Differences Between Seed Dormancy and Bud Dormancy of Peach (Prunus persica).

    Science.gov (United States)

    Wang, Dongling; Gao, Zhenzhen; Du, Peiyong; Xiao, Wei; Tan, Qiuping; Chen, Xiude; Li, Ling; Gao, Dongsheng

    2015-01-01

    Dormancy inhibits seed and bud growth of perennial plants until the environmental conditions are optimal for survival. Previous studies indicated that certain co-regulation pathways exist in seed and bud dormancy. In our study, we found that seed and bud dormancy are similar to some extent but show different reactions to chemical treatments that induce breaking of dormancy. Whether the abscisic acid (ABA) regulatory networks are similar in dormant peach seeds and buds is not well known; however, ABA is generally believed to play a critical role in seed and bud dormancy. In peach, some genes putatively involved in ABA synthesis and catabolism were identified and their expression patterns were studied to learn more about ABA homeostasis and the possible crosstalk between bud dormancy and seed dormancy mechanisms. The analysis demonstrated that two 9-cis-epoxycarotenoid dioxygenase-encoding genes seem to be key in regulating ABA biosynthesis to induce seed and bud dormancy. Three CYP707As play an overlapping role in controlling ABA inactivation, resulting in dormancy-release. In addition, Transcript analysis of ABA metabolism-related genes was much similar demonstrated that ABA pathways was similar in the regulation of vegetative and flower bud dormancy, whereas, expression patterns of ABA metabolism-related genes were different in seed dormancy showed that ABA pathway maybe different in regulating seed dormancy in peach.

  5. Water Recovery System Architecture and Operational Concepts to Accommodate Dormancy

    Science.gov (United States)

    Carter, Layne; Tabb, David; Anderson, Molly

    2017-01-01

    Future manned missions beyond low Earth orbit will include intermittent periods of extended dormancy. The mission requirement includes the capability for life support systems to support crew activity, followed by a dormant period of up to one year, and subsequently for the life support systems to come back online for additional crewed missions. NASA personnel are evaluating the architecture and operational concepts that will allow the Water Recovery System (WRS) to support such a mission. Dormancy could be a critical issue due to concerns with microbial growth or chemical degradation that might prevent water systems from operating properly when the crewed mission began. As such, it is critical that the water systems be designed to accommodate this dormant period. This paper identifies dormancy issues, concepts for updating the WRS architecture and operational concepts that will enable the WRS to support the dormancy requirement.

  6. Embryo Implantation: War in Times of Love.

    Science.gov (United States)

    Ashary, Nancy; Tiwari, Abhishek; Modi, Deepak

    2018-02-01

    Contrary to widespread belief, the implantation of an embryo for the initiation of pregnancy is like a battle, in that the embryo uses a variety of coercive tactics to force its acceptance by the endometrium. We propose that embryo implantation involves a three-step process: (1) identification of a receptive endometrium; (2) superimposition of a blastocyst-derived signature onto the receptive endometrium before implantation; and finally (3) breaching by the embryo and trophoblast invasion, culminating in decidualization and placentation. We review here the story that is beginning to emerge, focusing primarily on the cells that are in "combat" during this process. Copyright © 2018 Endocrine Society.

  7. Interchangeable effects of gibberellic acid and temperature on embryo growth, seed germination and epicotyl emergence in Ribes multiflorum ssp. sandalioticum (Grossulariaceae).

    Science.gov (United States)

    Mattana, E; Pritchard, H W; Porceddu, M; Stuppy, W H; Bacchetta, G

    2012-01-01

    Morphophysiological dormancy was investigated in seeds of Ribes multiflorum Kit ex Roem et Schult. ssp. sandalioticum Arrigoni, a rare mountain species endemic to Sardinia (Italy). There were no differences in imbibition rates between intact and scarified seeds, suggesting a lack of physical dormancy, while methylene blue solution (0.5%) highlighted a preferential pathway for solution entrance through the raphe. Embryos were small at seed dispersal, with an initial embryo:seed ratio (E:S) of ca. 0.2 (embryo length, ca. 0.5 mm), whereas the critical E:S ratio for germination was three times longer (ca. 0.6). Gibberellic acid (GA(3), 250 mg · l(-1)) and warm stratification (25 °C for 3 months) followed by low temperature (<15 °C) enhanced embryo growth rate (maximum of ca. 0.04 mm · day(-1) at 10 °C) and subsequent seed germination (radicle emergence; ca. 80% at 10 °C). Low germination occurred at warmer temperatures, and cold stratification (5 °C for 3 months) induced secondary dormancy. After radicle emergence, epicotyl emergence was delayed for ca. 2 months for seeds from three different populations. Mean time of epicotyl emergence was affected by GA(3) . Seeds of this species showed non-deep simple (root) - non-deep simple (epicotyl) morphophysiological dormancy, highlighting a high synchronisation with Mediterranean seasonality in all the investigated populations. © 2011 German Botanical Society and The Royal Botanical Society of the Netherlands.

  8. Deep simple epicotyl morphophysiological dormancy in seeds of two Viburnum species, with special reference to shoot growth and development inside the seed

    Science.gov (United States)

    Chien, Ching-Te; Chen, Shun-Ying; Tsai, Ching-Chu; Baskin, Jerry M.; Baskin, Carol C.; Kuo-Huang, Ling-Long

    2011-01-01

    Background and Aims In seeds with deep simple epicotyl morphophysiological dormancy, warm and cold stratification are required to break dormancy of the radicle and shoot, respectively. Although the shoot remains inside the seed all winter, little is known about its growth and morphological development prior to emergence in spring. The aims of the present study were to determine the temperature requirements for radicle and shoot emergence in seeds of Viburnum betulifolium and V. parvifolium and to monitor growth of the epicotyl, plumule and cotyledons in root-emerged seeds. Methods Fresh and pre-treated seeds of V. betulifolium and V. parvifolium were incubated under various temperature regimes and monitored for radicle and shoot emergence. Growth of the epicotyl and cotyledons at different stages was observed with dissecting and scanning electron microscopes. Key Results The optimum temperature for radicle emergence of seeds of both species, either kept continuously at a single regime or exposed to a sequence of regimes, was 20/10 °C. GA3 had no effect on radicle emergence. Cold stratification (5 °C) was required for shoot emergence. The shoot apical meristem in fresh seeds did not form a bulge until the embryo had grown to the critical length for radicle emergence. After radicle emergence, the epicotyl–plumule and cotyledons grew slowly at 5 and 20/10 °C, and the first pair of true leaves was initiated. However, the shoot emerged only from seeds that received cold stratification. Conclusions Seeds of V. betulifolium and V. parvifolium have deep simple epicotyl morphophysiological dormancy, C1bB (root)–C3 (epicotyl). Warm stratification was required to break the first part of physiological dormancy (PD), thereby allowing embryo growth and subsequently radicle emergence. Although cold stratification was not required for differentiation of the epicotyl–plumule, it was required to break the second part of PD, thereby allowing the shoot to emerge in spring

  9. Regulation of Dormancy in Barley by Blue Light and After-Ripening: Effects on Abscisic Acid and Gibberellin Metabolism1[W

    Science.gov (United States)

    Gubler, Frank; Hughes, Trijntje; Waterhouse, Peter; Jacobsen, John

    2008-01-01

    White light strongly promotes dormancy in freshly harvested cereal grains, whereas dark and after-ripening have the opposite effect. We have analyzed the interaction of light and after-ripening on abscisic acid (ABA) and gibberellin (GA) metabolism genes and dormancy in barley (Hordeum vulgare ‘Betzes’). Analysis of gene expression in imbibed barley grains shows that different ABA metabolism genes are targeted by white light and after-ripening. Of the genes examined, white light promotes the expression of an ABA biosynthetic gene, HvNCED1, in embryos. Consistent with this result, enzyme-linked immunosorbent assays show that dormant grains imbibed under white light have higher embryo ABA content than grains imbibed in the dark. After-ripening has no effect on expression of ABA biosynthesis genes, but promotes expression of an ABA catabolism gene (HvABA8′OH1), a GA biosynthetic gene (HvGA3ox2), and a GA catabolic gene (HvGA2ox3) following imbibition. Blue light mimics the effects of white light on germination, ABA levels, and expression of GA and ABA metabolism genes. Red and far-red light have no effect on germination, ABA levels, or HvNCED1. RNA interference experiments in transgenic barley plants support a role of HvABA8′OH1 in dormancy release. Reduced HvABA8′OH1 expression in transgenic HvABA8′OH1 RNAi grains results in higher levels of ABA and increased dormancy compared to nontransgenic grains. PMID:18408047

  10. Profiling the Proteome of Mycobacterium tuberculosis during Dormancy and Reactivation*

    Science.gov (United States)

    Gopinath, Vipin; Raghunandanan, Sajith; Gomez, Roshna Lawrence; Jose, Leny; Surendran, Arun; Ramachandran, Ranjit; Pushparajan, Akhil Raj; Mundayoor, Sathish; Jaleel, Abdul; Kumar, Ramakrishnan Ajay

    2015-01-01

    Tuberculosis, caused by Mycobacterium tuberculosis, still remains a major global health problem. The main obstacle in eradicating this disease is the ability of this pathogen to remain dormant in macrophages, and then reactivate later under immuno-compromised conditions. The physiology of hypoxic nonreplicating M. tuberculosis is well-studied using many in vitro dormancy models. However, the physiological changes that take place during the shift from dormancy to aerobic growth (reactivation) have rarely been subjected to a detailed investigation. In this study, we developed an in vitro reactivation system by re-aerating the virulent laboratory strain of M. tuberculosis that was made dormant employing Wayne's dormancy model, and compared the proteome profiles of dormant and reactivated bacteria using label-free one-dimensional LC/MS/MS analysis. The proteome of dormant bacteria was analyzed at nonreplicating persistent stage 1 (NRP1) and stage 2 (NRP2), whereas that of reactivated bacteria was analyzed at 6 and 24 h post re-aeration. Proteome of normoxially grown bacteria served as the reference. In total, 1871 proteins comprising 47% of the M. tuberculosis proteome were identified, and many of them were observed to be expressed differentially or uniquely during dormancy and reactivation. The number of proteins detected at different stages of dormancy (764 at NRP1, 691 at NRP2) and reactivation (768 at R6 and 983 at R24) was very low compared with that of the control (1663). The number of unique proteins identified during normoxia, NRP1, NRP2, R6, and R24 were 597, 66, 56, 73, and 94, respectively. We analyzed various biological functions during these conditions. Fluctuation in the relative quantities of proteins involved in energy metabolism during dormancy and reactivation was the most significant observation we made in this study. Proteins that are up-regulated or uniquely expressed during reactivation from dormancy offer to be attractive targets for therapeutic

  11. Abscisic acid (ABA) regulates grape bud dormancy, and dormancy release stimuli may act through modification of ABA metabolism

    Science.gov (United States)

    Zheng, Chuanlin; Halaly, Tamar; Acheampong, Atiako Kwame; Takebayashi, Yumiko; Jikumaru, Yusuke; Kamiya, Yuji; Or, Etti

    2015-01-01

    In warm-winter regions, induction of dormancy release by hydrogen cyanamide (HC) is mandatory for commercial table grape production. Induction of respiratory stress by HC leads to dormancy release via an uncharacterized biochemical cascade that could reveal the mechanism underlying this phenomenon. Previous studies proposed a central role for abscisic acid (ABA) in the repression of bud meristem activity, and suggested its removal as a critical step in the HC-induced cascade. In the current study, support for these assumptions was sought. The data show that ABA indeed inhibits dormancy release in grape (Vitis vinifera) buds and attenuates the advancing effect of HC. However, HC-dependent recovery was detected, and was affected by dormancy status. HC reduced VvXERICO and VvNCED transcript levels and induced levels of VvABA8’OH homologues. Regulation of these central players in ABA metabolism correlated with decreased ABA and increased ABA catabolite levels in HC-treated buds. Interestingly, an inhibitor of ethylene signalling attenuated these effects of HC on ABA metabolism. HC also modulated the expression of ABA signalling regulators, in a manner that supports a decreased ABA level and response. Taken together, the data support HC-induced removal of ABA-mediated repression via regulation of ABA metabolism and signalling. Expression profiling during the natural dormancy cycle revealed that at maximal dormancy, the HC-regulated VvNCED1 transcript level starts to drop. In parallel, levels of VvA8H-CYP707A4 transcript and ABA catabolites increase sharply. This may provide initial support for the involvement of ABA metabolism also in the execution of natural dormancy. PMID:25560179

  12. Dormancy contributes to the maintenance of microbial diversity.

    Science.gov (United States)

    Jones, Stuart E; Lennon, Jay T

    2010-03-30

    Dormancy is a bet-hedging strategy used by a variety of organisms to overcome unfavorable environmental conditions. By entering a reversible state of low metabolic activity, dormant individuals become members of a seed bank, which can determine community dynamics in future generations. Although microbiologists have documented dormancy in both clinical and natural settings, the importance of seed banks for the diversity and functioning of microbial communities remains untested. Here, we develop a theoretical model demonstrating that microbial communities are structured by environmental cues that trigger dormancy. A molecular survey of lake ecosystems revealed that dormancy plays a more important role in shaping bacterial communities than eukaryotic microbial communities. The proportion of dormant bacteria was relatively low in productive ecosystems but accounted for up to 40% of taxon richness in nutrient-poor systems. Our simulations and empirical data suggest that regional environmental cues and dormancy synchronize the composition of active communities across the landscape while decoupling active microbes from the total community at local scales. Furthermore, we observed that rare bacterial taxa were disproportionately active relative to common bacterial taxa, suggesting that microbial rank-abundance curves are more dynamic than previously considered. We propose that repeated transitions to and from the seed bank may help maintain the high levels of microbial biodiversity that are observed in nearly all ecosystems.

  13. Considering Intermittent Dormancy in an Advanced Life Support Systems Architecture

    Science.gov (United States)

    Sargusingh, Miriam J.; Perry, Jay L.

    2017-01-01

    Many advanced human space exploration missions being considered by the National Aeronautics and Space Administration (NASA) include concepts in which in-space systems cycle between inhabited and uninhabited states. Managing the life support system (LSS) may be particularly challenged during these periods of intermittent dormancy. A study to identify LSS management challenges and considerations relating to dormancy is described. The study seeks to define concepts suitable for addressing intermittent dormancy states and to evaluate whether the reference LSS architectures being considered by the Advanced Exploration Systems (AES) Life Support Systems Project (LSSP) are sufficient to support this operational state. The primary focus of the study is the mission concept considered to be the most challenging-a crewed Mars mission with an extensive surface stay. Results from this study are presented and discussed.

  14. Seed dormancy, seedling establishment and dynamics of the soil seed bank of Stipa bungeana (Poaceae) on the Loess Plateau of northwestern China.

    Science.gov (United States)

    Hu, Xiao Wen; Wu, Yan Pei; Ding, Xing Yu; Zhang, Rui; Wang, Yan Rong; Baskin, Jerry M; Baskin, Carol C

    2014-01-01

    Studying seed dormancy and its consequent effect can provide important information for vegetation restoration and management. The present study investigated seed dormancy, seedling emergence and seed survival in the soil seed bank of Stipa bungeana, a grass species used in restoration of degraded land on the Loess Plateau in northwest China. Dormancy of fresh seeds was determined by incubation of seeds over a range of temperatures in both light and dark. Seed germination was evaluated after mechanical removal of palea and lemma (hulls), chemical scarification and dry storage. Fresh and one-year-stored seeds were sown in the field, and seedling emergence was monitored weekly for 8 weeks. Furthermore, seeds were buried at different soil depths, and then retrieved every 1 or 2 months to determine seed dormancy and seed viability in the laboratory. Fresh seeds (caryopses enclosed by palea and lemma) had non-deep physiological dormancy. Removal of palea and lemma, chemical scarification, dry storage (afterripening), gibberellin (GA3) and potassium nitrate (KNO3) significantly improved germination. Dormancy was completely released by removal of the hulls, but seeds on which hulls were put back to their original position germinated to only 46%. Pretreatment of seeds with a 30% NaOH solution for 60 min increased germination from 25% to 82%. Speed of seedling emergence from fresh seeds was significantly lower than that of seeds stored for 1 year. However, final percentage of seedling emergence did not differ significantly for seeds sown at depths of 0 and 1 cm. Most fresh seeds of S. bungeana buried in the field in early July either had germinated or lost viability by September. All seeds buried at a depth of 5 cm had lost viability after 5 months, whereas 12% and 4% seeds of those sown on the soil surface were viable after 5 and 12 months, respectively.

  15. Seed dormancy, seedling establishment and dynamics of the soil seed bank of Stipa bungeana (Poaceae on the Loess Plateau of northwestern China.

    Directory of Open Access Journals (Sweden)

    Xiao Wen Hu

    Full Text Available Studying seed dormancy and its consequent effect can provide important information for vegetation restoration and management. The present study investigated seed dormancy, seedling emergence and seed survival in the soil seed bank of Stipa bungeana, a grass species used in restoration of degraded land on the Loess Plateau in northwest China. Dormancy of fresh seeds was determined by incubation of seeds over a range of temperatures in both light and dark. Seed germination was evaluated after mechanical removal of palea and lemma (hulls, chemical scarification and dry storage. Fresh and one-year-stored seeds were sown in the field, and seedling emergence was monitored weekly for 8 weeks. Furthermore, seeds were buried at different soil depths, and then retrieved every 1 or 2 months to determine seed dormancy and seed viability in the laboratory. Fresh seeds (caryopses enclosed by palea and lemma had non-deep physiological dormancy. Removal of palea and lemma, chemical scarification, dry storage (afterripening, gibberellin (GA3 and potassium nitrate (KNO3 significantly improved germination. Dormancy was completely released by removal of the hulls, but seeds on which hulls were put back to their original position germinated to only 46%. Pretreatment of seeds with a 30% NaOH solution for 60 min increased germination from 25% to 82%. Speed of seedling emergence from fresh seeds was significantly lower than that of seeds stored for 1 year. However, final percentage of seedling emergence did not differ significantly for seeds sown at depths of 0 and 1 cm. Most fresh seeds of S. bungeana buried in the field in early July either had germinated or lost viability by September. All seeds buried at a depth of 5 cm had lost viability after 5 months, whereas 12% and 4% seeds of those sown on the soil surface were viable after 5 and 12 months, respectively.

  16. Seed Germination Ecology of the Cold Desert Annual Isatis violascens (Brassicaceae): Two Levels of Physiological Dormancy and Role of the Pericarp.

    Science.gov (United States)

    Zhou, Yuan M; Lu, Juan J; Tan, Dun Y; Baskin, Carol C; Baskin, Jerry M

    2015-01-01

    The occurrence of various species of Brassicaceae with indehiscent fruits in the cold deserts of NW China suggests that there are adaptive advantages of this trait. We hypothesized that the pericarp of the single-seeded silicles of Isatis violascens restricts embryo expansion and thus prevents germination for 1 or more years. Thus, our aim was to investigate the role of the pericarp in seed dormancy and germination of this species. The effects of afterripening, treatment with gibberellic acid (GA3) and cold stratification on seed dormancy-break were tested using intact silicles and isolated seeds, and germination phenology was monitored in an experimental garden. The pericarp has a role in mechanically inhibiting germination of fresh seeds and promotes germination of nondormant seeds, but it does not facilitate formation of a persistent seed bank. Seeds in silicles in watered soil began to germinate earlier in autumn and germinated to higher percentages than isolated seeds. Sixty-two percent of seeds in the buried silicles germinated by the end of the first spring, and only 3% remained nongerminated and viable. Twenty to twenty-five percent of the seeds have nondeep physiological dormancy (PD) and 75-80% intermediate PD. Seeds with nondeep PD afterripen in summer and germinate inside the silicles in autumn if the soil is moist. Afterripening during summer significantly decreased the amount of cold stratification required to break intermediate PD. The presence of both nondeep and intermediate PD in the seed cohort may be a bet-hedging strategy.

  17. Seed Germination Ecology of the Cold Desert Annual Isatis violascens (Brassicaceae: Two Levels of Physiological Dormancy and Role of the Pericarp.

    Directory of Open Access Journals (Sweden)

    Yuan M Zhou

    Full Text Available The occurrence of various species of Brassicaceae with indehiscent fruits in the cold deserts of NW China suggests that there are adaptive advantages of this trait. We hypothesized that the pericarp of the single-seeded silicles of Isatis violascens restricts embryo expansion and thus prevents germination for 1 or more years. Thus, our aim was to investigate the role of the pericarp in seed dormancy and germination of this species. The effects of afterripening, treatment with gibberellic acid (GA3 and cold stratification on seed dormancy-break were tested using intact silicles and isolated seeds, and germination phenology was monitored in an experimental garden. The pericarp has a role in mechanically inhibiting germination of fresh seeds and promotes germination of nondormant seeds, but it does not facilitate formation of a persistent seed bank. Seeds in silicles in watered soil began to germinate earlier in autumn and germinated to higher percentages than isolated seeds. Sixty-two percent of seeds in the buried silicles germinated by the end of the first spring, and only 3% remained nongerminated and viable. Twenty to twenty-five percent of the seeds have nondeep physiological dormancy (PD and 75-80% intermediate PD. Seeds with nondeep PD afterripen in summer and germinate inside the silicles in autumn if the soil is moist. Afterripening during summer significantly decreased the amount of cold stratification required to break intermediate PD. The presence of both nondeep and intermediate PD in the seed cohort may be a bet-hedging strategy.

  18. The role of zeatin and gibberellic acid in breaking of the abscisic acid-induced dormancy in Triticale caryopses

    Directory of Open Access Journals (Sweden)

    Stanisław Weidner

    2014-01-01

    Full Text Available The investigations were conducted on the germinating embryos and the whole caryopses of Triticale. During preimbibition and 24 hours germination caryopses were treated with abscisic acid (ABA, which produced 63% inhibition of embryo growth. Gibberellin-A3 (GA3 reversed the ABA effect in 18%, while zeatin in 22%. The clear synergic reaction was observed (36% when both stimulators acted together. There was no significant effect of ABA, ABA and GA3, as well as ABA and zeatin on the synthesis of polyribosomal RNA in the initial period of germination of excised embryos. However, during 24 hours germination of whole caryopses ABA caused a twofold decrease in 3H-uridine incorporation into the total fraction of embryonic ribosomes. While the incorporation of 14C-aminoacid mixture into ribosomal proteins was even three-fold lower. Effect of GA3 and zeatin on breaking of the ABA-induced "dormancy" was studied. It was confirmed that the higher polyribosome contribution to the sum total of ribosomes the more intensive synthesis of ribosomal proteins. No higher 3H-uridine incorporation into polyribosomal fraction was observed. From the results it may be inferred that in the initial period of germination of Triticale caryopses regulation of protein biosynthesis occurs rather at the translation than transcription level.

  19. Triggering of final oocyte maturation with gonadotropin-releasing hormone agonist or human chorionic gonadotropin. Live birth after frozen-thawed embryo replacement cycles

    DEFF Research Database (Denmark)

    Griesinger, Georg; Kolibianakis, E M; Papanikolaou, E G

    2007-01-01

    . PATIENT(S): Patients under observation previously had been recruited into two concurrently performed, independent, randomized controlled trials (comparing hCG with GnRH-agonist for triggering final oocyte maturation in GnRH-antagonist multiple-dose protocols in normal responder patients) encompassing...

  20. Mining genes involved in the stratification of Paris Polyphylla seeds using high-throughput embryo Transcriptome sequencing

    Science.gov (United States)

    2013-01-01

    Background Paris polyphylla var. yunnanensis is an important medicinal plant. Seed dormancy is one of the main factors restricting artificial cultivation. The molecular mechanisms of seed dormancy remain unclear, and little genomic or transcriptome data are available for this plant. Results In this study, massive parallel pyrosequencing on the Roche 454-GS FLX Titanium platform was used to generate a substantial sequence dataset for the P. polyphylla embryo. 369,496 high quality reads were obtained, ranging from 50 to 1146 bp, with a mean of 219 bp. These reads were assembled into 47,768 unigenes, which included 16,069 contigs and 31,699 singletons. Using BLASTX searches of public databases, 15,757 (32.3%) unique transcripts were identified. Gene Ontology and Cluster of Orthologous Groups of proteins annotations revealed that these transcripts were broadly representative of the P. polyphylla embryo transcriptome. The Kyoto Encyclopedia of Genes and Genomes assigned 5961 of the unique sequences to specific metabolic pathways. Relative expression levels analysis showed that eleven phytohormone-related genes and five other genes have different expression patterns in the embryo and endosperm in the seed stratification process. Conclusions Gene annotation and quantitative RT-PCR expression analysis identified 464 transcripts that may be involved in phytohormone catabolism and biosynthesis, hormone signal, seed dormancy, seed maturation, cell wall growth and circadian rhythms. In particular, the relative expression analysis of sixteen genes (CYP707A, NCED, GA20ox2, GA20ox3, ABI2, PP2C, ARP3, ARP7, IAAH, IAAS, BRRK, DRM, ELF1, ELF2, SFR6, and SUS) in embryo and endosperm and at two temperatures indicated that these related genes may be candidates for clarifying the molecular basis of seed dormancy in P. polyphlla var. yunnanensis. PMID:23718911

  1. Overcoming dormancy and enhancing germination of Sphaeralcea munroana seeds

    Science.gov (United States)

    Olga A. Kildisheva; R. Kasten Dumroese; Anthony S. Davis

    2011-01-01

    The results of a series of experiments involving a variety of dormancy-breaking treatments indicate that Munro's globemallow [Sphaeralcea munroana (Douglas) Spach] seeds are physically dormant, possess a cap-like structure in the occlusion of the water gap, which inhibits imbibition, and can be artificially dislodged through boiling water scarification. The...

  2. Association studies of dormancy and cooking quality traits in direct ...

    Indian Academy of Sciences (India)

    Ph.D. thesis. University of Ibadan,. Nigeria. Rathi S., Baruah A. R., Chowdhury R. K. and Sarma R. N. 2011. QTL Analysis of seed dormancy in indigenous rice of Assam,. India. Cereal Res. Commun. 39, 137–146. Remington D. L., Thornsberry J. M., Matsuoka Y., Wilson L. M.,. Whitt S. R., Doebley J. et al. 2001 Structure of ...

  3. Metastasis Dormancy in Estrogen Receptor-Positive Breast Cancer

    Science.gov (United States)

    Zhang, Xiang H.-F.; Giuliano, Mario; Trivedi, Meghana V.; Schiff, Rachel; Kent Osborne, C.

    2013-01-01

    About 20-40% of breast cancer patients eventually develop recurrences in distant organs, which are often not detected until years to decades after the primary tumor diagnosis. This phenomenon is especially pronounced in ER+ breast cancer, suggesting that ER+ cancer cells may stay dormant for a protracted period of time, despite adjuvant therapies. Multiple mechanisms have been proposed to explain how cancer cells survive and remain in dormancy , and how they become reactivated and exit dormancy. These mechanisms include angiogenic switch, immunosurveillance, and interaction with extracellular matrix (ECM) and stromal cells. How to eradicate or suppress these dormant cancer cells remains a major clinical issue because of the lack of knowledge about the biological and clinical nature of these cells. Herein, we review the clinical manifestation of metastasis dormancy in ER+ tumors, the current biological insights of tumor dormancy obtained from various experimental models, and the clinical challenges to predict, detect, and treat dormant metastases. We also discuss future research directions toward a better understanding of the biological mechanisms and clinical management of ER+ dormant metastasis. PMID:24298069

  4. Association studies of dormancy and cooking quality traits in direct ...

    Indian Academy of Sciences (India)

    Association analysis was applied to a panel of accessions of Assam rice (indica) using 98 SSR markers for dormancy-related traits and cooking quality. Analysis of population structure revealed 10 subgroups in the population. The mean r 2 and D ′ value for all intrachromosomal loci pairs was 0.24 and 0.51, respectively.

  5. effect of hydrogen peroxide and thiourea on dormancy breaking of ...

    African Journals Online (AJOL)

    ACSS

    Les composés phénoliques des végétaux. Un exemple de métabolites secondaires d'importance économique. Lausanne : Presses polytechniques et universitaires romandes (Collection : Biologie). Mani, F. 2012. Contrôle de la dormance de microtubercules et de tubercules de pomme de terre (Solanum tuberosum L.).

  6. Evaluation of different methods to overcome in vitro seed dormancy ...

    African Journals Online (AJOL)

    SAM

    2014-09-03

    Sep 3, 2014 ... Seeds from yellow passion fruit (Passiflora edulis Sims) present dormancy imposed by the seed-coat. The present study ... seeds in absolute ethanol for 5, 10 and 25 min; physical scarification with wood sandpaper (no. 125); and total .... and seed coat fracture or fermenting seed with cytase. (Morley-Bunker ...

  7. Carbohydrate metabolism during potato tuber dormancy and sprouting

    NARCIS (Netherlands)

    Claassens, M.M.J.

    2002-01-01

    Potato tuber dormancy is part of the vegetative life cycle of potato. It refers to a period, in which no growth is occurring, although the tuber is stored under conditions that are favourable for growth. Factors in the tuber are responsible for this growth arrest; soon

  8. Breaking seed dormancy in oil rose ( Rosa damascena Mill.) by ...

    African Journals Online (AJOL)

    This study was carried out to determine the effects of microbial inoculation in breaking seed dormancy and on the germination of Rosa damascena Mill. Seeds of R. damascena Mill. are the most used scented rose species in rose oil production. The most important production centers around the world are Turkey and ...

  9. Perspectives of biotechnologies based on dormancy phenomenon for space researches

    Science.gov (United States)

    Alekseev, V.; Sychev, V.; Layus, D.; Levinsky, M.; Novikova, N.; Zakhodnova, T.

    Long term space missions will require a renewable source of food and an efficient method to recycle oxygen Plants especially aquatic micro algae provide an obvious solution to these problems However long duration plant growth and reproduction in space that is necessary for transportation of a control ecological life support system CELSS from Earth to other planets are problematic The introduction of heterotrophs in space CELSS is a more formidable problem as the absence of gravity creates additional difficulties for their life Dormancy phenomenon protected a great many animals and plants in harsh environmental conditions within a special resting phases of life cycle lasting from months up to hundred years This phenomenon can be quite perspective as a tool to overcome difficulties with CELSS transportation in space missions Cryptobiotic stages of microbes fungi unicellular algae and protists can survive in open space conditions that is important for interplanetary quarantine and biological security inside spacecraft Searching for life outside the Earth at such planet like Mars with extremely variable environment should be oriented on dormancy as crucial phases of a life cycle in such organisms Five major research programs aimed on study dormancy phenomenon for exobiology purposes and creation of new biotechnologies are discussed List of species candidate components of CELSS with dormancy in their life cycle used in space experiments at the Russian segment of International Space Station now includes 26 species from bacteria to fish The

  10. Breaking Dormancy In Gmelina arborea Roxb. Through Treatment ...

    African Journals Online (AJOL)

    Seeds of Gmelina arborea Roxb. were subjected to different treatment [chemical scarification with concentrated sulphuric acid (H2S04), potasium nitrate (KNO3), potasium nitrite (KNO2) and alternating temperature regimes] to ascertain the best treatment for terminating dormancy in the seeds. Initial viability and germination ...

  11. Physiological mechanisms for potato dormancy release and sprouting

    African Journals Online (AJOL)

    Cytokinins and gibberellins are required for bud breaking and sprout growth, respectively. The auxin seems to play a role in vascular development. Thus, tuber dormancy and sprouting can be controlled in potato by manipulation of Reactive Oxygen Species (ROS), especially H2O2 metabolism via the inhibition of catalase ...

  12. Effect of hydrogen peroxide and thiourea on dormancy breaking of ...

    African Journals Online (AJOL)

    Potato (Solanum tuberosum L.) microtubers or field-grown tubers have a dormant apical bud (also called tuber dormancy). They do not readily sprout even if environmental conditions are favorable, including optimum temperature and humidity. The objective of this study was to evaluate the involvement of hydrogen peroxide ...

  13. Effect of saturation on seed dormancy and germination of the ...

    African Journals Online (AJOL)

    laddiya

    2012-01-26

    Jan 26, 2012 ... the lixiviated solutions, their germination, but not their growth and development, was inhibited. Taken together, this work provides valuable insight into the regulation of seed dormancy and germination rate in L. chinensis, which may in turn have implications for improved propagation. Key words: Saturation ...

  14. Summer dormancy in edible dormice ( Glis glis) without energetic constraints

    Science.gov (United States)

    Bieber, Claudia; Ruf, Thomas

    2009-01-01

    Average longevity in free-living edible dormice ( Glis glis) can reach 9 years, which is extremely high for a small rodent. This remarkable life span has been related to a peculiar life history strategy and the rarity of reproductive bouts in these seed eaters. Most females (96%) reproduce only once or twice in their lifetime, predominantly during years of mast seeding of, e.g., beech, but entire populations can skip reproduction in years of low seed availability. Surprisingly, in non-reproductive years, large fractions of populations apparently vanished and were never captured above ground. Therefore, we determined the duration of above-ground activity, and body temperature profiles in a subset of animals, of dormice under semi-natural conditions in outdoor enclosures. We found that non-reproductive dormice returned to dormancy in underground burrows throughout summer after active seasons as short as 10 months per year in dormancy. This exceeds dormancy duration of any other mammal under natural conditions. Summer dormancy was not caused by energy constraints, as it occurred in animals in good condition, fed ad libitum and without climatic stress. We suggest that almost year-round torpor has evolved as a strategy to escape birds of prey, the major predators of this arboreal mammal. This unique predator-avoidance strategy clearly helps in explaining the unusually high longevity of dormice.

  15. Expression of seed dormancy in grain sorghum lines with contrasting pre-harvest sprouting behavior involves differential regulation of gibberellin metabolism genes.

    Science.gov (United States)

    Rodríguez, María Verónica; Mendiondo, Guillermina Mónica; Cantoro, Renata; Auge, Gabriela Alejandra; Luna, Virginia; Masciarelli, Oscar; Benech-Arnold, Roberto Luis

    2012-01-01

    Grain sorghum [Sorghum bicolor (L) moench] exhibits intraspecific variability for the rate of dormancy release and pre-harvest sprouting behavior. Two inbred lines with contrasting sprouting response were compared: IS9530 (resistant) and RedlandB2 (susceptible). Precocious dormancy release in RedlandB2 is related to an early loss of embryo sensitivity to ABA and higher levels of gibberellins in imbibed grains as compared with IS9530. With the aim of identifying potential regulatory sites for gibberellin metabolism involved in the expression of dormancy in immature grains of both lines, we carried out a time course analysis of transcript levels of putative gibberellin metabolism genes and hormone content (GA(1), GA(4), GA(8) and GA(34)). A lower embryonic GA(4) level in dormant IS9530 was related to a sharp and transient induction of two SbGA2-oxidase (inactivation) genes. In contrast, these genes were not induced in less dormant RedlandB2, while expression of two SbGA20-oxidase (synthesis) genes increased together with active GA(4) levels before radicle protrusion. Embryonic levels of GA(4) and its catabolite GA(34) correlated negatively. Thus, in addition to the process of gibberellin synthesis, inactivation is also important in regulating GA(4) levels in immature grains. A negative regulation by gibberellins was observed for SbGA20ox2, SbGA2ox1 and SbGA2ox3 and also for SbGID1 encoding a gibberellin receptor. We propose that the coordinated regulation at the transcriptional level of several gibberellin metabolism genes identified in this work affects the balance between gibberellin synthesis and inactivation processes, controlling active GA(4) levels during the expression of dormancy in maturing sorghum grains.

  16. The joint evolution of dispersal and dormancy in a metapopulation with local extinctions and kin competition.

    Science.gov (United States)

    Vitalis, Renaud; Rousset, François; Kobayashi, Yutaka; Olivieri, Isabelle; Gandon, Sylvain

    2013-06-01

    Dispersal and dormancy are two strategies that allow recolonization of empty patches and escape from kin competition. Because they presumably respond to similar evolutionary forces, it is tempting to consider that these strategies may substitute for each other. Yet in order to predict the outcome of the evolution of dispersal and dormancy, and to characterize the emerging covariation between both traits, it is necessary to consider models where dispersal and dormancy evolve jointly. Here, we analyze the evolution of dispersal and dormancy as a function of direct fitness costs, environmental variation, and competition among relatives. We consider two scenarios depending on whether the rates of dormancy for philopatric and dispersed individuals are constrained to be the same (unconditional dormancy) or allowed to be different (conditional dormancy). We show that only philopatric individuals should enter dormancy, at a rate increasing with increasing rates of local extinction and decreasing population sizes. When dormancy and dispersal evolve jointly, we observe a wide range of evolutionary outcomes. In particular, we find that the pattern of covariation between the evolutionarily stable rates of dispersal and dormancy is molded by the rate of extinction and the local population size. © 2013 The Author(s). Evolution © 2013 The Society for the Study of Evolution.

  17. Dormancy Signatures and Metastasis in Estrogen Receptor Positive and Negative Breast Cancer

    Science.gov (United States)

    Kim, Ryung S.; Avivar-Valderas, Alvaro; Estrada, Yeriel; Bragado, Paloma; Sosa, Maria Soledad; Aguirre-Ghiso, Julio A.; Segall, Jeffrey E.

    2012-01-01

    Breast cancers can recur after removal of the primary tumor and treatment to eliminate remaining tumor cells. Recurrence may occur after long periods of time during which there are no clinical symptoms. Tumor cell dormancy may explain these prolonged periods of asymptomatic residual disease and treatment resistance. We generated a dormancy gene signature from published experimental models and applied it to both breast cancer cell line expression data as well as four published clinical studies of primary breast cancers. We found that estrogen receptor (ER) positive breast cell lines and primary tumors have significantly higher dormancy signature scores (P<0.0000001) than ER- cell lines and tumors. In addition, a stratified analysis combining all ER+ tumors in four studies indicated 2.1 times higher hazard of recurrence among patients whose tumors had low dormancy scores (LDS) compared to those whose tumors had high dormancy scores (HDS) (p<0.000005). The trend was shown in all four individual studies. Suppression of two dormancy genes, BHLHE41 and NR2F1, resulted in increased in vivo growth of ER positive MCF7 cells. The patient data analysis suggests that disseminated ER positive tumor cells carrying a dormancy signature are more likely to undergo prolonged dormancy before resuming metastatic growth. Furthermore, genes identified with this approach might provide insight into the mechanisms of dormancy onset and maintenance as well as dormancy models using human breast cancer cell lines. PMID:22530051

  18. Dormancy signatures and metastasis in estrogen receptor positive and negative breast cancer.

    Directory of Open Access Journals (Sweden)

    Ryung S Kim

    Full Text Available Breast cancers can recur after removal of the primary tumor and treatment to eliminate remaining tumor cells. Recurrence may occur after long periods of time during which there are no clinical symptoms. Tumor cell dormancy may explain these prolonged periods of asymptomatic residual disease and treatment resistance. We generated a dormancy gene signature from published experimental models and applied it to both breast cancer cell line expression data as well as four published clinical studies of primary breast cancers. We found that estrogen receptor (ER positive breast cell lines and primary tumors have significantly higher dormancy signature scores (P<0.0000001 than ER- cell lines and tumors. In addition, a stratified analysis combining all ER+ tumors in four studies indicated 2.1 times higher hazard of recurrence among patients whose tumors had low dormancy scores (LDS compared to those whose tumors had high dormancy scores (HDS (p<0.000005. The trend was shown in all four individual studies. Suppression of two dormancy genes, BHLHE41 and NR2F1, resulted in increased in vivo growth of ER positive MCF7 cells. The patient data analysis suggests that disseminated ER positive tumor cells carrying a dormancy signature are more likely to undergo prolonged dormancy before resuming metastatic growth. Furthermore, genes identified with this approach might provide insight into the mechanisms of dormancy onset and maintenance as well as dormancy models using human breast cancer cell lines.

  19. Necessity of high temperature for the dormancy release of Narcissus tazetta var. chinensis.

    Science.gov (United States)

    Li, Xiao-Fang; Shao, Xing-Hua; Deng, Xin-Jie; Wang, Yang; Zhang, Xue-Ping; Jia, Lin-Yan; Xu, Jing; Zhang, Dong-Mei; Sun, Yue; Xu, Ling

    2012-09-15

    Winter dormancy has been extensively studied in many plants, while much less information is available for summer dormancy. Narcissus tazetta var. chinensis is characterized by a prolonged period of summer dormancy during the annual cycle. In the present study, we characterized the nature of dormancy in the controlled growth conditions and investigated the effects of temperature and ethylene on dormancy release. Cessation of growth and senescence of aerial tissues occurred even under conditions favorable for growth, suggesting an endo-dormancy process. Bulbs failed to sprout when they were exposed to low storage temperatures, while high temperature treatment preceding low storage temperatures, or heating interruption during low storage temperatures, could make bulbs sprouting. These results suggest that high temperatures are necessary for endo-dormancy release. Ethylene application during a later storage stage showed an obvious accelerative effect on bulb sprouting, whereas ethylene application during the middle stage had no effect on sprouting. The biological progression of dormancy was further studied through cytological and physiological analyses. Under natural conditions, the ethylene level was reduced to trace amounts with the transition and progression of dormancy. A transient peak in ethylene release was found when the plugged plasmodesmata (PD) began to re-open and flower initiation began. The most common PD possessed electron-dense deposits in endo-dormancy. These data indicate that endo-dormancy ends when flower initiation begins and ethylene peak occurs. Ethylene application had no effect on dormancy release, while it hastened sprouting only after the release from endo-dormancy by high temperature. Copyright © 2012 Elsevier GmbH. All rights reserved.

  20. Phylogeny of seed dormancy in Convolvulaceae, subfamily Convolvuloideae (Solanales).

    Science.gov (United States)

    Jayasuriya, K M G Gehan; Baskin, Jerry M; Geneve, Robert L; Baskin, Carol C

    2009-01-01

    The water gap is an important morphoanatomical structure in seeds with physical dormancy (PY). It is an environmental signal detector for dormancy break and the route of water into the non-dormant seed. The Convolvulaceae, which consists of subfamilies Convolvuloideae (11 tribes) and Humbertoideae (one tribe, monotypic Humberteae), is the only family in the asterid clade known to produce seeds with PY. The primary aim of this study was to compare the morphoanatomical characteristics of the water gap in seeds of species in the 11 tribes of the Convolvuloideae and to use this information, and that on seed dormancy and storage behaviour, to construct a phylogenetic tree of seed dormancy for the subfamily. Scanning electron microscopy (SEM) was used to define morphological changes in the hilum area during dormancy break; hand and vibratome sections were taken to describe the anatomy of the water gap, hilum and seed coat; and dye tracking was used to identify the initial route of water entry into the non-dormant seed. Results were compared with a recent cladogram of the family. Species in nine tribes have (a) layer(s) of palisade cells in the seed coat, a water gap and orthodox storage behaviour. Erycibe (Erycibeae) and Maripa (Maripeae) do not have a palisade layer in the seed coat or a water gap, and are recalcitrant. The hilar fissure is the water gap in relatively basal Cuscuteae, and bulges adjacent to the micropyle serve as the water gap in the Convolvuloideae, Dicranostyloideae (except Maripeae) and the Cardiochlamyeae clades. Seeds from the Convolvuloideae have morphologically prominent bulges demarcated by cell shape in the sclereid layer, whereas the Dicranostyloideae and Cardiochlamyeae have non-prominent bulges demarcated by the number of sub-cell layers. The anatomy and morphology of the hilar pad follow the same pattern. PY in the subfamily Convolvuloideae probably evolved in the aseasonal tropics from an ancestor with recalcitrant non-dormant seeds, and

  1. Live virus-free or die: coupling of antivirus immunity and programmed suicide or dormancy in prokaryotes

    Science.gov (United States)

    2012-01-01

    Background The virus-host arms race is a major theater for evolutionary innovation. Archaea and bacteria have evolved diverse, elaborate antivirus defense systems that function on two general principles: i) immune systems that discriminate self DNA from nonself DNA and specifically destroy the foreign, in particular viral, genomes, whereas the host genome is protected, or ii) programmed cell suicide or dormancy induced by infection. Presentation of the hypothesis Almost all genomic loci encoding immunity systems such as CRISPR-Cas, restriction-modification and DNA phosphorothioation also encompass suicide genes, in particular those encoding known and predicted toxin nucleases, which do not appear to be directly involved in immunity. In contrast, the immunity systems do not appear to encode antitoxins found in typical toxin-antitoxin systems. This raises the possibility that components of the immunity system themselves act as reversible inhibitors of the associated toxin proteins or domains as has been demonstrated for the Escherichia coli anticodon nuclease PrrC that interacts with the PrrI restriction-modification system. We hypothesize that coupling of diverse immunity and suicide/dormancy systems in prokaryotes evolved under selective pressure to provide robustness to the antivirus response. We further propose that the involvement of suicide/dormancy systems in the coupled antivirus response could take two distinct forms: 1) induction of a dormancy-like state in the infected cell to ‘buy time’ for activation of adaptive immunity; 2) suicide or dormancy as the final recourse to prevent viral spread triggered by the failure of immunity. Testing the hypothesis This hypothesis entails many experimentally testable predictions. Specifically, we predict that Cas2 protein present in all cas operons is a mRNA-cleaving nuclease (interferase) that might be activated at an early stage of virus infection to enable incorporation of virus-specific spacers into the CRISPR

  2. Live virus-free or die: coupling of antivirus immunity and programmed suicide or dormancy in prokaryotes

    Directory of Open Access Journals (Sweden)

    Makarova Kira S

    2012-11-01

    Full Text Available Abstract Background The virus-host arms race is a major theater for evolutionary innovation. Archaea and bacteria have evolved diverse, elaborate antivirus defense systems that function on two general principles: i immune systems that discriminate self DNA from nonself DNA and specifically destroy the foreign, in particular viral, genomes, whereas the host genome is protected, or ii programmed cell suicide or dormancy induced by infection. Presentation of the hypothesis Almost all genomic loci encoding immunity systems such as CRISPR-Cas, restriction-modification and DNA phosphorothioation also encompass suicide genes, in particular those encoding known and predicted toxin nucleases, which do not appear to be directly involved in immunity. In contrast, the immunity systems do not appear to encode antitoxins found in typical toxin-antitoxin systems. This raises the possibility that components of the immunity system themselves act as reversible inhibitors of the associated toxin proteins or domains as has been demonstrated for the Escherichia coli anticodon nuclease PrrC that interacts with the PrrI restriction-modification system. We hypothesize that coupling of diverse immunity and suicide/dormancy systems in prokaryotes evolved under selective pressure to provide robustness to the antivirus response. We further propose that the involvement of suicide/dormancy systems in the coupled antivirus response could take two distinct forms: 1 induction of a dormancy-like state in the infected cell to ‘buy time’ for activation of adaptive immunity; 2 suicide or dormancy as the final recourse to prevent viral spread triggered by the failure of immunity. Testing the hypothesis This hypothesis entails many experimentally testable predictions. Specifically, we predict that Cas2 protein present in all cas operons is a mRNA-cleaving nuclease (interferase that might be activated at an early stage of virus infection to enable incorporation of virus

  3. Regulation of abscisic acid metabolism in relation to the dormancy and germination of cereal grains

    OpenAIRE

    Justyna Fidler; Edyta Zdunek-Zastocka; Wiesław Bielawski

    2015-01-01

    Seed dormancy is of particular importance in the cultivation of cereals, as it directly affects the quality of crop yield. If the dormancy period is too short, this may lead to pre-harvest sprouting, whereas a dormancy period that is too long may cause uneven germination; both of these scenarios are associated with economic losses. Most enzymes engaged in the metabolism of abscisic acid (ABA) have been identified, and significant progress has been made in understanding the role of this phytoh...

  4. Dormancy and activation of human oocytes from primordial and primary follicles: molecular clues to oocyte regulation

    DEFF Research Database (Denmark)

    Ernst, Emil Hagen; Grøndahl, Marie Louise; Grund, Simon

    2017-01-01

    as putative mediators of oocyte dormancy and activation. WHAT IS KNOWN ALREADY: Cellular signaling pathways including PI3K/AKT and AKT/mTOR as well as TGF-β and IGF signaling are known to regulate the primordial-to-primary transition in mammalian follicle development. STUDY DESIGN, SIZE, DURATION: We...... isolated by Laser Capture Microdissection, and submitted to the HiSeq Illumina platform. Data mapping, quality control, filtering and expression analysis were performed using Tophat (2.0.4), Cufflinks (2.0.2), BWA (0.6.2) and software R. Modeling of complex biological systems was performed using the IPA......® software. Finally, qPCR and immunohistochemistry were employed to explore expression and localization of selected genes and products in human ovarian tissue. MAIN RESULTS AND THE ROLE OF CHANCE: We found 223 and 268 genes down-regulated and up-regulated, respectively, in the oocytes during the human...

  5. Dormancy break in Pithecellobium dulce (Roxb. Benth. seeds

    Directory of Open Access Journals (Sweden)

    Francisco Elder Carlos Bezerra Pereira

    2015-02-01

    Full Text Available This research aimed to evaluate different methods for breaking dormancy in seeds of Pithecellobium dulce (Roxb. Benth., arboreal species of multiple use in the semiarid region of Northeast Brazil. The treatments were: control – intact seeds (T1; immersion in water until it reaches 80 °C (T2, and 100 °C (T3, concentrated sulfuric acid for five minutes (T4, 10 minutes (T5 , and 15 minutes (T6, mechanical scarification with sandpaper number 80 (T7, mechanical scarification with sandpaper number 80 + immersion in water for six hours (T8, and for 12 hours (T9, soaking in water for 24 hours (T10, and for 48 hours (T11. The characteristics evaluated were such: emergency, mean emergency time, shoot length, root length, number of leaves, leaf area and total dry matter. The best method for breaking dormancy of seeds of Pithecellobium dulce (Roxb. Benth. is mechanical scarification with sandpaper number 80.

  6. The PHD-containing protein EARLY BOLTING IN SHORT DAYS regulates seed dormancy in Arabidopsis.

    Science.gov (United States)

    Narro-Diego, Laura; López-González, Leticia; Jarillo, Jose A; Piñeiro, Manuel

    2017-10-01

    The Arabidopsis protein EARLY BOLTING IN SHORT DAYS (EBS), a plant-specific transcriptional regulator, is involved in the control of flowering time by repressing the floral integrator FT. The EBS protein binds the H3K4me3 histone mark and interacts with histone deacetylases to modulate gene expression. Here, we show that EBS also participates in the regulation of seed dormancy. ebs mutations cause a reduction in seed dormancy, and the concurrent loss of function of the EBS homologue SHORT LIFE (SHL) enhances this dormancy alteration. Transcriptomic analyses in ebs mutant seeds uncovered the misregulation of several regulators of seed dormancy including the MADS box gene AGAMOUS-LIKE67 (AGL67). AGL67 interacts genetically with EBS in seed dormancy regulation, indicating that both loci act in the same pathway. Interestingly, EBS functions independently of the master regulator gene of dormancy DELAY OF GERMINATION 1 (DOG1) and other genes encoding chromatin remodelling factors involved in the control of seed dormancy. Altogether, these data show that EBS is a central repressor of germination during seed dormancy and that SHL acts redundantly with EBS in the control of this developmental process. Our observations suggest that a tightly regulated crosstalk among histone modifications is necessary for a proper control of seed dormancy. © 2017 John Wiley & Sons Ltd.

  7. Maternal environment affects the genetic basis of seed dormancy in Arabidopsis thaliana.

    Science.gov (United States)

    Postma, Froukje M; Ågren, Jon

    2015-02-01

    The genetic basis of seed dormancy, a key life history trait important for adaptive evolution in plant populations, has yet been studied only using seeds produced under controlled conditions in greenhouse environments. However, dormancy is strongly affected by maternal environmental conditions, and interactions between seed genotype and maternal environment have been reported. Consequently, the genetic basis of dormancy of seeds produced under natural field conditions remains unclear. We examined the effect of maternal environment on the genetic architecture of seed dormancy using a recombinant inbred line (RIL) population derived from a cross between two locally adapted populations of Arabidopsis thaliana from Italy and Sweden. We mapped quantitative trait loci (QTL) for dormancy of seeds produced in the greenhouse and at the native field sites of the parental genotypes. The Italian genotype produced seeds with stronger dormancy at fruit maturation than did the Swedish genotype in all three environments, and the maternal field environments induced higher dormancy levels compared to the greenhouse environment in both genotypes. Across the three maternal environments, a total of nine dormancy QTL were detected, three of which were only detected among seeds matured in the field, and six of which showed significant QTL × maternal environment interactions. One QTL had a large effect on dormancy across all three environments and colocalized with the candidate gene DOG1. Our results demonstrate the importance of studying the genetic basis of putatively adaptive traits under relevant conditions. © 2015 John Wiley & Sons Ltd.

  8. A combined physical and physiological dormancy controls seasonal seedling emergence of Geranium robertianum.

    Science.gov (United States)

    Vandelook, F; Van Assche, J A

    2010-09-01

    Temperate forest herbs with seeds exhibiting both a physical and a physiological dormancy mechanism are rare, and knowledge on the factors regulating germination of these species is fragmentary. The biennial Geranium robertianum L. grows mainly in temperate woodlands, but can also be found in exposed habitats. Seedlings of G. robertianum are known to emerge from spring until autumn, but little is known about the environmental factors regulating germination. In this study, phenology of seedling emergence and of physical dormancy loss was examined for seeds buried at shaded or sunny exposed locations. The role of temperature in regulating dormancy and germination was analysed by incubating seeds in temperature sequences simulating temperatures that seeds experience in nature. The results indicate that most seeds of G. robertianum buried in sunny conditions germinate immediately after physical dormancy loss in summer. Seeds buried in shaded conditions also lose physical dormancy mainly during summer, but remain physiologically dormant and do not germinate until late winter or early spring. Besides physical dormancy, seeds of G. robertianum also initially have a high level of physiological dormancy, which is reduced during dry storage. Physiological dormancy is reduced through chilling in winter, thus enabling the seeds to germinate at low temperatures. We conclude that a complex combination of physical and physiological dormancy ensures that G. robertianum seeds germinate in summer at exposed sites and in early spring at shaded sites.

  9. Human granuloma in vitro model, for TB dormancy and resuscitation.

    Directory of Open Access Journals (Sweden)

    Nidhi Kapoor

    Full Text Available Tuberculosis (TB is responsible for death of nearly two million people in the world annually. Upon infection, Mycobacterium tuberculosis (Mtb causes formation of granuloma where the pathogen goes into dormant state and can live for decades before resuscitation to develop active disease when the immune system of the host is weakened and/or suppressed. In an attempt to better understand host-pathogen interactions, several groups have been developing in vitro models of human tuberculosis granuloma. However, to date, an in vitro granuloma model in which Mtb goes into dormancy and can subsequently resuscitate under conditions that mimic weakening of the immune system has not been reported. We describe the development of a biomimetic in vitro model of human tuberculosis granuloma using human primary leukocytes, in which the Mtb exhibited characteristics of dormant mycobacteria as demonstrated by (1 loss of acid-fastness, (2 accumulation of lipid bodies (3 development of rifampicin-tolerance and (4 gene expression changes. Further, when these micro granulomas were treated with immunosuppressant anti-tumor necrosis factor-alpha monoclonal antibodies (anti-TNFα mAbs, resuscitation of Mtb was observed as has been found in humans. In this human in vitro granuloma model triacylglycerol synthase 1deletion mutant (Δtgs1 with impaired ability to accumulate triacylglycerides (TG, but not the complemented mutant, could not go into dormancy. Deletion mutant of lipY, with compromised ability to mobilize the stored TG, but not the complemented mutant, was unable to come out of dormancy upon treatment with anti-TNFα mAbs. In conclusion, we have developed an in vitro human tuberculosis granuloma model that largely exhibits functional features of dormancy and resuscitation observed in human tuberculosis.

  10. Macrophage Functions in Early Dissemination and Dormancy of Breast Cancer

    Science.gov (United States)

    2016-09-01

    Validity of mouse mammary tumour models for human breast 599   cancer: comparative pathology . Microscopy research and technique 52, 224-230, 600...and other factors that instruct DCCs to enter dormancy. In funding year 1 we provided evidence that early ErbB2+ lesions, but not healthy mammary ...in overt tumors with pathologically defined invasive characteristics [6, 7] and are important for growth of macro-metastases [7, 8], however

  11. Human granuloma in vitro model, for TB dormancy and resuscitation.

    Science.gov (United States)

    Kapoor, Nidhi; Pawar, Santosh; Sirakova, Tatiana D; Deb, Chirajyoti; Warren, William L; Kolattukudy, Pappachan E

    2013-01-01

    Tuberculosis (TB) is responsible for death of nearly two million people in the world annually. Upon infection, Mycobacterium tuberculosis (Mtb) causes formation of granuloma where the pathogen goes into dormant state and can live for decades before resuscitation to develop active disease when the immune system of the host is weakened and/or suppressed. In an attempt to better understand host-pathogen interactions, several groups have been developing in vitro models of human tuberculosis granuloma. However, to date, an in vitro granuloma model in which Mtb goes into dormancy and can subsequently resuscitate under conditions that mimic weakening of the immune system has not been reported. We describe the development of a biomimetic in vitro model of human tuberculosis granuloma using human primary leukocytes, in which the Mtb exhibited characteristics of dormant mycobacteria as demonstrated by (1) loss of acid-fastness, (2) accumulation of lipid bodies (3) development of rifampicin-tolerance and (4) gene expression changes. Further, when these micro granulomas were treated with immunosuppressant anti-tumor necrosis factor-alpha monoclonal antibodies (anti-TNFα mAbs), resuscitation of Mtb was observed as has been found in humans. In this human in vitro granuloma model triacylglycerol synthase 1deletion mutant (Δtgs1) with impaired ability to accumulate triacylglycerides (TG), but not the complemented mutant, could not go into dormancy. Deletion mutant of lipY, with compromised ability to mobilize the stored TG, but not the complemented mutant, was unable to come out of dormancy upon treatment with anti-TNFα mAbs. In conclusion, we have developed an in vitro human tuberculosis granuloma model that largely exhibits functional features of dormancy and resuscitation observed in human tuberculosis.

  12. Treatment-Induced Autophagy Associated with Tumor Dormancy and Relapse

    Science.gov (United States)

    2016-07-01

    6, 7]. Dec is an epigenetic therapy for acute myeloid leukemia , which may also inhibit the suppressive function of MDSCs [8]. We evaluated this...tumor dormancy, tumor relapse, chemotherapy, immunotherapy 16. SECURITY CLASSIFICATION OF: U 17. LIMITATION OF ABSTRACT 18. NUMBER OF PAGES 19a...D, Payne KK, et al. Activated NKT cells and NK cells render T cells resistant to myeloid -derived suppressor cells and result in an effective adoptive

  13. Methods for overcoming dormancy in Stryphnodendron pulcherrimum seeds

    Directory of Open Access Journals (Sweden)

    Adriano Gonçalves Pereira

    2016-09-01

    Full Text Available Seed dormancy is a phenomenon observed in several tropical species. This condition causes low and non-uniform germination. The present study was designed to identify an efficient method of breaking seed dormancy in Stryphnodendron pulcherrimum. Seeds of four mother plants were subjected to the following treatments: immersion in sulfuric acid for 2, 4, 6, 8, 10 and 12 min and scarification on 150-grit sandpaper. Seeds were sown on substrate containing sand and sawdust (1:1. It was evaluate the days to onset seedlings emergence, seedlings emergence (SE, emergence speed index (ESI, germination (G, hard seeds (HS, dead seeds (DS, dormant seeds (DMS, abnormal seedlings (AS and dry mass of aerial part (DMAP and roots (DMR. The experimental design was completely randomized with four replications of 25 seeds for each treatment. Data were subjected to analysis of variance and means compared by Tukey’s test (p < 0.05. Significant differences among treatments were observed for ESI, SE, G, HS, DMAP and DMR. Highest HS was observed in control treatment (85%. Highest G was observed in seeds scarified with sulfuric acid for 10 min (82% and 12 min (74%. These treatments also showed highest ESI, DMAP and DMR, indicating that these scarification treatments were the most efficient in overcoming dormancy.

  14. Bud dormancy in apple trees after thermal fluctuations

    Directory of Open Access Journals (Sweden)

    Rafael Anzanello

    2014-06-01

    Full Text Available The objective of this work was to evaluate the effect of heat waves on the evolution of bud dormancy, in apple trees with contrasting chilling requirements. Twigs of 'Castel Gala' and 'Royal Gala' were collected in orchards in Papanduva, state of Santa Catarina, Brazil, and were exposed to constant (3°C or alternating (3 and 15°C for 12/12 hours temperature, combined with zero, one or two days a week at 25°C. Two additional treatments were evaluated: constant temperature (3°C, with a heat wave of seven days at 25°C, in the beginning or in the middle of the experimental period. Periodically, part of the twigs was transferred to 25°C for daily budburst evaluation of apical and lateral buds. Endodormancy (dormancy induced by cold was overcome with less than 330 chilling hours (CH of constant cold in 'Castel Gala' and less than 618 CH in 'Royal Gala'. A daily 15°C-temperature cycle did not affect the endodormancy process. Heat waves during endodormancy resulted in an increased CH to achieve bud requirements. The negative effect of high temperature depended on the lasting of this condition. Chilling was partly cancelled during dormancy when the heat wave lasted 36 continuous hours or more. Therefore, budburst prediction models need adjustments, mainly for regions with mild and irregular winters, such as those of Southern Brazil.

  15. Dormancy, activation and viability of Rhizopus oligosporus sporangiospores.

    Science.gov (United States)

    Thanh, N V; Nout, M J R

    2004-04-15

    Interruption of dormancy to improve viability of Rhizopus oligosporus sporangiospores is crucial for the application of stored starter cultures for fungal (tempe) production. We aimed to assess the extent of dormancy and factors that could result in activation. Whereas heat treatments were unsuccessful, Malt Extract Broth (MEB) showed to be a good activation medium, with 80% of dormant spores being activated as measured by fluorescence microscopy using a fluorescent marker, compared with 11% with the control. Peptone and yeast extract but not glucose played an important role in activating dormant spores. Metabolically active (fluorescent) and swollen spores, followed by germ tubes were obtained after activation in MEB for 25 min., 2 and 4 h, respectively, at 37 degrees C. Simultaneously, some interesting transitions took place. Dormant spores represent 85-90% of the total spores at harvest and after drying. Their number decreased to 21-32% after activation with MEB with a concomitant increase of metabolically active spores. As a result of storage, some dormancy was lost, yielding an increase of active spores from 11.2% at harvest to 28.8% after 3 months storage. Levels of active spores were well correlated with their viability. By activation of dormant spores, their viability increased; levels of viable and active spores were maximum in 1 month old starter (61.7% and 75.9% of total spores, respectively) but gradually decreased with concomitant increase of the number of dead spores.

  16. Changes in RNA Splicing in Developing Soybean (Glycine max Embryos

    Directory of Open Access Journals (Sweden)

    Delasa Aghamirzaie

    2013-11-01

    Full Text Available Developing soybean seeds accumulate oils, proteins, and carbohydrates that are used as oxidizable substrates providing metabolic precursors and energy during seed germination. The accumulation of these storage compounds in developing seeds is highly regulated at multiple levels, including at transcriptional and post-transcriptional regulation. RNA sequencing was used to provide comprehensive information about transcriptional and post-transcriptional events that take place in developing soybean embryos. Bioinformatics analyses lead to the identification of different classes of alternatively spliced isoforms and corresponding changes in their levels on a global scale during soybean embryo development. Alternative splicing was associated with transcripts involved in various metabolic and developmental processes, including central carbon and nitrogen metabolism, induction of maturation and dormancy, and splicing itself. Detailed examination of selected RNA isoforms revealed alterations in individual domains that could result in changes in subcellular localization of the resulting proteins, protein-protein and enzyme-substrate interactions, and regulation of protein activities. Different isoforms may play an important role in regulating developmental and metabolic processes occurring at different stages in developing oilseed embryos.

  17. Demographic estimation methods for plants with dormancy

    Directory of Open Access Journals (Sweden)

    Kéry, M.

    2004-06-01

    , which has fully interactive state- and time-dependent survival and state transition rates. This model would become identifiable if at least some plants would be excavated in years when they do not show up aboveground. Our analyses for three analyzed populations of Cleistes and Cypripedium yielded annual ramet survival rates ranging from 0.86–0.96. Estimates of the average fraction dormant ranged from 0.02–0.30, but with up to half a population in the dormant state in some years. Ultrastructural modeling enables interesting hypotheses to be tested about the relationships of demographic rates with climatic covariates for instance. Such covariate modeling makes the CR approach particularly interesting for evolutionary–ecological questions about, e.g., the adaptive significance of the dormant state. Previous and foreseeable future applications of CR in plant ecology Since the paper by Alexander et al. (1997, it has become increasingly clear that CR models may be useful for demographic analysis of plant populations. In the future, we are likely to see increasing use of these methods that were originally developed for animal populations. Here is a summary about all previous applications that I have come across. I am grateful if readers point out to me any titles that I may have missed. If a reliable way to mark seeds can be devised, CR might indeed provide the analysis tool for tackling one of the ultimate frontiers in plant population ecology: the dynamics of the seed bank. Indeed, the first ever application of CR to plants that I have come across (Naylor, 1972 used a fluorescent dye to mark seeds and a Lincoln–Peterson–type estimator to estimate the seed bank size in an agricultural weed. The application of CR to plants with dormancy has been treated by Shefferson et al. (2001, 2003, Kéry et al. (submitted and Kéry & Gregg (submitted. Population size, and survival rates of plants whose aboveground states are easily overlooked have been estimated for an elusive

  18. Physical dormancy in seeds of the holoparasitic angiosperm Cuscuta australis (Convolvulaceae, Cuscuteae): dormancy-breaking requirements, anatomy of the water gap and sensitivity cycling.

    Science.gov (United States)

    Jayasuriya, K M G Gehan; Baskin, Jerry M; Geneve, Robert L; Baskin, Carol C; Chien, Ching-Te

    2008-07-01

    Dormancy in seeds of Cuscuta (Convolvulaceae, tribe Cuscuteae) is due to a water-impermeable seed coat (physical dormancy). In nondormant seeds of several species of this family, bulges adjacent to the micropyle have been identified as the initial route of water entry into seeds (water gap). However, there are claims that water enters seeds of Cuscuta spp. via the entire seed coat. Although several studies have been done on seed coat anatomy of Cuscuta, none has identified and/or characterized the morphology/anatomy of a water gap. Thus, the primary aim of this research was to identify and describe the morphology and anatomy of the water gap in seeds of Cuscuta australis. It was also determined if sensitivity cycling to dormancy-breaking treatments occurs in seeds of this species. Light microscopy, scanning electron microscopy, tissue-sectioning and dye-tracking and blocking experiments were used to investigate the morphology and anatomy of the water gap. Treatments simulating natural conditions were used to break seed dormancy. Storage of seeds at different temperatures was tested for their effect on sensitivity to dormancy-breaking treatment. Dormancy-breaking treatments caused the tightly closed hilar fissure to open. Staining was observed in cells below the hilum area but not in those below the seed coat away from the hilum. Sensitivity to dormancy-breaking treatment was induced by storing seeds dry and reduced by storing them wet. Whereas bulges adjacent to the micropyle act as the water gap in other species of Convolvulaceae with physical dormancy, the hilar fissure serves this function in Cuscuta. Cuscuta australis can cycle between insensitivity sensitivity to dormancy-breaking treatments.

  19. SOMATIC EMBRYOGENESIS AND MORPHOANATOMY OF Ocotea porosa SOMATIC EMBRYOS

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    Luciana Luiza Pelegrini

    2013-12-01

    Full Text Available http://dx.doi.org/10.5902/1980509812343Ocotea porosa seeds have strong tegument dormancy, recalcitrant behavior, low and irregular germinationand that makes its natural propagation difficult. The aim of this study was to establish a protocol ofregeneration of Ocotea porosa from somatic embryogenesis. Immature embryonic axes were inoculatedon WPM culture medium supplemented with 2.4-D (200 μM combined or not with hydrolyzed casein orglutamine (0.5 or 1 g l-1, during 90 days. The repetitive embryogenesis was induced on medium with 2.4-D(22.62 μM combined with 2-iP (2.46 μM followed by transfer to culture medium with hydrolyzed caseinor glutamine (1 g l-1 during 90 days. The maturation of somatic embryos was tested in culture mediumcontaining NAA (0.5 μM and 2-iP (5; 10 and 20 μM. The highest percentage of somatic embryos induction(8.3% was observed in WPM culture medium containing 200 μM 2.4-D and 1 g L-1 hydrolyzed casein andthe development of somatic embryos occurred indirectly. Repetitive somatic embryogenesis was promotedin WPM medium containing hydrolyzed casein or glutamine. However, the culture medium containinghydrolyzed casein promoted the maintenance of embryogenic capacity for more than two years. Duringthe maturity phase, there was a low progression of globular embryos to cordiform and torpedo stages.The different ontogenetic stages of somatic embryos of Ocotea porosa were characterized by histologicalstudies.

  20. SOMATIC EMBRYOGENESIS AND MORPHOANATOMY OF Ocotea porosa SOMATIC EMBRYOS

    Directory of Open Access Journals (Sweden)

    Luciana Luiza Pelegrini

    2013-01-01

    Full Text Available Ocotea porosa seeds have strong tegument dormancy, recalcitrant behavior, low and irregular germination and that makes its natural propagation difficult. The aim of this study was to establish a protocol of regeneration of Ocotea porosa from somatic embryogenesis. Immature embryonic axes were inoculated on WPM culture medium supplemented with 2.4-D (200 μM combined or not with hydrolyzed casein or glutamine (0.5 or 1 g l-1, during 90 days. The repetitive embryogenesis was induced on medium with 2.4-D (22.62 μM combined with 2-iP (2.46 μM followed by transfer to culture medium with hydrolyzed casein or glutamine (1 g l-1 during 90 days. The maturation of somatic embryos was tested in culture medium containing NAA (0.5 μM and 2-iP (5; 10 and 20 μM. The highest percentage of somatic embryos induction (8.3% was observed in WPM culture medium containing 200 μM 2.4-D and 1 g L-1 hydrolyzed casein and the development of somatic embryos occurred indirectly. Repetitive somatic embryogenesis was promoted in WPM medium containing hydrolyzed casein or glutamine. However, the culture medium containing hydrolyzed casein promoted the maintenance of embryogenic capacity for more than two years. During the maturity phase, there was a low progression of globular embryos to cordiform and torpedo stages. The different ontogenetic stages of somatic embryos of Ocotea porosa were characterized by histological studies.

  1. Changes in Protein Profiles of Poplar Tissues during the Induction of Bud Dormancy by Short-Day Photoperiods

    OpenAIRE

    Zoran, Jeknic; Tony H.H., Chen; Department of Horticulture, 4017 Agricultural and Life Sciences, Oregon State University; Department of Horticulture, 4017 Agricultural and Life Sciences, Oregon State University

    1999-01-01

    Vegetative bud dormancy in woody perennial plants of the temperate regions is an important adaptive strategy for withstanding low winter temperatures. We used shortday(SD) photoperiods to induce bud dormancy in poplar(Populus deltoides Bartr.ex Marsh.), and characterized changes in protein profiles duriong dormancy development. Short days alone, under warm temperatures(25℃) induced a high level of dormancy comparable to that developed naturally. Under SD conditions the amounts of acetone/tric...

  2. Secondary dormancy induction and release in Bromus tectorum seeds: The role of temperature, water potential and hydrothermal time

    Science.gov (United States)

    K. K. Hawkins; P. S. Allen; Susan Meyer

    2017-01-01

    Seeds of the winter annual Bromus tectorum lose primary dormancy in summer and are poised to germinate rapidly in the autumn. If rainfall is inadequate, seeds remain ungerminated and may enter secondary dormancy under winter conditions. We quantified conditions under which seeds enter secondary dormancy in the laboratory and field and also examined whether contrasting...

  3. Dormancy behaviors and underlying regulatory mechanisms: from perspective of pathways to epigenetic regulation

    Science.gov (United States)

    Temperate perennials exploit dormancy as one strategy to survive long term environmental stresses. As the current trend in global warming continues, many regions are experiencing warmer winters that fail to provide sufficient chilling temperature for dormancy release, impacting fruit tree productiv...

  4. Natural variation for seed longevity and seed dormancy are negatively correlated in Arabidopsis

    NARCIS (Netherlands)

    Nguyen, T.P.; Keizer, L.C.P.; Eeuwijk, van F.; Smeekens, S.C.M.; Bentsink, L.

    2012-01-01

    Dormancy is a state of metabolic arrest that facilitates the survival of organisms during environmental conditions incompatible with their regular course of life. Many organisms have deep dormant stages to promote an extended life span (increased longevity). In contrast, plants have seed dormancy

  5. Seed longevity and dormancy state in a disturbance-dependent forest herb, Ageratina altissima

    Science.gov (United States)

    Mame E. Redwood; Glenn R. Matlack; Cynthia D. Huebner

    2016-01-01

    Does seed dormancy allow disturbance-oriented forest herbs such as Ageratina altissima to persist in heterogeneous natural communities? To document seed longevity and dormancy state, Ageratina seeds were buried in nylon mesh bags in second-growth forest stands in south-eastern Ohio, USA. Bags were recovered at 2-month intervals...

  6. Seed dormancy and seed longevity: from genetic variation to gene identification

    NARCIS (Netherlands)

    Nguyen, T.P.|info:eu-repo/dai/nl/328228818

    2014-01-01

    Seed dormancy and seed longevity are the most important survival traits in the soil seed bank. Both traits are induced during seed maturation and evolved to assure seed survival during environmental conditions that cannot support the regular course of life. Seed dormancy is related to the timing of

  7. Key genes involved in desiccation tolerance and dormancy across life forms

    NARCIS (Netherlands)

    Costa, M.C.D.; Farrant, Jill M.; Oliver, Melvin J.; Ligterink, Wilco; Buitink, Julia; Hilhorst, H.M.W.

    2016-01-01

    Desiccation tolerance (DT, the ability of certain organisms to survive severe dehydration) was a key trait in the evolution of life in terrestrial environments. Likely, the development of desiccation-tolerant life forms was accompanied by the acquisition of dormancy or a dormancy-like stage as a

  8. Ethylene Is Not Involved in Hormone- and Bromoethane-Induced Dormancy Break in Russet Burbank Minitubers

    Science.gov (United States)

    The involvement of ethylene in the dormancy breaking actions of cytokinins, GA, and BE was investigated using Russet Burbank minitubers. Injection of 10µg tuber-1 BA, CP, GA, NG, or ZEA or 24 hour exposure to BE effectively broke dormancy and stimulated sprout growth over a two-week period. Althou...

  9. Detection of seed dormancy QTL in three F2 families of peach (Prunus persica)

    Science.gov (United States)

    Dormancy is a condition that delays or inhibits growth in seed, vegetative buds, and floral buds. In peach, seed germination occurs when seed accumulate sufficient stratification and growing degree hours to break dormancy and begin growing. Correlations have been reported between mean seed stratifi...

  10. Mapping fall dormancy and winter injury in tetraploid alfalfa (Medicago sativa L.)

    Science.gov (United States)

    Alfalfa is a widely planted perennial forage crop. Dormancy in autumn (fall dormancy) is generally negatively correlated with winter injury in alfalfa. To understand the genetic basis of the two traits, we identified quantitative trait loci (QTL) controlling autumn growth and winter injury using a...

  11. Phytochrome Transformation and Action in Seeds of Rumex crispus L. during Secondary Dormancy.

    Science.gov (United States)

    Taylorson, R B; Hendricks, S B

    1973-11-01

    Promotion of germination by red light fails after prolonged dark imbibition of Rumex crispus L. seeds, indicative of a secondary dormancy. The degree and rate of inception of the dormancy increases with increasing temperature. Following establishment of the dormancy, germination response to red light can be restored by either prolonged cold treatment or brief high temperature shifts. Loss of phytochrome was not a factor in the initial establishment of the dormancy. When the seeds are in secondary dormancy, the chromophore of phytochrome can be transformed to the far red-absorbing form, but the far red-absorbing form cannot induce germination. The responses to changes in temperature suggested dependence of germination on order left arrow over right arrow disorder transitions in components of the seeds.

  12. Embryo-maternal communication

    DEFF Research Database (Denmark)

    Østrup, Esben; Hyttel, Poul; Østrup, Olga

    2011-01-01

    Communication during early pregnancy is essential for successful reproduction. In this review we address the beginning of the communication between mother and developing embryo; including morphological and transcriptional changes in the endometrium as well as epigenetic regulation mechanisms...... directing the placentation. An increasing knowledge of the embryo-maternal communication might not only help to improve the fertility of our farm animals but also our understanding of human health and reproduction....

  13. Cryopreservation of canine embryos.

    Science.gov (United States)

    Abe, Yasuyuki; Suwa, Yoshinori; Asano, Tomoyoshi; Ueta, Yoshiko Yanagimoto; Kobayashi, Nanae; Ohshima, Natsumi; Shirasuna, Saori; Abdel-Ghani, Mohammed Ali; Oi, Maya; Kobayashi, Yoshiyasu; Miyoshi, Masafumi; Miyahara, Kazuro; Suzuki, Hiroshi

    2011-02-01

    The assisted reproductive techniques (ARTs) such as in vitro fertilization, embryo transfer, and cryopreservation of gametes have contributed considerably to the development of biomedical sciences in addition to improving infertility treatments in humans as well as the breeding of domestic animals. However, ARTs used in canine species have strictly limited utility when compared with other mammalian species, including humans. Although successful somatic cell cloning has been reported, artificial insemination by frozen semen to date is only available for the improved breeding and reproduction for companion and working dogs as well as guide dogs for the blind. We describe here the successful cryopreservation of embryos and subsequent embryo transfer in dogs. Canine embryos were collected from excised reproductive organs after artificial insemination and subsequently cryopreserved by a vitrification method. When the 4-cell to morula stage of cryopreserved embryos were nonsurgically transferred into the uteri of nine recipient bitches using a cystoscope, five recipients became pregnant and four of them delivered a total of seven pups. The cryopreservation of embryos in canine species will facilitate the transportation and storage of genetic materials and will aid in the elimination of vertically transmitted diseases in dogs. In addition, this technique will contribute to the improved breeding of companion and working dogs such as guide dogs, drug-detecting dogs, and quarantine dogs.

  14. To transfer fresh or thawed embryos?

    DEFF Research Database (Denmark)

    Pinborg, Anja

    2012-01-01

    and multiple pregnancies, thereby increasing the safety for mother and child. Finally the article describes the accumulating literature on perinatal and long-term child outcome after transfer of frozen/thawed embryos, including a discussion on the concerns regarding cryo techniques and their possible roles...... and cons of FER versus fresh-embryo transfer with regard to both single-cycle and cumulative pregnancy and delivery rates. The review discusses the obvious advantages of FER: minimizing the proportion of pharmacological and surgical treatments, and lowering the risk of ovarian hyperstimulation syndrome...

  15. Differential control of seed primary dormancy in Arabidopsis ecotypes by the transcription factor SPATULA

    Science.gov (United States)

    Vaistij, Fabián E.; Gan, Yinbo; Penfield, Steven; Gilday, Alison D.; Dave, Anuja; He, Zhesi; Josse, Eve-Marie; Choi, Giltsu; Halliday, Karen J.; Graham, Ian A.

    2013-01-01

    Freshly matured seeds exhibit primary dormancy, which prevents germination until environmental conditions are favorable. The establishment of dormancy occurs during seed development and involves both genetic and environmental factors that impact on the ratio of two antagonistic phytohormones: abscisic acid (ABA), which promotes dormancy, and gibberellic acid, which promotes germination. Although our understanding of dormancy breakage in mature seeds is well advanced, relatively little is known about the mechanisms involved in establishing dormancy during seed maturation. We previously showed that the SPATULA (SPT) transcription factor plays a key role in regulating seed germination. Here we investigate its role during seed development and find that, surprisingly, it has opposite roles in setting dormancy in Landsberg erecta and Columbia Arabidopsis ecotypes. We also find that SPT regulates expression of five transcription factor encoding genes: ABA-INSENSITIVE4 (ABI4) and ABI5, which mediate ABA signaling; REPRESSOR-OF-GA (RGA) and RGA-LIKE3 involved in gibberellic acid signaling; and MOTHER-OF-FT-AND-TFL1 (MFT) that we show here promotes Arabidopsis seed dormancy. Although ABI4, RGA, and MFT are repressed by SPT, ABI5 and RGL3 are induced. Furthermore, we show that RGA, MFT, and ABI5 are direct targets of SPT in vivo. We present a model in which SPT drives two antagonistic “dormancy-repressing” and “dormancy-promoting” routes that operate simultaneously in freshly matured seeds. Each of these routes has different impacts and this in turn explains the opposite effect of SPT on seed dormancy of the two ecotypes analyzed here. PMID:23754415

  16. A graphical method for identifying the six types of non-deep physiological dormancy in seeds.

    Science.gov (United States)

    Soltani, E; Baskin, C C; Baskin, J M

    2017-09-01

    We present a new seed dormancy classification scheme for the non-deep level of the class physiological dormancy (PD), which contains six types. Non-deep PD is divided into two sublevels: one for seeds that exhibit a dormancy continuum (types 1, 2 and 3) and the other for those that do not exhibit a dormancy continuum (types 4, 5 and 6). Analysis of previous studies showed that different types of non-deep PD also can be identified using a graphical method. Seeds with a dormancy (D) ↔ conditional dormancy (CD) ↔ non-dormancy (ND) cycle have a low germination percentage in the early stages of CD, and during dormancy loss the germination capacity increases. However, seeds with a CD/ND (i.e. D→CD↔ND) cycle germinate to a high percentage at a narrow range of temperatures in the early stages of CD. Cardinal temperatures for seeds with either a D/ND or a CD/ND cycle change during dormancy loss: the ceiling temperature increases in seeds with Type 1, the base temperature decreases in seeds with Type 2 and the base and ceiling temperatures decrease and increase, respectively, in seeds with Type 3. Criteria for distinguishing the six types of non-deep PD and models of the temperature functions of seeds with types 1, 2 and 3 with both types of dormancy cycles are presented. The relevancy of our results to modelling the timing of weed seedling emergence is briefly discussed. © 2017 German Botanical Society and The Royal Botanical Society of the Netherlands.

  17. Transcriptomic analysis of American ginseng seeds during the dormancy release process by RNA-Seq.

    Directory of Open Access Journals (Sweden)

    Jianjun Qi

    Full Text Available American ginseng (Panax quinquefolius L. is an important herb that is cultivated in China, North American, and South Korea. It is propagated from seed, but the seed has deep dormancy characteristics described as morphophysiological dormancy. Two-stage temperature stratification, a warm (15-20°C and cold (2°C stratification period of 6 months, has been used successfully for seed dormancy release. However, little is known about the molecular mechanisms of seed dormancy release in the stratification process. In this study, seed development after pollination and seed development in the dormancy release process were investigated in American ginseng. The transcriptome during seed dormancy release was analyzed using RNA-Seq technology and 78,207 unigenes (mean length 531 bp were generated. Based on similarity searches of public databases, 54,292 of the unigenes (69.4% were functionally annotated. Further, three digital gene expression (DGE libraries were sequenced and differences in gene expression at three stages during seed cold stratification were examined. The greatest number of differentially expressed genes occurred in the 90DCS versus 180DCS libraries, while the lowest number of differentially expressed genes occurred in the 135DCS verus 180DCS libraries. GO enrichment analysis revealed that 59, 29, and 39 GO terms were significantly enriched in the biological process, molecular function, and cell component GO categories, respectively. There were 25,190 genes with KEGG pathway annotation in the three DGE libraries and their enrichment pathways were compared. The gene expressions of 30 selected unigenes were validated using quantitative PCR. This study is the first to provide the transcriptome sequences for seed dormancy release in American ginseng, and demonstrates the successful use of DGE profiling data for analyzing transcriptomic variation during dormancy release. These data provide a basis for future researches of seed dormancy in

  18. Canalization of Seasonal Phenology in the Presence of Developmental Variation: Seed Dormancy Cycling in an Annual Weed.

    Science.gov (United States)

    Edwards, Brianne; Burghardt, Liana T; Kovach, Katherine E; Donohue, Kathleen

    2017-11-01

    Variation in the developmental timing in one life stage may ramify within and across generations to disrupt optimal phenology of other life stages. By focusing on a common mechanism of developmental arrest in plants-seed dormancy-we investigated how variation in flowering time influenced seed germination behavior and identified potential processes that can lead to canalized germination behavior despite variation in reproductive timing. We quantified effects of reproductive timing on dormancy cycling by experimentally manipulating the temperature during seed maturation and the seasonal timing of seed dispersal/burial, and by assessing temperature-dependent germination of un-earthed seeds over a seasonal cycle. We found that reproductive timing, via both seed-maturation temperature and the timing of dispersal, strongly influenced germination behavior in the weeks immediately following seed burial. However, buried seeds subsequently canalized their germination behavior, after losing primary dormancy and experiencing natural temperature and moisture conditions in the field. After the complete loss of primary dormancy, germination behavior was similar across seed-maturation and dispersal treatments, even when secondary dormancy was induced. Maternal effects themselves may contribute to the canalization of germination: first, by inducing stronger dormancy in autumn-matured seeds, and second by modifying the responses of those seeds to their ambient environment. Genotypes differed in dormancy cycling, with functional alleles of known dormancy genes necessary for the suppression of germination at warm temperatures in autumn through spring across multiple years. Loss of function of dormancy genes abolished almost all dormancy cycling. In summary, effects of reproductive phenology on dormancy cycling of buried seeds were apparent only as long as seeds retained primary dormancy, and a combination of genetically imposed seed dormancy, maternally induced seed dormancy, and

  19. Microbial dormancy improves development and experimental validation of ecosystem model.

    Science.gov (United States)

    Wang, Gangsheng; Jagadamma, Sindhu; Mayes, Melanie A; Schadt, Christopher W; Steinweg, J Megan; Gu, Lianhong; Post, Wilfred M

    2015-01-01

    Climate feedbacks from soils can result from environmental change followed by response of plant and microbial communities, and/or associated changes in nutrient cycling. Explicit consideration of microbial life-history traits and functions may be necessary to predict climate feedbacks owing to changes in the physiology and community composition of microbes and their associated effect on carbon cycling. Here we developed the microbial enzyme-mediated decomposition (MEND) model by incorporating microbial dormancy and the ability to track multiple isotopes of carbon. We tested two versions of MEND, that is, MEND with dormancy (MEND) and MEND without dormancy (MEND_wod), against long-term (270 days) carbon decomposition data from laboratory incubations of four soils with isotopically labeled substrates. MEND_wod adequately fitted multiple observations (total C-CO2 and (14)C-CO2 respiration, and dissolved organic carbon), but at the cost of significantly underestimating the total microbial biomass. MEND improved estimates of microbial biomass by 20-71% over MEND_wod. We also quantified uncertainties in parameters and model simulations using the Critical Objective Function Index method, which is based on a global stochastic optimization algorithm, as well as model complexity and observational data availability. Together our model extrapolations of the incubation study show that long-term soil incubations with experimental data for multiple carbon pools are conducive to estimate both decomposition and microbial parameters. These efforts should provide essential support to future field- and global-scale simulations, and enable more confident predictions of feedbacks between environmental change and carbon cycling.

  20. Dormancy breaking in seeds of species of the Nicotiana genus

    OpenAIRE

    Juan Luis Pérez-Rodríguez; Gilberto Torrecilla-Guerra; Otilio Ruiz-Padrón; Marcos Martínez- Montero

    2014-01-01

    In the germplasm bank of the Tobacco Research Institute of Cuba the germinative power was determined in 11 species belonging to the genus Nicotiana. All the evaluated species presented high dormancy degree which obtained less than 40% of germination. For the species Nicotianamegalosiphon Heurck and Mueller the effect of potassium nitrate (3.0 g/L), giberelic acid (0.15 g/L), stratification to 5 0C (49 days), Fitomás (1%), sulfuric acid (0.5 min) and criopreservation (49 days)...

  1. A laboratory simulation of Arabidopsis seed dormancy cycling provides new insight into its regulation by clock genes and the dormancy-related genes DOG1, MFT, CIPK23 and PHYA.

    Science.gov (United States)

    Footitt, Steven; Ölçer-Footitt, Hülya; Hambidge, Angela J; Finch-Savage, William E

    2017-08-01

    Environmental signals drive seed dormancy cycling in the soil to synchronize germination with the optimal time of year, a process essential for species' fitness and survival. Previous correlation of transcription profiles in exhumed seeds with annual environmental signals revealed the coordination of dormancy-regulating mechanisms with the soil environment. Here, we developed a rapid and robust laboratory dormancy cycling simulation. The utility of this simulation was tested in two ways: firstly, using mutants in known dormancy-related genes [DELAY OF GERMINATION 1 (DOG1), MOTHER OF FLOWERING TIME (MFT), CBL-INTERACTING PROTEIN KINASE 23 (CIPK23) and PHYTOCHROME A (PHYA)] and secondly, using further mutants, we test the hypothesis that components of the circadian clock are involved in coordination of the annual seed dormancy cycle. The rate of dormancy induction and relief differed in all lines tested. In the mutants, dog1-2 and mft2, dormancy induction was reduced but not absent. DOG1 is not absolutely required for dormancy. In cipk23 and phyA dormancy, induction was accelerated. Involvement of the clock in dormancy cycling was clear when mutants in the morning and evening loops of the clock were compared. Dormancy induction was faster when the morning loop was compromised and delayed when the evening loop was compromised. © 2017 The Authors Plant, Cell & Environment Published by John Wiley & Sons Ltd.

  2. Embryo manipulation and experimentation.

    Science.gov (United States)

    Warren, M A

    1991-09-01

    I have argued that early human embryos are not human beings, and do not have normal rights. Like human sperm and ova, they are both alive and biologically human. However, they lack the physiological development necessary to sustain a capacity for sentience. If Ford is right, then they are not yet individual human organisms. But the more important point is that their lack of a capacity for sentience makes them inappropriate candidates for the ascription of moral rights. Thus, research on human embryos produced in vitro is not a wrong against them--at least so long as experimentally manipulated embryos are not returned to the womb, or artificially gestated to a stage at which they might become sentient. Some of the more difficult issues about embryo experimentation involve the rights of women as experimental subject and donors. The consent of both male and female gamete donors should normally be required for the production or experimental use of IVF embryos. (Possible exceptions might include cases in which one or both progenitors have died, and the survivor or other responsible family member wished to donate the (frozen) IVF embryos for research or other uses.) However, it is women's rights that are most apt to be endangered, for example, if the large scale therapeutic or commercial use of human embryos leads to a demand for large numbers of ova. Thus, it is vital that researchers and policy-makers heed feminist concerns about embryo research and the new biomedical technologies it may yield. Given adequate information and appropriate procedural protections, women are capable of making autonomous decisions about donating ova or embryos for biomedical research. But regulatory safeguards are needed to ensure against their being coerced, deceived, or manipulated into becoming ovum or embryo donors. As Daniel Callahan has detailed, biomedical technology has reached the point where we can no longer afford to provide everyone with all of the innovative therapies that might

  3. Development of a new clinically applicable device for embryo evaluation which measures embryo oxygen consumption.

    Science.gov (United States)

    Kurosawa, Hiroki; Utsunomiya, Hiroki; Shiga, Naomi; Takahashi, Aiko; Ihara, Motomasa; Ishibashi, Masumi; Nishimoto, Mitsuo; Watanabe, Zen; Abe, Hiroyuki; Kumagai, Jin; Terada, Yukihiro; Igarashi, Hideki; Takahashi, Toshifumi; Fukui, Atsushi; Suganuma, Ryota; Tachibana, Masahito; Yaegashi, Nobuo

    2016-10-01

    Does a new system-the chip-sensing embryo respiration monitoring system (CERMs)-enable evaluation of embryo viability for potential application in a clinical IVF setting? The system enabled the oxygen consumption rate of spheroids, bovine embryos and frozen-thawed human embryos to be measured, and this rate corresponded to the developmental potential of embryos. To date, no reliable and clinically suitable objective evaluation methods for embryos are available, which circumvent the differences in inter-observer subjective view. Existing systems such as the scanning electrochemical microscopy (SECM) technique, which enables the measurement of oxygen consumption rate in embryos, need improvement in usability before they can be applied to a clinical setting. This is a prospective original research study. The feasibility of measuring the oxygen consumption rate was assessed using CERMs for 9 spheroids, 9 bovine embryos and 30 redundant frozen-thawed human embryos. The endpoints for the study were whether CERMs could detect a dissolved oxygen gradient with high sensitivity, had comparable accuracy to the SECM measuring system with improved usability, and could predict the development of an embryo to a blastocyst by measuring the oxygen consumption rate. The relationship between the oxygen consumption rate and standard morphological evaluation was also examined. We developed a new CERMs, which enables the oxygen consumption rate to be measured automatically using an electrochemical method. The device was initially used for measuring a dissolved oxygen concentration gradient in order to calculate oxygen consumption rate using nine spheroids. Next, we evaluated data correlation between the CERMs and the SECM measuring systems using nine bovine embryos. Finally, the oxygen consumption rates of 30 human embryos, which were frozen-thawed on 2nd day after fertilization, were measured by CERMs at 6, 24, 48, 72 and 96 h after thawing with standard morphological evaluation

  4. Paths of water entry and structures involved in the breaking of seed dormancy of Lupinus.

    Science.gov (United States)

    Robles-Díaz, Erika; Flores, Joel; Yáñez-Espinosa, Laura

    2016-03-15

    Physical dormancy is the water impermeability of the seed coat caused by one or more palisade cell layer(s) called macrosclereids. The specialised structure for water entry sites is the water gap, which serves as a detector of environmental cues for germination. In Fabaceae, the water gap is the lens, although another seed structure for water entry could exist. In this study, we identified the initial site of water entry, observed the hydration of a cushion-like structure near the radicle, described the anatomy of the water gap, and analysed the association of anatomical seed traits with the initial site of water entry and the imbibition velocity of six species of Lupinus from the state of Jalisco, Mexico. Dye tracking with a toluidine blue solution was used to identify the initial site of water entry. The anatomical description was performed using conventional microtechnique and a light microscope. The entry of the toluidine solution into seeds of L. montanus was observed after 6h, followed by L. exaltatus and L. mexicanus after 18h and L. elegans, L. reflexus and L. rotundiflorus after 48h. The site of water entry was the lens in L. elegans, L. exaltatus, L. reflexus and L. rotundiflorus and the micropyle in L. mexicanus and L. montanus. The cushion-like structure was responsible for water accumulation in embryo imbibition. Significant differences among anatomical seed traits such as thickness in the hilar region, the counter-palisade layer, cushion-like structure, epidermis, hypodermis, and innermost parenchyma layer were found among the species. Copyright © 2016 Elsevier GmbH. All rights reserved.

  5. Influence of Simazin 50 and Dicuran on oxidative phosphorylation in the mitochondria of spring barley (Damazy embryos

    Directory of Open Access Journals (Sweden)

    J. Tłuczkiewicz

    2015-06-01

    Full Text Available Oxidative phosphorylation was investigated in the embryos of spring barley (Damazy grain collected from plants sprayed in the period of shooting with Simazin 50 (2-chloro-4,6-etylamino-S-triazine and Dicuran (N(3-chloro-4-methylphenolN',N'dimethylurea as well as in embryos of grains germinated in solutions of these herbicides and in 2,4-dinitrophenol. The analyses were performed on grain of varying ripeness (waxy, full post-harvest dormancy and at various stages of germination (24, 48 h. It was found that the herbicides applied reduced succinate oxidation by the embryonal mitochondria and also depressed to the same exten the estirifi-cation of inorganic phosphate. Owing to this the P/O ratio did not show significant changes. Herbicide in germinated embryos solutions uncoupled oxidative phosphorylation. Simazin 50 (3 g/l. and Dicuran

  6. Magnetic resonance microimaging indicates water diffusion correlates with dormancy induction in cultured hybrid poplar (Populus spp.) buds.

    Science.gov (United States)

    Kalcsits, Lee; Kendall, Edward; Silim, Salim; Tanino, Karen

    2009-10-01

    Water content and mobility, which are factors known to be associated with dormancy induction in woody plants on a tissue level, were measured using non-destructive magnetic resonance microimaging (MRMI). Two cultured poplar clones ('Okanese' - temperature-insensitive dormancy and 'Walker' - temperature-sensitive dormancy) were subjected to dormancy differentiating temperature regimes, 18.5/3.5 degrees C and 18.5/13.5 degrees C (day/night), under a short photoperiod. Apparent diffusion coefficient, an indicator of water mobility, correlated with dormancy development in the axillary bud and vascular bud trace regions. In contrast, T(1) relaxation time, an indicator of static biophysical water properties, did not correlate significantly with dormancy in the regions that were examined. Although MRMI studies using T(1) relaxation measurements have dominated the phytological field, our work indicates that water mobility is an important factor in studies examining water changes during dormancy induction in the critical tissues of woody plants.

  7. Seed dormancy in breding lines of eggplant (Solanum melongena L.

    Directory of Open Access Journals (Sweden)

    Zdravković Jasmina

    2011-01-01

    Full Text Available Six eggplant (Solanum melongena L. genotypes were studied for the seed dormancy, a common trait of this vegetable crop. Two genotypes (33 and 34 were the breeding lines while other four (1-00261, 2-02619, 7-00568, 12-00823 belong to exotic germplasm of the Institute for Vegetable Crops in Smederevska Palanka. In order to break the dormancy the seeds were treated with: 1 low temperature (HLS, at 40C for: 96, 72, and 48 hours, continually; 2 hormones, i.e. with Gibberellic acid (GA3 in three concentrations: 5 ml/100ml; 15 ml/100ml and 25 ml/100ml, for 24 hours and after that seed were left to germinate; 3 chemicals, with potassium nitrate (KNO3 solution in concentration: 0.5, 1 and 1.5% for 24 hours. Non-treated seeds were the control. We analyzed seed germination and seed germination energy. Three genotypes (33, 7 and 12 represent the least stabile genotypes, since they reacted positively to treatments, and the most intensively to treatment with Gibberellic acid 25ml/100ml.

  8. Methods to overcome dormancy in tree tomato (Solanum betaceum seeds

    Directory of Open Access Journals (Sweden)

    Carlos Kosera Neto

    2015-12-01

    Full Text Available The tree tomato (Solanum betaceum is a poorly known species that has fruits with great economic potential, as it can be consumed in natura or industrialized. However, for reaching this potential, it is necessary the development of technologies for seedlings production. The propagation of this species is mainly done by seeds, but the seed germination process is usually slow, especially under stress conditions. This study aimed at verifying whether tree tomato seeds have dormancy and which is the best method to obtain fast and uniform germination. A completely randomized design was adopted in a 5 x 2 factorial arrangement (methods to overcome dormancy x light, with four replications of 50 or 60 seeds, depending on the production cycle. The methods tested were cold stratification, hydropriming, priming with GA3 solution and control, with or without light. Seed germination and germination rate index, as well as the beginning and average time of germination, were also evaluated. The use of GA3 at a concentration of 100 mg L-1 or 300 mg L-1 is recommended to the germination of tree tomato seeds.

  9. Overcoming dormancy in seeds of cotton-silk tree

    Directory of Open Access Journals (Sweden)

    Irinaldo Lima do Nascimento

    2012-06-01

    Full Text Available Cotton-silk tree Ceiba glaziovii (kuntze k. Schu belongs to family Bombacaceas and is locally known as barriguda. It is widely used in landscaping and reforestation, neverdeless seed dormancy affects reproduction in this species. The objective of this study was to evaluate the effectiveness of different methods to overcome dormancy in the germination process. Treatments included mechanical scarification with 85-grit sandpaper, chemical scarification with concentrated sulfuric acid for 5, 10, 15 and 20 minutes, physical scarification with hot water at 60°, 70°, 80°and 90° C for one minute, imbibition in distilled water for 24, 48 and 72 hours, oven heating at 65° C for 1, 2, 3 and 4 hours, and a control treatment. Each treatment included four replicates of 25 seeds, using a completely randomized experimental design, and means were compared by the Scott-Knott test at the 5% probability level. Assessed parameters included emergence percentage, emergence rate index, dry matter and length of plants. The most recommended treatments were mechanical scarification, immersion in sulfuric acid for 5, 10 and 15 minutes and immersion in distilled water for 48 hours.

  10. Mapping of QTL for seed dormancy in a winter oilseed rape doubled haploid population.

    Science.gov (United States)

    Schatzki, Jörg; Schoo, Burkhard; Ecke, Wolfgang; Herrfurth, Cornelia; Feussner, Ivo; Becker, Heiko C; Möllers, Christian

    2013-09-01

    Following winter oilseed rape cultivation, considerable numbers of volunteer oilseed rape plants may occur in subsequent years in following crops. The appearance of volunteer oilseed rape plants is based on the capability of the seeds to become secondary dormant and to survive in this stage for many years in the soil. Genetic reduction of secondary seed dormancy in oilseed rape could provide a means to reduce the frequency of volunteer plants and especially the dispersal of transgenic oilseed rape. The objective of the present study was to analyse the inheritance of primary and secondary seed dormancy in a winter oilseed rape doubled haploid population derived from the cross Express 617 × R53 and to study correlations to other seed traits. Field experiments were performed in Germany for 2 years at two locations with two replicates. Seeds harvested from open pollinated plants were used for all analyses, including a laboratory test for seed dormancy. A previously developed molecular marker map of the doubled haploid population was used to map QTL of the relevant traits. For primary, secondary and total seed dormancy, the results showed significant effects of the genotypes and their interactions, with years and locations. Two, four and five QTL were detected for primary, secondary and total seed dormancy which explained 19, 35 and 42 % of the phenotypic variance, respectively. Results show that secondary seed dormancy is a heritable trait and that selection for low secondary seed dormancy is possible.

  11. Jasmonic acid-dependent regulation of seed dormancy following maternal herbivory in Arabidopsis.

    Science.gov (United States)

    Singh, Prashant; Dave, Anuja; Vaistij, Fabian E; Worrall, Dawn; Holroyd, Geoff H; Wells, Jonathan G; Kaminski, Filip; Graham, Ian A; Roberts, Michael R

    2017-06-01

    Maternal experience of abiotic environmental factors such as temperature and light are well known to control seed dormancy in many plant species. Maternal biotic stress alters offspring defence phenotypes, but whether it also affects seed dormancy remains unexplored. We exposed Arabidopsis thaliana plants to herbivory and investigated plasticity in germination and defence phenotypes in their offspring, along with the roles of phytohormone signalling in regulating maternal effects. Maternal herbivory resulted in the accumulation of jasmonic acid-isoleucine and loss of dormancy in seeds of stressed plants. Dormancy was also reduced by engineering seed-specific accumulation of jasmonic acid in transgenic plants. Loss of dormancy was dependent on an intact jasmonate signalling pathway and was associated with increased gibberellin content and reduced abscisic acid sensitivity during germination. Altered dormancy was only observed in the first generation following herbivory, whereas defence priming was maintained for at least two generations. Herbivory generates a jasmonic acid-dependent reduction in seed dormancy, mediated by alteration of gibberellin and abscisic acid signalling. This is a direct maternal effect, operating independently from transgenerational herbivore resistance priming. © 2017 The Authors. New Phytologist © 2017 New Phytologist Trust.

  12. Regulation of abscisic acid metabolism in relation to the dormancy and germination of cereal grains

    Directory of Open Access Journals (Sweden)

    Justyna Fidler

    2015-03-01

    Full Text Available Seed dormancy is of particular importance in the cultivation of cereals, as it directly affects the quality of crop yield. If the dormancy period is too short, this may lead to pre-harvest sprouting, whereas a dormancy period that is too long may cause uneven germination; both of these scenarios are associated with economic losses. Most enzymes engaged in the metabolism of abscisic acid (ABA have been identified, and significant progress has been made in understanding the role of this phytohormone in the induction and maintenance of dormancy, mainly as a result of research conducted in Arabidopsis. Much less is known about the metabolism and function of ABA in cereal grains, especially in relation to dormancy and germination. This review focuses on the regulation of ABA metabolism in dormant and non-dormant cereal grains, in both the dry state and upon imbibition. Moreover, this review describes the influence of factors such as after-ripening, light, temperature, nitric oxide, and reactive oxygen species (ROS on the dormancy and germination of cereal grains. These factors, with the exception of ROS, appear to affect the level of dormancy and germination of grains through regulation of ABA metabolism.

  13. A Novel Method to Overcome Coat-Imposed Seed Dormancy in Lupinus albus L. and Trifolium pratense L.

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    Iskender Tiryaki

    2014-01-01

    Full Text Available We have developed a novel method to overcome coat-imposed seed dormancy in legume plants. Seeds of Lupinus albus L. and Trifolium pratense L. were stored in a freezer at −80°C for a period of time and then immediately treated with or without hot water at 90°C for 5 seconds. Germination tests were carried out in darkness at 20±1.0°C with four replications in a completely randomized design. Final germination percentage (FGP, germination rate, and synchrony of seeds were evaluated. The results showed that new approach of freeze-thaw scarification provided high percentage of germinations in white lupin (84.16% and red clover (74.50% seeds while control seeds had FGPs of 3.3% and 26.0%, respectively. The immediate thawing of frozen seeds in hot water for 5 seconds was found not only an effective and reliable but also the quickest seed treatment method to prevail against coat-imposed seed dormancy in legume species and may become operationally applicable to other plant species.

  14. The First Human Cloned Embryo.

    Science.gov (United States)

    Cibelli, Jose B.; Lanza, Robert P.; West, Michael D.; Ezzell, Carol

    2002-01-01

    Describes a process known as parthenogenesis which produces cloned, early-stage embryos and human embryos generated only from eggs. Speculates that this technology puts therapeutic cloning within reach. (DDR)

  15. Transcriptome analysis identifies novel responses and potential regulatory genes involved in seasonal dormancy transitions of leafy spurge (Euphorbia esula L.).

    Science.gov (United States)

    Horvath, David P; Chao, Wun S; Suttle, Jeffrey C; Thimmapuram, Jyothi; Anderson, James V

    2008-11-12

    Dormancy of buds is a critical developmental process that allows perennial plants to survive extreme seasonal variations in climate. Dormancy transitions in underground crown buds of the model herbaceous perennial weed leafy spurge were investigated using a 23 K element cDNA microarray. These data represent the first large-scale transcriptome analysis of dormancy in underground buds of an herbaceous perennial species. Crown buds collected monthly from August through December, over a five year period, were used to monitor the changes in the transcriptome during dormancy transitions. Nearly 1,000 genes were differentially-expressed through seasonal dormancy transitions. Expected patterns of gene expression were observed for previously characterized genes and physiological processes indicated that resolution in our analysis was sufficient for identifying shifts in global gene expression. Gene ontology of differentially-expressed genes suggests dormancy transitions require specific alterations in transport functions (including induction of a series of mitochondrial substrate carriers, and sugar transporters), ethylene, jasmonic acid, auxin, gibberellic acid, and abscisic acid responses, and responses to stress (primarily oxidative and cold/drought). Comparison to other dormancy microarray studies indicated that nearly half of the genes identified in our study were also differentially expressed in at least two other plant species during dormancy transitions. This comparison allowed us to identify a particular MADS-box transcription factor related to the DORMANCY ASSOCIATED MADS-BOX genes from peach and hypothesize that it may play a direct role in dormancy induction and maintenance through regulation of FLOWERING LOCUS T.

  16. Ovarian stimulation and embryo quality

    NARCIS (Netherlands)

    Baart, Esther; Macklon, Nick S.; Fauser, Bart J. C. M.

    To Study the effects of different ovarian stimulation approaches on oocyte and embryo quality, it is imperative to assess embryo quality with a reliable and objective method. Embryos rated as high quality by standardized morphological assessment are associated with higher implantation and pregnancy

  17. impact on embryo quality

    Directory of Open Access Journals (Sweden)

    Marijan Tandara

    2013-05-01

    Conclusions: In men with poorer semen quality, evaluated by standard semen parameters, a higher proportion of sperm with damaged DNA can also be expected. Higher sperm DNA damage, established by Halosperm test, also had an impact on embryo quality in this group of patients.

  18. Embryo cryopreservation and in vitro culture of preimplantation embryos in Campbell's hamster (Phodopus campbelli).

    Science.gov (United States)

    Amstislavsky, Sergei; Brusentsev, Eugeny; Kizilova, Elena; Igonina, Tatyana; Abramova, Tatyana; Rozhkova, Irina

    2015-04-01

    The aims of this study were to compare different protocols of Campbell's hamster (Phodopus campbelli) embryos freezing-thawing and to explore the possibilities of their in vitro culture. First, the embryos were flushed from the reproductive ducts 2 days post coitum at the two-cell stage and cultured in rat one-cell embryo culture medium (R1ECM) for 48 hours. Most (86.7%) of the two-cell embryos developed to blastocysts in R1ECM. Second, the embryos at the two- to eight-cell stages were flushed on the third day post coitum. The eight-cell embryos were frozen in 0.25 mL straws according to standard procedures of slow cooling. Ethylene glycol (EG) was used either as a single cryoprotectant or in a mixture with sucrose. The survival of frozen-thawed embryos was assessed by double staining with fluorescein diacetate and propidium iodide. The use of EG as a single cryoprotectant resulted in fewer alive embryos when compared with control (fresh embryos), but combined use of EG and sucrose improved the survival rate after thawing. Furthermore, granulocyte-macrophage colony-stimulating factor rat (2 ng/mL) improved the rate of the hamster frozen-thawed embryo development in vitro by increasing the final cell number and alleviating nuclear fragmentation. Our data show the first attempt in freezing and thawing Campbell's hamster embryos and report the possibility of successful in vitro culture for this species in R1ECM supplemented with granulocyte-macrophage colony-stimulating factor. Copyright © 2015 Elsevier Inc. All rights reserved.

  19. Quebra de dormência, viabilidade e conservação de sementes de buriti (Mauritia flexuosa Dormancy breaking, viability and conservation of Mauritia flexuosa seeds

    Directory of Open Access Journals (Sweden)

    Maria Roseli Nicoli Spera

    2001-12-01

    Full Text Available Os objetivos deste trabalho foram avaliar a viabilidade de embriões de buriti (Mauritia flexuosa L. pelo teste de tetrazólio e cultivo in vitro, o tratamento térmico na quebra de dormência das sementes, e o efeito do armazenamento em duas temperaturas na conservação das sementes. A viabilidade de embriões de sementes recém-colhidas foi condizente com os resultados de germinação de embriões in vitro, com valores superiores a 90%. O estudo da quebra de dormência foi feito com tratamento das sementes em temperaturas de 30, 35 e 40ºC por períodos de 15, 30 e 45 dias. Até 15 e 30 dias, os resultados obtidos foram maiores que os do controle. Sementes armazenadas em saco de plástico por um período de quatro meses e meio, sob temperatura de 20ºC, apresentaram resultados de germinação de embrião superiores a 90%, e sob temperatura de 30ºC houve perda total da viabilidade.The present work was conducted to evaluate the viability of embryos of Mauritia flexuosa L. by tetrazolium test and in vitro culture, high temperature treatment on dormancy breaking, and the effect of storage at different temperatures on seed conservation. The viability of newly harvested embryos presented a high correlation with the rate of embryo germination in vitro. The rate of viability was higher than 90% either when evaluated by the tetrazolium method or by in vitro embryo culture. Dormancy breaking of seeds was tested by treating the seeds under temperatures of 30, 35 and 40ºC for 15, 30, and 45 days. Great variation was observed among treatments, but, at least on day 15 and on day 30, the germination was higher than in the control. Seeds stored in plastic bags for four and a half months and temperature of 20ºC presented a germination rate higher than 90% while in the seeds stored at 30ºC the viability was zero.

  20. Embryo Aggregation in Pig Improves Cloning Efficiency and Embryo Quality.

    Science.gov (United States)

    Buemo, Carla Paola; Gambini, Andrés; Moro, Lucia Natalia; Hiriart, María Inés; Fernández-Martín, Rafael; Collas, Philippe; Salamone, Daniel Felipe

    2016-01-01

    In this study, we analyzed the effects of the cloned embryo aggregation on in vitro embryo development and embryo quality by measuring blastocyst diameter and cell number, DNA fragmentation levels and the expression of genes associated with pluripotency, apoptosis, trophoblast and DNA methylation in the porcine. Zona-free reconstructed cloned embryos were cultured in the well of the well system, placing one (1x non aggregated group) or three (3x group) embryos per microwell. Our results showed that aggregation of three embryos increased blastocyst formation rate and blastocyst diameter of cloned pig embryos. DNA fragmentation levels in 3x aggregated cloned blastocysts were significantly decreased compared to 1x blastocysts. Levels of Oct4, Klf4, Igf2, Bax and Dnmt 1 transcripts were significantly higher in aggregated embryos, whereas Nanog levels were not affected. Transcripts of Cdx2 and Bcl-xl were essentially non-detectable. Our study suggests that embryo aggregation in the porcine may be beneficial for cloned embryo development and embryo quality, through a reduction in apoptotic levels and an improvement in cell reprogramming.

  1. Seed storage-mediated dormancy alleviation in Fabaceae from campo rupestre

    Directory of Open Access Journals (Sweden)

    Naïla Nativel

    2015-09-01

    Full Text Available ABSTRACTWe studied the effects of seed storage on germination and dormancy alleviation in three species of Fabaceae endemic to campo rupestrein southeastern Brazil. Fresh seeds of Collaea cipoensis, Mimosa maguirei and Mimosa foliolosawere set to germinate and germination of seeds after four, five and 13 years of storage was tested. Seed viability was maintained for all species after the full storage period. Seed storage significantly increased germination percentage and decreased germination time for C. cipoensisand M. foliolosa, suggesting the alleviation of physical dormancy with storage. However, we did not find evidence of dormancy alleviation in M. maguirei since stored seeds showed a decrease in germination in comparison to that of fresh seeds. Our data indicate species-specific storage-mediated dormancy alleviation, which will have important implications for restoration of campo rupestre.

  2. Genes controlling seed dormancy and pre-harvest sprouting in a rice-wheat-barley comparison

    DEFF Research Database (Denmark)

    Li, Chengdao; Ni, Peixiang; Francki, Michael

    2004-01-01

    . A major QTL controlling both pre-harvest sprouting and seed dormancy has been identified on the long arm of barley chromosome 5H, and it explains over 70% of the phenotypic variation. Comparative genomics approaches among barley, wheat and rice were used to identify candidate gene(s) controlling seed...... dormancy and hence one aspect of pre-harvest sprouting. The barley seed dormancy/pre-harvest sprouting QTL was located in a region that showed good synteny with the terminal end of the long arm of rice chromosome 3. The rice DNA sequences were annotated and a gene encoding GA20-oxidase was identified...... was syntenic to both rice chromosome 3 and 11. In both cases, corresponding QTLs for seed dormancy have been mapped in rice. Udgivelsesdato: 2004-May...

  3. Dormancy cycling and persistence of seeds in soil of a cold desert halophyte shrub

    National Research Council Canada - National Science Library

    Cao, Dechang; Baskin, Carol C; Baskin, Jerry M; Yang, Fan; Huang, Zhenying

    2014-01-01

    .... In this study it was hypothesized that the long-lived halophytic cold desert shrub Kalidium gracile has a seed bank and dormancy cycling, which help restrict germination to a favourable time for seedling survival...

  4. Effect of ethanol and plant growth regulators on termination of potato microtuber dormancy

    Directory of Open Access Journals (Sweden)

    Wróbel Sławomir

    2015-12-01

    Full Text Available The duration of dormancy varies significantly among cultivars, but even short dormancy can limit usage of potato microtubers for seed production. The aim of the research was to test efficacy of dormancy breaking by treatment with an aqueous solution of ethyl alcohol, saccharose, gibberellic acid and kinetin (ethanol treatment in comparison to treatment with aqueous solution of thiourea, daminozide and gibberellic acid (standard treatment. Prolonging the period of microtuber production at the in vitro stage significantly favored the short-ening of the dormancy and facilitated its breaking. While the standard treatment had the strongest effect, the ethanol treatment was slightly less efficient. The statistically significant differences were only observed during the first 13 days after the microtuber treatment. After that time, efficacy of ethanol and standard treatments was similar to control treatment with water. The investigated treatments had no effect on the natural decrease of ABA level in microtubers.

  5. The effects of temperature on the dormancy and germination of Cirsium arvense (L. Scop. seeds

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    Anna Bochenek

    2011-01-01

    Full Text Available The ecophysiological regulation of seed dormancy in perennial species and those with a varied life cycle has not been studied in detail yet. That is why an attempt has been made to determine the Cirsium arvense seed water relations during stratification and afterripening at different temperatures and germination at constant or fluctuating temperatures on the basis of the hydrotime model. The obtained results showed that breaking of the primary dormancy of achenes took place only during the first stratification month at moderate temperatures, mainly due to an increase in the average water-stress tolerance in a seed population. The induction of secondary seed dormancy during after-ripening at all temperatures resulted mostly from a substantial loss of the seeds' ability to tolerate water stress. Fluctuating temperatures affected neither seed germination nor the hydrotime model parameters. The analysis of the variations of hydrotime model parameters allows a better understanding of the physiological basis of seed dormancy relief and induction.

  6. Obscured phylogeny and possible recombinational dormancy in Escherichia coli

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    Sawyer Stanley A

    2011-06-01

    Full Text Available Abstract Background Escherichia coli is one of the best studied organisms in all of biology, but its phylogenetic structure has been difficult to resolve with current data and analytical techniques. We analyzed single nucleotide polymorphisms in chromosomes of representative strains to reconstruct the topology of its emergence. Results The phylogeny of E. coli varies according to the segment of chromosome analyzed. Recombination between extant E. coli groups is largely limited to only three intergroup pairings. Conclusions Segment-dependent phylogenies most likely are legacies of a complex recombination history. However, E. coli are now in an epoch in which they no longer broadly share DNA. Using the definition of species as organisms that freely exchange genetic material, this recombinational dormancy could reflect either the end of E. coli as a species, or herald the coalescence of E. coli groups into new species.

  7. An Endosperm-Associated Cuticle Is Required for Arabidopsis Seed Viability, Dormancy and Early Control of Germination.

    Directory of Open Access Journals (Sweden)

    Julien De Giorgi

    2015-12-01

    Full Text Available Cuticular layers and seeds are prominent plant adaptations to terrestrial life that appeared early and late during plant evolution, respectively. The cuticle is a waterproof film covering plant aerial organs preventing excessive water loss and protecting against biotic and abiotic stresses. Cutin, consisting of crosslinked fatty acid monomers, is the most abundant and studied cuticular component. Seeds are dry, metabolically inert structures promoting plant dispersal by keeping the plant embryo in an arrested protected state. In Arabidopsis thaliana seeds, the embryo is surrounded by a single cell endosperm layer itself surrounded by a seed coat layer, the testa. Whole genome analyses lead us to identify cutin biosynthesis genes as regulatory targets of the phytohormones gibberellins (GA and abscisic acid (ABA signaling pathways that control seed germination. Cutin-containing layers are present in seed coats of numerous species, including Arabidopsis, where they regulate permeability to outer compounds. However, the role of cutin in mature seed physiology and germination remains poorly understood. Here we identify in mature seeds a thick cuticular film covering the entire outer surface of the endosperm. This seed cuticle is defective in cutin-deficient bodyguard1 seeds, which is associated with alterations in endospermic permeability. Furthermore, mutants affected in cutin biosynthesis display low seed dormancy and viability levels, which correlates with higher levels of seed lipid oxidative stress. Upon seed imbibition cutin biosynthesis genes are essential to prevent endosperm cellular expansion and testa rupture in response to low GA synthesis. Taken together, our findings suggest that in the course of land plant evolution cuticular structures were co-opted to achieve key physiological seed properties.

  8. NATURAL ACID IN OVERCOMING PINHA SEED DORMANCY (ANNONA SQUAMOSA L.

    Directory of Open Access Journals (Sweden)

    A. R. Santos

    2018-02-01

    Full Text Available The production of good quality seedlings becomes essential strategy for those who wish to become production that is more competitive. To induce dormancy breaking and germination and emergence of these, the imbibing of natural acid in seeds can be an alternative for the optimization of this process. The aim of this study is to evaluate the dormancy breaking in Anonna seeds squamosa immersed in different natural acid in times through the lemon juice Rangpur (Citrus limonia Osbeck. This work is being conducted in Biotecnogia laboratory greenhouse at the Federal Institute Goiano campus Urutaí where the seeds were soaked in lemon juice Rangpur (C. limonia in five different times, each time constituting a treatment: seeds without soaking in lemon groove variety Cravo '(T1; soaked for 8 hours (T2; soaked for 16 hours (T3; soaked for 24 hours (T4; soaked for 32 hours (T5. The seeds were sown in plastic boxes with dimensions 40 x 27 x 10 cm, containing washed sand substrate, 2 cm deep in spacing of 2 x 2 cm. The germination percentage data were determined up to 45 days after sowing (DAS, and survival to 73 (DAS. After 73 DAS were evaluated after 73 days of sowing, they were evaluated; germination and survival; emergence speed index (EVI; total length of seedlings; shoot length of seedlings and radicle length (cm; Stem diameter (mm; pair of leaf number (MPN; total fresh mass changes (MFT; dry matter of shoot and radicle (g. There was not statistical diseases among treatments. T4 treatment in comparison to others on the numerical difference CTM, NPF, DC and CPA.

  9. Dormancy in reproductive vegetative buds in creeping perennials dominating the agricultural weed flora in Scandinavia

    OpenAIRE

    Liew, Josefine

    2013-01-01

    Dormancy, which is the inability to initiate normal growth under otherwise favourable conditions, is an adaptation to escape sprouting prior to seasonal cold temperatures and/or drought in areas where winters are harsh or summers dry. Dormancy in woody perennials of northern temperate areas is, in general, induced by photoperiodic and/or temperature changes, and released after prolonged exposure to chilling. Besides being species specific, northern ecotypes are usually more sensitive to induc...

  10. Catalase inhibition accelerates dormancy release and sprouting in potato (Solanum tuberosum L.) tubers.

    OpenAIRE

    Mohammed Bajji; Mahmoud M’Hamdi; Frédéric Gastiny; Jorge A. Rojas-Beltran; Patrick du Jardin

    2007-01-01

    The involvement of hydrogen peroxide (H2O2) metabolism in dormancy release and sprouting of potato (Solanum tuberosum L.) tubers has been investigated using three complementary approaches. In the first approach, the evolution of the sprouting kinetics, H2O2 content and antioxidant enzyme activities were examined during tuber storage. The most important changes occurred at the « bud/sprout » level. In particular, dormancy release was accompanied by a transient but remarkable increase in H2O2 c...

  11. Metagenomic analysis of buffalo rumen microbiome: Effect of roughage diet on Dormancy and Sporulation genes

    OpenAIRE

    Singh, K.M.; Reddy, B; Patel, A K; H. Panchasara; Parmar, N.; Patel, A.B.; T.M. Shah; V.D. Bhatt; Joshi, C. G.

    2014-01-01

    Buffalo rumen microbiome experiences a variety of diet stress and represents reservoir of Dormancy and Sporulation genes. However, the information on genomic responses to such conditions is very limited. The Ion Torrent PGM next generation sequencing technology was used to characterize general microbial diversity and the repertoire of microbial genes present, including genes associated with Dormancy and Sporulation in Mehsani buffalo rumen metagenome. The research findings revealed the abunda...

  12. Presowing treatments to breaking seed dormancy of Pterocarya stenoptera C. DC. as an indicator of potential invasiveness

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    Grbić Mihailo

    2011-01-01

    Full Text Available The Small-winged wingnut is a 12 to 20 metres tall, deciduous and fast growing tree with large substantial branches that spread as wide as the tree is tall. The 15 to 30 cm long winged fruit catkins, which turn brown in the autumn, are suspended below the branches. The species is not described by domestic authors in Serbia. The seed was introduced from Sofia (from the Arboretum of the Forestry University of Sofia, Bulgaria - Lesotehničeski universitet, Sofija, and subjected to classical stratification and naked stratification during the period of 1 and 2 months. Germination capacity varied among the treatments. The largest number of germinated seeds was observed in the shorter stratifications, (1 month the classical (56.5% and the naked (51.0% with no significant difference. The values of real germination of all treatments were between 69-88%. High value of RG, compared to GC, indicated that more than 40% of the seeds were empty. However, the results of the control as well as other parameters of seed germination clearly point to the fact that practically no deep embryo dormancy was observed, but the seed is recalcitrant and microbiotic. The results indicate a non-invasive character of the species in terms of reproductive potential.

  13. Involvement of the ethylene response pathway in dormancy induction in chrysanthemum

    Science.gov (United States)

    Sumitomo, Katsuhiko; Satoh, Shigeru; Hisamatsu, Tamotsu

    2008-01-01

    Temperature plays a significant role in the annual cycling between growth and dormancy of the herbaceous perennial chrysanthemum (Chrysanthemum morifolium Ramat.). After exposure to high summer temperatures, cool temperature triggers dormancy. The cessation of flowering and rosette formation by the cessation of elongation are characteristic of dormant plants, and can be stimulated by exogenous ethylene. Thus, the ethylene response pathway may be involved in temperature-induced dormancy of chrysanthemum. Transgenic chrysanthemums expressing a mutated ethylene receptor gene were used to assess this involvement. The transgenic lines showed reduced ethylene sensitivity: ethylene causes leaf yellowing in wild-type chrysanthemums, but leaves remained green in the transgenic lines. Extension growth and flowering of wild-type and transgenic lines varied between temperatures: at 20 °C, the transgenic lines showed the same stem elongation and flowering as the wild type; at cooler temperatures, the wild type formed rosettes with an inability to flower and entered dormancy, but some transgenic lines continued to elongate and flower. This supports the involvement of the ethylene response pathway in the temperature-induced dormancy of chrysanthemum. At the highest dosage of ethephon, an ethylene-releasing agent, wild-type plants formed rosettes with an inability to flower and became dormant, but one transgenic line did not. This confirms that dormancy is induced via the ethylene response pathway. PMID:18952907

  14. Chilling-Mediated DNA Methylation Changes during Dormancy and Its Release Reveal the Importance of Epigenetic Regulation during Winter Dormancy in Apple (Malus x domestica Borkh.)

    Science.gov (United States)

    Kumar, Gulshan; Rattan, Usha Kumari; Singh, Anil Kumar

    2016-01-01

    Winter dormancy is a well known mechanism adopted by temperate plants, to mitigate the chilling temperature of winters. However, acquisition of sufficient chilling during winter dormancy ensures the normal phenological traits in subsequent growing period. Thus, low temperature appears to play crucial roles in growth and development of temperate plants. Apple, being an important temperate fruit crop, also requires sufficient chilling to release winter dormancy and normal phenological traits, which are often associated with yield and quality of fruits. DNA cytosine methylation is one of the important epigenetic modifications which remarkably affect the gene expression during various developmental and adaptive processes. In present study, methylation sensitive amplified polymorphism was employed to assess the changes in cytosine methylation during dormancy, active growth and fruit set in apple, under differential chilling conditions. Under high chill conditions, total methylation was decreased from 27.2% in dormant bud to 21.0% in fruit set stage, while no significant reduction was found under low chill conditions. Moreover, the demethylation was found to be decreased, while methylation increased from dormant bud to fruit set stage under low chill as compared to high chill conditions. In addition, RNA-Seq analysis showed high expression of DNA methyltransferases and histone methyltransferases during dormancy and fruit set, and low expression of DNA glcosylases during active growth under low chill conditions, which was in accordance with changes in methylation patterns. The RNA-Seq data of 47 genes associated with MSAP fragments involved in cellular metabolism, stress response, antioxidant system and transcriptional regulation showed correlation between methylation and their expression. Similarly, bisulfite sequencing and qRT-PCR analysis of selected genes also showed correlation between gene body methylation and gene expression. Moreover, significant association

  15. Cycling of Sensitivity to Physical Dormancy-break in Seeds of Ipomoea lacunosa (Convolvulaceae) and Ecological Significance

    Science.gov (United States)

    Jayasuriya, K. M. G. G.; Baskin, J. M.; Baskin, C. C.

    2008-01-01

    Background and Aims Although a claim has been made that dormancy cycling occurs in seeds of Ipomoea lacunosa (Convolvulaceae) with physical dormancy, this would seem to be impossible since the water gap cannot be closed again after it opens (dormancy break). On the other hand, changes in sensitivity (sensitive ↔ non-sensitive) to dormancy-breaking factors have been reported in seeds of Fabaceae with physical dormancy. The primary aim of the present study was to determine if sensitivity cycling also occurs in physically dormant seeds of I. lacunosa. Methods Treatments simulating conditions in the natural habitat of I. lacunosa were used to break seed dormancy. Storage of seeds at temperatures simulating those in spring, summer, autumn and winter were tested for their effect on sensitivity change. Seeds made non-dormant were stored dry in different temperature regimes to test for dormancy cycling. In addition, seeds collected on different dates (i.e. matured under different climatic conditions) were used to test for maternal effects on sensitivity to dormancy-breaking factors. Key Results Sensitivity was induced by storing seeds under wet conditions and reversed by storing them under dry conditions at low (≤5 °C) or high (≥30 °C) temperatures, demonstrating that seeds of I. lacunosa can cycle between sensitive and insensitive states. Sensitive seeds required ≥2 h at 35 °C on moist sand for release of dormancy. However, there is no evidence to support dormancy cycling per se. Conceptual models are proposed for sensitivity cycling and germination phenology of I. lacunosa in the field. Conclusions Seasonal germination behaviour of physically dormant I. lacunosa seeds can be explained by sensitivity cycling but not by dormancy cycling per se. Convolvulaceae is only the second of 16 families known to contain species with physical dormancy for which sensitivity cycling has been demonstrated. PMID:18032427

  16. Dormancy, ABA content and sensitivity of a barley mutant to ABA application during seed development and after ripening

    OpenAIRE

    Romagosa, Ignacio; Prada, Darío; Moralejo, María Ángeles; Sopena, A.; Muñoz, Pilar; Casas Cendoya, Ana María; Swanston, J. S.; Molina-Cano, José Luis

    2001-01-01

    Assessment of dormancy inception, maintenance and release was studied for artificially dried immature seeds harvested throughout seed development in the barley cv. Triumph and its mutant line TL43. Each was grown in Spain and Scotland under low and high dormancy inducing conditions, respectively. Both TL43 and Triumph followed a similar pattern of release from dormancy across the seasons, although seeds of TL43 were able to germinate at an earlier seed development stage. Abscisic acid (ABA) c...

  17. Dormancy release and flowering time in Ziziphus jujuba Mill., a "direct flowering" fruit tree, has a facultative requirement for chilling.

    Science.gov (United States)

    Meir, Michal; Ransbotyn, Vanessa; Raveh, Eran; Barak, Simon; Tel-Zur, Noemi; Zaccai, Michele

    2016-03-15

    In deciduous fruit trees, the effect of chilling on flowering has mostly been investigated in the "indirect flowering" group, characterized by a period of rest between flower bud formation and blooming. In the present study, we explored the effects of chilling and chilling deprivation on the flowering of Ziziphus jujuba, a temperate deciduous fruit tree belonging to the "direct flowering" group, in which flower bud differentiation, blooming and fruit development occur after dormancy release, during a single growing season. Dormancy release, vegetative growth and flowering time in Z. jujuba cv. Ben-Li were assessed following several treatments of chilling. Chilling treatments quantitatively decreased the timing of vegetative bud dormancy release, thereby accelerating flowering, but had no effect on the time from dormancy release to flowering. Trees grown at a constant temperature of 25°C, without chilling, broke dormancy and flowered, indicating the facultative character of chilling in this species. We measured the expression of Z. jujuba LFY and AP1 homologues (ZjLFY and ZjAP1). Chilling decreased ZjLFY expression in dormant vegetative buds but had no effect on ZjAP1expression, which reached peak expression before dormancy release and at anthesis. In conclusion, chilling is not obligatory for dormancy release of Z. jujuba cv. Ben-Li vegetative buds. However, the exposure to chilling during dormancy does accelerate vegetative bud dormancy release and flowering. Copyright © 2016 Elsevier GmbH. All rights reserved.

  18. Tanned or burned: the role of fire in shaping physical seed dormancy.

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    Bruno Moreira

    Full Text Available Plant species with physical seed dormancy are common in mediterranean fire-prone ecosystems. Because fire breaks seed dormancy and enhances the recruitment of many species, this trait might be considered adaptive in fire-prone environments. However, to what extent the temperature thresholds that break physical seed dormancy have been shaped by fire (i.e., for post-fire recruitment or by summer temperatures in the bare soil (i.e., for recruitment in fire-independent gaps remains unknown. Our hypothesis is that the temperature thresholds that break physical seed dormancy have been shaped by fire and thus we predict higher dormancy lost in response to fire than in response to summer temperatures. We tested this hypothesis in six woody species with physical seed dormancy occurring in fire-prone areas across the Mediterranean Basin. Seeds from different populations of each species were subject to heat treatments simulating fire (i.e., a single high temperature peak of 100 °C, 120 °C or 150 °C for 5 minutes and heat treatments simulating summer (i.e., temperature fluctuations; 30 daily cycles of 3 hours at 31 °C, 4 hours at 43 °C, 3 hours at 33 °C and 14 hours at 18 °C. Fire treatments broke dormancy and stimulated germination in all populations of all species. In contrast, summer treatments had no effect over the seed dormancy for most species and only enhanced the germination in Ulex parviflorus, although less than the fire treatments. Our results suggest that in Mediterranean species with physical dormancy, the temperature thresholds necessary to trigger seed germination are better explained as a response to fire than as a response to summer temperatures. The high level of dormancy release by the heat produced by fire might enforce most recruitment to be capitalized into a single post-fire pulse when the most favorable conditions occur. This supports the important role of fire in shaping seed traits.

  19. Tanned or Burned: The Role of Fire in Shaping Physical Seed Dormancy

    Science.gov (United States)

    Moreira, Bruno; Pausas, Juli G.

    2012-01-01

    Plant species with physical seed dormancy are common in mediterranean fire-prone ecosystems. Because fire breaks seed dormancy and enhances the recruitment of many species, this trait might be considered adaptive in fire-prone environments. However, to what extent the temperature thresholds that break physical seed dormancy have been shaped by fire (i.e., for post-fire recruitment) or by summer temperatures in the bare soil (i.e., for recruitment in fire-independent gaps) remains unknown. Our hypothesis is that the temperature thresholds that break physical seed dormancy have been shaped by fire and thus we predict higher dormancy lost in response to fire than in response to summer temperatures. We tested this hypothesis in six woody species with physical seed dormancy occurring in fire-prone areas across the Mediterranean Basin. Seeds from different populations of each species were subject to heat treatments simulating fire (i.e., a single high temperature peak of 100°C, 120°C or 150°C for 5 minutes) and heat treatments simulating summer (i.e., temperature fluctuations; 30 daily cycles of 3 hours at 31°C, 4 hours at 43°C, 3 hours at 33°C and 14 hours at 18°C). Fire treatments broke dormancy and stimulated germination in all populations of all species. In contrast, summer treatments had no effect over the seed dormancy for most species and only enhanced the germination in Ulex parviflorus, although less than the fire treatments. Our results suggest that in Mediterranean species with physical dormancy, the temperature thresholds necessary to trigger seed germination are better explained as a response to fire than as a response to summer temperatures. The high level of dormancy release by the heat produced by fire might enforce most recruitment to be capitalized into a single post-fire pulse when the most favorable conditions occur. This supports the important role of fire in shaping seed traits. PMID:23227267

  20. Dormancy cycling and persistence of seeds in soil of a cold desert halophyte shrub

    Science.gov (United States)

    Cao, Dechang; Baskin, Carol C.; Baskin, Jerry M.; Yang, Fan; Huang, Zhenying

    2014-01-01

    Background and Aims Formation of seed banks and dormancy cycling are well known in annual species, but not in woody species. In this study it was hypothesized that the long-lived halophytic cold desert shrub Kalidium gracile has a seed bank and dormancy cycling, which help restrict germination to a favourable time for seedling survival. Methods Fresh seeds were buried in November 2009 and exhumed and tested for germination monthly from May 2010 to December 2011 over a range of temperatures and salinities. Germination recovery and viability were determined after exposure to salinity and water stress. Seedling emergence and dynamics of the soil seed bank were investigated in the field. Key Results Seeds of K. gracile had a soil seed bank of 7030 seeds m−2 at the beginning of the growing season. About 72 % of the seeds were depleted from the soil seed bank during a growing season, and only 1·4 % of them gave rise to seedlings that germinated early enough to reach a stage of growth at which they could survive to overwinter. About 28 % of the seeds became part of a persistent soil seed bank. Buried seeds exhibited an annual non-dormancy/conditional dormancy (ND/CD) cycle, and germination varied in sensitivity to salinity during the cycle. Dormancy cycling is coordinated with seasonal environmental conditions in such a way that the seeds germinate in summer, when there is sufficient precipitation for seedling establishment. Conclusions Kalidium gracile has three life history traits that help ensure persistence at a site: a polycarpic perennial life cycle, a persistent seed bank and dormancy cycling. The annual ND/CD cycle in seeds of K. gracile contributes to seedling establishment of this species in the unpredictable desert environment and to maintenance of a persistent soil seed bank. This is the first report of a seed dormancy cycle in a cold desert shrub. PMID:24249808

  1. Dormancy cycling and persistence of seeds in soil of a cold desert halophyte shrub.

    Science.gov (United States)

    Cao, Dechang; Baskin, Carol C; Baskin, Jerry M; Yang, Fan; Huang, Zhenying

    2014-01-01

    Formation of seed banks and dormancy cycling are well known in annual species, but not in woody species. In this study it was hypothesized that the long-lived halophytic cold desert shrub Kalidium gracile has a seed bank and dormancy cycling, which help restrict germination to a favourable time for seedling survival. Fresh seeds were buried in November 2009 and exhumed and tested for germination monthly from May 2010 to December 2011 over a range of temperatures and salinities. Germination recovery and viability were determined after exposure to salinity and water stress. Seedling emergence and dynamics of the soil seed bank were investigated in the field. Seeds of K. gracile had a soil seed bank of 7030 seeds m(-2) at the beginning of the growing season. About 72 % of the seeds were depleted from the soil seed bank during a growing season, and only 1·4 % of them gave rise to seedlings that germinated early enough to reach a stage of growth at which they could survive to overwinter. About 28 % of the seeds became part of a persistent soil seed bank. Buried seeds exhibited an annual non-dormancy/conditional dormancy (ND/CD) cycle, and germination varied in sensitivity to salinity during the cycle. Dormancy cycling is coordinated with seasonal environmental conditions in such a way that the seeds germinate in summer, when there is sufficient precipitation for seedling establishment. Kalidium gracile has three life history traits that help ensure persistence at a site: a polycarpic perennial life cycle, a persistent seed bank and dormancy cycling. The annual ND/CD cycle in seeds of K. gracile contributes to seedling establishment of this species in the unpredictable desert environment and to maintenance of a persistent soil seed bank. This is the first report of a seed dormancy cycle in a cold desert shrub.

  2. Changing climate cues differentially alter zooplankton dormancy dynamics across latitudes.

    Science.gov (United States)

    Jones, Natalie T; Gilbert, Benjamin

    2016-03-01

    In seasonal climates, dormancy is a common strategy that structures biodiversity and is necessary for the persistence of many species. Climate change will likely alter dormancy dynamics in zooplankton, the basis of aquatic food webs, by altering two important hatching cues: mean temperatures during the ice-free season, and mean day length when lakes become ice free. Theory suggests that these changes could alter diversity, hatchling abundances and phenology within lakes, and that these responses may diverge across latitudes due to differences in optimal hatching cues and strategies. To examine the role of temperature and day length on hatching dynamics, we collected sediment from 25 lakes across a 1800 km latitudinal gradient and exposed sediment samples to a factorial combination of two photoperiods (12 and 16 h) and two temperatures (8 and 12 °C) representative of historical southern (short photoperiod, warm) and northern (long photoperiod, cool) lake conditions. We tested whether sensitivity to these hatching cues varies by latitudinal origin and differs among taxa. Higher temperatures advanced phenology for all taxa, and these advances were greatest for cladocerans followed by copepods and rotifers. Although phenology differed among taxa, the effect of temperature did not vary with latitude. The latitudinal origin of the egg bank influenced egg abundance and hatchling abundance and diversity, with these latter effects varying with taxa, temperature and photoperiod. Copepod hatchling abundances peaked at mid-latitudes in the high temperature and long photoperiod treatments, whereas hatchling abundances of other zooplankton were greatest at low latitudes and high temperature. The overall diversity of crustacean zooplankton (copepods and cladocerans) also reflected distinct responses of each taxa to our treatments, with the greatest diversity occurring at mid-latitudes (~56 °N) in the shorter photoperiod treatment. Our results demonstrate that hatching cues

  3. Dormancy breaking and germination of Enterolobium contortisiliquum (Vell. Morong seed

    Directory of Open Access Journals (Sweden)

    Ubirajara Contro Malavasi

    2004-11-01

    Full Text Available Enterolobium contortisiliquum (Vell. Morong. is a Mimosaceae tropical tree species recommended for heterogeneous reforestation of degraded tropical areas. "Timburi" seeds present low germination due to the high degree of seed dormancy. Different methods to overcome seed dormancy was compared: sanding, sanding followed by 24 hours water (25ºC soaking, imbibition in boiling water followed by exposure to water at room temperature (28ºC, and concentrated sulfuric acid (5, 15, 30, 60, 120 or 180 minutes followed by washing with tap water. All seeds were germinated in rolled towels at 25ºC and 12 hours photoperiod. Total germination, first count of germination test and germination velocity index were recorded. Mechanical scarification (sanding, chemical scarification (treatment with acid for 30, 60, 120 or 180 minutes and mechanical scarification followed by cold water imbibition were efficient in promoting germination. For practical purposes, mechanical scarification is highly recommended for forest nurseries.Enterolobium contortisiliquum (Vell. Morong. é uma espécie arbórea tropical recomendada para reflorestamentos heterogêneos de áreas degradadas. Sementes de timburi apresentam baixa germinação causada pela dormência das sementes. Diferentes métodos de superação da dormência das sementes foram comparados: lixa, lixa seguida por embebição em água (25ºC por 24 horas, embebição em água fervente seguida por embebição em água a temperatura ambiente (28ºC, e ácido sulfúrico concentrado (5, 15, 30, 60, 120 ou 180 minutos seguido de lavagem com água corrente. Todas as sementes forma germinadas em rolos de papel a 25ºC e fotoperíodo de 12 horas. Germinação total, primeira contagem do teste de germinação e índice de velocidade de germinação foram anotados. Escarificação mecânica (lixa, escarificação química (tratamento com ácido por 30, 60, 120 ou 180 minutos e escarificação mecânica seguida de embebição em

  4. Gender determination of avian embryo

    Energy Technology Data Exchange (ETDEWEB)

    Daum, Keith A. (Idaho Falls, ID); Atkinson, David A. (Idaho Falls, ID)

    2002-01-01

    Disclosed is a method for gender determination of avian embryos. During the embryo incubation process, the outer hard shells of eggs are drilled and samples of allantoic fluid are removed. The allantoic fluids are directly introduced into an ion mobility spectrometer (IMS) for analysis. The resulting spectra contain the relevant marker peaks in the positive or negative mode which correlate with unique mobilities which are sex-specific. This way, the gender of the embryo can be determined.

  5. Oviduct: roles in fertilization and early embryo development.

    Science.gov (United States)

    Li, Shuai; Winuthayanon, Wipawee

    2017-01-01

    Animal oviducts and human Fallopian tubes are a part of the female reproductive tract that hosts fertilization and pre-implantation development of the embryo. With an increasing understanding of roles of the oviduct at the cellular and molecular levels, current research signifies the importance of the oviduct on naturally conceived fertilization and pre-implantation embryo development. This review highlights the physiological conditions within the oviduct during fertilization, environmental regulation, oviductal fluid composition and its role in protecting embryos and supplying nutrients. Finally, the review compares different aspects of naturally occurring fertilization and assisted reproductive technology (ART)-achieved fertilization and embryo development, giving insight into potential areas for improvement in this technology. © 2017 Society for Endocrinology.

  6. Accurate and noninvasive embryos screening during in vitro fertilization (IVF) assisted by Raman analysis of embryos culture medium Accurate and noninvasive embryos screening during IVF

    Science.gov (United States)

    Shen, A. G.; Peng, J.; Zhao, Q. H.; Su, L.; Wang, X. H.; Hu, J. M.; Yang, J.

    2012-04-01

    In combination with morphological evaluation tests, we employ Raman spectroscopy to select higher potential reproductive embryos during in vitro fertilization (IVF) based on chemical composition of embryos culture medium. In this study, 57 Raman spectra are acquired from both higher and lower quality embryos culture medium (ECM) from 10 patients which have been preliminarily confirmed by clinical assay. Data are fit by using a linear combination model of least squares method in which 12 basis spectra represent the chemical features of ECM. The final fitting coefficients provide insight into the chemical compositions of culture medium samples and are subsequently used as criterion to evaluate the quality of embryos. The relative fitting coefficients ratios of sodium pyruvate/albumin and phenylalanine/albumin seem act as key roles in the embryo screening, attaining 85.7% accuracy in comparison with clinical pregnancy. The good results demonstrate that Raman spectroscopy therefore is an important candidate for an accurate and noninvasive screening of higher quality embryos, which potentially decrease the time-consuming clinical trials during IVF.

  7. Transcriptome analysis of chestnut (Castanea sativa) tree buds suggests a putative role for epigenetic control of bud dormancy.

    Science.gov (United States)

    Santamaría, María Estrella; Rodríguez, Roberto; Cañal, María Jesús; Toorop, Peter E

    2011-09-01

    Recent papers indicated that epigenetic control is involved in transitions in bud dormancy, purportedly controlling gene expression. The present study aimed to identify genes that are differentially expressed in dormant and non-dormant Castanea sativa buds. Two suppression subtractive hybridization cDNA libraries were constructed to characterize the transcriptomes of dormant apical buds of C. sativa, and buds in which dormancy was released. A total of 512 expressed sequence tags (ESTs) were generated in a forward and reverse subtractive hybridization experiment. Classification of these ESTs into functional groups demonstrated that dormant buds were predominantly characterized by genes associated with stress response, while non-dormant buds were characterized by genes associated with energy, protein synthesis and cellular components for development and growth. ESTs for a few genes involved in different forms of epigenetic modification were found in both libraries, suggesting a role for epigenetic control in bud dormancy different from that in growth. Genes encoding histone mono-ubiquitinase HUB2 and histone acetyltransferase GCN5L were associated with dormancy, while a gene encoding histone H3 kinase AUR3 was associated with growth. Real-time RT-PCR with a selection of genes involved in epigenetic modification and stress tolerance confirmed the expression of the majority of investigated genes in various stages of bud development, revealing a cyclical expression pattern concurring with the growth seasons for most genes. However, senescing leaves also showed an increased expression of several of the genes associated with dormancy, implying pleiotropy. Furthermore, a comparison between these subtraction cDNA libraries and the poplar bud dormancy transcriptome and arabidopsis transcriptomes for seed dormancy and non-dormancy indicated a common basis for dormancy in all three systems. Bud dormancy and non-dormancy in C. sativa were characterized by distinct sets of genes

  8. Seed Dormancy in Arabidopsis Requires Self-Binding Ability of DOG1 Protein and the Presence of Multiple Isoforms Generated by Alternative Splicing

    OpenAIRE

    Kazumi Nakabayashi; Melanie Bartsch; Jia Ding; Soppe, Wim J. J.

    2015-01-01

    The Arabidopsis protein DELAY OF GERMINATION 1 (DOG1) is a key regulator of seed dormancy, which is a life history trait that determines the timing of seedling emergence. The amount of DOG1 protein in freshly harvested seeds determines their dormancy level. DOG1 has been identified as a major dormancy QTL and variation in DOG1 transcript levels between accessions contributes to natural variation for seed dormancy. The DOG1 gene is alternatively spliced. Alternative splicing increases the tran...

  9. Dormancy overcome and seedling quality of pecan in nursery

    Directory of Open Access Journals (Sweden)

    Tales Poletto

    Full Text Available ABSTRACT: This study evaluated the efficiency of methods to overcome seed dormancy in different storage periods in the production of pecan seedlings. Seeds were submitted to the following treatments: T1, T4 and T7 - control treatments (seeds with no treatment, stored at room temperature for 30, 60 and 90 days, respectively, T2, T5 and T8 - stratification (seeds were distributed in boxes with wet sand maintained at a temperature of 4°C for 30, 60 and 90 days, respectively, T3, T6 and T9 - scarification + stratification (seeds scarified with sandpaper n.80 and stratified by 30, 60 and 90 days, respectively, in completely random experimental design. Plant height, stem diameter, number of leaves, full emergence and emergence speed index (ESI were evaluated after 14 weeks of sowing. The best development of pecan 'plants, their emergence, and ESI were observed in the stratification treatment for 90 day as well as in the scarification + stratification treatment for 90 day. Storing seeds in uncontrolled environment reduced their viability.

  10. Dormancy breaking in seeds of species of the Nicotiana genus

    Directory of Open Access Journals (Sweden)

    Juan Luis Pérez-Rodríguez

    2014-01-01

    Full Text Available In the germplasm bank of the Tobacco Research Institute of Cuba the germinative power was determined in 11 species belonging to the genus Nicotiana. All the evaluated species presented high dormancy degree which obtained less than 40% of germination. For the species Nicotianamegalosiphon Heurck and Mueller the effect of potassium nitrate (3.0 g/L, giberelic acid (0.15 g/L, stratification to 5 0C (49 days, Fitomás (1%, sulfuric acid (0.5 min and criopreservation (49 days on the germination of seeds was investigated. Starting from the results that they showed higher germination percentages, the influence of the combination of different levels of giberelic acid (0.00; 0.05; 010; 0.15; 0.20 and 0.25 g/L with stratification to 5 0C (0; 7; 21; 35 and 49 days and criopreservation (0; 7; 21; 35 and 49 days on the germination of the seed was studied. The highest percentage in germination was observed after the exposition to 49 days to 5 0C followed by a period of 24 h in 0.20 g/L giberelic acid. When exposing the seeds from the 10 remaining species to the established procedure for the N. megalosiphon significantly superior germination percentages they were reached (of 49%to 84% to those obtained through the traditional germination rehearsals.

  11. Relationship between weed dormancy and herbicide rotations: implications in resistance evolution.

    Science.gov (United States)

    Darmency, Henri; Colbach, Nathalie; Le Corre, Valérie

    2017-10-01

    It is suggested that selection for late germinating seed cohorts is significantly associated with herbicide resistance in some cropping systems. In turn, it is conceivable that rotating herbicide modes of action selects for populations with mutations for increased secondary dormancy, thus partially overcoming the delaying effect of rotation on resistance evolution. Modified seed dormancy could affect management strategies - like herbicide rotation - that are used to prevent or control herbicide resistance. Here, we review the literature for data on seed dormancy and germination dynamics of herbicide-resistant versus susceptible plants. Few studies use plant material with similar genetic backgrounds, so there are few really comparative data. Increased dormancy and delayed germination may co-occur with resistance to ACCase inhibitors, but there is no clear-cut link with resistance to other herbicide classes. Population shifts are due in part to pleiotropic effects of the resistance genes, but interaction with the cropping system is also possible. We provide an example of a model simulation that accounts for genetic diversity in the dormancy trait, and subsequent consequences for various cropping systems. We strongly recommend adding more accurate and detailed mechanistic modelling to the current tools used today to predict the efficiency of prevention and management of herbicide resistance. These models should be validated through long-term experimental designs including mono-herbicide versus chemical rotation in the field. © 2017 Society of Chemical Industry. © 2017 Society of Chemical Industry.

  12. Dormancy cycles in buried seeds of three perennial Xyris (Xyridaceae) species from the Brazilian campo rupestre.

    Science.gov (United States)

    Oliveira, T G S; Diamantino, I P; Garcia, Q S

    2017-09-01

    Dormancy cycles are an important mechanism for avoiding seed germination under unfavourable periods for seedling establishment. This mechanism has been scarcely studied in tropical species. Here, we studied three tropical and perennial species of Xyris, X. asperula, X. subsetigera and X. trachyphylla, to investigate in situ longevity and the existence of seasonal seed dormancy cycles. Seeds of three species of Xyris were buried in their natural habitat, with samples exhumed bimonthly for 18 months. Germination of exhumed seeds was assessed under a 12-h photoperiod over a broad range of temperatures. Seeds of X. trachyphylla were also subjected to treatments to overcome secondary dormancy. Seeds of all species are able to form a persistent seed bank and exhibit seasonal changes in germinability. Secondary dormancy was acquired during the rainy summer and was overcome during the subsequent dry season (autumn/winter). Desiccation partially overcomes secondary dormancy in X. trachyphylla seeds. Soil seed bank persistence and synchronisation of seed germination under favourable conditions for seedling establishment contribute to the persistence and regeneration of X. asperula, X. subsetigera and X. trachyphylla in their natural environment. © 2017 German Botanical Society and The Royal Botanical Society of the Netherlands.

  13. OVERCOMING SEED DORMANCY IN Annona macroprophyllata AND Annona purpureaUSING PLANT GROWTH REGULATORS

    Directory of Open Access Journals (Sweden)

    GISELA FERREIRA

    Full Text Available ABSTRACT Some Annonaceae seeds are known to exhibit dormancy mechanisms ranging from possible seed coat impermeability to physiological dormancy. Thus, the aim of this study was to evaluate the effects of gibberellin (GA GA3 and GA4+7 + benzyladenine (GA4+7 + BA application in seeds of Annona macroprophyllata Donn. Sm (papausa and Annona purpurea Moc. & Sessé ex Dunal (chincuya. The experiment was performed by the application of GA3 and GA4+7 + BA on seeds in concentrations of 0, 200, 400, 500, 600, 800 and 1000 mg L-1. The regulators broke the dormancy of both species. However, application of the GA4+7 + BA mixture had more significant results, with greater increases in germination in A. macroprophyllata than in A. purpurea. Treatments that promoted the highest germinations were GA4+7 + BA at a concentration of 200 mg L-1 for A. macroprophyllata (77% and 200 mg L-1 of GA4+7 + BA and 500 mg L-1 of GA3 for A. purpurea (30% and 29%, respectively. Rate index, mean time and frequency of germination were distinct for both species and both treatments. Although both GA3 and GA4+7 + BA promote germination, the GA4+7 + BA mixture was more effective than GA3 to overcoming seed dormancy of both species, A. purpurea has a harder dormancy than A. macroprophyllata

  14. Who abandons embryos after IVF?

    LENUS (Irish Health Repository)

    Walsh, A P H

    2010-04-01

    This investigation describes features of in vitro fertilisation (IVF) patients who never returned to claim their embryos following cryopreservation. Frozen embryo data were reviewed to establish communication patterns between patient and clinic; embryos were considered abandoned when 1) an IVF patient with frozen embryo\\/s stored at our facility failed to make contact with our clinic for > 2 yrs and 2) the patient could not be located after a multi-modal outreach effort was undertaken. For these patients, telephone numbers had been disconnected and no forwarding address was available. Patient, spouse and emergency family contact\\/s all escaped detection efforts despite an exhaustive public database search including death records and Internet directory portals. From 3244 IVF cycles completed from 2000 to 2008, > or = 1 embryo was frozen in 1159 cases (35.7%). Those without correspondence for > 2 yrs accounted for 292 (25.2%) patients with frozen embryos; 281 were contacted by methods including registered (signature involving abandoned embryos did not differ substantially from other patients. The goal of having a baby was achieved by 10\\/11 patients either by spontaneous conception, adoption or IVF. One patient moved away with conception status unconfirmed. The overall rate of embryo abandonment was 11\\/1159 (< 1%) in this IVF population. Pre-IVF counselling minimises, but does not totally eliminate, the problem of abandoned embryos. As the number of abandoned embryos from IVF accumulates, their fate urgently requires clarification. We propose that clinicians develop a policy consistent with relevant Irish Constitutional provisions to address this medical dilemma.

  15. Effect of low temperature on dormancy breaking and growth after planting in lily bulblets regenerated in vitro

    NARCIS (Netherlands)

    Langens-Gerrits, M.M.; Miller, W.B.; Croes, A.; Klerk, de G.J.M.

    2003-01-01

    Lilies regenerating on scale segments may develop dormancy in vitro depending on the culture conditions. The dormancy is broken by storage for several weeks at a low temperature ( 5 degreesC). The effect of the low temperature on sprouting, time of leaf emergence and further bulb growth was studied.

  16. Early wound reactions of Japanese maple during winter dormancy – the effect of two contrasting temperature regimes

    NARCIS (Netherlands)

    Copini, P.; Ouden, den J.; Decuyper, M.; Mohren, G.M.J.; Loomans, A.J.M.; Sass-Klaassen, U.G.W.

    2014-01-01

    During winter dormancy, temperate trees are capable of only a restricted response to wounding. Depending on the ambient temperature during winter dormancy, wounded trees may start compartmentalization, e.g. by producing inhibitory compounds, but it is thought that processes involving cell

  17. Transcriptome analysis identifies novel responses and potential regulatory genes involved in seasonal dormancy transitions of leafy spurge (Euphorbia esula L.)

    Science.gov (United States)

    Dormancy transitions in crown buds of leafy spurge were investigated using 23K element cDNA microarrays. These data represent the first large-scale transcriptome analysis of dormancy in underground buds of an herbaceous perennial species. Crown buds collected monthly from August through December, ov...

  18. Embryos, genes, and birth defects

    National Research Council Canada - National Science Library

    Ferretti, Patrizia

    2006-01-01

    ... Structural anomalies The genesis of chromosome abnormalities Embryo survival The cause of high levels of chromosome abnormality in human embryos Relative parental risks - age, translocations, inversions, gonadal and germinal mosaics 33 33 34 35 36 44 44 45 4 Identification and Analysis of Genes Involved in Congenital Malformation Syndromes Peter J. Scambler Ge...

  19. Assessment of Seed Germination and Dormancy of Thirty Seeds Lots of

    Directory of Open Access Journals (Sweden)

    H.R Ehyaee

    2012-06-01

    Full Text Available Most seeds of medicinal plants due to ecological adaptation to environmental conditions have several types of dormancy. Hence, it's necessary to recognize ecological factors that affect dormancy and provide optimum conditions for germination in medicinal plant species. Thirty seed lots were used to estimate germination and dormancy of medicinal plants. Treatments were KNO3, (2% and scarification of seeds by sand paper, hypochlorite sodium and removing the seed coat with four replicates of 25 seeds. Maximum and minimum germination observed in H2O for Digitalis purpure 100% and Saponaria officinalis 0%. In KNO3 treatment, Portulaca oleracea had the highest germination of 91% and Hyocyamus niger had no any germinated seeds. In sand paper treatment, the Saponaria officinalis and Datura stramonium had maximum, 33% and minimum 0% germination respectively.

  20. Transcriptome analysis identifies novel responses and potential regulatory genes involved in seasonal dormancy transitions of leafy spurge (Euphorbia esula L.

    Directory of Open Access Journals (Sweden)

    Thimmapuram Jyothi

    2008-11-01

    Full Text Available Abstract Background Dormancy of buds is a critical developmental process that allows perennial plants to survive extreme seasonal variations in climate. Dormancy transitions in underground crown buds of the model herbaceous perennial weed leafy spurge were investigated using a 23 K element cDNA microarray. These data represent the first large-scale transcriptome analysis of dormancy in underground buds of an herbaceous perennial species. Crown buds collected monthly from August through December, over a five year period, were used to monitor the changes in the transcriptome during dormancy transitions. Results Nearly 1,000 genes were differentially-expressed through seasonal dormancy transitions. Expected patterns of gene expression were observed for previously characterized genes and physiological processes indicated that resolution in our analysis was sufficient for identifying shifts in global gene expression. Conclusion Gene ontology of differentially-expressed genes suggests dormancy transitions require specific alterations in transport functions (including induction of a series of mitochondrial substrate carriers, and sugar transporters, ethylene, jasmonic acid, auxin, gibberellic acid, and abscisic acid responses, and responses to stress (primarily oxidative and cold/drought. Comparison to other dormancy microarray studies indicated that nearly half of the genes identified in our study were also differentially expressed in at least two other plant species during dormancy transitions. This comparison allowed us to identify a particular MADS-box transcription factor related to the DORMANCY ASSOCIATED MADS-BOX genes from peach and hypothesize that it may play a direct role in dormancy induction and maintenance through regulation of FLOWERING LOCUS T.

  1. The role of the testa during development and in establishment of dormancy of the legume seed

    Directory of Open Access Journals (Sweden)

    Petr eSmýkal

    2014-07-01

    Full Text Available Timing of seed germination is one of the key steps in plant life cycles. It determines the beginning of plant growth in natural or agricultural ecosystems. In the wild, many seeds exhibit dormancy and will only germinate after exposure to certain environmental conditions. In contrast, crop seeds germinate as soon as they are imbibed usually at planting time. These domestication-triggered changes represent adaptations to cultivation and human harvesting. Germination is one of the common sets of traits recorded in different crops and termed the domestication syndrome. Moreover, legume seed imbibition has a crucial role in cooking properties. Different seed dormancy classes exist among plant species. Physical dormancy (often called hardseededness, as found in legumes, involves the development of a water-impermeable seed coat, caused by the presence of phenolics- and suberin-impregnated layers of palisade cells. The dormancy release mechanism primarily involves seed responses to temperature changes in the habitat, resulting in testa permeability to water. The underlying genetic controls in legumes have not been identified yet. However, positive correlation was shown between phenolics content (e.g., pigmentation, the requirement for oxidation and the activity of catechol oxidase in relation to pea seed dormancy, while epicatechin levels showed a significant positive correlation with soybean hardseededness. MYB transcription factors, WD40 proteins and enzymes of the anthocyanin biosynthesis pathway were involved in seed testa colour in soybean, pea and Medicago, but were not tested directly in relation to seed dormancy. These phenolic compounds play important roles in defence against pathogens, as well as affecting the nutritional quality of products, and because of their health benefits, they are of industrial and medicinal interest. In this review, we discuss the role of the testa in mediating legume seed germination, with a focus on structural and

  2. The role of the testa during development and in establishment of dormancy of the legume seed

    Science.gov (United States)

    Smýkal, Petr; Vernoud, Vanessa; Blair, Matthew W.; Soukup, Aleš; Thompson, Richard D.

    2014-01-01

    Timing of seed germination is one of the key steps in plant life cycles. It determines the beginning of plant growth in natural or agricultural ecosystems. In the wild, many seeds exhibit dormancy and will only germinate after exposure to certain environmental conditions. In contrast, crop seeds germinate as soon as they are imbibed usually at planting time. These domestication-triggered changes represent adaptations to cultivation and human harvesting. Germination is one of the common sets of traits recorded in different crops and termed the “domestication syndrome.” Moreover, legume seed imbibition has a crucial role in cooking properties. Different seed dormancy classes exist among plant species. Physical dormancy (often called hardseededness), as found in legumes, involves the development of a water-impermeable seed coat, caused by the presence of phenolics- and suberin-impregnated layers of palisade cells. The dormancy release mechanism primarily involves seed responses to temperature changes in the habitat, resulting in testa permeability to water. The underlying genetic controls in legumes have not been identified yet. However, positive correlation was shown between phenolics content (e.g., pigmentation), the requirement for oxidation and the activity of catechol oxidase in relation to pea seed dormancy, while epicatechin levels showed a significant positive correlation with soybean hardseededness. myeloblastosis family of transcription factors, WD40 proteins and enzymes of the anthocyanin biosynthesis pathway were involved in seed testa color in soybean, pea and Medicago, but were not tested directly in relation to seed dormancy. These phenolic compounds play important roles in defense against pathogens, as well as affecting the nutritional quality of products, and because of their health benefits, they are of industrial and medicinal interest. In this review, we discuss the role of the testa in mediating legume seed germination, with a focus on

  3. Study of Effective Methods to Break Seed Dormancy of Henbane Hyoscyamus reticulatus L.(

    Directory of Open Access Journals (Sweden)

    esmaeil rezaei-chiyaneh

    2014-09-01

    Full Text Available Henbane Hyoscyamus reticulatus L. is a plant species in solanaceae family that seeds hardly germinate because of seed dormancy. In order to determine the best methods for seed dormancy breaking in henbane, a experiment was conducted as a completely randomized design with three replications. The treatments included moist pre-chilling (at 4 °C for 7, 14, 21 and 28 days, combined treatment of gibberellic acid (500 ppm and moist chilling at 4 °C for 7, 14, 21 and 28 days, soaking the seeds in hormones gibberellic acid, kinetin, auxin (250, 500, 750 and 1000 ppm for 24 h, KNO3 (0.1, 0.2 and 0.4%, Hot water (70 and 90 °C for 5, 10 and 15 minutes, soaking seeds under running water for 24 and 48h, soaking the seeds in sulfuric acid 70% and 90% (5, 10 and 15 minutes and mechanical scarification with sandpaper. The results showed that seed dormancy in henbane is physiological since the highest germination percentage (96% was obtained by using the combined treatment of gibberellic acid (500 ppm and pre-chilling (for 25 days. In addition, moist chilling and gibberellic acid treatments -by itself- on breaking seed dormancy were remarkable in this plant as germination increased up to 40 and 81%, respectively. Effects of hormones were also statistically significant on increasing seed germination but compared with the salient effect of combined chilling with gibberellic acid treatment and gibberellic acid treatment was not so remarkable. On the other hand, other applied treatments (Hot water, sulfuric acid and mechanical scarification with sandpaper had no effects on breaking seed dormancy in henbane which indicates that the type of seed dormancy in henbane is not physical or it is due to the accumulation of inhibitory substance in seed coat.

  4. Catalase inhibition accelerates dormancy release and sprouting in potato (Solanum tuberosum L. tubers

    Directory of Open Access Journals (Sweden)

    Mohammed Bajji

    2007-01-01

    Full Text Available The involvement of hydrogen peroxide (H2O2 metabolism in dormancy release and sprouting of potato (Solanum tuberosum L. tubers has been investigated using three complementary approaches. In the first approach, the evolution of the sprouting kinetics, H2O2 content and antioxidant enzyme activities were examined during tuber storage. The most important changes occurred at the « bud/sprout » level. In particular, dormancy release was accompanied by a transient but remarkable increase in H2O2 content. In the second approach, the effect of a catalase (CAT, EC 1.11.1.6 inhibitor (thiourea or of exogenous H2O2 application on tuber sprouting behaviour was assessed. Both treatments resulted in a reduction of the dormancy period and in rapid and synchronised sprouting of the treated tubers when compared to the control as well as in increased sprout number per tuber. In the third approach, the effect of CAT inhibition on potato tuber dormancy and sprouting was evaluated using the transgenic technology. Plants partially repressed in their CAT activity were produced and, once again, CAT inhibition resulted in acceleration of the sprouting kinetics and in increased sprout number of the transgenic tubers compared to those from the wild type. It thus appears that tuber dormancy and sprouting can be controlled in potato by the manipulation of H2O2 metabolism via the inhibition of CAT activity. The possible mechanisms whereby CAT inhibitors or H2O2 overcome dormancy and promote sprouting in the potato tuber are discussed in relation to what is known in other plant models (seeds and fruit tree buds.

  5. Candidate genes associated with bud dormancy release in blackcurrant (Ribes nigrum L.).

    Science.gov (United States)

    Hedley, Peter E; Russell, Joanne R; Jorgensen, Linzi; Gordon, Sandra; Morris, Jenny A; Hackett, Christine A; Cardle, Linda; Brennan, Rex

    2010-09-14

    The detrimental effects of mild winter temperatures on the consistency of cropping of blackcurrant (Ribes nigrum L.) in parts of Europe have led to increasing interest in the genetic control of dormancy release in this species. This study examined patterns of gene expression in leaf buds of blackcurrant to identify key differential changes in these profiles around the time of budbreak. Using leaf bud tissue of blackcurrant, a cDNA library was generated as a source of blackcurrant ESTs for construction of a custom microarray, which was used to identify differential gene expression during dormancy release. Gene activity was lowest in early stages of dormancy, increasing to reach a maximum around the time of budbreak. Genes with significantly changing expression profiles were clustered and evidence is provided for the transient activity of genes previously associated with dormancy processes in other species. Expression profiling identified candidate genes which were mapped onto a blackcurrant genetic linkage map containing budbreak-related QTL. Three genes, which putatively encode calmodulin-binding protein, beta tubulin and acetyl CoA carboxylase respectively, were found to co-localise with budbreak QTL. This study provides insight into the genetic control of dormancy transition in blackcurrant, identifying key changes in gene expression around budbreak. Genetic mapping of ESTs enabled the identification of genes which co-localise with previously-characterised blackcurrant QTL, and it is concluded that these genes have probable roles in release of dormancy and can therefore provide a basis for the development of genetic markers for future breeding deployment.

  6. Candidate genes associated with bud dormancy release in blackcurrant (Ribes nigrum L.

    Directory of Open Access Journals (Sweden)

    Hedley Peter E

    2010-09-01

    Full Text Available Abstract Background The detrimental effects of mild winter temperatures on the consistency of cropping of blackcurrant (Ribes nigrum L. in parts of Europe have led to increasing interest in the genetic control of dormancy release in this species. This study examined patterns of gene expression in leaf buds of blackcurrant to identify key differential changes in these profiles around the time of budbreak. Results Using leaf bud tissue of blackcurrant, a cDNA library was generated as a source of blackcurrant ESTs for construction of a custom microarray, which was used to identify differential gene expression during dormancy release. Gene activity was lowest in early stages of dormancy, increasing to reach a maximum around the time of budbreak. Genes with significantly changing expression profiles were clustered and evidence is provided for the transient activity of genes previously associated with dormancy processes in other species. Expression profiling identified candidate genes which were mapped onto a blackcurrant genetic linkage map containing budbreak-related QTL. Three genes, which putatively encode calmodulin-binding protein, beta tubulin and acetyl CoA carboxylase respectively, were found to co-localise with budbreak QTL. Conclusions This study provides insight into the genetic control of dormancy transition in blackcurrant, identifying key changes in gene expression around budbreak. Genetic mapping of ESTs enabled the identification of genes which co-localise with previously-characterised blackcurrant QTL, and it is concluded that these genes have probable roles in release of dormancy and can therefore provide a basis for the development of genetic markers for future breeding deployment.

  7. ABA crosstalk with ethylene and nitric oxide in seed dormancy and germination

    Science.gov (United States)

    Arc, Erwann; Sechet, Julien; Corbineau, Françoise; Rajjou, Loïc; Marion-Poll, Annie

    2013-01-01

    Dormancy is an adaptive trait that enables seed germination to coincide with favorable environmental conditions. It has been clearly demonstrated that dormancy is induced by abscisic acid (ABA) during seed development on the mother plant. After seed dispersal, germination is preceded by a decline in ABA in imbibed seeds, which results from ABA catabolism through 8′-hydroxylation. The hormonal balance between ABA and gibberellins (GAs) has been shown to act as an integrator of environmental cues to maintain dormancy or activate germination. The interplay of ABA with other endogenous signals is however less documented. In numerous species, ethylene counteracts ABA signaling pathways and induces germination. In Brassicaceae seeds, ethylene prevents the inhibitory effects of ABA on endosperm cap weakening, thereby facilitating endosperm rupture and radicle emergence. Moreover, enhanced seed dormancy in Arabidopsis ethylene-insensitive mutants results from greater ABA sensitivity. Conversely, ABA limits ethylene action by down-regulating its biosynthesis. Nitric oxide (NO) has been proposed as a common actor in the ABA and ethylene crosstalk in seed. Indeed, convergent evidence indicates that NO is produced rapidly after seed imbibition and promotes germination by inducing the expression of the ABA 8′-hydroxylase gene, CYP707A2, and stimulating ethylene production. The role of NO and other nitrogen-containing compounds, such as nitrate, in seed dormancy breakage and germination stimulation has been reported in several species. This review will describe our current knowledge of ABA crosstalk with ethylene and NO, both volatile compounds that have been shown to counteract ABA action in seeds and to improve dormancy release and germination. PMID:23531630

  8. Study of Effective Methods to Break Seed Dormancy of Henbane )Hyoscyamus reticulatus L.(

    OpenAIRE

    esmaeil rezaei-chiyaneh; Mehdi Tajbakhsh; o Valizadegan; f Banaei Asl; h Mahdavikia

    2014-01-01

    Henbane Hyoscyamus reticulatus L. is a plant species in solanaceae family that seeds hardly germinate because of seed dormancy. In order to determine the best methods for seed dormancy breaking in henbane, a experiment was conducted as a completely randomized design with three replications. The treatments included moist pre-chilling (at 4 °C) for 7, 14, 21 and 28 days, combined treatment of gibberellic acid (500 ppm) and moist chilling at 4 °C for 7, 14, 21 and 28 days, soaking the seeds in h...

  9. Cellular recycling of proteins in seed dormancy alleviation and germination

    Directory of Open Access Journals (Sweden)

    Krystyna Oracz

    2016-07-01

    Full Text Available Each step of the seed-to-seed cycle of plant development including seed germination is characterized by a specific set of proteins. The continual renewal and/or replacement of these biomolecules are crucial for optimal plant adaptation. As proteins are the main effectors inside the cells, their levels need to be tightly regulated. This is partially achieved by specific proteolytic pathways via multicatalytic protease complexes defined as 20S and 26S proteasomes. In plants, the 20S proteasome is responsible for degradation of carbonylated proteins, while the 26S being a part of ubiquitin-proteasome pathway (UPP is known to be involved in proteolysis of phytohormone signaling regulators. On the other hand, the role of translational control of plant development is also well documented, especially in the context of pollen tube growth and light signaling. Despite the current progress that has been made in seed biology, the sequence of cellular events that determine if the seed can germinate or not are still far from complete understanding. The role and mechanisms of regulation of proteome composition during processes occurring in the plant’s photosynthetic tissues have been well characterized since many years, but in nonphotosynthetic seeds it has emerged as a tempting research task only since the last decade. This review discusses the recent discoveries providing insights into the role of protein turnover in seed dormancy alleviation, and germination, with a focus on the control of translation and proteasomal proteolysis. The presented novel data of translatome profiling in seeds highlighted that post-transcriptional regulation of germination results from a timely regulated initiation of translation. In addition, the importance of 26S proteasome in the degradation of regulatory elements of cellular signaling and that of the 20S complex in proteolysis of specific carbonylated proteins in hormonal- and light-dependent processes occurring in seeds is

  10. EFFECTS OF STORAGE PERIODS AND METHODS OF OVERCOMING DORMANCY IN SEEDS OF PASSIFLORA

    Directory of Open Access Journals (Sweden)

    Telma Miranda dos Santos

    2012-07-01

    Full Text Available The aim of this work was to evaluate the effects of storage period and treatement with hot water at 50ºC or scarification on dormancy break down on Passiflora mucronata seeds. The storage periods were 0, 1, 4 and 12 months. The seeds were sown onto Germitest paper roll and incubated in a germination chamber under 20ºC/8h-30ºC/16h alternate temperature, at 16-h photoperiod (fluorescent light at 32 mol m-2 s-1 irradiance. The percent germination was evaluated, and the seeds germinated on moistened Germitest paper rolls in distilled water at a ratio of two and a half times the paper weight. The seeds were transferred to a germination chamber with alternating temperatures of 20-30º C and photoperiod of 16 h until the end of the experiment at 31 days. The experiment was analyzed as completely randomized designed with four replications, in which each plot was constituted by 50 seeds. The storage periods had significant effect on the variable studied, where the higher germination was obtained at freshly harvested seeds. At the first month of evaluation the germination decreased. After 4 and 12 months of storage, no germination was detected. The treatment with hot water at 50º or scarification favored the germination of the Passiflora seeds stored by one and four months, however even with the stimulus of the treatments, the values of final germination were low. The treatments were not efficient to stimulate the seed germination stored by 12 months.

  11. Carbon monoxide and the embryo.

    Science.gov (United States)

    Robkin, M A

    1997-04-01

    Mammals are homeotherms and expend considerable energy maintaining their body temperatures. The temperature of a mammalian embryo on the other hand is maintained by the mother and the embryo can devote its metabolic energy to growth and development. The mammalian embryo is acting as a poikilotherm and its energy needs are thus considerably less than if it were a comparably sized homeotherm. The energy requirements of the preimplantation rat embryo are generated by anaerobic metabolism. As it grows, aerobic metabolism develops. In culture, the addition of carbon monoxide to the perfusing gas for early rat embryos has a much smaller effect than decreasing the oxygen concentration. Carbon monoxide appears to be a relatively mild toxicant until the embryo is much larger, is depending much more on transport of oxygen by red blood cells, and the fraction of required metabolic energy produced by anaerobic metabolism has become quite small. The effect from smoking during gestation may be either by the concomitant reduction in food intake or a more direct toxic effect from some components in the smoke. Carbon monoxide does not seem to be the culprit. The possible mitigating effect of a compensatory increase in fetal hematocrit in response to any hypoxia must also be considered. Humans have no yolk sac placenta as rodents do, but if the switch from anaerobic to aerobic metabolism is correlated with the stage of development, then carbon monoxide exposure should not represent any significant risk to the human embryo until later in gestation.

  12. Gladiolus hybridus ABSCISIC ACID INSENSITIVE 5 (GhABI5) is an important transcription factor in ABA signaling that can enhance Gladiolus corm dormancy and Arabidopsis seed dormancy.

    Science.gov (United States)

    Wu, Jian; Seng, Shanshan; Sui, Juanjuan; Vonapartis, Eliana; Luo, Xian; Gong, Benhe; Liu, Chen; Wu, Chenyu; Liu, Chao; Zhang, Fengqin; He, Junna; Yi, Mingfang

    2015-01-01

    The phytohormone abscisic acid (ABA) regulates plant development and is crucial for abiotic stress response. In this study, cold storage contributes to reducing endogenous ABA content, resulting in dormancy breaking of Gladiolus. The ABA inhibitor fluridone also promotes germination, suggesting that ABA is an important hormone that regulates corm dormancy. Here, we report the identification and functional characterization of the Gladiolus ABI5 homolog (GhABI5), which is a basic leucine zipper motif transcriptional factor (TF). GhABI5 is expressed in dormant vegetative organs (corm, cormel, and stolon) as well as in reproductive organs (stamen), and it is up-regulated by ABA or drought. Complementation analysis reveals that GhABI5 rescues the ABA insensitivity of abi5-3 during seed germination and induces the expression of downstream ABA response genes in Arabidopsis thaliana (EM1, EM6, and RD29B). Down-regulation of GhABI5 in dormant cormels via virus induced gene silence promotes sprouting and reduces the expression of downstream genes (GhLEA and GhRD29B). The results of this study reveal that GhABI5 regulates bud dormancy (vegetative organ) in Gladiolus in addition to its well-studied function in Arabidopsis seeds (reproductive organ).

  13. Time indices of multiphasic development in genotypes of sweet cherry are similar from dormancy to cessation of pit growth.

    Science.gov (United States)

    Gibeaut, David M; Whiting, Matthew D; Einhorn, Todd

    2017-02-01

    The archetypical double sigmoid-shaped growth curve of the sweet cherry drupe (Prunus avium) does not address critical development from eco-dormancy to anthesis and has not been correlated to reproductive bud development. Accurate representation of the growth and development of post-anthesis ovaries is confounded by anthesis timing, fruiting-density and the presence of unfertilized and defective ovaries whose growth differs from those that persist to maturation. These factors were addressed to assess pre-anthesis and full-season growth and development of three sweet cherry cultivars, 'Chelan', 'Bing' and 'Sweetheart', differing primarily in seasonal duration and fruit size. Volume was calculated from photographic measurements of reproductive buds, ovaries and pits at all phases of development. A population of unfertilized ovaries was produced using bee-exclusion netting to enable a statistical comparison with an open pollinated population to detect differences in size and shape between successful and failing fruit growth. Anthesis timing and fruiting-density were manipulated by floral extinction at the spur and whole-tree scales. Developmental time indices were analysed using polynomial curve fitting of log-transformed data supported by Richards and logistic functions of asymptotic growth of the pit and maturing fruit, respectively. Pre-anthesis growth began at the completion of eco-dormancy. A slight decline in relative growth rate (RGR) was observed during bud scale separation approx. -16 d from anthesis (DFA) before resumption of exponential growth to a maximum about 14 DFA. After anthesis, reduced growth of unfertilized or defective ovaries was partly discriminated from successful fruit at 5 DFA and completely at 25 DFA. Time indices of RGR inflections were similar among cultivars when adjusted for anthesis date alone, until the end of pit growth. Asymptotic growth of the pit underpinned the declining growth rate of fruit at the end of the first exponential

  14. Future aspects of micromanipualtion with embryos for

    African Journals Online (AJOL)

    implantation embryos which are then aggregated within one. Figure 3 ... Aggregating the two. \\sr. Figure 7 Scheme for producing chimeras by microsurgery. Embryo ll. A. (( %)). \\\\% tl. \\/. I oenuoins tne. Y embryo. Table 1a Results after transfer of half-embryos (review) .... After isolation and dissociation of the inner cell mass,.

  15. Genome-wide identification of WRKY family genes in peach and analysis of WRKY expression during bud dormancy.

    Science.gov (United States)

    Chen, Min; Tan, Qiuping; Sun, Mingyue; Li, Dongmei; Fu, Xiling; Chen, Xiude; Xiao, Wei; Li, Ling; Gao, Dongsheng

    2016-06-01

    Bud dormancy in deciduous fruit trees is an important adaptive mechanism for their survival in cold climates. The WRKY genes participate in several developmental and physiological processes, including dormancy. However, the dormancy mechanisms of WRKY genes have not been studied in detail. We conducted a genome-wide analysis and identified 58 WRKY genes in peach. These putative genes were located on all eight chromosomes. In bioinformatics analyses, we compared the sequences of WRKY genes from peach, rice, and Arabidopsis. In a cluster analysis, the gene sequences formed three groups, of which group II was further divided into five subgroups. Gene structure was highly conserved within each group, especially in groups IId and III. Gene expression analyses by qRT-PCR showed that WRKY genes showed different expression patterns in peach buds during dormancy. The mean expression levels of six WRKY genes (Prupe.6G286000, Prupe.1G393000, Prupe.1G114800, Prupe.1G071400, Prupe.2G185100, and Prupe.2G307400) increased during endodormancy and decreased during ecodormancy, indicating that these six WRKY genes may play a role in dormancy in a perennial fruit tree. This information will be useful for selecting fruit trees with desirable dormancy characteristics or for manipulating dormancy in genetic engineering programs.

  16. Dispersal, dormancy and life-history tradeoffs at the individual, population and species levels in southern African Asteraceae.

    Science.gov (United States)

    de Waal, Caroli; Anderson, Bruce; Ellis, Allan G

    2016-04-01

    Dispersal and dormancy are important risk-reducing strategies in unpredictable environments. Negative covariation between these strategies is theoretically expected, but empirical evidence is limited and inconsistent. Moreover, covariation may be affected by other life-history traits and may vary across levels of biological organization. We assessed dispersal (vertical fall time of fruits, a proxy for wind dispersal ability) and dormancy (germination fractions measured during germination trials) in populations of 15 annual and 12 perennial wind-dispersed species in six Asteraceae genera from South Africa. Dormancy was higher in annuals than in perennials, whereas fall time was largely determined by evolutionary history. Controlling for phylogeny, dispersal and dormancy was negatively associated across species and life-history categories. Negative covariation between dispersal and dormancy was not evident at either the individual level (except for seed heteromorphic species) or the population level. Our study provides rare empirical support for the theoretical expectation of tradeoffs between dormancy and the alternative risk-reducing strategies, perenniality and dispersal, but refutes the expectation of increased dispersability in perennials. Although negative covariation between dispersal and dormancy at the species level appears not to be a simple consequence of upscaling individual-level mechanistic tradeoffs, our findings suggest that selection for one strategy may constrain evolution of the other. © 2015 The Authors. New Phytologist © 2015 New Phytologist Trust.

  17. Effects of Oxygen and Respiratory Inhibitors on Induction and Release of Dormancy in Aerial Tubers of Begonia evansiana.

    Science.gov (United States)

    Esashi, Y; Nagao, M

    1973-03-01

    Effects of O(2) and some respiratory inhibitors on the induction and release of bud dormancy were examined with the aerial tubers of different ages of Begonia evansiana Andr. Oxygen was needed not only for tuber sprouting but also during the chilling process at 2 to 5 C to break tuber dormancy. If the mature tubers were exposed to blue light during the chilling period, their dormancy was strikingly released even by the chilling given under an O(2) concentration as low as 3%. Blue light pretreatment promoted photo-sprouting of immature tubers only when given under lower O(2) concentrations. On the other hand, red light became effective in inducing dormancy in the immature tubers and in prolonging dormancy in the mature tubers as O(2) tension was increased. This was also the case with the induction of dormancy in the immature tubers by exposing them to a lower temperature (17 C) in the dark. The development of dormancy was suppressed by 2,4-dinitrophenol, p-nitrophenol, and sodium azide.

  18. Temperature-driven plasticity in growth cessation and dormancy development in deciduous woody plants: a working hypothesis suggesting how molecular and cellular function is affected by temperature during dormancy induction.

    Science.gov (United States)

    Tanino, Karen K; Kalcsits, Lee; Silim, Salim; Kendall, Edward; Gray, Gordon R

    2010-05-01

    The role of temperature during dormancy development is being reconsidered as more research emerges demonstrating that temperature can significantly influence growth cessation and dormancy development in woody plants. However, there are seemingly contradictory responses to warm and low temperature in the literature. This research/review paper aims to address this contradiction. The impact of temperature was examined in four poplar clones and two dogwood ecotypes with contrasting dormancy induction patterns. Under short day (SD) conditions, warm night temperature (WT) strongly accelerated timing of growth cessation leading to greater dormancy development and cold hardiness in poplar hybrids. In contrast, under long day (LD) conditions, low night temperature (LT) can completely bypass the short photoperiod requirement in northern but not southern dogwood ecotypes. These findings are in fact consistent with the literature in which both coniferous and deciduous woody plant species' growth cessation, bud set or dormancy induction are accelerated by temperature. The contradictions are addressed when photoperiod and ecotypes are taken into account in which the combination of either SD/WT (northern and southern ecotypes) or LD/LT (northern ecotypes only) are separated. Photoperiod insensitive types are driven to growth cessation by LT. Also consistent is the importance of night temperature in regulating these warm and cool temperature responses. However, the physiological basis for these temperature effects remain unclear. Changes in water content, binding and mobility are factors known to be associated with dormancy induction in woody plants. These were measured using non-destructive magnetic resonance micro-imaging (MRMI) in specific regions within lateral buds of poplar under SD/WT dormancing inducing conditions. Under SD/WT, dormancy was associated with restrictions in inter- or intracellular water movement between plant cells that reduces water mobility during dormancy

  19. Genome-wide association mapping revealed a diverse genetic basis of seed dormancy across subpopulations in rice (Oryza sativa L.).

    Science.gov (United States)

    Magwa, Risper Auma; Zhao, Hu; Xing, Yongzhong

    2016-01-25

    Seed dormancy is an adaptive trait employed by flowering plants to avoid harsh environmental conditions for the continuity of their next generations. In cereal crops, moderate seed dormancy could help prevent pre-harvest sprouting and improve grain yield and quality. We performed a genome wide association study (GWAS) for dormancy, based on seed germination percentage (GP) in freshly harvested seeds (FHS) and after-ripened seeds (ARS) in 350 worldwide accessions that were characterized with strong population structure of indica, japonica and Aus subpopulations. The germination tests revealed that Aus and indica rice had stronger seed dormancy than japonica rice in FHS. Association analysis revealed 16 loci significantly associated with GP in FHS and 38 in ARS. Three out of the 38 loci detected in ARS were also detected in FHS and 13 of the ARS loci were detected near previously mapped dormancy QTL. In FHS, three of the association loci were located within 100 kb around previously cloned GA/IAA inactivation genes such as GA2ox3, EUI1 and GH3-2 and one near dormancy gene, Sdr4. In ARS, an association signal was detected near ABA signaling gene ABI5. No association peaks were commonly detected among the sub-populations in FHS and only one association peak was detected in both indica and japonica populations in ARS. Sdr4 and GA2OX3 haplotype analysis showed that Aus and indica II (IndII) varieties had stronger dormancy alleles whereas indica I (IndI) and japonica had weak or non-dormancy alleles. The association study and haplotype analysis together, indicate an involvement of independent genes and alleles contributing towards regulation and natural variation of seed dormancy among the rice sub-populations.

  20. Effect of pre-germination treatments on the dormancy breaking and ...

    African Journals Online (AJOL)

    The highest mean values of 8, 14.65 cm and 5 were obtained for germination count, plant height and leaf number respectively from nicked seeds soaked in water for 24 hours. Dormancy in Garcinia kola seeds can be removed by nicking the seeds and soaking in cold water for a day. Keywords: Germination, growth, seed ...

  1. Effect of exogenous hormones and chilling on dormancy breaking of seed of Asafoetida (Ferula assafoetida L.)

    NARCIS (Netherlands)

    Otroshy, M.; Zamani, A.; Khodambashi, M.; Ebrahimi, M.; Struik, P.C.

    2009-01-01

    Asafoetida (Ferula assafoetida L.) is a medicinal plant with a problematic seed germination. Seeds of this plant have a long dormancy. The present research was carried out to investigate whether exogenous application of the hormones Gibberellic Acid (GA3), N6-furfurylaminopurine (kinetin) and

  2. Dormancy and Root Regeneration of Black Walnut Seedlings: Effects of Chilling

    Science.gov (United States)

    W.J. Rietveld; Robert D. Williams

    1978-01-01

    New root and shoot growth of black walnut seedlings were strongly dependent on the amount of time they were kept at a cold temperature. Physiological dormancy ended after approximately 3,100 hours at 3C, but growth responses continued to increase after 4,600 hours. Root regeneration was strongly correlated with shoot growth.

  3. Induction and release of secondary dormancy under field conditions in Bromus tectorum

    Science.gov (United States)

    Phil S. Allen; S. E. Meyer; K. Foote

    2010-01-01

    Bromus tectorum L. is a facultative winter annual grass originally from Eurasia. During the past century, this species has become highly invasive in the western United States, where it has displaced millions of hectares of native vegetation. Seeds of B. tectorum lose primary dormancy through dry after-ripening, and nearly all seeds are capable of germinating in...

  4. Inheritance of fresh seed dormancy in Spanish-type peanut ( Arachis ...

    African Journals Online (AJOL)

    Production and seed quality in peanut (Arachis hypogaea L.) can be reduced substantially by in situ germination under unpredictable rainfed environments. Inheritance of fresh seed dormancy in Spanish x Spanish crosses was studied with two sets of segregating populations, an F2 population derived from true F1 hybrids ...

  5. The effect of environmental conditions on the seasonal dormancy pattern and germination of weed seeds

    NARCIS (Netherlands)

    Bouwmeester, H.J.

    1990-01-01

    Weeds cause considerable losses in horticultural and agricultural crops. Weeds are still predominantly controlled with herbicides. To reduce the use of chemicals, a better understanding of the biology of weeds is required. In this thesis the effect of environmental conditions on dormancy

  6. The effect of altitude on breaking seed dormancy and stimulation of ...

    African Journals Online (AJOL)

    Persian hogweed is a perennial herb and aromatic plant which has pharmaceutical and fodder values, and the main propagation method of this species is seed. The goal of this study was to investigate the effect of altitude on breaking dormancy and stimulate seed germination of this species. The study was designed and ...

  7. Seed production temperature regulation of primary dormancy occurs through control of seed coat phenylpropanoid metabolism.

    Science.gov (United States)

    MacGregor, Dana R; Kendall, Sarah L; Florance, Hannah; Fedi, Fabio; Moore, Karen; Paszkiewicz, Konrad; Smirnoff, Nicholas; Penfield, Steven

    2015-01-01

    Environmental changes during seed production are important drivers of lot-to-lot variation in seed behaviour and enable wild species to time their life history with seasonal cues. Temperature during seed set is the dominant environmental signal determining the depth of primary dormancy, although the mechanisms though which temperature changes impart changes in dormancy state are still only partly understood. We used molecular, genetic and biochemical techniques to examine the mechanism through which temperature variation affects Arabidopsis thaliana seed dormancy. Here we show that, in Arabidopsis, low temperatures during seed maturation result in an increase in phenylpropanoid gene expression in seeds and that this correlates with higher concentrations of seed coat procyanidins. Lower maturation temperatures cause differences in coat permeability to tetrazolium, and mutants with increased seed coat permeability and/or low procyanidin concentrations are less able to enter strongly dormant states after exposure to low temperatures during seed maturation. Our data show that maternal temperature signalling regulates seed coat properties, and this is an important pathway through which the environmental signals control primary dormancy depth. © 2014 The Authors New Phytologist © 2014 New Phytologist Trust.

  8. Biochemical properties and expression analysis of potato cytokinin oxidases during tuber dormancy

    Science.gov (United States)

    At harvest and for an indeterminate period thereafter, potato tubers are dormant and will not sprout. Tuber dormancy is lost during postharvest storage and the subsequent sprouting results in the loss of tuber processing and nutritional qualities. Endogenous cytokinins have been posited to play a p...

  9. Variation in saltgrass growth and time of fall dormancy related to geographical and climatic factors.

    Science.gov (United States)

    Hrvoje Rukavina; Harrison Hughes; Randy Johnson

    2008-01-01

    Development of a new turfgrass cultivar requires an evaluation of numerous traits as well as an understanding of environmental factors influencing those traits. Growth or ability to fill in gaps and time of fall dormancy (fall color retention) that indicates cold hardiness are important traits for turfgrasses. This study was initiated to characterize variation in...

  10. Dormancy-breaking and salinity/water stress effects on seed ...

    African Journals Online (AJOL)

    Atlas cypress (Cupressus atlantica Gaussen) is an endemic coniferous medicinal species geographically restricted to the N'Fis valley river in the High Atlas Mountains in South-Western Morocco. Eight dormancy-breaking treatments, 5 NaCl concentrations, and 5 water potentials were tested on the germination of Altas ...

  11. NR2F1 controls tumor cell dormancy via SOX9 and RARβ driven quiescence programs

    Science.gov (United States)

    Sosa, Maria Soledad; Parikh, Falguni; Maia, Alexandre Gaspar; Estrada, Yeriel; Bosch, Almudena; Bragado, Paloma; Ekpin, Esther; George, Ajish; Zheng, Yang; Lam, Hung-Ming; Morrissey, Colm; Chung, Chi-Yeh; Farias, Eduardo F.; Bernstein, Emily; Aguirre-Ghiso, Julio A.

    2014-01-01

    Metastases can originate from disseminated tumor cells (DTCs), which may be dormant for years before reactivation. Here we find that the orphan nuclear receptor NR2F1 is epigenetically upregulated in experimental HNSCC dormancy models and in DTCs from prostate cancer patients carrying dormant disease for 7–18 years. NR2F1-dependent dormancy is recapitulated by a co-treatment with the DNA demethylating agent 5-Aza-C and retinoic acid across various cancer types. NR2F1-induced quiescence is dependent on SOX9, RARβ and CDK inhibitors. Intriguingly, NR2F1 induces global chromatin repression and the pluripotency gene NANOG, which contributes to dormancy of DTCs in the bone marrow. When NR2F1 is blocked in vivo, growth arrest or survival of dormant DTCs is interrupted in different organs. We conclude that NR2F1 is a critical node in dormancy induction and maintenance by integrating epigenetic programs of quiescence and survival in DTCs. PMID:25636082

  12. Differentially expressed genes associated with dormancy or germination of Arabidopsis thaliana seeds

    NARCIS (Netherlands)

    Toorop, P.E.; Barroco, R.M.; Engler, G.; Groot, S.P.C.; Hilhorst, H.W.M.

    2005-01-01

    Differential display analysis using dormant and non-dormant Arabidopsis thaliana (L.) Heynh seeds resulted in a set of genes that were associated with either dormancy or germination. Expression of the germination-associated genes AtRPL36B and AtRPL27B, encoding two ribosomal proteins, was

  13. Quantitative trait loci for seed dormancy in wild barley (Hordeum spontaneum C. Koch)

    NARCIS (Netherlands)

    Vanhala, T.; Stam, P.

    2006-01-01

    A quantitative trait locus analysis was carried out to unravel the genetic basis of dormancy in wild barley (Hordeum spontaneum) from Israel. Two accessions, Ashkelon and Mehola, from divergent environments were crossed to produce a mapping population. A linkage map was produced from the F2

  14. Potato tuber cytokinin oxidase/dehydrogenase genes: Biochemical properties, activity, and expression during tuber dormancy progression

    Science.gov (United States)

    The enzymatic and biochemical properties of the proteins encoded by five potato cytokinin oxidase/dehydrogenase (CKX)-like genes functionally expressed in yeast and the effects of tuber dormancy progression on StCKX expression and cytokinin metabolism were examined in meristems isolated from field-g...

  15. Chemomechanically engineered 3D organotypic platforms of bladder cancer dormancy and reactivation.

    Science.gov (United States)

    Pavan Grandhi, Taraka Sai; Potta, Thrimoorthy; Nitiyanandan, Rajeshwar; Deshpande, Indrani; Rege, Kaushal

    2017-10-01

    Tumors undergo periods of dormancy followed by reactivation leading to metastatic disease. Arrest in the G0/G1 phase of the cell cycle and resistance to chemotherapeutic drugs are key hallmarks of dormant tumor cells. Here, we describe a 3D platform of bladder cancer cell dormancy and reactivation facilitated by a novel aminoglycoside-derived hydrogel, Amikagel. These 3D dormant tumor microenvironments (3D-DTMs) were arrested in the G0/G1 phase and were highly resistant to anti-proliferative drugs. Inhibition of targets in the cellular protein production machinery led to induction of endoplasmic reticulum (ER) stress and complete ablation of 3D-DTMs. Nanoparticle-mediated calcium delivery significantly accelerated ER stress-mediated 3D-DTM death. Transfer of 3D-DTMs onto weaker and adhesive Amikagels resulted in selective reactivation of a sub-population of N-cadherin deficient cells from dormancy. Whole-transcriptome analyses further indicated key biochemical differences between dormant and proliferative cancer cells. Taken together, our results indicate that 3D bladder cancer microenvironments of dormancy and reactivation can facilitate fundamental advances and novel drug discovery in cancer. Copyright © 2017. Published by Elsevier Ltd.

  16. Expectant Fathers, Abortion, and Embryos.

    Science.gov (United States)

    Purvis, Dara E

    2015-01-01

    One thread of abortion criticism, arguing that gender equality requires that men be allowed to terminate legal parental status and obligations, has reinforced the stereotype of men as uninterested in fatherhood. As courts facing disputes over stored pre-embryos weigh the equities of allowing implantation of the pre-embryos, this same gender stereotype has been increasingly incorporated into a legal balancing test, leading to troubling implications for ART and family law. © 2015 American Society of Law, Medicine & Ethics, Inc.

  17. [Cryopreservation of early human embryo stages].

    Science.gov (United States)

    Vökler, T; Fliess, F R

    1988-01-01

    A short review of freezing procedures applied to early human embryos is given. It is noted that human embryos survived freezing and thawing at a developmental stage of 1. cell to blastocyst. But it seems to be necessary to use for any developmental stage of early embryo a special freezing and thawing method. Embryo survival is correlated with their morphologic features where as neither age of embryos nor developmental stage were involved in freezing and thawing ability.

  18. Lessons from Embryos: Haeckel's Embryo Drawings, Evolution, and Secondary Biology Textbooks

    Science.gov (United States)

    Wellner, Karen L.

    2014-01-01

    In 1997, developmental biologist Michael Richardson compared his research team's embryo photographs to Ernst Haeckel's 1874 embryo drawings and called Haeckel's work "noncredible". "Science" soon published "Haeckel's Embryos: Fraud Rediscovered," and Richardson's comments further reinvigorated criticism of Haeckel by…

  19. In vitro and in vivo quality of bovine embryos in vitro produced with sex-sorted sperm.

    Science.gov (United States)

    Trigal, B; Gómez, E; Caamaño, J N; Muñoz, M; Moreno, J; Carrocera, S; Martín, D; Diez, C

    2012-10-15

    In this work we analyzed the effects of three culture systems on developmental ability of bovine embryos in vitro produced with sexed sperm, the survival to vitrification (cryologic vitrification method) of such blastocysts, and their pregnancy rates after embryo transfer to recipients, both as fresh and after vitrification/warming. Finally, we measured the accuracy of the sorting protocol by a polymerase chain reaction-based method to validate the embryo sex at blastocyst stages. We confirmed an individual effect of the bull as well as development rates of embryos produced with sorted sperm lower than embryos with unsorted sperm, independent of the culture system used. The cryoresistance to vitrification of embryos produced with sexed sperm did not differ from that of conventionally produced embryos (re-expansion rates at 24 and 48 h: 74.6% vs. 75.5%, and 64.5% vs. 68.1% for embryos produced with conventional and sorted sperm, respectively; hatching rates at 48 h: 63.55% vs. 55.5% for embryos produced with conventional and sorted sperm, respectively). Finally, no significant differences were found in pregnancy rates after the embryo transfer of fresh and vitrified/warmed blastocysts (52.8% vs. 42.0%, respectively; P > 0.05). Male and female embryos produced with sorted sperm showed the same quality in terms of developmental ability, cryoresistance, and pregnancy rates after transfer. Our culture system, coupled with the vitrification in fiber plugs, provides good quality sex-known embryos which survive vitrification at similar rates than embryos produced with conventional unsorted sperm; also it produces good pregnancy rates after transfer of sexed embryos both fresh and after vitrification and warming. Copyright © 2012 Elsevier Inc. All rights reserved.

  20. Blastocyst Morphology Holds Clues Concerning The Chromosomal Status of The Embryo

    Directory of Open Access Journals (Sweden)

    Rita de Cassia Savio Figueira

    2015-07-01

    Full Text Available Background: Embryo morphology has been proposed as an alternative marker of chromosomal status. The objective of this retrospective cohort study was to investigate the association between the chromosomal status on day 3 of embryo development and blastocyst morphology. Materials and Methods: A total of 596 embryos obtained from 106 cycles of intracytoplasmic sperm injection (ICSI followed by preimplantation genetic aneuploidy screening (PGS were included in this retrospective study. We evaluated the relationship between blastocyst morphological features and embryonic chromosomal alteration. Results: Of the 564 embryos with fluorescent in situ hybridization (FISH results, 200 reached the blastocyst stage on day 5 of development. There was a significantly higher proportion of euploid embryos in those that achieved the blastocyst stage (59.0% compared to embryos that did not develop to blastocysts (41.2% on day 5 (P<0.001. Regarding blastocyst morphology, we observed that all embryos that had an abnormal inner cell mass (ICM were aneuploid. Embryos with morphologically normal ICM had a significantly higher euploidy rate (62.1%, P<0.001. As regards to the trophectoderm (TE morphology, an increased rate of euploidy was observed in embryos that had normal TE (65.8% compared to embryos with abnormal TE (37.5%, P<0.001. Finally, we observed a two-fold increase in the euploidy rate in high-quality blastocysts with both high-quality ICM and TE (70.4% compared to that found in low-quality blastocysts (31.0%, P<0.001. Conclusion: Chromosomal abnormalities do not impair embryo development as aneuploidy is frequently observed in embryos that reach the blastocyst stage. A high-quality blastocyst does not represent euploidy of chromosomes 13, 14, 15, 16, 18, 21, 22, X and Y. However, aneuploidy is associated with abnormalities in the ICM morphology. Further studies are necessary to confirm whether or not the transfer of blastocysts with low-quality ICM should be

  1. Effects of chilling and ABA on (/sup 3/H)gibberellin A/sub 4/ metabolism in somatic embryos of grape (Vitis vinifera L. x V. rupestris Scheele)

    Energy Technology Data Exchange (ETDEWEB)

    Pearce, D.; Pharis, R.P.; Rajasekaran, K.; Mullins, M.G.

    1987-06-01

    Previous work has indicated that changes in gibberellin (GA) metabolism may be involved in chilling-induced release from dormancy in somatic embryos of grape (Vitis vinifera L. x V. rupestris Scheele). The authors have chilled somatic embryos of grape for 2, 4, or 8 weeks, then incubated them with (/sup 3/H)GA/sub 4/ (of high specific activity, 4.81 x 10/sup 19/ becquerel per millimole) for 48 hours at 26/sup 0/C. Chilling had little effect on the total amount of free (/sup 3/H)GA-like metabolites formed during incubation at 26/sup 0/C, but did change the relative proportions of individual metabolites. The amount of highly water-soluble (/sup 3/H) metabolites formed at 26/sup 0/C decreased in embryos chilled for 4 or 8 weeks. The concentration of endogeneous GA precursors (e.g., GA/sub 12/ aldehyde-, kaurene, and kaurenoic acid-like substances) increased in embryos chilled for 4 or 8 weeks. Treatment with abscisic acid (ABA) (known to inhibit germination in grape embryos) concurrent with (/sup 3/H)GA/sub 4/ treatment at 26/sup 0/C, reduced the uptake of (/sup 3/H) GA/sub 4/ but had little effect on the qualitative spectrum of metabolites. However, in the embryos chilled for 8 weeks and then treated with ABA for 48 hours at 26/sup 0/C, there was a higher concentration of GA precursors than in untreated control embryos. Chilled embryos thus have an enhanced potential for an increase in free GAs through synthesis from increased amounts of GA precursors, or through a reduced ability to form highly water-soluble GA metabolites (i.e., GA conjugates or polyhydroxylated free GAs).

  2. Embryo density may affect embryo quality during in vitro culture in a microwell group culture dish.

    Science.gov (United States)

    Lehner, Adam; Kaszas, Zita; Murber, Akos; Rigo, Janos; Urbancsek, Janos; Fancsovits, Peter

    2017-08-01

    Culturing embryos in groups is a common practice in mammalian embryology. Since the introduction of different microwell dishes, it is possible to identify oocytes or embryos individually. As embryo density (embryo-to-volume ratio) may affect the development and viability of the embryos, the purpose of this study was to assess the effect of different embryo densities on embryo quality. Data of 1337 embryos from 228 in vitro fertilization treatment cycles were retrospectively analyzed. Embryos were cultured in a 25 μl microdrop in a microwell group culture dish containing 9 microwells. Three density groups were defined: Group 1 with 2-4 (6.3-12.5 μl/embryo), Group 2 with 5-6 (4.2-5.0 μl/embryo), and Group 3 with 7-9 (2.8-3.6 μl/embryo) embryos. Proportion of good quality embryos was higher in Group 2 on both days (D2: 18.9 vs. 31.5 vs. 24.7%; p Culturing 5-6 embryos together in a culture volume of 25 μl may benefit embryo quality. As low egg number, position, and distance of the embryos may influence embryo quality, results should be interpreted with caution.

  3. In vitro and in vivo quality of bovine embryos in vitro produced with sex-sorted sperm

    OpenAIRE

    Trigal, B.; Gómez, E.; Caamaño, J.N. (José); Muñoz, M.; Moreno, Javier; Carrocera, S.; Martín, D.; Díez, C.

    2013-01-01

    In this work we analyzed the effects of three culture systems on developmental ability of bovine embryos in vitro produced with sexed sperm, the survival to vitrification (cryologic vitrification method) of such blastocysts, and their pregnancy rates after embryo transfer to recipients, both as fresh and after vitrification/warming. Finally, we measured the accuracy of the sorting protocol by a polymerase chain reaction-based method to validate the embryo sex at blastocyst stages. We confirme...

  4. Incorporating microbial dormancy dynamics into soil decomposition models to improve quantification of soil carbon dynamics of northern temperate forests

    Science.gov (United States)

    He, Yujie; Yang, Jinyan; Zhuang, Qianlai; Harden, Jennifer W.; McGuire, A. David; Liu, Yaling; Wang, Gangsheng; Gu, Lianhong

    2015-01-01

    Soil carbon dynamics of terrestrial ecosystems play a significant role in the global carbon cycle. Microbial-based decomposition models have seen much growth recently for quantifying this role, yet dormancy as a common strategy used by microorganisms has not usually been represented and tested in these models against field observations. Here we developed an explicit microbial-enzyme decomposition model and examined model performance with and without representation of microbial dormancy at six temperate forest sites of different forest types. We then extrapolated the model to global temperate forest ecosystems to investigate biogeochemical controls on soil heterotrophic respiration and microbial dormancy dynamics at different temporal-spatial scales. The dormancy model consistently produced better match with field-observed heterotrophic soil CO2 efflux (RH) than the no dormancy model. Our regional modeling results further indicated that models with dormancy were able to produce more realistic magnitude of microbial biomass (soil organic carbon) and soil RH (7.5 ± 2.4 Pg C yr−1). Spatial correlation analysis showed that soil organic carbon content was the dominating factor (correlation coefficient = 0.4–0.6) in the simulated spatial pattern of soil RHwith both models. In contrast to strong temporal and local controls of soil temperature and moisture on microbial dormancy, our modeling results showed that soil carbon-to-nitrogen ratio (C:N) was a major regulating factor at regional scales (correlation coefficient = −0.43 to −0.58), indicating scale-dependent biogeochemical controls on microbial dynamics. Our findings suggest that incorporating microbial dormancy could improve the realism of microbial-based decomposition models and enhance the integration of soil experiments and mechanistically based modeling.

  5. Slowed aging during reproductive dormancy is reflected in genome-wide transcriptome changes in Drosophila melanogaster.

    Science.gov (United States)

    Kučerová, Lucie; Kubrak, Olga I; Bengtsson, Jonas M; Strnad, Hynek; Nylin, Sören; Theopold, Ulrich; Nässel, Dick R

    2016-01-13

    In models extensively used in studies of aging and extended lifespan, such as C. elegans and Drosophila, adult senescence is regulated by gene networks that are likely to be similar to ones that underlie lifespan extension during dormancy. These include the evolutionarily conserved insulin/IGF, TOR and germ line-signaling pathways. Dormancy, also known as dauer stage in the larval worm or adult diapause in the fly, is triggered by adverse environmental conditions, and results in drastically extended lifespan with negligible senescence. It is furthermore characterized by increased stress resistance and somatic maintenance, developmental arrest and reallocated energy resources. In the fly Drosophila melanogaster adult reproductive diapause is additionally manifested in arrested ovary development, improved immune defense and altered metabolism. However, the molecular mechanisms behind this adaptive lifespan extension are not well understood. A genome wide analysis of transcript changes in diapausing D. melanogaster revealed a differential regulation of more than 4600 genes. Gene ontology (GO) and KEGG pathway analysis reveal that many of these genes are part of signaling pathways that regulate metabolism, stress responses, detoxification, immunity, protein synthesis and processes during aging. More specifically, gene readouts and detailed mapping of the pathways indicate downregulation of insulin-IGF (IIS), target of rapamycin (TOR) and MAP kinase signaling, whereas Toll-dependent immune signaling, Jun-N-terminal kinase (JNK) and Janus kinase/signal transducer and activator of transcription (JAK/STAT) pathways are upregulated during diapause. Furthermore, we detected transcriptional regulation of a large number of genes specifically associated with aging and longevity. We find that many affected genes and signal pathways are shared between dormancy, aging and lifespan extension, including IIS, TOR, JAK/STAT and JNK. A substantial fraction of the genes affected by

  6. Chromatin remodeling in mammalian embryos.

    Science.gov (United States)

    Cabot, Birgit; Cabot, Ryan A

    2018-03-01

    The mammalian embryo undergoes a dramatic amount of epigenetic remodeling during the first week of development. In this review, we discuss several epigenetic changes that happen over the course of cleavage development, focusing on covalent marks (e.g., histone methylation and acetylation) and non-covalent remodeling (chromatin remodeling via remodeling complexes; e.g., SWI/SNF-mediated chromatin remodeling). Comparisons are also drawn between remodeling events that occur in embryos from a variety of mammalian species. © 2018 Society for Reproduction and Fertility.

  7. Seed Dormancy, Seedling Establishment and Dynamics of the Soil Seed Bank of Stipa bungeana (Poaceae) on the Loess Plateau of Northwestern China

    OpenAIRE

    Hu, Xiao Wen; Wu, Yan Pei; Ding, Xing Yu; Zhang, Rui; Wang, Yan Rong; Baskin, Jerry M.; Baskin, Carol C.

    2014-01-01

    Studying seed dormancy and its consequent effect can provide important information for vegetation restoration and management. The present study investigated seed dormancy, seedling emergence and seed survival in the soil seed bank of Stipa bungeana, a grass species used in restoration of degraded land on the Loess Plateau in northwest China. Dormancy of fresh seeds was determined by incubation of seeds over a range of temperatures in both light and dark. Seed germination was evaluated after m...

  8. Genetic and Hormonal Regulation of Chlorophyll Degradation during Maturation of Seeds with Green Embryos

    Directory of Open Access Journals (Sweden)

    Galina Smolikova

    2017-09-01

    Full Text Available The embryos of some angiosperms (usually referred to as chloroembryos contain chlorophylls during the whole period of embryogenesis. Developing embryos have photochemically active chloroplasts and are able to produce assimilates, further converted in reserve biopolymers, whereas at the late steps of embryogenesis, seeds undergo dehydration, degradation of chlorophylls, transformation of chloroplast in storage plastids, and enter the dormancy period. However, in some seeds, the process of chlorophyll degradation remains incomplete. These residual chlorophylls compromise the quality of seed material in terms of viability, nutritional value, and shelf life, and represent a serious challenge for breeders and farmers. The mechanisms of chlorophyll degradation during seed maturation are still not completely understood, and only during the recent decades the main pathways and corresponding enzymes could be characterized. Among the identified players, the enzymes of pheophorbide a oxygenase pathway and the proteins encoded by STAY GREEN (SGR genes are the principle ones. On the biochemical level, abscisic acid (ABA is the main regulator of seed chlorophyll degradation, mediating activity of corresponding catabolic enzymes on the transcriptional level. In general, a deep insight in the mechanisms of chlorophyll degradation is required to develop the approaches for production of chlorophyll-free high quality seeds.

  9. Genetic and Hormonal Regulation of Chlorophyll Degradation during Maturation of Seeds with Green Embryos.

    Science.gov (United States)

    Smolikova, Galina; Dolgikh, Elena; Vikhnina, Maria; Frolov, Andrej; Medvedev, Sergei

    2017-09-16

    The embryos of some angiosperms (usually referred to as chloroembryos) contain chlorophylls during the whole period of embryogenesis. Developing embryos have photochemically active chloroplasts and are able to produce assimilates, further converted in reserve biopolymers, whereas at the late steps of embryogenesis, seeds undergo dehydration, degradation of chlorophylls, transformation of chloroplast in storage plastids, and enter the dormancy period. However, in some seeds, the process of chlorophyll degradation remains incomplete. These residual chlorophylls compromise the quality of seed material in terms of viability, nutritional value, and shelf life, and represent a serious challenge for breeders and farmers. The mechanisms of chlorophyll degradation during seed maturation are still not completely understood, and only during the recent decades the main pathways and corresponding enzymes could be characterized. Among the identified players, the enzymes of pheophorbide a oxygenase pathway and the proteins encoded by STAY GREEN (SGR) genes are the principle ones. On the biochemical level, abscisic acid (ABA) is the main regulator of seed chlorophyll degradation, mediating activity of corresponding catabolic enzymes on the transcriptional level. In general, a deep insight in the mechanisms of chlorophyll degradation is required to develop the approaches for production of chlorophyll-free high quality seeds.

  10. Nitric oxide implication in the control of seed dormancy and germination

    Science.gov (United States)

    Arc, Erwann; Galland, Marc; Godin, Béatrice; Cueff, Gwendal; Rajjou, Loïc

    2013-01-01

    Germination ability is regulated by a combination of environmental and endogenous signals with both synergistic and antagonistic effects. Nitric oxide (NO) is a potent dormancy-releasing agent in many species, including Arabidopsis, and has been suggested to behave as an endogenous regulator of this physiological blockage. Distinct reports have also highlighted a positive impact of NO on seed germination under sub-optimal conditions. However, its molecular mode of action in the context of seed biology remains poorly documented. This review aims to focus on the implications of this radical in the control of seed dormancy and germination. The consequences of NO chemistry on the investigations on both its signaling and its targets in seeds are discussed. NO-dependent protein post-translational modifications are proposed as a key mechanism underlying NO signaling during early seed germination. PMID:24065970

  11. Selection for low or high primary dormancy in Lolium rigidum Gaud seeds results in constitutive differences in stress protein expression and peroxidase activity

    Science.gov (United States)

    Goggin, Danica E.; Powles, Stephen B.; Steadman, Kathryn J.

    2011-01-01

    Seed dormancy in wild Lolium rigidum Gaud (annual ryegrass) populations is highly variable and not well characterized at the biochemical level. To identify some of the determinants of dormancy level in these seeds, the proteomes of subpopulations selected for low and high levels of primary dormancy were compared by two-dimensional polyacrylamide gel electrophoresis of extracts from mature, dry seeds. High-dormancy seeds showed higher expression of small heat shock proteins, enolase, and glyoxalase I than the low-dormancy seeds. The functional relevance of these differences in protein expression was confirmed by the fact that high-dormancy seeds were more tolerant to high temperatures imposed at imbibition and had consistently higher glyoxalase I activity over 0–42 d dark stratification. Higher expression of a putative glutathione peroxidase in low-dormancy seeds was not accompanied by higher activity, but these seeds had a slightly more oxidized glutathione pool and higher total peroxidase activity. Overall, these biochemical and physiological differences suggest that L. rigidum seeds selected for low dormancy are more prepared for rapid germination via peroxidase-mediated cell wall weakening, whilst seeds selected for high dormancy are constitutively prepared to survive environmental stresses, even in the absence of stress during seed development. PMID:20974739

  12. A Conserved Carbon Starvation Response Underlies Bud Dormancy in Woody and Herbaceous Species

    Directory of Open Access Journals (Sweden)

    Carlos Tarancón

    2017-05-01

    Full Text Available Plant shoot systems give rise to characteristic above-ground plant architectures. Shoots are formed from axillary meristems and buds, whose growth and development is modulated by systemic and local signals. These cues convey information about nutrient and water availability, light quality, sink/source organ activity and other variables that determine the timeliness and competence to maintain development of new shoots. This information is translated into a local response, in meristems and buds, of growth or quiescence. Although some key genes involved in the onset of bud latency have been identified, the gene regulatory networks (GRNs controlled by these genes are not well defined. Moreover, it has not been determined whether bud dormancy induced by environmental cues, such as a low red-to-far-red light ratio, shares genetic mechanisms with bud latency induced by other causes, such as apical dominance or a short-day photoperiod. Furthermore, the evolution and conservation of these GRNs throughout angiosperms is not well established. We have reanalyzed public transcriptomic datasets that compare quiescent and active axillary buds of Arabidopsis, with datasets of axillary buds of the woody species Vitis vinifera (grapevine and apical buds of Populus tremula x Populus alba (poplar during the bud growth-to-dormancy transition. Our aim was to identify potentially common GRNs induced during the process that leads to bud para-, eco- and endodormancy. In Arabidopsis buds that are entering eco- or paradormancy, we have identified four induced interrelated GRNs that correspond to a carbon (C starvation syndrome, typical of tissues undergoing low C supply. This response is also detectable in poplar and grapevine buds before and during the transition to dormancy. In all eukaryotes, C-limiting conditions are coupled to growth arrest and latency like that observed in dormant axillary buds. Bud dormancy might thus be partly a consequence of the underlying C

  13. BMP7 Induces Dormancy of Prostatic Tumor Stem Cell in Bone

    Science.gov (United States)

    2013-07-01

    and x-ray radiography of bone lesions from representative mice in each group four weeks after inoculation. Osteolytic lesions are indicated by arrow...n = 12) were co-injected with HS5 into tibiae of nude mice. Left panel: BLI and x-ray radiography of representative mice in each group four weeks...dormancy in bone microenvironment” as a Co-I with my mentor. 5. I did oral presentations of this project in the journal club of UMMC cancer

  14. What can be learnt about disease progression in breast cancer dormancy from relapse data?

    Science.gov (United States)

    Willis, Lisa; Graham, Trevor A; Alarcón, Tomás; Alison, Malcolm R; Tomlinson, Ian P M; Page, Karen M

    2013-01-01

    Breast cancer patients have an anomalously high rate of relapse many years--up to 25 years--after apparently curative surgery removed the primary tumour. Disease progression during the intervening years between resection and relapse is poorly understood. There is evidence that the disease persists as dangerous, tiny metastases that remain at a growth restricted, clinically undetectable size until a transforming event restarts growth. This is the starting point for our study, where patients who have metastases that are all tiny and growth-restricted are said to have cancer dormancy. Can long-term follow-up relapse data from breast cancer patients be used to extract knowledge about the progression of the undetected disease? Here, we evaluate whether this is the case by introducing and analysing four simple mathematical models of cancer dormancy. These models extend the common assumption that a random transforming event, such as a mutation, can restart growth of a tiny, growth-restricted metastasis; thereafter, cancer dormancy progresses to detectable metastasis. We find that physiopathological details, such as the number of random transforming events that metastases must undergo to escape from growth restriction, cannot be extracted from relapse data. This result is unsurprising. However, the same analysis suggested a natural question that does have a surprising answer: why are interesting trends in long-term relapse data not more commonly observed? Further, our models indicate that (a) therapies which induce growth restriction among metastases but do not prevent increases in metastases' tumourigenicity may introduce a time post-surgery when more patients are prone to relapse; and (b), if a number of facts about disease progression are first established, how relapse data might be used to estimate clinically relevant variables, such as the likely numbers of undetected growth-restricted metastases. This work is a necessary, early step in building a quantitative

  15. What can be learnt about disease progression in breast cancer dormancy from relapse data?

    Directory of Open Access Journals (Sweden)

    Lisa Willis

    Full Text Available Breast cancer patients have an anomalously high rate of relapse many years--up to 25 years--after apparently curative surgery removed the primary tumour. Disease progression during the intervening years between resection and relapse is poorly understood. There is evidence that the disease persists as dangerous, tiny metastases that remain at a growth restricted, clinically undetectable size until a transforming event restarts growth. This is the starting point for our study, where patients who have metastases that are all tiny and growth-restricted are said to have cancer dormancy. Can long-term follow-up relapse data from breast cancer patients be used to extract knowledge about the progression of the undetected disease? Here, we evaluate whether this is the case by introducing and analysing four simple mathematical models of cancer dormancy. These models extend the common assumption that a random transforming event, such as a mutation, can restart growth of a tiny, growth-restricted metastasis; thereafter, cancer dormancy progresses to detectable metastasis. We find that physiopathological details, such as the number of random transforming events that metastases must undergo to escape from growth restriction, cannot be extracted from relapse data. This result is unsurprising. However, the same analysis suggested a natural question that does have a surprising answer: why are interesting trends in long-term relapse data not more commonly observed? Further, our models indicate that (a therapies which induce growth restriction among metastases but do not prevent increases in metastases' tumourigenicity may introduce a time post-surgery when more patients are prone to relapse; and (b, if a number of facts about disease progression are first established, how relapse data might be used to estimate clinically relevant variables, such as the likely numbers of undetected growth-restricted metastases. This work is a necessary, early step in building a

  16. Mapping of Candidate Genes Involved in Bud Dormancy and Flowering Time in Sweet Cherry (Prunus avium.

    Directory of Open Access Journals (Sweden)

    Sophie Castède

    Full Text Available The timing of flowering in perennial plants is crucial for their survival in temperate climates and is regulated by the duration of bud dormancy. Bud dormancy release and bud break depend on the perception of cumulative chilling during endodormancy and heat during the bud development. The objectives of this work were to identify candidate genes involved in dormancy and flowering processes in sweet cherry, their mapping in two mapping progenies 'Regina' × 'Garnet' and 'Regina' × 'Lapins', and to select those candidate genes which co-localized with quantitative trait loci (QTLs associated with temperature requirements for bud dormancy release and flowering. Based on available data on flowering processes in various species, a list of 79 candidate genes was established. The peach and sweet cherry orthologs were identified and primers were designed to amplify sweet cherry candidate gene fragments. Based on the amplified sequences of the three parents of the mapping progenies, SNPs segregations in the progenies were identified. Thirty five candidate genes were genetically mapped in at least one of the two progenies and all were in silico mapped. Co-localization between candidate genes and QTLs associated with temperature requirements and flowering date were identified for the first time in sweet cherry. The allelic composition of the candidate genes located in the major QTL for heat requirements and flowering date located on linkage group 4 have a significant effect on these two traits indicating their potential use for breeding programs in sweet cherry to select new varieties adapted to putative future climatic conditions.

  17. Analysis of basic leucine zipper genes and their expression during bud dormancy in peach (Prunus persica).

    Science.gov (United States)

    Sun, Ming-Yue; Fu, Xi-Ling; Tan, Qiu-Ping; Liu, Li; Chen, Min; Zhu, Cui-Ying; Li, Ling; Chen, Xiu-De; Gao, Dong-Sheng

    2016-07-01

    Dormancy is a biological characteristic developed to resist the cold conditions in winter. The bZIP transcription factors are present exclusively in eukaryotes and have been identified and classified in many species. bZIP proteins are known to regulate numerous biological processes, however, the role of bZIP in bud dodormancy has not been studied extensively. In total, 50 PpbZIP transcription factor-encoding genes were identified and categorized them into 10 groups (A-I and S). Similar intron/exon structures, additional conserved motifs, and DNA-binding site specificity supported our classification scheme. Additionally, chromosomal distribution and collinearity analyses suggested that expansion of the PpbZIP transcription factor family was due to segment/chromosomal duplications. We also predicted the dimerization properties based on characteristic features of the leucine zipper and classified PpbZIP proteins into 23 subfamilies. Furthermore, qRT-PCR results indicated that PpbZIPs genes may be involved in regulating dormancy. The same gene of different species might participate in different regulating networks through interactions with specific partners. Our expression profiling results complemented the microarray data, suggesting that co-expression patterns of bZIP transcription factors during dormancy differed among deciduous fruit trees. Our findings further clarify the molecular characteristics of the PpbZIP transcription factor family, including potential gene functions during dormancy. This information may facilitate further research on the evolutionary history and biological functions of bZIP proteins in peach and other rosaceae plants. Copyright © 2016 Elsevier Masson SAS. All rights reserved.

  18. NITRIC OXIDE IMPLICATION IN THE CONTROL OF SEED DORMANCY AND GERMINATION

    OpenAIRE

    Erwann eArc; Marc eGalland; Béatrice eGodin; Gwendal eCueff; Loïc eRAJJOU

    2013-01-01

    Germination ability is regulated by a combination of environmental and endogenous signals with both synergistic and antagonistic effects. Nitric oxide (NO) is a potent dormancy-releasing agent in many species, including Arabidopsis, and has been suggested to behave as an endogenous regulator of this physiological blockage. Distinct reports have also highlighted a positive impact of NO on seed germination under sub-optimal conditions. However, its molecular mode of action in the context of see...

  19. Correlation analysis of human embryo LeY glycan antigen expression and embryo quality.

    Science.gov (United States)

    Gu, Juan; Sui, Linlin; Ma, Yanni; Guo, Zhenzhen; Zhang, Man; Zhu, Chenyang; Cai, Zhu; Kong, Ying

    2017-07-01

    This study assessed the feasibility of using LeY glycan secretion level in human embryos as a method of judging embryo quality. Embryo culture media from patients receiving in vitro fertilization-embryo transfer was collected, and quality scores of embryos were recorded. Secretions of LeY in the culture media in different development stages (from 4-cell to 10-cell), embryos in the same development stage of the same patients (8-cell/I) and embryos in the same development stage of different patients (8-cell/I) were examined by dot-blot. Embryos were divided into a hypersecretion group and hyposecretion group, based on their LeY secretion level. The embryo quality was evaluated by clinical observations, the number which developed to D3 cell stage and the number of successful embryo transplantations. LeY secretion increased as embryos developed from 4-cell to 10-cell (PLeY of 8/I is not identical; development speed of embryos with different secretion level of LeY was also different. The number of embryos which developed to 6-cell or higher was 82.2% in the LeY hypersecretion group but only 60% in the hyposecretion group. The rate of successful transplantation was significantly higher in the hypersecretion group (71.1 vs. 40%). In conclusion, LeY glycan secretion level in human embryos is closely related to embryo quality. LeY may become a useful measure to evaluate embryo quality in the future.

  20. Notch1 maintains dormancy of olfactory horizontal basal cells, a reserve neural stem cell.

    Science.gov (United States)

    Herrick, Daniel B; Lin, Brian; Peterson, Jesse; Schnittke, Nikolai; Schwob, James E

    2017-07-11

    The remarkable capacity of the adult olfactory epithelium (OE) to regenerate fully both neurosensory and nonneuronal cell types after severe epithelial injury depends on life-long persistence of two stem cell populations: the horizontal basal cells (HBCs), which are quiescent and held in reserve, and mitotically active globose basal cells. It has recently been demonstrated that down-regulation of the ΔN form of the transcription factor p63 is both necessary and sufficient to release HBCs from dormancy. However, the mechanisms by which p63 is down-regulated after acute OE injury remain unknown. To identify the cellular source of potential signaling mechanisms, we assessed HBC activation after neuron-only and sustentacular cell death. We found that ablation of sustentacular cells is sufficient for HBC activation to multipotency. By expression analysis, next-generation sequencing, and immunohistochemical examination, down-regulation of Notch pathway signaling is coincident with HBC activation. Therefore, using HBC-specific conditional knockout of Notch receptors and overexpression of N1ICD, we show that Notch signaling maintains p63 levels and HBC dormancy, in contrast to its suppression of p63 expression in other tissues. Additionally, Notch1, but not Notch2, is required to maintain HBC dormancy after selective neuronal degeneration. Taken together, our data indicate that the activation of HBCs observed after tissue injury or sustentacular cell ablation is caused by the reduction/elimination of Notch signaling on HBCs; elimination of Jagged1 expressed by sustentacular cells may be the ligand responsible.

  1. Herbaceous peony in warm climate: Modelling stem elongation and growers profit responses to dormancy conditions

    Directory of Open Access Journals (Sweden)

    Menashe Cohen

    2016-09-01

    Full Text Available We analysed the data collected for herbaceous peony cultivated in a warm climate region and stored in winter under three constant chilling temperatures. We used the quadratic regression model to describe the stem elongation responses to winter dormancy conditions, and the logistic function to describe the weekly stems elongation. The predicted maximal stem length from the first model was used as the input parameter for the second model. More than 4000 data for various (a chilling constant temperatures during dormancy, (b dormancy duration, and (c germination duration, were used. The models were applied to determine the optimal number of chill units. For this purpose, two criteria were used in different versions of the model: the maximal stem length and the maximal profit of farmers. For the two chilling temperatures of 2 °C and 6 °C, the optimal values of chill units (in the models of a maximal stem length and maximal profit of farmers are close to one another, and the values of a maximal stem length and maximal profit are significantly different. In the case of the third chilling temperature of 10 °C, the model failed to determine the optimal number of chill units. The method of inverse confidence intervals for testing the significance of the optimal number of chill units was used.

  2. Towards Better Understanding of Pea Seed Dormancy Using Laser Desorption/Ionization Mass Spectrometry

    Directory of Open Access Journals (Sweden)

    Monika Cechová

    2017-10-01

    Full Text Available Seed coats of six pea genotypes contrasting in dormancy were studied by laser desorption/ionization mass spectrometry (LDI-MS. Multivariate statistical analysis discriminated dormant and non-dormant seeds in mature dry state. Separation between dormant and non-dormant types was observed despite important markers of particular dormant genotypes differ from each other. Normalized signals of long-chain hydroxylated fatty acids (HLFA in dormant JI64 genotype seed coats were significantly higher than in other genotypes. These compounds seem to be important markers likely influencing JI64 seed imbibition and germination. HLFA importance was supported by study of recombinant inbred lines (JI64xJI92 contrasting in dormancy but similar in other seed properties. Furthemore HLFA distribution in seed coat was studied by mass spectrometry imaging. HLFA contents in strophiole and hilum are significantly lower compared to other parts indicating their role in water uptake. Results from LDI-MS experiments are useful in understanding (physical dormancy (first phases of germination mechanism and properties related to food processing technologies (e.g., seed treatment by cooking.

  3. Overcoming dormancy and determining optimal temperature for slender serradella seed germination

    Directory of Open Access Journals (Sweden)

    Rodrigo Ramos Lopes

    2015-12-01

    Full Text Available ABSTRACT The objective of this study was to identify the most efficient method for overcoming coat-imposed dormancy and determine the optimal germination temperature for Ornithopus pinnatus seeds. Treatments to overcome dormancy were: intact seeds; immersion in hot water at 60 ºC, followed by soaking in the same water (unheated/24 h; immersion in hot water at 90 ºC, followed by soaking in the same water (unheated/24 h; mechanical scarification; chemical scarification, H2SO4/5 min; and chemical scarification, H2SO4/10 min. Percentages were calculated for germinated, abnormal, dormant, and dead seeds. Optimal germination temperatures were calculated using eight constant temperatures (0, 5, 10, 15, 20, 25, 30, and 35 °C, with 8 h of light and 16 h of darkness. Germination rate, frequency, and synchronization index of germination were used as parameters to establish optimum temperature for germination. A completely randomized experimental design was used, with twelve repetitions of 100 seeds per treatment. Data obtained were subjected to analysis of variance and Tukey's test at a 5% significance level. O. pinnatus seeds exhibit dormancy caused by the seed coat's impermeability to water. Mechanical scarification was efficient in promoting seed germination. The species is stenothermal, meaning it cannot tolerate significant temperature variations. The germination rate of seeds was linearly dependent on temperature. Synchronization of the germination process is greater in the optimum temperature range, established between 15 and 20 °C.

  4. What prolongs a butterfly's life?: Trade-offs between dormancy, fecundity and body size.

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    Elena Haeler

    Full Text Available In butterflies, life span often increases only at the expense of fecundity. Prolonged life span, on the other hand, provides more opportunities for oviposition. Here, we studied the association between life span and summer dormancy in two closely related species of Palearctic Meadow Brown butterflies, the endemic Maniola nurag and the widespread M. jurtina, from two climatic provenances, a Mediterranean and a Central European site, and tested the relationships between longevity, body size and fecundity. We experimentally induced summer dormancy and hence prolonged the butterflies' life in order to study the effects of such a prolonged life. We were able to modulate longevity only in Mediterranean females by rearing them under summer photoperiodic conditions (light 16 h : dark 8 h, thereby more than doubling their natural life span, to up to 246 days. Central European individuals kept their natural average live span under all treatments, as did Mediterranean individuals under autumn treatment (light 11: dark 13. Body size only had a significant effect in the smaller species, M. nurag, where it affected the duration of dormancy and lifetime fecundity. In the larger species, M. jurtina, a prolonged adult life span did, surprisingly, not convey any fecundity loss. In M. nurag, which generally deposited fewer eggs, extended life had a fecundity cost. We conclude that Mediterranen M. jurtina butterflies have an extraordinary plasticity in aging which allows them to extend life span in response to adverse environmental conditions and relieve the time limitation on egg-laying while maintaining egg production at equal levels.

  5. In silico discovery of the dormancy regulons in a number of Actinobacteria genomes

    Energy Technology Data Exchange (ETDEWEB)

    Gerasimova, Anna; Dubchak, Inna; Arkin, Adam; Gelfand, Mikhail

    2010-11-16

    Mycobacterium tuberculosis is a dangerous Actinobacteria infecting nearly one third of the human population. It becomes dormant and phenotypically drug resistant in response to stresses. An important feature of the M. tuberculosis pathogenesis is the prevalence of latent infection without disease, making understanding of the mechanisms used by the bacteria to exist in this state and to switch to metabolically active infectious form a vital problem to consider. M. tuberculosis dormancy is regulated by the three-component regulatory system of two kinases (DosT and DevS) and transcriprional regulator (DevR). DevR activates transcription of a set of genes, which allow the bacteria to survive long periods of anaerobiosis, and may be important for long-term survival within the host during latent infection. The DevR-regulon is studied experimentally in M. tuberculosis and few other phylogenetically close Mycobacteria spp. As many other two-component systems, the devRS operon is autoregulated. However, the mechanism of the dormancy is not completely clear even for these bacteria and there is no data describing the dormancy regulons in other species.

  6. Embryo growth in mature celery seeds

    NARCIS (Netherlands)

    Toorn, van der P.

    1989-01-01

    Germination of celery seeds is slow, due to the need for embryo growth before radicle protrusion can occur. Germination rate was correlated with embryo growth rate. Celery seeds with different embryo growth rates were obtained with fluid density separation of a seed lot. Low density seeds

  7. Mechanistic dissection of plant embryo initiation

    NARCIS (Netherlands)

    Radoeva, T.M.

    2016-01-01

    Land plants can reproduce sexually by developing an embryo from a fertilized egg cell, the zygote. After fertilization, the zygote undergoes several rounds of controlled cell divisions to generate a mature embryo. However, embryo formation can also be induced in a variety of other cell types in many

  8. Salt Induces Features of a Dormancy-Like State in Seeds of Eutrema (Thellungiella salsugineum, a Halophytic Relative of Arabidopsis

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    Yana Kazachkova

    2016-08-01

    Full Text Available The salinization of land is a major factor limiting crop production worldwide. Halophytes adapted to high levels of salinity are likely to possess useful genes for improving crop tolerance to salt stress, as well as providing a food source on marginal lands. However, despite being salt-tolerant plants, the seeds of many halophytes will not germinate on saline soils, yet little is understood regarding biochemical and gene expression changes underlying salt-mediated inhibition of halophyte seed germination. We have used the halophytic Arabidopsis relative model system, Eutrema (Thellungiella salsugineum to explore salt-mediated inhibition of germination. We show that E. salsugineum seed germination is inhibited by salt to a far greater extent than in Arabidopsis, and that this inhibition is in response to the osmotic component of salt exposure. E. salsugineum seeds remain viable even when germination is completely inhibited, and germination resumes once seeds are transferred to non-saline conditions. Moreover, removal of the seed coat from salt-treated seeds allows embryos to germinate on salt-containing medium. Mobilization of seed storage reserves is restricted in salt-treated seeds, while many germination-associated metabolic changes are arrested or progress to a lower extent. Salt-exposed seeds are further characterized by a reduced GA/ABA ratio and increased expression of the germination repressor genes, RGL2, ABI5 and DOG1. Furthermore, a salt-mediated increase in expression of a LATE EMBRYOGENESIS ABUNDANT gene and accretion of metabolites involved in osmoprotection indicates induction of processes associated with stress tolerance, and accumulation of easily mobilized carbon reserves. Overall, our results suggest that salt inhibits E. salsugineum seed germination by inducing a seed state with molecular features of dormancy while a physical constraint to radicle emergence is provided by the seed coat layers. This seed state could facilitate

  9. Transcriptome analysis of seed dormancy after rinsing and chilling in ornamental peaches (Prunus persica (L.) Batsch).

    Science.gov (United States)

    Kanjana, Worarad; Suzuki, Tomohiro; Ishii, Kazuo; Kozaki, Toshinori; Iigo, Masayuki; Yamane, Kenji

    2016-08-08

    Ornamental peaches cv. 'Yaguchi' (Prunus persica (L.) Batsch) can be propagated via seeds. The establishment of efficient seed treatments for early germination and seedling growth is required to shorten nursery and breeding periods. It is important, therefore, to identify potential candidate genes responsible for the effects of rinsing and chilling on seed germination. We hypothesized that longer rinsing combined with chilling of seeds can alter the genes expression in related to dormancy and then raise the germination rate in the peach. To date, most molecular studies in peaches have involved structural genomics, and few transcriptome studies of seed germination have been conducted. In this study, we investigated the function of key seed dormancy-related genes using next-generation sequencing to profile the transcriptomes involved in seed dormancy in peaches. De novo assembly and analysis of the transcriptome identified differentially expressed and unique genes present in this fruit. De novo RNA-sequencing of peach was performed using the Illumina Miseq 2000 system. Paired-end sequence from mRNAs generated high quality sequence reads (9,049,964, 10,026,362 and 10,101,918 reads) from 'Yaguchi' peach seeds before rinsed (BR) and after rinsed for 2 or 7 days with a chilling period of 4 weeks (termed 2D4W and 7D4W), respectively. The germination rate of 7D4W was significantly higher than that of 2D4W. In total, we obtained 51,366 unique sequences. Differential expression analysis identified 7752, 8469 and 506 differentially expressed genes from BR vs 2D4W, BR vs 7D4W and 2D4W vs 7D4W libraries respectively, filtered based on p-value and an adjusted false discovery rate of less than 0.05. This study identified genes associated with the rinsing and chilling process that included those associated with phytohormones, the stress response and transcription factors. 7D4W treatment downregulated genes involved in ABA synthesis, catabolism and signaling pathways, which

  10. Extensive transcriptome changes during natural onset and release of vegetative bud dormancy in Populus

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    Glenn Thomas Howe

    2015-12-01

    Full Text Available To survive winter, many perennial plants become endodormant, a state of suspended growth maintained even in favorable growing environments. To understand vegetative bud endodormancy, we collected paradormant, endodormant, and ecodormant axillary buds from Populus trees growing under natural conditions. Of 44,441 Populus gene models analyzed using NimbleGen microarrays, we found that 1,362 (3.1% were differentially expressed among the three dormancy states, and another 429 (1.0% were differentially expressed during only one of the two dormancy transitions (false discovery rate p-value < 0.05. Of all differentially expressed genes, 69% were down-regulated from paradormancy to endodormancy, which was expected given the lower metabolic activity associated with endodormancy. Dormancy transitions were accompanied by changes in multiple genes associated with DNA methylation (via RNA-directed DNA methylation and histone modifications (via Polycomb Repressive Complex 2, confirming and extending knowledge of chromatin modification as major features of dormancy transitions. Among the chromatin-associated genes, we found two genes similar to SPT (SUPPRESSOR OF TY that were strongly up-regulated during endodormancy. Transcription factor genes and gene sets that were atypically up-regulated during endodormancy include a gene that seems to encode a trihelix transcription factor and genes associated with proteins involved in responses to ethylene, cold, and other abiotic stresses. These latter transcription factors include ETHYLENE INSENSITIVE 3 (EIN3, ETHYLENE-RESPONSIVE ELEMENT BINDING PROTEIN (EBP, ETHYLENE RESPONSE FACTOR (ERF, ZINC FINGER PROTEIN 10 (ZAT10, ZAT12, and WRKY DNA-binding domain proteins. Analyses of phytohormone-associated genes suggest important changes in responses to ethylene, auxin, and brassinosteroids occur during endodormancy. We found weaker evidence for changes in genes associated with salicylic acid and jasmonic acid, and little

  11. Nitric oxide and reactive oxygen species mediate metabolic changes in barley seed embryo during germination

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    Zhenguo eMa

    2016-02-01

    Full Text Available The levels of nitric oxide (NO and reactive oxygen species (ROS, ATP/ADP ratios, reduction levels of ascorbate and glutathione, expression of the genes encoding proteins involved in metabolism of NO and activities of the enzymes involved in fermentation and in metabolism of NO and ROS were studied in the embryos of germinating seeds of two barley (Hordeum vulgare L. cultivars differing in dormancy level. The level of NO production continuously increased after imbibition while the level of nitrosylated SH-groups in proteins increased. This corresponded to the decrease of free SH-groups in proteins. At early stage of germination (0-48 h postimbibition the genes encoding class 1 phytoglobin (the protein scavenging NO and S-nitrosoglutathione reductase (scavenging S-nitrosoglutathione were markedly expressed. More dormant cultivar exhibited lower ATP/ADP and ascorbate/dehydroascorbate ratios and lower lactate and alcohol dehydrogenase activities, while the production of NO and nitrosylation of proteins was higher as compared to the non-dormant cultivar. The obtained data indicate that at the onset of germination NO is actively generated causing nitrosylation of SH-groups and a switch from respiration to fermentation. After radicle protrusion the metabolism changes in a more reducing type as recorded by ratio of reduced and oxidized glutathione and ascorbate. The turnover of NO by the scavenging systems (phytoglobin, S-nitrosoglutathione reductase and interaction with ROS might contribute to the maintenance of redox and energy balance of germinating seeds and lead to alleviation of dormancy.

  12. Rotenone Decreases Hatching Success in Brine Shrimp Embryos by Blocking Development: Implications for Zooplankton Egg Banks.

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    Joseph A Covi

    Full Text Available While many zooplankton species recover quickly after the treatment of water resources with the piscicide, rotenone, some fail to reach pretreatment population density or, in rare cases, do not reappear at all. The variable impact of rotenone on zooplankton populations could stem from differences in the capacity of species to switch entirely to anaerobic catabolic pathways in the presence of rotenone, which blocks mitochondrial electron transport. Alternatively, variable responses among species could originate from differences in permeability of dormant life-stages to lipophilic chemicals like rotenone. The purpose of the present study was to determine the effects of rotenone on development, emergence and hatching of zooplankton embryos that lack both the anaerobic capacity to develop in the presence of rotenone and a permeability barrier to prevent the entry of rotenone during dormancy. Post-diapause embryos of the brine shrimp, Artemia franciscana, were employed as a model system, because they are permeable to lipophilic compounds when dechorionated and require aerobic conditions to support development. Early development in this species is also well characterized in the literature. Brine shrimp embryos were exposed to rotenone while development was either slowed by chilling or suspended by anoxia. Development, emergence and hatching were then observed in rotenone-free artificial seawater. The data presented demonstrate that rotenone freely diffuses across the embryonic cuticle in a matter of hours, and prevents development and emergence after brief exposures to ecologically relevant concentrations (0.025-0.5 mg L-1 of the piscicide. Neither the removal of rotenone from the environment, nor the removal of embryonic water with a hypertonic solution, are sufficient to reverse this block on development and emergence. These data indicate that rotenone could impair recruitment from egg banks for species of zooplankton that lack both an embryonic

  13. Rotenone Decreases Hatching Success in Brine Shrimp Embryos by Blocking Development: Implications for Zooplankton Egg Banks.

    Science.gov (United States)

    Covi, Joseph A; Hutchison, Evan R; Neumeyer, Courtney H; Gunderson, Matthew D

    While many zooplankton species recover quickly after the treatment of water resources with the piscicide, rotenone, some fail to reach pretreatment population density or, in rare cases, do not reappear at all. The variable impact of rotenone on zooplankton populations could stem from differences in the capacity of species to switch entirely to anaerobic catabolic pathways in the presence of rotenone, which blocks mitochondrial electron transport. Alternatively, variable responses among species could originate from differences in permeability of dormant life-stages to lipophilic chemicals like rotenone. The purpose of the present study was to determine the effects of rotenone on development, emergence and hatching of zooplankton embryos that lack both the anaerobic capacity to develop in the presence of rotenone and a permeability barrier to prevent the entry of rotenone during dormancy. Post-diapause embryos of the brine shrimp, Artemia franciscana, were employed as a model system, because they are permeable to lipophilic compounds when dechorionated and require aerobic conditions to support development. Early development in this species is also well characterized in the literature. Brine shrimp embryos were exposed to rotenone while development was either slowed by chilling or suspended by anoxia. Development, emergence and hatching were then observed in rotenone-free artificial seawater. The data presented demonstrate that rotenone freely diffuses across the embryonic cuticle in a matter of hours, and prevents development and emergence after brief exposures to ecologically relevant concentrations (0.025-0.5 mg L-1) of the piscicide. Neither the removal of rotenone from the environment, nor the removal of embryonic water with a hypertonic solution, are sufficient to reverse this block on development and emergence. These data indicate that rotenone could impair recruitment from egg banks for species of zooplankton that lack both an embryonic barrier to the entry of

  14. The transcription factor p8 regulates autophagy during diapause embryo formation in Artemia parthenogenetica.

    Science.gov (United States)

    Lin, Cheng; Jia, Sheng-Nan; Yang, Fan; Jia, Wen-Huan; Yu, Xiao-Jian; Yang, Jin-Shu; Yang, Wei-Jun

    2016-07-01

    Autophagy is an essential homeostatic process by which cytoplasmic components, including macromolecules and organelles, are degraded by lysosome. Increasing evidence suggests that phosphorylated AMP-activated protein kinase (p-AMPK) and target of rapamycin (TOR) play key roles in the regulation of autophagy. However, the regulation of autophagy in quiescent cells remains unclear, despite the fact that autophagy is known to be critical for normal development, regeneration, and degenerative diseases. Here, crustacean Artemia parthenogenetica was used as a model system because they produced and released encysted embryos that enter a state of obligate dormancy in cell quiescence to withstand various environmental threats. We observed that autophagy was increased before diapause stage but dropped to extremely low level in diapause cysts in Artemia. Western blot analyses indicated that the regulation of autophagy was AMPK/TOR independent during diapause embryo formation. Importantly, the level of p8 (Ar-p8), a stress-inducible transcription cofactor, was elevated at the stage just before diapause and was absent in encysted embryos, indicating that Ar-p8 may regulate autophagy. The results of Ar-p8 knockdown revealed that Ar-p8 regulated autophagy during diapause formation in Artemia. Moreover, we observed that activating transcription factors 4 and 6 (ATF4 and ATF6) responded to Ar-p8-regulated autophagy, indicating that autophagy targeted endoplasmic reticulum (ER) during diapause formation in Artemia. Additionally, AMPK/TOR-independent autophagy was validated in human gastric cancer MKN45 cells overexpressing Ar-p8. The findings presented here may provide insights into the role of p8 in regulating autophagy in quiescent cells.

  15. Low temperature dormancy affects the quantity and quality of the female sexual attractiveness pheromone in red-sided garter snakes.

    Science.gov (United States)

    Parker, M Rockwell; Mason, Robert T

    2009-10-01

    Low temperature dormancy is a necessary requirement of the annual cycle of most nonmigratory, temperate vertebrates. The red-sided garter snake, Thamnophis sirtalis parietalis, overwinters in communal dens during its prolonged winter dormancy (8 mo), and upon emergence, reproductive behavior of both sexes is maximal. Previous work on this species showed that male courtship behavior is maximally induced after simulated low temperature dormancy. The purpose of this study was to determine whether low temperature dormancy affects the pheromone profiles of individual female red-sided garter snakes. We collected females in the fall at den sites in Manitoba, Canada, and extracted pheromones from individuals at three different time points: fall (field), winter (lab), and spring (lab). Total skin lipid and pheromone fraction masses increased from fall to spring, and pheromone profiles were distinctly different in the fall and spring. Pheromone profiles became dominated by the long-chain, unsaturated methyl ketone components of the blend by the time snakes emerged in the spring. Further, the amounts of both saturated and unsaturated components increased from fall to spring, suggesting significant sex pheromone synthesis was induced by low temperature dormancy.

  16. Cholesterol plays a larger role during Mycobacterium tuberculosis in vitro dormancy and reactivation than previously suspected.

    Science.gov (United States)

    Soto-Ramirez, Maria D; Aguilar-Ayala, Diana A; Garcia-Morales, Lazaro; Rodriguez-Peredo, Sofia M; Badillo-Lopez, Claudia; Rios-Muñiz, Diana E; Meza-Segura, Mario A; Rivera-Morales, Gelen Y; Leon-Solis, Lizbel; Cerna-Cortes, Jorge F; Rivera-Gutierrez, Sandra; Helguera-Repetto, Addy C; Gonzalez-Y-Merchand, Jorge A

    2017-03-01

    It is known that cholesterol plays a key role for Mycobacterium tuberculosis (Mtb) adaptation and survival within the host, thus contributing to the establishment of dormancy. It has been extensively demonstrated that fatty acids are the main energy source of Mtb during infection and dormancy, and it has been proposed that these molecules are implicated in reactivation of bacilli from a dormant state. We used in vitro models to analyze Mtb gene expression during dormancy and reactivation when fatty acids and cholesterol are the unique carbon source in the media. Our results suggest that cholesterol might function as a signal to trigger Mtb expression of some genes required for stress protection earlier than the one induced by fatty acids alone, indicating that cholesterol is very favorable for its development. This process is so conducive that cholesterol-adapted bacilli can reactivate their growth after NRP2 dormancy state even 10 min post ventilation. Thus, we hypothesize that cholesterol is not only involved in Mtb dormancy but that it also plays a critical role for favorable and almost immediate reactivation from an in vitro long-lasting dormant state induced by hypoxia. Copyright © 2016 Elsevier Ltd. All rights reserved.

  17. The Time Required for Dormancy Release in Arabidopsis Is Determined by DELAY OF GERMINATION1 Protein Levels in Freshly Harvested Seeds[OA

    Science.gov (United States)

    Nakabayashi, Kazumi; Bartsch, Melanie; Xiang, Yong; Miatton, Emma; Pellengahr, Silke; Yano, Ryoichi; Seo, Mitsunori; Soppe, Wim J.J.

    2012-01-01

    Seed dormancy controls the start of a plant’s life cycle by preventing germination of a viable seed in an unfavorable season. Freshly harvested seeds usually show a high level of dormancy, which is gradually released during dry storage (after-ripening). Abscisic acid (ABA) has been identified as an essential factor for the induction of dormancy, whereas gibberellins (GAs) are required for germination. The molecular mechanisms controlling seed dormancy are not well understood. DELAY OF GERMINATION1 (DOG1) was recently identified as a major regulator of dormancy in Arabidopsis thaliana. Here, we show that the DOG1 protein accumulates during seed maturation and remains stable throughout seed storage and imbibition. The levels of DOG1 protein in freshly harvested seeds highly correlate with dormancy. The DOG1 protein becomes modified during after-ripening, and its levels in stored seeds do not correlate with germination potential. Although ABA levels in dog1 mutants are reduced and GA levels enhanced, we show that DOG1 does not regulate dormancy primarily via changes in hormone levels. We propose that DOG1 protein abundance in freshly harvested seeds acts as a timer for seed dormancy release, which functions largely independent from ABA. PMID:22829147

  18. Ecotopic expression of a novel peach (Prunus persica) CBF transcription factor in apple (Malus x domestica) results in short-day induced dormancy and increased cold hardiness

    Science.gov (United States)

    Regulation of growth and dormancy in temperate perennials such as fruit trees is essential, as is the ability to acclimate to freezing temperatures. Depending on the species, the onset of either dormancy and or cold acclimation can be triggered to varying degrees by either or both low, non-freezing...

  19. Expressional regulation of PpDAM5 and PpDAM6, peach (Prunus persica) dormancy-associated MADS-box genes, by low temperature and dormancy-breaking reagent treatment

    OpenAIRE

    Yamane, Hisayo; Ooka, Tomomi; Jotatsu, Hiroaki; Hosaka, Yukari; Sasaki, Ryuta; Tao, Ryutaro

    2011-01-01

    The present study investigated the expressional regulation of PpDAM5 and PpDAM6, two of the six peach (Prunus persica) dormancy-associated MADS-box genes, in relation to lateral bud endodormancy. PpDAM5 and PpDAM6 were originally identified as homologues of Arabidopsis SHORT VEGETATIVE PHASE/AGAMOUS-LIKE 24 identified in the EVERGROWING locus of peach. Furthermore, PpDAM5 and PpDAM6 have recently been suggested to be involved in terminal bud dormancy. In this study, seasonal expression analys...

  20. Negative Regulation of Abscisic Acid Signaling by the Fagus sylvatica FsPP2C1 Plays A Role in Seed Dormancy Regulation and Promotion of Seed Germination1

    Science.gov (United States)

    González-García, Mary Paz; Rodríguez, Dolores; Nicolás, Carlos; Rodríguez, Pedro Luis; Nicolás, Gregorio; Lorenzo, Oscar

    2003-01-01

    FsPP2C1 was previously isolated from beech (Fagus sylvatica) seeds as a functional protein phosphatase type-2C (PP2C) with all the conserved features of these enzymes and high homology to ABI1, ABI2, and PP2CA, PP2Cs identified as negative regulators of ABA signaling. The expression of FsPP2C1 was induced upon abscisic acid (ABA) treatment and was also up-regulated during early weeks of stratification. Furthermore, this gene was specifically expressed in ABA-treated seeds and was hardly detectable in vegetative tissues. In this report, to provide genetic evidence on FsPP2C1 function in seed dormancy and germination, we used an overexpression approach in Arabidopsis because transgenic work is not feasible in beech. Constitutive expression of FsPP2C1 under the cauliflower mosaic virus 35S promoter confers ABA insensitivity in Arabidopsis seeds and, consequently, a reduced degree of seed dormancy. Additionally, transgenic 35S:FsPP2C1 plants are able to germinate under unfavorable conditions, as inhibitory concentrations of mannitol, NaCl, or paclobutrazol. In vegetative tissues, Arabidopsis FsPP2C1 transgenic plants show ABA-resistant early root growth and diminished induction of the ABA-response genes RAB18 and KIN2, but no effect on stomatal closure regulation. Seed and vegetative phenotypes of Arabidopsis 35S:FsPP2C1 plants suggest that FsPP2C1 negatively regulates ABA signaling. The ABA inducibility of FsPP2C1 expression, together with the transcript accumulation mainly in seeds, suggest that it could play an important role modulating ABA signaling in beechnuts through a negative feedback loop. Finally, we suggest that negative regulation of ABA signaling by FsPP2C1 is a factor contributing to promote the transition from seed dormancy to germination during early weeks of stratification. PMID:12970481

  1. Transcriptomic analysis of ‘Suli’ pear (Pyrus pyrifolia white pear group buds during the dormancy by RNA-Seq

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    Liu Guoqin

    2012-12-01

    Full Text Available Abstract Background Bud dormancy is a critical developmental process that allows perennial plants to survive unfavorable environmental conditions. Pear is one of the most important deciduous fruit trees in the world, but the mechanisms regulating bud dormancy in this species are unknown. Because genomic information for pear is currently unavailable, transcriptome and digital gene expression data for this species would be valuable resources to better understand the molecular and biological mechanisms regulating its bud dormancy. Results We performed de novo transcriptome assembly and digital gene expression (DGE profiling analyses of ‘Suli’ pear (Pyrus pyrifolia white pear group using the Illumina RNA-seq system. RNA-Seq generated approximately 100 M high-quality reads that were assembled into 69,393 unigenes (mean length = 853 bp, including 14,531 clusters and 34,194 singletons. A total of 51,448 (74.1% unigenes were annotated using public protein databases with a cut-off E-value above 10-5. We mainly compared gene expression levels at four time-points during bud dormancy. Between Nov. 15 and Dec. 15, Dec. 15 and Jan. 15, and Jan. 15 and Feb. 15, 1,978, 1,024, and 3,468 genes were differentially expressed, respectively. Hierarchical clustering analysis arranged 190 significantly differentially-expressed genes into seven groups. Seven genes were randomly selected to confirm their expression levels using quantitative real-time PCR. Conclusions The new transcriptomes offer comprehensive sequence and DGE profiling data for a dynamic view of transcriptomic variation during bud dormancy in pear. These data provided a basis for future studies of metabolism during bud dormancy in non-model but economically-important perennial species.

  2. Dormancy of growth-stunted malignant melanoma: sustainable and smoldering patterns

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    Claudine Piérard-Franchimont

    2014-09-01

    Full Text Available The presentations of primary and metastatic cutaneous malignant melanoma (CMM are very diverse. Evidence increasingly indicates that single CMM cells spread to distant sites quite early during cancer progression and are soon eliminated before they become clinically detectable. However bulky metastases which appear at a later stage might derive from some of these early neoplastic cells. It seems that local CMM single cell micro-metastases commonly predict sentinel lymph node involvement without overtly reflecting CMM progression to bulky visceral metastases. This study is intended to review the current understanding of the mechanisms underlying two CMM presentations. The first is the long interval, apparently disease-free, with persistent CMM dormancy, which may precede overt metastatic growth. Immunosurveillance may induce dormancy in single CMM cells disseminated in the body by blocking their proliferation cycle. The second is the socalled CMM smoldering phenomenon, which is marked by an alternate progression and regression of CMM locally with metastases that wax and wane for long periods of time over restricted skin areas. These very diverse patterns of CMM progression are likely to be ascribable to a number of biological factors, including the activation of CMM stem cells, and the combined phenotypic heterogeneity and variability in proliferative amplification in CMM cell clusters. Furthermore an adequate stimulation of CMM immune-surveillance and the induction of a specific stromal structure and vascular response are required. In this context, most early CMM tumors are in part controlled by lymphocytemediated responses before they become clinically detectable. However both the role of immune-surveillance and the mechanisms underlying both persistent and smoldering CMM dormancy remain unclear.

  3. Dormancy of growth-stunted malignant melanoma: sustainable and smoldering patterns.

    Science.gov (United States)

    Piérard-Franchimont, Claudine; Hermanns-Lê, Trinh; Delvenne, Philippe; Piérard, Gerald E

    2014-09-23

    The presentations of primary and metastatic cutaneous malignant melanoma (CMM) are very diverse. Evidence increasingly indicates that single CMM cells spread to distant sites quite early during cancer progression and are soon eliminated before they become clinically detectable. However bulky metastases which appear at a later stage might derive from some of these early neoplastic cells. It seems that local CMM single cell micro-metastases commonly predict sentinel lymph node involvement without overtly reflecting CMM progression to bulky visceral metastases. This study is intended to review the current understanding of the mechanisms underlying two CMM presentations. The first is the long interval, apparently disease-free, with persistent CMM dormancy, which may precede overt metastatic growth. Immunosurveillance may induce dormancy in single CMM cells disseminated in the body by blocking their proliferation cycle. The second is the so-called CMM smoldering phenomenon, which is marked by an alternate progression and regression of CMM locally with metastases that wax and wane for long periods of time over restricted skin areas. These very diverse patterns of CMM progression are likely to be ascribable to a number of biological factors, including the activation of CMM stem cells, and the combined phenotypic heterogeneity and variability in proliferative amplification in CMM cell clusters. Furthermore an adequate stimulation of CMM immune-surveillance and the induction of a specific stromal structure and vascular response are required. In this context, most early CMM tumors are in part controlled by lymphocyte-mediated responses before they become clinically detectable. However both the role of immune-surveillance and the mechanisms underlying both persistent and smoldering CMM dormancy remain unclear.

  4. Use of the Coelomic Grafting Technique for Prolonged ex utero Cultivation of Late Preprimitive Streak-Stage Rabbit Embryos.

    Science.gov (United States)

    Püschel, Bernd; Männer, Jörg

    2016-01-01

    Due to its morphological similarity with the early human embryo, the pregastrulation-stage rabbit may represent an appropriate mammalian model for studying processes involved in early human development. The usability of mammalian embryos for experimental studies depends on the availability of whole embryo culture methods facilitating prolonged ex utero development. While currently used culture methods yield high success rates for embryos from primitive streak stages onward, the success rate of extended cultivation of preprimitive streak-stage mammalian embryos is low for all previously established methods and for all studied species. This limits the usability of preprimitive streak-stage rabbit embryos in experimental embryology. We have tested whether the extraembryonic coelom of 4-day-old chick embryos may be used for prolonged ex utero culture of preprimitive streak-stage rabbit embryos (stage 2, 6.2 days post coitum). We found that, within this environment, stage 2 rabbit blastocysts can be cultured at decreasing success rates (55% after 1 day, 35% after 2 days, 15% after 3 days) up to a maximum of 72 h. Grafted blastocysts can continue development from the onset of gastrulation to early organogenesis and thereby form all structures characterizing age-matched controls (e.g. neural tube, somites, beating heart). Compared to normal controls, successfully cultured embryos developed at a slower rate and finally showed some structural and gross morphological anomalies. The method presented here was originally developed for whole embryo culture of mouse embryos by Gluecksohn-Schoenheimer in 1941. It is a simple and inexpensive method that may represent a useful extension to presently available ex utero culture systems for rabbit embryos. © 2016 S. Karger AG, Basel.

  5. Piglets produced by transfer of vitrified porcine embryos after stepwise dilution of cryoprotectants.

    Science.gov (United States)

    Kobayashi, S; Takei, M; Kano, M; Tomita, M; Leibo, S P

    1998-02-01

    A total of 498 porcine embryos at various stages of development collected from superovulated gilts was used to investigate cryopreservation. First, blastocysts (BL), expanded blastocysts (ExB), and hatched blastocysts (HB) were used to determine the effect of exposure to concentrated solutions of ethylene glycol as cryoprotective additives (CPAs) on embryo survival. Then, survival of other embryos after vitrification by rapid cooling was determined. Based on their development after 48 h in culture, embryos were not injured by being exposed to 2.0 M ethylene glycol (EG) for 15 min or to 2.0 M EG for 5 min and then to a solution of 8.0 M EG in 7% polyvinylpyrrolidone (PVP) for 1 min. The CPAs were removed from the embryos by diluting them with 1.7 M galactose. To vitrify the embryos, they were exposed to 2.0 M EG for 5 min and then were pipetted directly into short columns of 8.0 M EG-PVP contained within (1.25-ml plastic straws and separated from long columns of 1.7 M galactose by an air bubble. The straws were plunged directly into LN2. After the straws were warmed rapidly in a 25 degrees C water bath, the embryos were immediately mixed with galactose within the straws by shaking them vigorously to mix the contents. In sequential experiments, three methods were used to dilute the CPA solutions. Method 1: Embryos in the EG-PVP-galactose mixture were expelled from the straws and rinsed and cultured in modified CZB medium (mCZB). Method II: Embryos in the mixture were placed briefly into 1.5 M EG and then rinsed and cultured in mCZB. Method III: Embryos in the mixture were rinsed in 1.0 M EG and then in 0.5 M EG and finally rinsed with mCZB and cultured. After 48 h in culture, the respective percentages of survival of embryos vitrified as BL, ExB, or HB were: Method I, 21, 32, and 13%; Method II, 9, 40, and 24%; Method III, 35, 85, and 71%. Of 20 additional ExB vitrified embryos diluted by Method III and transferred into a recipient, four developed into live piglets

  6. Discovering genes associated with dormancy in the monogonont rotifer Brachionus plicatilis

    Directory of Open Access Journals (Sweden)

    Kube Michael

    2009-03-01

    Full Text Available Abstract Background Microscopic monogonont rotifers, including the euryhaline species Brachionus plicatilis, are typically found in water bodies where environmental factors restrict population growth to short periods lasting days or months. The survival of the population is ensured via the production of resting eggs that show a remarkable tolerance to unfavorable conditions and remain viable for decades. The aim of this study was to generate Expressed Sequence Tags (ESTs for molecular characterisation of processes associated with the formation of resting eggs, their survival during dormancy and hatching. Results Four normalized and four subtractive libraries were constructed to provide a resource for rotifer transcriptomics associated with resting-egg formation, storage and hatching. A total of 47,926 sequences were assembled into 18,000 putative transcripts and analyzed using both Blast and GO annotation. About 28–55% (depending on the library of the clones produced significant matches against the Swissprot and Trembl databases. Genes known to be associated with desiccation tolerance during dormancy in other organisms were identified in the EST libraries. These included genes associated with antioxidant activity, low molecular weight heat shock proteins and Late Embryonic Abundant (LEA proteins. Real-time PCR confirmed that LEA transcripts, small heat-shock proteins and some antioxidant genes were upregulated in resting eggs, therefore suggesting that desiccation tolerance is a characteristic feature of resting eggs even though they do not necessarily fully desiccate during dormancy. The role of trehalose in resting-egg formation and survival remains unclear since there was no significant difference between resting-egg producing females and amictic females in the expression of the tps-1 gene. In view of the absence of vitellogenin transcripts, matches to lipoprotein lipase proteins suggest that, similar to the situation in dipterans, these

  7. Seed dormancy and germination of Halophila ovalis mediated by simulated seasonal temperature changes

    Science.gov (United States)

    Statton, John; Sellers, Robert; Dixon, Kingsley W.; Kilminster, Kieryn; Merritt, David J.; Kendrick, Gary A.

    2017-11-01

    The seagrass, Halophila ovalis plays an important ecological and sediment stability role in estuarine systems in Australia with the species in decline in many sites. Halophila ovalis is a facultative annual, relying mainly on recruitment from the sediment seed bank for the annual regeneration of meadows. Despite this, there is little understanding of seed dormancy releasing mechanisms and germination cues. Using H. ovalis seed from the warm temperate Swan River Estuary in Western Australia, the germination ecology of H. ovalis was investigated by simulating the natural seasonal variation in water temperatures. The proportion of germinating seeds was found to be significantly different among temperature treatments (p future.

  8. Genome-Wide Identification of Different Dormant Medicago sativa L. MicroRNAs in Response to Fall Dormancy

    Science.gov (United States)

    Du, Hongqi; Sun, Xiaoge; Shi, Yinghua; Wang, Chengzhang

    2014-01-01

    Background MicroRNAs (miRNAs) are a class of regulatory small RNAs (sRNAs) that regulate gene post-transcriptional expression in plants and animals. High-throughput sequencing technology is capable of identifying small RNAs in plant species. Alfalfa (Medicago sativa L.) is one of the most widely cultivated perennial forage legumes worldwide, and fall dormancy is an adaptive characteristic related to the biomass production and winter survival in alfalfa. Here, we applied high-throughput sRNA sequencing to identify some miRNAs that were responsive to fall dormancy in standard variety (Maverick and CUF101) of alfalfa. Results Four sRNA libraries were generated and sequenced from alfalfa leaves in two typical varieties at distinct seasons. Through integrative analysis, we identified 51 novel miRNA candidates of 206 families. Additionally, we identified 28 miRNAs associated with fall dormancy in standard variety (Maverick and CUF101), including 20 known miRNAs and eight novel miRNAs. Both high-throughput sequencing and RT-qPCR confirmed that eight known miRNA members were up-regulated and six known miRNA members were down-regulated in response to fall dormancy in standard variety (Maverick and CUF101). Among the 51 novel miRNA candidates, five miRNAs were up-regulated and three miRNAs were down-regulated in response to fall dormancy in standard variety (Maverick and CUF101), and five of them were confirmed by Northern blot analysis. Conclusion We identified 20 known miRNAs and eight new miRNA candidates that were responsive to fall dormancy in standard variety (Maverick and CUF101) by high-throughput sequencing of small RNAs from Medicago sativa. Our data provide a useful resource for investigating miRNA-mediated regulatory mechanisms of fall dormancy in alfalfa, and these findings are important for our understanding of the roles played by miRNAs in the response of plants to abiotic stress in general and fall dormancy in alfalfa. PMID:25473944

  9. Genome-wide identification of different dormant Medicago sativa L. MicroRNAs in response to fall dormancy.

    Science.gov (United States)

    Fan, Wenna; Zhang, Senhao; Du, Hongqi; Sun, Xiaoge; Shi, Yinghua; Wang, Chengzhang

    2014-01-01

    MicroRNAs (miRNAs) are a class of regulatory small RNAs (sRNAs) that regulate gene post-transcriptional expression in plants and animals. High-throughput sequencing technology is capable of identifying small RNAs in plant species. Alfalfa (Medicago sativa L.) is one of the most widely cultivated perennial forage legumes worldwide, and fall dormancy is an adaptive characteristic related to the biomass production and winter survival in alfalfa. Here, we applied high-throughput sRNA sequencing to identify some miRNAs that were responsive to fall dormancy in standard variety (Maverick and CUF101) of alfalfa. Four sRNA libraries were generated and sequenced from alfalfa leaves in two typical varieties at distinct seasons. Through integrative analysis, we identified 51 novel miRNA candidates of 206 families. Additionally, we identified 28 miRNAs associated with fall dormancy in standard variety (Maverick and CUF101), including 20 known miRNAs and eight novel miRNAs. Both high-throughput sequencing and RT-qPCR confirmed that eight known miRNA members were up-regulated and six known miRNA members were down-regulated in response to fall dormancy in standard variety (Maverick and CUF101). Among the 51 novel miRNA candidates, five miRNAs were up-regulated and three miRNAs were down-regulated in response to fall dormancy in standard variety (Maverick and CUF101), and five of them were confirmed by Northern blot analysis. We identified 20 known miRNAs and eight new miRNA candidates that were responsive to fall dormancy in standard variety (Maverick and CUF101) by high-throughput sequencing of small RNAs from Medicago sativa. Our data provide a useful resource for investigating miRNA-mediated regulatory mechanisms of fall dormancy in alfalfa, and these findings are important for our understanding of the roles played by miRNAs in the response of plants to abiotic stress in general and fall dormancy in alfalfa.

  10. Methanol as a cryoprotectant for equine embryos.

    Science.gov (United States)

    Bass, L D; Denniston, D J; Maclellan, L J; McCue, P M; Seidel, G E; Squires, E L

    2004-09-15

    Equine embryos (n=43) were recovered nonsurgically 7-8 days after ovulation and randomly assigned to be cryopreserved in one of two cryoprotectants: 48% (15M) methanol (n=22) or 10% (136 M) glycerol (n=21). Embryos (300-1000 microm) were measured at five intervals after exposure to glycerol (0, 2, 5, 10 and 15 min) or methanol (0, 15, 35, 75 and 10 min) to determine changes (%) in diameter over time (+/-S.D.). Embryos were loaded into 0.25-ml plastic straws, sealed, placed in a programmable cell freezer and cooled from room temperature (22 degrees C) to -6 degrees C. Straws were then seeded, held at -6 degrees C for 10 min and then cooled to -33 degrees C before being plunged into liquid nitrogen. Two or three embryos within a treatment group were thawed and assigned to be either cultured for 12 h prior to transfer or immediately nonsurgically transferred to a single mare. Embryo diameter decreased in all embryos upon initial exposure to cryoprotectant. Embryos in methanol shrank and recovered slightly to 76+/-8 % of their original diameter; however, embryos in glycerol continued to shrink, reaching 57+/-6 % of their original diameter prior to cryopreservation. Survival rates of embryos through Day 16 of pregnancy were 38 and 23%, respectively (P>0.05) for embryos cryopreserved in the presence of glycerol or methanol. There was no difference in pregnancy rates of mares receiving embryos that were cultured prior to transfer or not cultured (P>0.05). Preliminary experiments indicated that 48% methanol was not toxic to fresh equine embryos but methanol provided no advantage over glycerol as a cryoprotectant for equine blastocysts.

  11. Palaeontology: pterosaur embryo from the Early Cretaceous.

    Science.gov (United States)

    Wang, Xiaolin; Zhou, Zhonghe

    2004-06-10

    Dinosaur embryos have been discovered all over the world, but so far no pterosaur embryos have been reported. Here we describe a Chinese fossil from the Early Cretaceous period containing an embryo that is unambiguously a pterosaur. The embryonic skeleton, which is exquisitely preserved in its egg, is associated with eggshell fragments, wing membranes and skin imprints. This discovery confirms that pterosaurs were egg-layers and sheds new light on our understanding of pterosaur development.

  12. Somatic embryogenesis and plant regeneration from embryo rescue ...

    African Journals Online (AJOL)

    The application of tissue culture techniques, particularly in the area of embryo rescue, has had a major impact on the maintenance and development of hybrid embryo from wide crosses. Embryo rescue techniques are directed towards obtaining more efficient survival of embryos in situations where very immature embryos ...

  13. Transmission of Campylobacter coli in chicken embryos

    Directory of Open Access Journals (Sweden)

    Daise Aparecida Rossi

    2012-06-01

    Full Text Available Campylobacter coli is an important species involved in human cases of enteritis, and chickens are carriers of the pathogen mainly in developing country. The current study aimed to evaluate the transmission of C. coli and its pathogenic effects in chicken embryos. Breeder hens were inoculated intra-esophageally with C. coli isolated from chickens, and their eggs and embryos were analyzed for the presence of bacteria using real-time PCR and plate culture. The viability of embryos was verified. In parallel, SPF eggs were inoculated with C. coli in the air sac; after incubation, the embryos were submitted to the same analysis as the embryos from breeder hens. In embryos and fertile eggs from breeder hens, the bacterium was only identified by molecular methods; in the SPF eggs, however, the bacterium was detected by both techniques. The results showed no relationship between embryo mortality and positivity for C. coli in the embryos from breeder hens. However, the presence of bacteria is a cause of precocious mortality for SPF embryos. This study revealed that although the vertical transmission is a possible event, the bacteria can not grow in embryonic field samples.

  14. Developmental toxicity of arecoline, the major alkaloid in betel nuts, in zebrafish embryos.

    Science.gov (United States)

    Chang, Bei-En; Liao, Mei-Hui; Kuo, M Yen-Ping; Chen, Chi-Hsiang

    2004-01-01

    The major alkaloid in the betel nut, arecoline, has been reported to be potent in inducing developmentally toxic effects by generally lowering the embryo weight and retarding development of the embryo. This study examined the adverse effects of arecoline and tried to unravel the mechanism through the tools of molecular biology. Arecoline was administered to zebrafish embryos by incubation at concentrations ranging from 0.01-0.04% (wt/vol) and lethality and morphological changes were recorded. The expression of genes was analyzed by reverse transcription-polymerase chain reaction (RT-PCR) and whole-mount in situ hybridization. In addition, the protective effects of several antioxidants were tested. The survival rate of treated embryos during a three-day incubation significantly declined as the arecoline concentration increased. Treated embryos showed general growth retardation and lower rate of heartbeat. When examined at the 24-hr stage, the relative amounts of transcripts of p53, p21, and cyclin D1, and the spatial expression patterns of these genes in treated groups, were comparable to those of the untreated early stages of embryos. Finally, the addition of glutathione (GSH) or its precursor, N-acetyl-L-cysteine (NAC), ameliorated the developmental retardation of embryos by arecoline. Arecoline-treated embryos exhibited general developmental retardation in a dose-dependent manner. Our results from RT-PCR, in situ hybridization, and antioxidant-protection experiments indicate that the mechanism underlying growth retardation by arecoline in embryos is predominantly due to a general cytotoxic effect induced by depletion of intracellular thiols. Copyright 2003 Wiley-Liss, Inc.

  15. Cardio-respiratory development in bird embryos: new insights from a venerable animal model

    Directory of Open Access Journals (Sweden)

    Warren W. Burggren

    Full Text Available ABSTRACT The avian embryo is a time-honored animal model for understanding vertebrate development. A key area of extensive study using bird embryos centers on developmental phenotypic plasticity of the cardio-respiratory system and how its normal development can be affected by abiotic factors such as temperature and oxygen availability. Through the investigation of the plasticity of development, we gain a better understanding of both the regulation of the developmental process and the embryo's capacity for self-repair. Additionally, experiments with abiotic and biotic stressors during development have helped delineate not just critical windows for avian cardio-respiratory development, but the general characteristics (e.g., timing and dose-dependence of critical windows in all developing vertebrates. Avian embryos are useful in exploring fetal programming, in which early developmental experiences have implications (usually negative later in life. The ability to experimentally manipulate the avian embryo without the interference of maternal behavior or physiology makes it particularly useful in future studies of fetal programming. The bird embryo is also a key participant in studies of transgenerational epigenetics, whether by egg provisioning or effects on the germline that are transmitted to the F1 generation (or beyond. Finally, the avian embryo is heavily exploited in toxicology, in which both toxicological testing of potential consumer products as well as the consequences of exposure to anthropogenic pollutants are routinely carried out in the avian embryo. The avian embryo thus proves useful on numerous experimental fronts as an animal model that is concurrently both of adequate complexity and sufficient simplicity for probing vertebrate cardio-respiratory development.

  16. Humidity-regulated dormancy onset in the Fabaceae: a conceptual model and its ecological implications for the Australian wattle Acacia saligna.

    Science.gov (United States)

    Tozer, Mark G; Ooi, Mark K J

    2014-09-01

    Seed dormancy enhances fitness by preventing seeds from germinating when the probability of seedling survival and recruitment is low. The onset of physical dormancy is sensitive to humidity during ripening; however, the implications of this mechanism for seed bank dynamics have not been quantified. This study proposes a model that describes how humidity-regulated dormancy onset may control the accumulation of a dormant seed bank, and seed experiments are conducted to calibrate the model for an Australian Fabaceae, Acacia saligna. The model is used to investigate the impact of climate on seed dormancy and to forecast the ecological implications of human-induced climate change. The relationship between relative humidity and dormancy onset was quantified under laboratory conditions by exposing freshly matured non-dormant seeds to constant humidity levels for fixed durations. The model was field-calibrated by measuring the response of seeds exposed to naturally fluctuating humidity. The model was applied to 3-hourly records of humidity spanning the period 1972-2007 in order to estimate both temporal variability in dormancy and spatial variability attributable to climatic differences among populations. Climate change models were used to project future changes in dormancy onset. A sigmoidal relationship exists between dormancy and humidity under both laboratory and field conditions. Seeds ripened under field conditions became dormant following very short exposure to low humidity (humidity did not increase dormancy significantly. It is predicted that populations growing in a temperate climate produce 33-55 % fewer dormant seeds than those in a Mediterranean climate; however, dormancy in temperate populations is predicted to increase as a result of climate change. Humidity-regulated dormancy onset may explain observed variation in physical dormancy. The model offers a systematic approach to modelling this variation in population studies. Forecast changes in climate have

  17. In vitro culture and embryo metabolism of cattle and sheep embryos - a decade of achievement.

    Science.gov (United States)

    Thompson, J G

    2000-07-02

    At the beginning of the 1990s, co-culture of cattle and sheep embryos was the most favoured method to support embryo development, but the use of this system has hampered progress in raising the efficiency of embryo production. Furthermore, little was known of the requirements of embryos and the biochemistry of early embryo development. As the decade progressed, energy metabolism studies improved our understanding of the energy substrate requirements for embryo development. Furthermore, an appreciation of the reproductive tract environment increased. This resulted in more "defined" systems, which have evolved further in the development of "sequential" media systems, where components change in accordance to the needs of the embryo. Nevertheless, wholly defined systems, such as the replacement of albumin with PVA, are less able to support similar levels of development as protein-containing medium, and the resulting embryos are metabolically compromised. This highlights the nutritive role of albumin. One area in which much work has been conducted, but yet no unifying theory has emerged, is that of the interactive roles of growth factors (including autocrine/paracrine), cytokines and extra-cellular matrix molecules in the development of a viable embryo. A new concept is that of regulation of energy metabolism. Compounds such as ethylenediamine tetraacetic acid (EDTA), NaN(3) and 2,4-dinitrophenol have been shown to increase embryo development and quality of resulting embryos. This demonstrates that the process of ATP production is a key regulator of in vitro embryo development.

  18. Dormancy in Peach (Prunus persica L.) Flower Buds 1

    Science.gov (United States)

    Luna, Virginia; Lorenzo, Eugenia; Reinoso, Herminda; Tordable, Maria C.; Abdala, Guillermina; Pharis, Richard P.; Bottini, Ruben

    1990-01-01

    Flower buds of peach (Prunus persica L.) trees, cv Novedad de Cordoba (Argentina), were collected near the end of the dormant period and immediately before anthesis. After removal of scale leaves, morphological observations of representative buds, made on transverse and longitudinal microtome sections, showed that all verticils making up the flower are present in an undifferentiated form during the dormant period (June). Flower buds collected at the end of dormant period (August) showed additional growth and differentiation, at which time formation of two ovules was beginning in the unicarpelar gynoecium. Dehiscence of anthers had not yet occurred 10 days before full bloom, and the ovules were still developing. Free endogenous gibberellin (GA)-like substances were quantified by bioassay (Tan-ginbozu dwarf rice microdrop) after SiO2 partition column chromatography, reversed phase C18-high performance liquid chromatography, and finally Nucleosil [N(CH3)2]high performance liquid chromatography. Bioactive fractions were then subjected to capillary gas chromatography-mass spectrometry-selected ion monitoring (GC-MS-SIM). Gibberellins A1, A3, and A8 were tentatively identified in peach flower buds using GC-SIM and Kovat's retention indices, and relative amounts approximated by GC-SIM (2:8:6 for GA1, GA3, and GA8, respectively). The highest concentration (330 nanograms per gram dry weight) of free GA1/GA3 was found in dormant buds (June) and diminished thereafter. The concentration free of GA1/GA3 did not increase immediately prior to bud break. However, high GA1/GA3 concentrations occurred during stages where rate of growth and cellular differentiation of (mainly fertile) verticils can be influenced. Images Figure 1 PMID:16667435

  19. Adoption first? The disposition of human embryos.

    Science.gov (United States)

    Murphy, Timothy F

    2014-06-01

    Anja Karnein has suggested that because of the importance of respect for persons, law and policy should require some human embryos created in vitro to be available for adoption for a period of time. If no one comes forward to adopt the embryos during that time, they may be destroyed (in the case of embryos left over from fertility medicine) or used in research (in the case of embryos created for that purpose or left over from fertility medicine). This adoption option would increase the number of embryos available for couples looking for help in having children, but that effect is less important--Karnein argues--than the observance of respect for human persons. As possible persons, she holds that embryos ought to be treated, as if they will become children, if only for a while. If enacted as a matter of law and policy, an 'adoption option' would wrongly interfere with the dispositional rights women and men ought to have over embryos they create in the course of trying to have children. Karnein's proposal would also deprive researchers of certainty that the embryos they create for research would actually be available that way, leading to increased burdens of time and money and maybe even to more embryos than would otherwise be produced. Karnein's analysis does not show, moreover, that any duty of rescue applies to embryos. No woman is required to adopt any embryo, which significantly undercuts the justification for an obligatory adoption period. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://group.bmj.com/group/rights-licensing/permissions.

  20. Seed Biology Updates - Highlights and New Discoveries in Seed Dormancy and Germination Research.

    Science.gov (United States)

    Nonogaki, Hiroyuki

    2017-01-01

    An understanding of the biology of seeds has been greatly advanced in recent years. The progresses, particularly in the field of seed dormancy and germination research, have been made at a remarkable speed. Some of the possible epigenetic mechanisms, including an involvement of non-coding RNA, which were predicted for DELAY OF GERMINATION1 just a few years ago, have now been demonstrated with strong molecular and genetic evidence. Imprinting, or parent-of-origin-specific gene silencing/expression, which was characterized particularly for developing seeds, was also found in imbibed seeds and suggested for dormancy mechanisms. Hormone biology in seeds, which is the most advanced and almost a traditional area of seed research, also presents a new dimension. Upstream regulators of hormone metabolism and hormone transporters, such as abscisic acid and gibberellin influx/efflux carriers, have been identified. Characterization of the novel posttranslational modification pathways, including the N-end rule and S -nitrosylation pathways, which play a critical role in turnover of the major hormone signal transduction proteins, also expanded our knowledge about the complexity of hormone signaling in seeds. These progresses made at the molecular level are significant steps toward a better understanding of how seeds translate soil and other environmental signals into their internal hormone biology and make an important decision to stay dormant or commence with germination.

  1. Reversal of dormancy in switchgrass with low-light photoperiod extension.

    Science.gov (United States)

    Van Esbroeck, G A; Hussey, M A; Sanderson, M A

    2004-01-01

    Some switchgrass (Panicum virgatum L.) cultivars originating in the northern USA show limited late-summer and fall growth when grown in more southerly locations despite adequate temperature and moisture. Our objective was to determine the effects of low-light photoperiod extension on the dry matter yield of switchgrass cultivars originating from contrasting latitudes. Seedlings of the four cultivars (Cave-in-Rock, 'Caddo', 'Kanlow', and 'Alamo') were grown for 100 d in a greenhouse in winter under ambient (11.2-12.2 h) and extended (18 h) photoperiods. Photoperiod extension was with 7 micromol m(-2) s(-1) photosynthetic photon flux density. Cultivars responded differently to photoperiod extension (Pphotoperiods were observed in Cave-in-Rock (+98%) and Caddo (+129%). The dry matter yield of Kanlow increased by 31%, whereas dry matter yield of the southernmost cultivar Alamo was not affected by photoperiod extension. Yield increases for Cave-in-Rock and Caddo were associated with increased tiller number and weight. A reversal of dormancy for some cultivars with a photoperiodic signal verified that dormancy was not simply a result of a low radiant input.

  2. Effect of storage in overcoming seed dormancy of Annona coriacea Mart. seeds

    Directory of Open Access Journals (Sweden)

    DAIANE M. DRESCH

    2014-12-01

    Full Text Available The aim of this study was to evaluate the effect of pre-treatments on overcoming dormancy of A. coriacea seeds. Seeds were processed and stored in polyethylene bags at temperatures of at -18°C (42% RH, 5°C (34% RH, 15°C (60% RH and 25°C (34% RH, during 0, 30, 60, 90, 120 and 150 days. After storage, seeds were immersed in 350 mg.L−1 gibberellic acid for 144 hours. Sowing was carried out in plastic bags containing Red Latosol + Bioplant®. Moisture content, emergence percentage, emergence speed index, length and dry mass of seedlings, were evaluated. The experimental design was completely randomized in a factorial with four replications of 50 seeds each. The seed storage at 5°C and subsequent immersion in gibberellic acid was efficient to reach high percentage, emergence speed and plant growth. A. coriacea seeds showed non-deep simple morphophysiological dormancy wherein the physiological component can be overcome after the seeds are storage at 5°C for a maximum period of 53 days and subsequent immersed in exogenous GA (350 mg.L−1 for 144 hours.

  3. METHODS FOR OVERCOMING SEED DORMANCY AND THE INITIAL GROWTH OF Ziziphus joazeiro Mart. IN DIFFERENT SOILS

    Directory of Open Access Journals (Sweden)

    JOSENARA DAIANE DE SOUZA COSTA

    2016-01-01

    Full Text Available Considering the potential and importance of biodiversity of the Caatinga biome, studies on endemic species are relevant to conservation of its natural resources. The objectives of this work was to evaluate seed viability and physical methods for overcoming seed dormancy in juazeiro (Ziziphus joazeiro Mart. and assess the influence of different types of soil on the initial growth of juazeiro plants. The experiments were conducted in three stages. In the first stage, the viability of seeds from different lots was evaluated using the tetrazolium test. The second stage was conducted in a plant nursery, evaluating the application of physical processes (scarification with sandpaper and hammer in overcoming seed dormancy, and the initial growth of the plants. In the third step, the chlorophyll a and b contents, gas exchange and dry matter accumulation were evaluated in young juazeiro plants in three types of soil (Oxisol, Entisol and Vertisol. The results indicate that the viability of juazeiro seeds is greatly influenced by differences between the progenitor plants and by storage conditions, which enable a longevity of two years when stored at 22°C and 16% of relative humidity. The scarification methods with sandpaper and hammer are not efficient to reduce the time and uniform seed germination. The juazeiro plants have high growth potential in different edaphic environments, adapting well to soils of different textures and chemical compositions.

  4. Differentially expressed genes associated with dormancy or germination of Arabidopsis thaliana seeds.

    Science.gov (United States)

    Toorop, Peter E; Barroco, Rosa Maria; Engler, Gilbert; Groot, Steven P C; Hilhorst, Henk W M

    2005-07-01

    Differential display analysis using dormant and non-dormant Arabidopsis thaliana (L.) Heynh seeds resulted in a set of genes that were associated with either dormancy or germination. Expression of the germination-associated genes AtRPL36B and AtRPL27B, encoding two ribosomal proteins, was undetectable in the dry seed, low in dormant seed, and high under conditions that allowed completion of germination. Expression of these genes was also found to be light-regulated and to correlate with germination speed. Expression of the dormancy-associated genes ATS2 and ATS4, encoding a caleosin-like protein and a protein similar to a low-temperature-induced protein respectively, was high in the dry seed and decreased during germination. Expression of ATS2 and ATS4 was high in primary and secondary dormant seed but low in after-ripened or chilled seed. The expression of both genes was also light-regulated, but no relationship with temperature-dependent germination speed was found.

  5. Targeted mRNA oxidation regulates sunflower seed dormancy alleviation during dry after-ripening.

    Science.gov (United States)

    Bazin, Jérémie; Langlade, Nicolas; Vincourt, Patrick; Arribat, Sandrine; Balzergue, Sandrine; El-Maarouf-Bouteau, Hayat; Bailly, Christophe

    2011-06-01

    After-ripening is the mechanism by which dormant seeds become nondormant during their dry storage after harvest. The absence of free water in mature seeds does not allow detectable metabolism; thus, the processes associated with dormancy release under these conditions are largely unknown. We show here that sunflower (Helianthus annuus) seed alleviation of dormancy during after-ripening is associated with mRNA oxidation and that this oxidation is prevented when seeds are maintained dormant. In vitro approaches demonstrate that mRNA oxidation results in artifacts in cDNA-amplified fragment length polymorphim analysis and alters protein translation. The oxidation of transcripts is not random but selective, and, using microarrays, we identified 24 stored mRNAs that became highly oxidized during after-ripening. Oxidized transcripts mainly correspond to genes involved in responses to stress and in cell signaling. Among them, protein phosphatase 2C PPH1, mitogen-activated protein kinase phosphatase 1, and phenyl ammonia lyase 1 were identified. We propose that targeted mRNA oxidation during dry after-ripening of dormant seeds could be a process that governs cell signaling toward germination in the early steps of seed imbibition.

  6. 9 CFR 98.16 - The embryo collection unit.

    Science.gov (United States)

    2010-01-01

    ... a table or countertop that is impervious to moisture. The room also must contain a microscope with a minimum of 50x magnification, and equipment for freezing the embryos. (d) Embryo storage area. The embryo...

  7. Interspecies embryo reconstruction in Tibetan antelope Pantholops ...

    African Journals Online (AJOL)

    user

    2011-03-21

    Mar 21, 2011 ... Interspecies implantation and mitochondria fate of panda-rabbit cloned embryos. Biol. Reprod. 67: 637-642. Dominko T, Ramalho-Santos J, Chan A, Moreno R, Luetjens C, Simerly. C, Hewitson L, Takahashi D, Martinovich C, White J (1999). Optimization strategies for production of mammalian embryos by.

  8. Human stem cell ethics: beyond the embryo.

    Science.gov (United States)

    Sugarman, Jeremy

    2008-06-05

    Human embryonic stem cell research has elicited powerful debates about the morality of destroying human embryos. However, there are important ethical issues related to stem cell research that are unrelated to embryo destruction. These include particular issues involving different types of cells used, the procurement of such cells, in vivo use of stem cells, intellectual property, and conflicts of interest.

  9. Embryo transfer using cryopreserved Boer goat blastocysts ...

    African Journals Online (AJOL)

    The aim of this trial was to evaluate the effect of embryo cryopreservation techniques on the survivability of embryos and fertility following transfer to Boer goat does. The oestrous cycles of 27 mature recipients Boer goat does were synchronised using controlled internal drug release dispensers (CIDR's) for 16 days. At CIDR ...

  10. Respiration and hemoglobin function in the giant African bullfrog Pyxicephalus adspersus Tschudi (Anura: Pyxicephalidae) during rest, exercise and dormancy

    DEFF Research Database (Denmark)

    van Aardt, W.J; Weber, Roy E.

    2010-01-01

    of dormancy in soil without forming cocoons. With virtually no information available on the associated respiratory adaptations, we measured oxygen consumption rates of resting and exercising bullfrogs together with haematological and gas-binding properties of blood and haemoglobin (Hb) solutions from non...

  11. Germination and dormancy of single tomato seeds : a study using non-invasive molecular and biophysical techniques

    NARCIS (Netherlands)

    Spoelstra, P.

    2002-01-01

    Formation , germination and dormancy of seeds are important steps in the life cycle of higher plants. The seed is the generative dispersal unit, which enables plants to spread and survive through periods or seasons of less favourable conditions. In agriculture tomato is

  12. Heart rate and body weight alterations in juvenile specimens of the tropical land snail Megalobulimus sanctipauli during dormancy

    Directory of Open Access Journals (Sweden)

    Rizzatti A.C.S.

    2001-01-01

    Full Text Available The time course of heart rate and body weight alterations during the natural period of dormancy were determined in active feeding and dormant juvenile specimens of Megalobulimus sanctipauli. In both groups, heart rate markedly decreased during the first 40 days of dormancy, tending to stabilize thereafter. This time period coincided with the decrease in environmental temperature during autumn-winter. At the end of the dormancy period, surviving active feeding and dormant snails showed a significant decrease in heart rate which, however, was significantly greater in the latter group. Total body weight decreased concomitantly with heart rate in dormant snails but remained constant in active feeding snails. Body hydration induced significant increases in weight and heart rate in surviving dormant snails. Feeding following hydration promoted a new significant increase in heart rate but not in weight. These results indicate that the decrease in heart rate observed in juvenile specimens of M. sanctipauli during dormancy may be due to at least three factors: 1 decrease in environmental temperature during autumn-winter, 2 starvation which leads to the depletion of endogenous fuel reserves and to a probable decrease in hemolymph nutrient levels, and 3 dehydration which leads to a probable decrease in hemolymph volume and venous return and/or to an increase in hemolymph osmolarity.

  13. Predicting seed dormancy loss and germination timing for Bromus tectorum in a semi-arid environment using hydrothermal time models

    Science.gov (United States)

    Susan E. Meyer; Phil S. Allen

    2009-01-01

    A principal goal of seed germination modelling for wild species is to predict germination timing under fluctuating field conditions. We coupled our previously developed hydrothermal time, thermal and hydrothermal afterripening time, and hydration-dehydration models for dormancy loss and germination with field seed zone temperature and water potential measurements from...

  14. Global biogeography of seed dormancy is determined by seasonality and seed size: a case study in the legumes.

    Science.gov (United States)

    Rubio de Casas, Rafael; Willis, Charles G; Pearse, William D; Baskin, Carol C; Baskin, Jerry M; Cavender-Bares, Jeannine

    2017-06-01

    Seed dormancy is expected to provide ecological advantages by adjusting germination to the favorable growth period. However, many species produce nondormant seeds, particularly in wet tropical forests, a biogeographic pattern that is not well accounted for in current models. We hypothesized that the global distribution of dormant seeds derives from their adaptive value in predictably fluctuating (i.e. seasonal) environments. However, the advantage conferred by dormancy might ultimately depend on other seed attributes, particularly size. This general model was tested within a phylogenetically informed framework using a data set comprising > 216 000 world-wide observations of Fabaceae, spanning three orders of magnitude in seed size and including both dormant and nondormant seeds. Our results confirmed our hypothesis: nondormant seeds can only evolve in climates with long growing seasons and/or in lineages that produce larger seeds. Conversely, dormancy should be evolutionarily stable in temperate lineages with small seeds. When the favorable season is fleeting, seed dormancy is the only adaptive strategy. Based on these results, we predict that, within a given lineage, taxa producing larger, nondormant seeds will necessarily predominate in aseasonal environments, while plants bearing small, dormant seeds will be dominant under short growing seasons. © 2017 The Authors. New Phytologist © 2017 New Phytologist Trust.

  15. Comparative mapping of seed dormancy loci between tropical and temperate ecotypes of weedy rice (Oryza sativa L.)

    Science.gov (United States)

    Genotypic variation for seed dormancy (SD) in a species contributes to plant adaptation and weed persistence in agroecosystems. This research aimed to address the similarity of SD genes between distinct ecotypes using weedy rice as a model system. Quantitative trait locus mapping identified a total ...

  16. Winter warming delays dormancy release, advances budburst, alters carbohydrate metabolism and reduces yield in a temperate shrub

    DEFF Research Database (Denmark)

    Pagter, Majken; Andersen, Uffe Brandt; Andersen, Lillie

    2015-01-01

    winter warming modifies phenological traits in a woody perennial known to have a large chilling requirement and to be sensitive to spring frost. Warming delayed dormancy release more in the cultivar ‘Narve Viking’ than in the cultivar ‘Titania’, but advanced budburst and flowering predominantly...

  17. Rape embryogenesis. III. Embryo development in time

    Directory of Open Access Journals (Sweden)

    Teresa Tykarska

    2014-01-01

    Full Text Available It was found that the growth curve of the rape embryo axis is of triple sigmoid type. Embryo growth occurs in 3 phases corresponding to 3 different periods of development. Phase I includes growth of the apical cell up to it's division into two layers of octants. Phase II comprises the increase of the spherical proembryo to the change of its symmetry from radial to bilateral. Phase III includes, growth of the embryo from the heart stage up to the end of embryogenesis. In each phase the relative growth rate increases drastically and then diminishes. The differences in growth intensity during the same phase are several-fold. The growth intensity maximum of the embryo axis occurs in phase II. The phasic growth intensity maxima occur: in phase I during apical cell elongation, :before its division, and in phases II and III in the periods of cell division ;growth in globular and torpedo-shaped -shaped embryos.

  18. Nucleolar ultrastructure in bovine nuclear transfer embryos

    DEFF Research Database (Denmark)

    Kaňka, Jiří; Smith, Steven Dale; Soloy, Eva

    1999-01-01

    (nonactivated) or S phase (activated) cytoplasts. Control embryos were fixed at the two-, four-, early eight- and late eight-cell stages; nuclear transfer embryos were fixed at 1 and 3 hr post fusion and at the two-, four-, and eight-cell stages. Control embryos possessed a nucleolar precursor body throughout...... at 1 hr after fusion and, by 3 hr after fusion, it was restored again. At this time, the reticulated fibrillo-granular nucleolus had an almost round shape. The nucleolar precursor body seen in the two-cell stage nuclear transfer embryos consisted of intermingled filamentous components and secondary...... time intervals after fusion. In the two-cell stage nuclear transfer embryo, the originally reticulated nucleolus of the donor blastomere had changed into a typical nucleolar precursor body consisting of a homogeneous fibrillar structure. A primary vacuole appeared in the four-cell stage nuclear...

  19. Embryo transfer in domestic South American camelids.

    Science.gov (United States)

    Sumar, Julio B

    2013-01-10

    Intraspecific and interspecific embryo transfer in domestic South American camelids is developing into a well-established technique. Reports reveal many benefits of using reproductive biotechnologies to allow rapid propagation of alpacas and llamas of high genetic merit (e.g., high fiber quality, preserve color variation). The objective of this review is to provide up-to-date information about embryo transfer in domestic South American camelids. Specific information is provided on criteria for male selection, donor and recipient synchronization, the practice of single- vs. super-ovulation protocols, embryo recovery and transfer techniques, advances in cryopreservation of embryos, results of intra- and inter-specific transfer, and the future of the embryo transfer in domestic South American camelids. Copyright © 2012. Published by Elsevier B.V.

  20. Noninvasive metabolomic profiling as an adjunct to morphology for noninvasive embryo assessment in women undergoing single embryo transfer

    NARCIS (Netherlands)

    Seli, E.; Vergouw, C.G.; Morita, H.; Botros, L.; Roos, P.; Lambalk, C.B.; Yamashita, N.; Kato, O.; Sakkas, D.

    2010-01-01

    Objective: To determine whether metabolomic profiling of spent embryo culture media correlates with reproductive potential of human embryos. Design: Retrospective study. Setting: Academic and a private assisted reproductive technology (ART) programs. Patient(s): Women undergoing single embryo

  1. Potential of human twin embryos generated by embryo splitting in assisted reproduction and research.

    Science.gov (United States)

    Noli, Laila; Ogilvie, Caroline; Khalaf, Yacoub; Ilic, Dusko

    2017-03-01

    Embryo splitting or twinning has been widely used in veterinary medicine over 20 years to generate monozygotic twins with desirable genetic characteristics. The first human embryo splitting, reported in 1993, triggered fierce ethical debate on human embryo cloning. Since Dolly the sheep was born in 1997, the international community has acknowledged the complexity of the moral arguments related to this research and has expressed concerns about the potential for reproductive cloning in humans. A number of countries have formulated bans either through laws, decrees or official statements. However, in general, these laws specifically define cloning as an embryo that is generated via nuclear transfer (NT) and do not mention embryo splitting. Only the UK includes under cloning both embryo splitting and NT in the same legislation. On the contrary, the Ethics Committee of the American Society for Reproductive Medicine does not have a major ethical objection to transferring two or more artificially created embryos with the same genome with the aim of producing a single pregnancy, stating that 'since embryo splitting has the potential to improve the efficacy of IVF treatments for infertility, research to investigate the technique is ethically acceptable'. Embryo splitting has been introduced successfully to the veterinary medicine several decades ago and today is a part of standard practice. We present here an overview of embryo splitting experiments in humans and non-human primates and discuss the potential of this technology in assisted reproduction and research. A comprehensive literature search was carried out using PUBMED and Google Scholar databases to identify studies on embryo splitting in humans and non-human primates. 'Embryo splitting' and 'embryo twinning' were used as the keywords, alone or in combination with other search phrases relevant to the topics of biology of preimplantation embryos. A very limited number of studies have been conducted in humans and non

  2. Transcriptome analysis of mouse stem cells and early embryos.

    Directory of Open Access Journals (Sweden)

    Alexei A Sharov

    2003-12-01

    Full Text Available Understanding and harnessing cellular potency are fundamental in biology and are also critical to the future therapeutic use of stem cells. Transcriptome analysis of these pluripotent cells is a first step towards such goals. Starting with sources that include oocytes, blastocysts, and embryonic and adult stem cells, we obtained 249,200 high-quality EST sequences and clustered them with public sequences to produce an index of approximately 30,000 total mouse genes that includes 977 previously unidentified genes. Analysis of gene expression levels by EST frequency identifies genes that characterize preimplantation embryos, embryonic stem cells, and adult stem cells, thus providing potential markers as well as clues to the functional features of these cells. Principal component analysis identified a set of 88 genes whose average expression levels decrease from oocytes to blastocysts, stem cells, postimplantation embryos, and finally to newborn tissues. This can be a first step towards a possible definition of a molecular scale of cellular potency. The sequences and cDNA clones recovered in this work provide a comprehensive resource for genes functioning in early mouse embryos and stem cells. The nonrestricted community access to the resource can accelerate a wide range of research, particularly in reproductive and regenerative medicine.

  3. Murine hematopoietic stem cell dormancy controlled by induction of a novel short form of PSF1 by histone deacetylase inhibitors

    Energy Technology Data Exchange (ETDEWEB)

    Han, Yinglu; Gong, Zhi-Yuan [Department of Signal Transduction, Research Institute for Microbial Diseases, Osaka University, 3-1 Yamada-oka, Suita, Osaka 565-0871 (Japan); Takakura, Nobuyuki, E-mail: ntakaku@biken.osaka-u.ac.jp [Department of Signal Transduction, Research Institute for Microbial Diseases, Osaka University, 3-1 Yamada-oka, Suita, Osaka 565-0871 (Japan); Japan Science Technology Agency, CREST, K' s Gobancho, 7, Gobancho, Chiyoda-ku, Tokyo 102-0076 (Japan)

    2015-06-10

    Hematopoietic stem cells (HSCs) can survive long-term in a state of dormancy. Little is known about how histone deacetylase inhibitors (HDACi) affect HSC kinetics. Here, we use trichostatin A (TSA), a histone deacetylase inhibitor, to enforce histone acetylation and show that this suppresses cell cycle entry by dormant HSCs. Previously, we found that haploinsufficiency of PSF1, a DNA replication factor, led to attenuation of the bone marrow (BM) HSC pool size and lack of acute proliferation after 5-FU ablation. Because PSF1 protein is present in CD34{sup +} transiently amplifying HSCs but not in CD34{sup −} long-term reconstituting-HSCs which are resting in a dormant state, we analyzed the relationship between dormancy and PSF1 expression, and how a histone deacetylase inhibitor affects this. We found that CD34{sup +} HSCs produce long functional PSF1 (PSF1a) but CD34{sup −} HSCs produce a shorter possibly non-functional PSF1 (PSF1b, c, dominantly PSF1c). Using PSF1a-overexpressing NIH-3T3 cells in which the endogenous PSF1 promoter is suppressed, we found that TSA treatment promotes production of the shorter form of PSF1 possibly by inducing recruitment of E2F family factors upstream of the PSF1 transcription start site. Our data document one mechanism by which histone deacetylase inhibitors affect the dormancy of HSCs by regulating the DNA replication factor PSF1. - Highlights: • Hematopoetic stem cell dormancy is controlled by histone deacetylation inhibitors. • Dormancy of HSCs is associated with a shorter form of non-functional PSF1. • Histone deacetylase inhibitors suppress PSF1 promoter activity.

  4. Transcript profiling of Paoenia ostii during artificial chilling induced dormancy release identifies activation of GA pathway and carbohydrate metabolism.

    Directory of Open Access Journals (Sweden)

    Shupeng Gai

    Full Text Available Endo-dormant flower buds must pass through a period of chilling to reinitiate growth and subsequent flowering, which is a major obstacle to the forcing culture of tree peony in winter. Customized cDNA microarray (8×15 K element was used to investigate gene expression profiling in tree peony 'Feng Dan Bai' buds during 24 d chilling treatment at 0-4°C. According to the morphological changes after the whole plants were transferred to green house, endo-dormancy was released after 18 d chilling treatment, and prolonged chilling treatment increased bud break rate. Pearson correlation hierarchical clustering of sample groups was highly consistent with the dormancy transitions revealed by morphological changes. Totally 3,174 significantly differentially-expressed genes (P<0.05 were observed through endo-dormancy release process, of which the number of up-regulated (1,611 and that of down-regulated (1,563 was almost the same. Functional annotation of differentially-expressed genes revealed that cellular process, metabolic process, response to stimulus, regulation of biological process and development process were well-represented. Hierarchical clustering indicated that activation of genes involved in carbohydrate metabolism (Glycolysis, Citrate cycle and Pentose phosphate pathway, energy metabolism and cell growth. Based on the results of GO analysis, totally 51 probes presented in the microarray were associated with GA response and GA signaling pathway, and 22 of them were differently expressed. The expression profiles also revealed that the genes of GA biosynthesis, signaling and response involved in endo-dormancy release. We hypothesized that activation of GA pathway played a central role in the regulation of dormancy release in tree peony.

  5. The small heat shock protein p26 aids development of encysting Artemia embryos, prevents spontaneous diapause termination and protects against stress.

    Directory of Open Access Journals (Sweden)

    Allison M King

    Full Text Available Artemia franciscana embryos enter diapause as encysted gastrulae, a physiological state of metabolic dormancy and enhanced stress resistance. The objective of this study was to use RNAi to investigate the function of p26, an abundant, diapause-specific small heat shock protein, in the development and behavior of encysted Artemia embryos (cysts. RNAi methodology was developed where injection of Artemia females with dsRNA specifically eliminated p26 from cysts. p26 mRNA and protein knock down were, respectively, confirmed by RT-PCR and immuno-probing of western blots. ArHsp21 and ArHsp22, diapause-related small heat shock proteins in Artemia cysts sharing a conserved α-crystallin domain with p26, were unaffected by injection of females with dsRNA for p26, demonstrating the specificity of protein knock down. Elimination of p26 delayed cyst release from females demonstrating that this molecular chaperone influences the development of diapause-destined embryos. Although development was slowed the metabolic activities of cysts either containing or lacking p26 were similar. p26 inhibited diapause termination after prolonged incubation of cysts in sea water perhaps by a direct effect on termination or indirectly because p26 is necessary for the preservation of diapause maintenance. Cyst diapause was however, terminated by desiccation and freezing, a procedure leading to high mortality within cyst populations lacking p26 and indicating the protein is required for stress tolerance. Cysts lacking p26 were also less resistant to heat shock. This is the first in vivo study to show that knock down of a small heat shock protein slows the development of diapause-destined embryos, suggesting a role for p26 in the developmental process. The same small heat shock protein prevents spontaneous termination of diapause and provides stress protection to encysted embryos.

  6. The small heat shock protein p26 aids development of encysting Artemia embryos, prevents spontaneous diapause termination and protects against stress.

    Science.gov (United States)

    King, Allison M; MacRae, Thomas H

    2012-01-01

    Artemia franciscana embryos enter diapause as encysted gastrulae, a physiological state of metabolic dormancy and enhanced stress resistance. The objective of this study was to use RNAi to investigate the function of p26, an abundant, diapause-specific small heat shock protein, in the development and behavior of encysted Artemia embryos (cysts). RNAi methodology was developed where injection of Artemia females with dsRNA specifically eliminated p26 from cysts. p26 mRNA and protein knock down were, respectively, confirmed by RT-PCR and immuno-probing of western blots. ArHsp21 and ArHsp22, diapause-related small heat shock proteins in Artemia cysts sharing a conserved α-crystallin domain with p26, were unaffected by injection of females with dsRNA for p26, demonstrating the specificity of protein knock down. Elimination of p26 delayed cyst release from females demonstrating that this molecular chaperone influences the development of diapause-destined embryos. Although development was slowed the metabolic activities of cysts either containing or lacking p26 were similar. p26 inhibited diapause termination after prolonged incubation of cysts in sea water perhaps by a direct effect on termination or indirectly because p26 is necessary for the preservation of diapause maintenance. Cyst diapause was however, terminated by desiccation and freezing, a procedure leading to high mortality within cyst populations lacking p26 and indicating the protein is required for stress tolerance. Cysts lacking p26 were also less resistant to heat shock. This is the first in vivo study to show that knock down of a small heat shock protein slows the development of diapause-destined embryos, suggesting a role for p26 in the developmental process. The same small heat shock protein prevents spontaneous termination of diapause and provides stress protection to encysted embryos.

  7. Embryo cryopreservation and preeclampsia risk.

    Science.gov (United States)

    Sites, Cynthia K; Wilson, Donna; Barsky, Maya; Bernson, Dana; Bernstein, Ira M; Boulet, Sheree; Zhang, Yujia

    2017-11-01

    To determine whether assisted reproductive technology (ART) cycles involving cryopreserved-warmed embryos are associated with the development of preeclampsia. Retrospective cohort study. IVF clinics and hospitals. A total of 15,937 births from ART: 9,417 singleton and 6,520 twin. We used linked ART surveillance, birth certificate, and maternal hospitalization discharge data, considering resident singleton and twin births from autologous or donor eggs from 2005-2010. We compared the frequency of preeclampsia diagnosis for cryopreserved-warmed versus fresh ET and used multivariable logistic regression to adjust for confounders. Among pregnancies conceived with autologous eggs resulting in singletons, preeclampsia was greater after cryopreserved-warmed versus fresh ET (7.51% vs. 4.29%, adjusted odds ratio = 2.17 [95% CI 1.67-2.82]). Preeclampsia without and with severe features, preeclampsia with preterm delivery, and chronic hypertension with superimposed preeclampsia were more frequent after cryopreserved-warmed versus fresh ET (3.99% vs. 2.55%; 2.95% vs. 1.41%; 2.76 vs. 1.48%; and 0.95% vs. 0.43%, respectively). Among pregnancies from autologous eggs resulting in twins, the frequency of preeclampsia with severe features (9.26% vs. 5.70%) and preeclampsia with preterm delivery (14.81% vs. 11.74%) was higher after cryopreserved versus fresh transfers. Among donor egg pregnancies, rates of preeclampsia did not differ significantly between cryopreserved-warmed and fresh ET (10.78% vs. 12.13% for singletons and 28.0% vs. 25.15% for twins). Among ART pregnancies conceived using autologous eggs resulting in live births, those involving transfer of cryopreserved-warmed embryos, as compared with fresh ETs, had increased risk for preeclampsia with severe features and preeclampsia with preterm delivery. Copyright © 2017 American Society for Reproductive Medicine. All rights reserved.

  8. Neural tube closure in the chick embryo is multiphasic.

    Science.gov (United States)

    Van Straaten, H W; Janssen, H C; Peeters, M C; Copp, A J; Hekking, J W

    1996-11-01

    Progression of neurulation in the chick embryo has not been well documented. To provide a detailed description, chick embryos were stained in ovo after the least manipulation possible to avoid distortion of the neural plate and folds. This allowed a morphological and morphometric description of the process of neurulation in relatively undisturbed chick embryos. Neurulation comprises several specific phases with distinct closure patterns and closure rates. The first closure event occurs, de novo, in the future mesencephalon at the 4-6 somite stage (sst 4-6). Soon afterwards, at sst 6-7, de novo closure is seen at the rhombocervical level in the form of multisite contacts of the neural folds. These contacts occur in register with the somites, suggesting that the somites may play a role in forcing elevation and apposition of the neural folds. The mesencephalic] and rhombocervical closure events define an intervening rhombencephalic neuropore, which is present for a brief period before it closes. The remaining pear-shaped posterior neuropore (PNP) narrows and displaces caudally, but its length remains constant in embryos with seven to ten somites, indicating that the caudal extension of the rhombocervical closure point and elongation of the caudal neural plate are keeping pace with each other. From sst 10 onward, the tapered cranial portion of the PNP closes fast in a zipper-like manner, and, subsequently, the wide caudal portion of the PNP closes rapidly as a result of the parallel alignment of its folds, with numerous button-like temporary contact points. A role for convergent extension in this closure event is suggested. The final remnant of the PNP closes at sst 18. Thus, as in mammals, chick neurulation involves multisite closure and probably results form several different development mechanisms at varying levels of the body axis.

  9. Dormancy-breaking requirements of Sophora tomentosa and Erythrina speciosa (Fabaceae) seeds.

    Science.gov (United States)

    Luzia Delgado, Carolina Maria; Souza de Paula, Alexandre; Santos, Marisa; Silveira Paulilo, Maria Terezinha

    2015-03-01

    The physical dormancy of seeds has been poorly studied in species from tropical forests, such as the Atlantic Forest. This study aimed to examine the effect of moderate alternating temperatures on breaking the physical dormancy of seeds, the morphoanatomy and histochemistry of seed coats, and to locate the structure/region responsible for water entrance into the seed, after breaking the physical dormancy of seeds of two woody Fabaceae (subfamily Faboideae) species that occur in the Brazilian Atlantic Forest: Sophora tomentosa and Erythrina speciosa. To assess temperature effect, seeds were incubated in several temperature values that occur in the Atlantic Forest. For morphological and histochemical studies, sections of fixed seeds were subjected to different reagents, and were observed using light or epifluorescence microscopy, to analyze the anatomy and histochemistry of the seed coat. Treated and nonreated seeds were also analyzed using a scanning electron microscope (SEM) to observe the morphology of the seed coat. To localize the specific site of water entrance, the seeds were blocked with glue in different regions and also immersed in ink. In the present work a maximum temperature fluctuation of 15 degrees C was applied during a period of 20 days and these conditions did not increase the germination of S. tomentosa or E. speciosa. These results may indicate that these seeds require larger fluctuation of temperature than the applied or/and longer period of exposition to the temperature fluctuation. Blocking experiments water inlet combined with SEM analysis of the structures of seed coat for both species showed that besides the lens, the hilum and micropyle are involved in water absorption in seeds scarified with hot water. In seeds of E. speciosa the immersion of scarified seeds into an aniline aqueous solution showed that the solution first entered the seed through the hilum. Both species showed seed morphological and anatomical features for seed coats of the

  10. Tumor dormancy, oncogene addiction, cellular senescence, and self-renewal programs.

    Science.gov (United States)

    Bellovin, David I; Das, Bikul; Felsher, Dean W

    2013-01-01

    Cancers are frequently addicted to initiating oncogenes that elicit aberrant cellular proliferation, self-renewal, and apoptosis. Restoration of oncogenes to normal physiologic regulation can elicit dramatic reversal of the neoplastic phenotype, including reduced proliferation and increased apoptosis of tumor cells (Science 297(5578):63-64, 2002). In some cases, oncogene inactivation is associated with compete elimination of a tumor. However, in other cases, oncogene inactivation induces a conversion of tumor cells to a dormant state that is associated with cellular differentiation and/or loss of the ability to self-replicate. Importantly, this dormant state is reversible, with tumor cells regaining the ability to self-renew upon oncogene reactivation. Thus, understanding the mechanism of oncogene inactivation-induced dormancy may be crucial for predicting therapeutic outcome of targeted therapy. One important mechanistic insight into tumor dormancy is that oncogene addiction might involve regulation of a decision between self-renewal and cellular senescence. Recent evidence suggests that this decision is regulated by multiple mechanisms that include tumor cell-intrinsic, cell-autonomous mechanisms and host-dependent, tumor cell-non-autonomous programs (Mol Cell 4(2):199-207, 1999; Science 297(5578):102-104, 2002; Nature 431(7012):1112-1117, 2004; Proc Natl Acad Sci U S A 104(32):13028-13033, 2007). In particular, the tumor microenvironment, which is known to be critical during tumor initiation (Cancer Cell 7(5):411-423, 2005; J Clin Invest 121(6):2436-2446, 2011), prevention (Nature 410(6832):1107-1111, 2001), and progression (Cytokine Growth Factor Rev 21(1):3-10, 2010), also appears to dictate when oncogene inactivation elicits the permanent loss of self-renewal through induction of cellular senescence (Nat Rev Clin Oncol 8(3):151-160, 2011; Science 313(5795):1960-1964, 2006; N Engl J Med 351(21):2159-21569, 2004). Thus, oncogene addiction may be best modeled as

  11. [Association of human chorionic gonadotropin level in embryo culture media with early embryo development].

    Science.gov (United States)

    Wang, Haiying; Zhang, Renli; Han, Dong; Liu, Caixia; Cai, Jiajie; Bi, Yanling; Wen, Anmin; Quan, Song

    2014-06-01

    To investigate the association of human chorionic gonadotropin (HCG) level on day 3 of embryo culture with embryo development. Spent culture media were collected from individually cultured embryos on day 3 of in vitro fertilization and embryo transfer (IVF-ET) cycles. HCG concentration in the culture media was measured using an ELISA kit and its association with embryo development was assessed. In the 163 samples of embryo culture media from 60 patients, HCG was positive in 153 sample (93.8%) with a mean level of 0.85 ± 0.43 mIU/ml. The concentration of hCG in the culture media increased gradually as the number of blastomeres increased (F=2.273, P=0.03), and decreased as the morphological grade of the embryo was lowered (F=3.900, P=0.02). ELISA is capable of detecting HCG levels in spent culture media of embryos on day 3 of in vitro culture. The concentration of HCG in spent culture media is positively correlated with the status of early embryo development and implantation rate and thus serves as a useful marker for embryo selection in IVF-ET procedure.

  12. Glassfrog embryos hatch early after parental desertion.

    Science.gov (United States)

    Delia, Jesse R J; Ramírez-Bautista, Aurelio; Summers, Kyle

    2014-06-22

    Both parental care and hatching plasticity can improve embryo survival. Research has found that parents can alter hatching time owing to a direct effect of care on embryogenesis or via forms of care that cue the hatching process. Because parental care alters conditions critical for offspring development, hatching plasticity could allow embryos to exploit variation in parental behaviour. However, this interaction of parental care and hatching plasticity remains largely unexplored. We tested the hypothesis that embryos hatch early to cope with paternal abandonment in the glassfrog Hyalinobatrachium fleischmanni (Centrolenidae). We conducted male-removal experiments in a wild population, and examined embryos' response to conditions with and without fathers. Embryos hatched early when abandoned, but extended development in the egg stage when fathers continued care. Paternal care had no effect on developmental rate. Rather, hatching plasticity was due to embryos actively hatching at different developmental stages, probably in response to deteriorating conditions without fathers. Our experimental results are supported by a significant correlation between the natural timing of abandonment and hatching in an unmanipulated population. This study demonstrates that embryos can respond to conditions resulting from parental abandonment, and provides insights into how variation in care can affect selection on egg-stage adaptations.

  13. Nucleolar remodeling in nuclear transfer embryos

    DEFF Research Database (Denmark)

    Laurincik, Jozef; Maddox-Hyttel, Poul

    2007-01-01

    Transcription of the ribosomal RNA (rRNA) genes occurs in the nucleolus and results in ribosome biogenesis. The rRNA gene activation and the associated nucleolus formation may be used as a marker for the activation of the embryonic genome in mammalian embryos and, thus serve to evaluate the devel...... reprogramming and may help to explain the abnormalities observed in a proportion of fetuses and offspring derived from nuclear transfer embryos....... the developmental potential of embryos originating from varied nuclear transfer protocols. In bovine in vivo developed embryos, functional ribosome-synthesizing nucleoli become structurally distinct toward the end of the 4th post-fertilization cell cycle. In embryonic cell nuclear transfer embryos, fully developed...... nucleoli are not apparent until the 5th cell cycle, whereas in somatic cell nuclear transfer embryos the functional nucleoli emerge already during the 3rd cell cycle. Intergeneric reconstructed embryos produced by the fusion of bovine differentiated somatic cell to a nonactivated ovine cytoplast fail...

  14. Lineage specification in the early mouse embryo.

    Science.gov (United States)

    Lanner, Fredrik

    2014-02-01

    Before the mammalian embryo is ready to implant in the uterine wall, the single cell zygote must divide and differentiate into three distinct tissues; trophectoderm (prospective placenta), primitive endoderm (prospective yolk sac), and pluripotent epiblast cells which will form the embryo proper. In this review I will discuss our current understanding of how positional information, cell polarization, signaling pathways, and transcription factor networks converge to drive and regulate the progressive segregation of the first three cell types in the mouse embryo. © 2013 Published by Elsevier Inc.

  15. Cypripedium calceolus germination in situ: seed longevity, and dormancy breakage by long incubation and cold winters

    Directory of Open Access Journals (Sweden)

    Hanne N. Rasmussen

    2012-02-01

    Full Text Available A successful in situ germination experiment with Cypripedium calceolus, the European Lady’s slipper, is reported here for the first time. The seeds originated from controlled pollinations within and between two closely related Danish populations. The seeds were sown ripe in seed packets in proximity of mother plants. Germination was first observed after 4.5 y in the ground, following two successive cold and snowy winters, and only in one population. Seedlings expanded through the sides of the broken testa and were hair-less. A corresponding set of seeds, germinated in vitro as asymbiotic controls, responded positively to repeated cold stratifications after long incubation, suggesting that time (leaching? and chilling are dormancy breakage factors.

  16. Hysteroscopic Subendometrial Embryo Delivery (SEED,Mechanical Embryo Implantation

    Directory of Open Access Journals (Sweden)

    Michael Kamrava

    2010-01-01

    Full Text Available Background: A major hurdle to improved in vitro fertilization (IVF success rate is defectiveendometrial receptivity and implantation. Various techniques have been advocated to increaseimplantation while reducing side effects. Currently, embryo transfer (ET is performed blindlywithout direct visualization. As such, we sought to develop a technique utilizing a flexible minihysteroscopewith a flexible catheter for direct implantation of the blastocyst(s.Materials and Methods: This was a case study performed at West Coast IVF Clinic, Inc., BeverlyHills, California 90212. A total of 15 IVF Cycles in 13 patients (average age = 29 underwentvisually directed ET and endometrial implantation. All women received luteal support.The main outcome measure in this study, both clinically and procedurally, was the relevantdevelopment and assessment of a novel surgical technology.Results: In this study, eight (60% pregnancies ensued [5 (62.5% clinical and 3 (37.5%biochemical]. Of note, there was no uterine scratching, uterine bleeding, or ectopic pregnancies.Significantly, high-order pregnancies were decreased; only one twin was conceived.Conclusion: Preliminary data suggest mechanically assisting implantation with a hysteroscopicblastocyst ET (SEED offers a viable option for improving pregnancy outcome.

  17. Effects of temperature and photoperiod on postponing bermudagrass (Cynodon dactylon [L.] Pers.) turf dormancy.

    Science.gov (United States)

    Esmaili, Somayeh; Salehi, Hassan

    2012-06-15

    Growth chamber and field experiments were carried out to determine the effects of extended photoperiod under low and freezing temperatures on bermudagrass turf dormancy at Bajgah, in the southern part of Iran. The experiment in the growth chamber was conducted with four temperature regimes (15, 7.5, 0 and -7.5°C) and three light durations (8, 12 and 16h) in a completely randomized design with four replications. The field study was conducted in two consecutive years (2008-2009) with three light durations (8, 12 and 16h) in months with natural short day length and arranged in a randomized complete blocks design with three replications. Results in both experiments showed that decreasing temperature and photoperiod decreased verdure fresh and dry weight, shoot height, tiller density, leaf area and chlorophyll and relative water contents (RWC). However, rooting depth and fresh weight of roots increased in the growth chamber. Decreasing the temperature and light duration increased electrolyte leakage and proline content. Reducing sugars increased with decreasing temperature and declined with lowering light duration in both shoots and roots. Starch content of both shoots and roots showed an adverse trend compared to reducing sugars; starch content increased in both shoots and roots in all treatments by shortening the photoperiod. Practically, the problem of bermudagrass turf's dormancy could be solved via increasing the photoperiod in months with short day lengths. This treatment would be efficient and useful for turfgrass managers to apply in landscapes and stadiums. Copyright © 2012 Elsevier GmbH. All rights reserved.

  18. ( Zea mays l .) from mature zygotic embryo through callus initiation

    African Journals Online (AJOL)

    The use of immature zygotic embryos as an explant for maize regeneration has been hampered by the strictly limited suitable duration of immature embryos for culture. In contrast, mature zygotic embryos harvested from dry seeds are ubiquitous. However, generally mature embryos and especially tropical maize genotypes ...

  19. Ultrastructural changes in goat interspecies and intraspecies reconstructed early embryos

    DEFF Research Database (Denmark)

    Tao, Yong; Gheng, Lizi; Zhang, Meiling

    2008-01-01

    development. The zona pellucida (ZP) in all three types of embryos became thinner and ZP pores in both GC and GG embryos showed an increased rate of development, especially for GC embryos, while in vivo-produced embryos had smooth ZP. The Golgi apparatus (Gi) and rough endoplasmic reticulum (RER) of the two...

  20. High efficiency stratification of apple cultivar Ligol seed dormancy by phytohormones, heat shock and pulsed radio frequency.

    Science.gov (United States)

    Grzesik, Mieczysław; Górnik, Krzysztof; Janas, Regina; Lewandowki, Mariusz; Romanowska-Duda, Zdzislawa; Duijn, Bert van

    2017-09-28

    The aim of the study was to improve the effect of stratification of apple "Ligol" seeds by application of selected compounds, phytohormones, and physical methods For this purpose the seeds were stratified at 3°C in distilled water or in the presence of potassium nitrate (KNO3), ethephon (ET), carbon monoxide (CO), hydrogen peroxide (H2O2), a mixture of KNO3, ET, CO, H2O2, gibberellins (GA3), 6-benzylaminopurine (BAP), jasmonic acid (JA), salicylic acid (SA) and a mixture of SA, GA3, BAP, JA, nitric oxide (NO), hydrogen chloride (HCL). Arranged protocols included various durations and combinations of selected compounds and phytohormones as well as laser and red light, heat shock - 2h heat shock (45°C) and Pulsed Radio Frequency (PRF) were investigated by germination tests and the activity of selected enzymes, gas exchange and index of chlorophyll in leaves. The obtained results showed the possibility to shorten more effectively the time of the apple 'Ligol' dormancy removal by treatments of the stratified seeds at 3°C with different biological and physical methods Selected compounds and phytohormones acted collectively as a regulatory complex controlling the course of release from dormancy. Physical methods (PRF and heat shock) additionally contributed to dormancy breakage. Duration of phytohormones or compounds impacts during stratification should be prolonged to minimum 7days to assure more balanced conditions of the regulatory complex for the acceleration of dormancy a removal. The most beneficial results were obtained after seed stratification for 7days on filter paper moistened in KNO3+Etephon+CO+H2O2 at 3°C, and then on filter paper moistened in phytohormones (GA3+BAP+JA) till the end of seed germination (3°C). The application of this protocol could be a very useful tool in a shortening the apple breeding cycle since the period of removing dormancy was reduced by 38days in comparison to stratified in water. PRF has also the additive role in breaking

  1. Roles for blue light, jasmonate and nitric oxide in the regulation of dormancy and germination in wheat grain (Triticum aestivum L.).

    Science.gov (United States)

    Jacobsen, John V; Barrero, Jose M; Hughes, Trijntje; Julkowska, Magdalena; Taylor, Jennifer M; Xu, Qian; Gubler, Frank

    2013-07-01

    Abscisic acid (ABA) plays a central role in seed dormancy and transcriptional regulation of genes coding for ABA biosynthetic and degradation enzymes is responsible for control of ABA content. However, little is known about signalling both before and after ABA regulation, in particular, how environmental signals are perceived and transduced. We are interested in these processes in cereal grains, particularly in relation to the development of strategies for controlling pre-harvest sprouting in barley and wheat. Our previous studies have indicated possible components of dormancy control and here we present evidence that blue light, nitric oxide (NO) and jasmonate are major controlling elements in wheat grain. Using microarray and pharmacological studies, we have found that blue light inhibits germination in dormant grain and that methyl jasmonate (MJ) and NO counteract this effect by reducing dormancy. We also present evidence that NO and jasmonate play roles in dormancy control in vivo. ABA was reduced by MJ and this was accompanied by reduced levels of expression of TaNCED1 and increased expression of TaABA8'OH-1 compared with dormant grain. Similar changes were caused by after-ripening. Analysis of global gene expression showed that although jasmonate and after-ripening caused important changes in gene expression, the changes were very different. While breaking dormancy, MJ had only a small number of target genes including gene(s) encoding beta-glucosidase. Our evidence indicates that NO and MJ act interdependently in controlling reduction of ABA and thus the demise of dormancy.

  2. Differential expression of gibberellin- and abscisic acid-related genes implies their roles in the bud activity-dormancy transition of tea plants.

    Science.gov (United States)

    Yue, Chuan; Cao, Hongli; Hao, Xinyuan; Zeng, Jianming; Qian, Wenjun; Guo, Yuqiong; Ye, Naixing; Yang, Yajun; Wang, Xinchao

    2017-12-06

    Thirty genes involved in GA and ABA metabolism and signalling were identified, and the expression profiles indicated that they play crucial roles in the bud activity-dormancy transition in tea plants. Gibberellin (GA) and abscisic acid (ABA) are fundamental phytohormones that extensively regulate plant growth and development, especially bud dormancy and sprouting transition in perennial plants. However, there is little information on GA- and ABA-related genes and their expression profiles during the activity-dormancy transition in tea plants. In the present study, 30 genes involved in the metabolism and signalling pathways of GA and ABA were first identified, and their expression patterns in different tissues were assessed. Further evaluation of the expression patterns of selected genes in response to GA 3 and ABA application showed that CsGA3ox, CsGA20ox, CsGA2ox, CsZEP and CsNCED transcripts were differentially expressed after exogenous treatment. The expression profiles of the studied genes during winter dormancy and spring sprouting were investigated, and somewhat diverse expression patterns were found for GA- and ABA-related genes. This diversity was associated with the bud activity-dormancy cycle of tea plants. These results indicate that the genes involved in the metabolism and signalling of GA and ABA are important for regulating the bud activity-dormancy transition in tea plants.

  3. Timing embryo biopsy for PGD - before or after cryopreservation?

    Science.gov (United States)

    Shinar, S; Kornecki, N; Schwartz, T; Mey-Raz, N; Amir, H; Almog, B; Shavit, T; Hasson, J

    2016-09-01

    Pre-implantation genetic diagnosis (PGD) is required in order to screen and diagnose embryos of patients at risk of having a genetically affected offspring. A biopsy to diagnose the genetic profile of the embryo may be performed either before or after cryopreservation. The aim of this study was to determine which biopsy timing yields higher embryo survival rates. Retrospective cohort study of all PGD patients in a public IVF unit between 2010 and 2013. Inclusion criteria were patients with good-quality embryos available for cryopreservation by the slow freezing method. Embryos were divided into two groups: biopsy before and biopsy after cryopreservation. The primary outcome was embryo survival rates post thawing. Sixty-five patients met inclusion criteria. 145 embryos were biopsied before cryopreservation and 228 embryos were cryopreserved and biopsied after thawing. Embryo survival was significantly greater in the latter group (77% vs. 68%, p Cryopreservation preceding biopsy results in better embryo survival compared to biopsy before cryopreservation.

  4. Advanced optical imaging in living embryos

    OpenAIRE

    Canaria, Christie A.; Lansford, Rusty

    2010-01-01

    Developmental biology investigations have evolved from static studies of embryo anatomy and into dynamic studies of the genetic and cellular mechanisms responsible for shaping the embryo anatomy. With the advancement of fluorescent protein fusions, the ability to visualize and comprehend how thousands to millions of cells interact with one another to form tissues and organs in three dimensions (xyz) over time (t) is just beginning to be realized and exploited. In this review, we explore recen...

  5. Embryo disposition and the new death scene

    Directory of Open Access Journals (Sweden)

    Ellison, David

    2011-01-01

    Full Text Available In the IVF clinic - a place designed principally for the production and implantation of embryos - scientists and IVF recipients are faced with decisions regarding the disposition of frozen embryos. At this time there are hundred of thousands of cryopreserved embryos awaiting such determinations. They may be thawed for transfer to the woman herself, they may be donated for research or for use by other infertile couples, they may remain in frozen storage, or they may variously be discarded by being allowed to 'succumb', or 'perish'. Where the choice is discard, some IVF clients have chosen to formalise the process through ceremony. A new language is emerging in response to the desires of the would-be-parents who might wish to characterise the discard experience as a ‘good death’. This article examines the procedure known as ‘compassionate transfer’ where the embryo to be discarded is placed in the woman’s vagina where it is clear that it will not develop further. An alternate method has the embryo transferred in the usual manner but without the benefit of fertility-enhancing hormones at a point in the cycle unreceptive to implantation. The embryo destined for disposal is thus removed from the realm of technological possibility and ‘returned’ to the female body for a homely death. While debates continue about whether or not embryos constitute life, new practices are developing in response to the emotional experience of embryo discard. We argue that compassionate transfer is a death scene taking shape. In this article, we take the measure of this new death scene’s fabrication, and consider the form, significance, and legal complexity of its ceremonies.

  6. [In vitro fertilization and embryo transfer. Personal experiences in the introduction of laboratory methodology].

    Science.gov (United States)

    Fliess, F R; Sudik, R

    1984-01-01

    Our laboratory technique includes recovery and handling with gametes outside the body, in vitro fertilization, culture of embryos, and finally embryo-transfer. Time-table, culture media and technique of the cultivation as well as laboratory devices are described and than compared with informations about methods from other teams. The necessity of transport of the follicle fluids from operating theatre to laboratory is given caused by local conditions. All dates about number of oocytes (73), quantities of preovulatory oocytes (47) and cleavage rates (55%) are descended from 30 laparoscopic oocyte recoveries of the 2. in vitro fertilization program of the university woman hospital in Rostock, January and February 1984.

  7. Miniaturized embryo array for automated trapping, immobilization and microperfusion of zebrafish embryos.

    Directory of Open Access Journals (Sweden)

    Jin Akagi

    Full Text Available Zebrafish (Danio rerio has recently emerged as a powerful experimental model in drug discovery and environmental toxicology. Drug discovery screens performed on zebrafish embryos mirror with a high level of accuracy the tests usually performed on mammalian animal models, and fish embryo toxicity assay (FET is one of the most promising alternative approaches to acute ecotoxicity testing with adult fish. Notwithstanding this, automated in-situ analysis of zebrafish embryos is still deeply in its infancy. This is mostly due to the inherent limitations of conventional techniques and the fact that metazoan organisms are not easily susceptible to laboratory automation. In this work, we describe the development of an innovative miniaturized chip-based device for the in-situ analysis of zebrafish embryos. We present evidence that automatic, hydrodynamic positioning, trapping and long-term immobilization of single embryos inside the microfluidic chips can be combined with time-lapse imaging to provide real-time developmental analysis. Our platform, fabricated using biocompatible polymer molding technology, enables rapid trapping of embryos in low shear stress zones, uniform drug microperfusion and high-resolution imaging without the need of manual embryo handling at various developmental stages. The device provides a highly controllable fluidic microenvironment and post-analysis eleuthero-embryo stage recovery. Throughout the incubation, the position of individual embryos is registered. Importantly, we also for first time show that microfluidic embryo array technology can be effectively used for the analysis of anti-angiogenic compounds using transgenic zebrafish line (fli1a:EGFP. The work provides a new rationale for rapid and automated manipulation and analysis of developing zebrafish embryos at a large scale.

  8. Dormancy, ABA content and sensitivity of a barley mutant to ABA application during seed development and after ripening.

    Science.gov (United States)

    Romagosa, I; Prada, D; Moralejo, M A; Sopena, A; Muñoz, P; Casas, A M; Swanston, J S; Molina-Cano, J L

    2001-07-01

    Assessment of dormancy inception, maintenance and release was studied for artificially dried immature seeds harvested throughout seed development in the barley cv. Triumph and its mutant line TL43. Each was grown in Spain and Scotland under low and high dormancy inducing conditions, respectively. Both TL43 and Triumph followed a similar pattern of release from dormancy across the seasons, although seeds of TL43 were able to germinate at an earlier seed development stage. Abscisic acid (ABA) content was also studied in immature grains throughout the seed development period. Total amount of ABA in seeds of Triumph and TL43 was higher in plants grown in Scotland than in Spain. However, no clear genotypic differences in ABA pattern in the course of grain development could be detected whilst significant genotypic differences were observed for germination percentage (GP). Endogenous ABA content alone throughout grain development did not explain genetic differences in GP within environments. Environmental and genetic differences in dormancy were also observed on mature seeds throughout the after-ripening period. The initial germination (GP(0)) played a key role in the sensitivity to ABA of post-harvest mature seeds. For the same after-ripening stage, TL43 was more insensitive to exogenous ABA than Triumph. However, ABA responses in seeds of the two genotypes with similar GP(0) at different after-ripening stages were comparable. Therefore, differences in exogenous ABA sensitivity of post-harvest mature grain of these two genotypes seemed to be determined by, or coincident with, the initial germination percentage.

  9. Hollow Fiber Membrane Bioreactor Systems for Wastewater Processing: Effects of Environmental Stresses Including Dormancy Cycling and Antibiotic Dosing

    Science.gov (United States)

    Coutts, Janelle L.; Hummerick, Mary E.; Lunn, Griffin M.; Larson, Brian D.; Spencer, LaShelle E.; Kosiba, Michael L.; Khodadad, Christina L.; Catechis, John A.; Birmele, Michele N.; Wheeler, Raymond M.

    2016-01-01

    Membrane-aerated biofilm reactors (MABRs) have been studied for a number of years as an alternate approach for treating wastewater streams during space exploration. While the technology provides a promising pre-treatment for lowering organic carbon and nitrogen content without the need for harsh stabilization chemicals, several challenges must be addressed before adoption of the technology in future missions. One challenge is the transportation of bioreactors containing intact, active biofilms as a means for rapid start-up on the International Space Station or beyond. Similarly, there could be a need for placing these biological systems into a dormant state for extended periods when the system is not in use, along with the ability for rapid restart. Previous studies indicated that there was little influence of storage condition (4 or 25 C, with or without bulk fluid) on recovery of bioreactors with immature biofilms (48 days old), but that an extensive recovery time was required (20+ days). Bioreactors with fully established biofilms (13 months) were able to recover from a 7-month dormancy within 4 days (approximately 1 residence). Further dormancy and recovery testing is presented here that examines the role of biofilm age on recovery requirements, repeated dormancy cycle capabilities, and effects of long-duration dormancy cycles (8-9 months) on HFMB systems. Another challenge that must be addressed is the possibility of antibiotics entering the wastewater stream. Currently, for most laboratory tests of biological water processors, donors providing urine may not contribute to the study when taking antibiotics because the effects on the system are yet uncharacterized. A simulated urinary tract infection event, where an opportunistic, pathogenic organism, E. coli, was introduced to the HFMBs followed by dosing with an antibiotic, ciprofloxacin, was completed to study the effect of the antibiotic on reactor performance and to also examine the development of

  10. Morphological assessment on day 4 and its prognostic power in selecting viable embryos for transfer.

    Science.gov (United States)

    Fabozzi, Gemma; Alteri, Alessandra; Rega, Emilia; Starita, Maria Flavia; Piscitelli, Claudio; Giannini, Pierluigi; Colicchia, Antonio

    2016-08-01

    The aim of this study was to describe a system for embryo morphology scoring at the morula stage and to determine the efficiency of this model in selecting viable embryos for transfer. In total, 519 embryos from 122 patients undergoing intracytoplasmic sperm injection (ICSI) were scored retrospectively on day 4 according to the grading system proposed in this article. Two separate quality scores were assigned to each embryo in relation to the grade of compaction and fragmentation and their developmental fate was then observed on days 5 and 6. Secondly, the prediction value of this scoring system was compared with the prediction value of the traditional scoring system adopted on day 3. Morulas classified as grade A showed a significant higher blastocyst formation rate (87.2%) compared with grades B, C and D (63.8, 41.3 and 15.0%, respectively), (P < 0.001). Furthermore, the ability to form top quality blastocysts was significantly higher for grade A morulas with respect to grades B, and C and D (37.8% vs. 22.4% vs. 11.1%), (P < 0.001). Finally, the morula scoring system showed more prediction power with respect to the embryo scoring a value of 1 [Akaike information criterion (AIC) index 16.4 vs. 635.3 and Bayesian information criterion (BIC) index -68.8 vs. -30.0 for morulas and embryos respectively]. In conclusion, results demonstrated that the presented scoring system allows for the evaluation of eligible embryos for transfer as a significant correlation between the grade of morula, blastulation rate and blastocyst quality was observed. Furthermore, the morula scoring system was shown to be the best predictive model when compared with the traditional scoring system performed on day 3.

  11. Morphology and anatomy of physical dormancy in Ipomoea lacunosa: identification of the water gap in seeds of Convolvulaceae (Solanales).

    Science.gov (United States)

    Jayasuriya, K M G Gehan; Baskin, Jerry M; Geneve, Robert L; Baskin, Carol C

    2007-07-01

    Convolvulaceae is the most advanced plant family (asterid clade) that produces seeds with physical dormancy (water-impermeable seed coat). There are several different opinions about the nature of the specialized structure ('water gap') in the seed coat through which water initially enters seeds of Convolvulaceae, but none of them has been documented clearly. The primary aim of the study was to identify the water gap in seeds of Ipomoea lacunosa (Convolvulaceae) and to describe its morphology, anatomy and function. Light microscopy, scanning electron microscopy, tissue-sectioning, dye-tracking and blocking experiments were used to describe the morphology, anatomy and function of the water gap in seeds of I. lacunosa. Dormancy-breaking treatments caused slits to form around the two bulges on the seed coat adjacent to the hilum, and dye entered the seed only via the disrupted bulges. Bulge anatomy differs from that of the rest of the seed coat. Sclereid cells of the bulges are more compacted and elongated than those in the hilum pad and in the rest of the seed coat away from the bulges. The transition area between elongated and square-shaped sclereid cells is the place where the water gap opens. Morphology/anatomy of the water gap in Convolvulaceae differs from that of taxa in the other 11 angiosperm plant families that produce seeds with physical dormancy for which it has been described.

  12. Experimental climate warming enforces seed dormancy in South African Proteaceae but seedling drought resilience exceeds summer drought periods.

    Science.gov (United States)

    Arnolds, Judith L; Musil, Charles F; Rebelo, Anthony G; Krüger, Gert H J

    2015-04-01

    Two hypotheses-that elevated night-time temperatures due to climate warming would enforce post-fire dormancy of Proteaceae seed due to low moisture, and that periods without rain during summer would exceed desiccation periods tolerated by Proteaceae seedlings-were tested empirically. Enforced dormancy, i.e., the inability to germinate due to an environmental restraint, was tested by measuring seed germination in 11 Proteaceae species in experimental mesocosms whose soils were artificially elevated by 1.4 and 3.5 °C above ambient by far-red wavelength filtered infrared lamps. Diminished totality of germination and velocities were observed in 91 and 64%, respectively, of the Proteaceae species tested. Drought resilience was tested in one-year-old seedlings of 16 Proteaceae species by withholding water from potted plants during summer in a greenhouse. The most drought-resilient Proteaceae species displayed the lowest initial transpiration rates at field capacity, the smallest declines in transpiration rate with decreasing soil water content, and the lowest water losses by transpiration. Projected drought periods leading to the complete cessation of transpiration in all Proteaceae species greatly exceeded the number of days without rain per month during summer in the current distribution ranges of those species. It was therefore concluded that enforced seed dormancy induced by elevated night-time temperatures is the post-fire recruitment stage of Proteaceae that is most sensitive to climate warming.

  13. Cloning and characterization of a novel Gladiolus hybridus AFP family gene (GhAFP-like) related to corm dormancy

    Energy Technology Data Exchange (ETDEWEB)

    Wu, Jian; Seng, Shanshan [Beijing Key Laboratory of Development and Quality Control of Ornamental Crops, Department of Ornamental Horticulture and Landscape Architecture, China Agricultural University, Beijing 100193 (China); Carianopol, Carina [Department of Biological Sciences, University of Toronto, Toronto, Ontario (Canada); Sui, Juanjuan [College of Biology, Fuyang Normal College, Fuyang, Anhui (China); Yang, Qiuyan; Zhang, Fengqin; Jiang, Huiru [Beijing Key Laboratory of Development and Quality Control of Ornamental Crops, Department of Ornamental Horticulture and Landscape Architecture, China Agricultural University, Beijing 100193 (China); He, Junna, E-mail: hejunna@cau.edu.cn [Beijing Key Laboratory of Development and Quality Control of Ornamental Crops, Department of Ornamental Horticulture and Landscape Architecture, China Agricultural University, Beijing 100193 (China); Yi, Mingfang, E-mail: ymfang@cau.edu.cn [Beijing Key Laboratory of Development and Quality Control of Ornamental Crops, Department of Ornamental Horticulture and Landscape Architecture, China Agricultural University, Beijing 100193 (China)

    2016-02-26

    Abscisic acid (ABA) is an important phytohormone controlling seed dormancy. AFPs (ABA INSENSITIVE FIVE BINDING PROTEINS) are reported to be negative regulators of the ABA signaling pathway. The involvement of AFPs in dormant vegetative organs remains poorly understood. Here, we isolated and characterized a novel AFP family member from Gladiolus dormant cormels, GhAFP-like, containing three conserved domains of the AFP family. Quantitative PCR analysis revealed that GhAFP-like was expressed in dormant organs and its expression was down-regulated along with corm storage. GhAFP-like was verified to be a nuclear-localized protein. Overexpressing GhAFP-like in Arabidopsis thaliana not only showed weaker seed dormancy with insensitivity to ABA, but also changed the expression of some ABA related genes. In addition, a primary root elongation assay showed GhAFP-like may involve in auxin signaling response. The results in this study indicate that GhAFP-like acts as a negative regulator in ABA signaling and is related to dormancy. - Highlights: • GhAFP-like is expessed in dormant corm. • Overexpressing GhAFP-like showed early germination and insensitivity to ABA. • Overexpressing GhAFP-like changed ABI5 downstream genes expression.

  14. Meanings of the embryo in Japan: narratives of IVF experience and embryo ownership

    NARCIS (Netherlands)

    Kato, M.; Sleeboom-Faulkner, M.

    2011-01-01

    This article explores the sociocultural meanings of the embryo implied in the narratives of 58 women who have undergone in vitro fertilisation in Japan over a period from 2006 to 2008. We argue that a lack of sufficient analysis of the sociocultural meanings of the embryo result in a situation where

  15. Full-term potential of goat in vitro produced embryos after different cryopreservation methods.

    Science.gov (United States)

    Ferreira-Silva, José Carlos; Moura, Marcelo Tigre; Silva, Túlio Diego; Oliveira, Luis Rennan Sampaio; Chiamenti, Adauto; Figueirêdo Freitas, Vicente José; Oliveira, Marcos Antonio Lemos

    2017-04-01

    Cryopreservation of preimplantation embryos represents a major challenge due to their shape and relatively large cells. Embryo source and cryopreservation method are key factors to cryotolerance efficiency and few reports have investigated more promising protocols for goat embryos. The study was aimed to compare different cryopreservation methods for goat in vitro produced (IVP) embryos. Goat blastocysts were subjected to conventional freezing (CF), Dimethyl sulfoxide vitrification (DMSO-V) and Dimethylformamide vitrification (DMF-V). Cryopreserved blastocysts were assessed for re-expansion, cell viability and in vivo development rates. Blastocyst re-expansion after cryopreservation was similar between groups, but cell viability was lower for DMF-V (32%) than CF (68%) and DMSO-V (60%). Pregnancy and delivery rates were similar for CF (60% and 50%) and DMSO-V (50% and 45%) and higher then DMF-V (20% and 15%), respectively. Finally, kidding rates were also indistinguishable for CF (40%) and DMSO-V (35%), but higher then DMF-V (12.5%). In conclusion, conventional freezing and vitrification using DMSO have similar efficiencies for cryopreservation of goat IVP embryos and cryoprotectant for vitrification affects its outcome. Copyright © 2017 Elsevier Inc. All rights reserved.

  16. Developmental competence of porcine chimeric embryos produced by aggregation

    DEFF Research Database (Denmark)

    Li, Juan; Jakobsen, Jannik E.; Xiong, Qiang

    2015-01-01

    The purpose of our study was to compare the developmental competence and blastomere allocation of porcine chimeric embryos formed by micro-well aggregation. Chimeras were created by aggregating either two blastomeres originating from 2-cell embryos or two whole embryos, where embryos were produced...... either by parthenogenetic activation (PA) or handmade cloning (HMC). Results showed that the developmental competence of chimeric embryos, evaluated based on their blastocyst rate and total cell number per blastocyst, was increased when two whole 2-cell stage embryos (PA or HMC) were aggregated....... In comparison, when two blastomeres were aggregated, the developmental competence of the chimeric embryos decreased if the blastomeres were either from PA or from HMC embryos, but not if they were from different sources, i.e. one PA and one HMC blastomere. To evaluate the cell contribution in embryo formation...

  17. Patients' Attitudes towards the Surplus Frozen Embryos in China

    Directory of Open Access Journals (Sweden)

    Xuan Jin

    2013-01-01

    Full Text Available Background. Assisted reproductive techniques have been used in China for more than 20 years. This study investigates the attitudes of surplus embryo holders towards embryos storage and donation for medical research. Methods. A total of 363 couples who had completed in vitro fertilization (IVF treatment and had already had biological children but who still had frozen embryos in storage were invited to participate. Interviews were conducted by clinics in a narrative style. Results. Family size was the major reason for participants’ (discontinuation of embryo storage; moreover, the moral status of embryos was an important factor for couples choosing embryo storage, while the storage fee was an important factor for couples choosing embryo disposal. Most couples discontinued the storage of their embryos once their children were older than 3 years. In our study, 58.8% of the couples preferred to dispose of surplus embryos rather than donate them to research, citing a lack of information and distrust in science as significant reasons for their decision. Conclusions. Interviews regarding frozen embryos, including patients’ expectations for embryo storage and information to assist them with decisions regarding embryo disposal, are beneficial for policies addressing embryo disposition and embryo donation in China.

  18. Metabolite profiling of somatic embryos of Cyclamen persicum in comparison to zygotic embryos, endosperm and testa

    Directory of Open Access Journals (Sweden)

    Traud eWinkelmann

    2015-08-01

    Full Text Available Somatic embryogenesis has been shown to be an efficient in vitro plant regeneration system for many crops such as the important ornamental plant Cyclamen persicum, for which this regeneration pathway of somatic embryogenesis is of interest for the vegetative propagation of parental lines as well as elite plants. However, somatic embryogenesis is not commercially used in many crops due to several unsolved problems, such as malformations, asynchronous development, deficiencies in maturation and germination of somatic embryos. In contrast, zygotic embryos in seeds develop and germinate without abnormalities in most cases. Instead of time-consuming and labor-intensive experiments involving tests of different in vitro culture conditions and plant growth regulator supplements, we follow a more directed approach. Zygotic embryos served as a reference and were compared to somatic embryos in metabolomic analyses allowing the future optimization of the in vitro system. The aims of this study were to detect differences in the metabolite profiles of torpedo stage somatic and zygotic embryos of C. persicum. Moreover, major metabolites in endosperm and testa were identified and quantified.Two sets of extracts of two to four biological replicates each were analyzed. In total 52 metabolites were identified and quantified in the different tissues. One of the most significant differences between somatic and zygotic embryos was that the proline concentration in the zygotic embryos was about 40 times higher than that found in somatic embryos. Epicatechin, a scavenger for reactive oxygen species, was found in highest abundance in the testa. Sucrose, the most abundant metabolite was detected in significantly higher concentrations in zygotic embryos. Also, a yet unknown trisaccharide, was significantly enriched in zygotic embryos.

  19. Formation of somatic embryos in Persea americana Mill var Catalina from immature zygotic embryos.

    Directory of Open Access Journals (Sweden)

    Lillien Fajardo Rosabal

    2005-04-01

    Full Text Available The establishment of embryogenic culture of avocado have been achieved in different genotypes, usually the immature zygotic embryos are the initial explants and the process has been described in several variety. In the present paper the induction of the somatic embryogenesis in avocado (Catalina variety from zygotic embryos is proposed. Zygotic embryos taken from unripe fruits were used as explants . The fruits were divided into five groups according to their size. The embryos were cultured in a medium containing 4-amino-3,5,6 trichlorpicolinic acid (Picloram in concentrations of 0.1, 0.4, and 0.6 uM. The culture medium used for the induction of the somatic embryogenesis consisted of: Macro B5, Micro MS, thiamine (0.8 mg.l-1, myo-inositol (100 mg.l-1, sucrose (30g.l-1 and pH 5.7. The number of zygotic embryos with opened cotyledonal leaves was evaluated starting from the third day of culture. It was also evaluated the number of fenolized zygotic embryos at the third week of culture and the presence of somatic embryos five weeks after the culture initiation. The formation of somatic embryos was achieved in all the treatments. The highest number of explants that formed somatic embryos was achieved when a concentration of 0.6 uM of Picloram was used and the second group of size (0.71 x 0.65 mm observing significant differences between the different groups of fruit size. Keywords: avocado, cotyledonal leafs, somatic embryo,

  20. Metabolite profiling of somatic embryos of Cyclamen persicum in comparison to zygotic embryos, endosperm, and testa

    Science.gov (United States)

    Winkelmann, Traud; Ratjens, Svenja; Bartsch, Melanie; Rode, Christina; Niehaus, Karsten; Bednarz, Hanna

    2015-01-01

    Somatic embryogenesis has been shown to be an efficient in vitro plant regeneration system for many crops such as the important ornamental plant Cyclamen persicum, for which this regeneration pathway of somatic embryogenesis is of interest for the vegetative propagation of parental lines as well as elite plants. However, somatic embryogenesis is not commercially used in many crops due to several unsolved problems, such as malformations, asynchronous development, deficiencies in maturation and germination of somatic embryos. In contrast, zygotic embryos in seeds develop and germinate without abnormalities in most cases. Instead of time-consuming and labor-intensive experiments involving tests of different in vitro culture conditions and plant growth regulator supplements, we follow a more directed approach. Zygotic embryos served as a reference and were compared to somatic embryos in metabolomic analyses allowing the future optimization of the in vitro system. The aims of this study were to detect differences in the metabolite profiles of torpedo stage somatic and zygotic embryos of C. persicum. Moreover, major metabolites in endosperm and testa were identified and quantified. Two sets of extracts of two to four biological replicates each were analyzed. In total 52 metabolites were identified and quantified in the different tissues. One of the most significant differences between somatic and zygotic embryos was that the proline concentration in the zygotic embryos was about 40 times higher than that found in somatic embryos. Epicatechin, a scavenger for reactive oxygen species, was found in highest abundance in the testa. Sucrose, the most abundant metabolite was detected in significantly higher concentrations in zygotic embryos. Also, a yet unknown trisaccharide, was significantly enriched in zygotic embryos. PMID:26300898

  1. De novo characterization of fall dormant and nondormant alfalfa (Medicago sativa L.) leaf transcriptome and identification of candidate genes related to fall dormancy.

    Science.gov (United States)

    Zhang, Senhao; Shi, Yinghua; Cheng, Ningning; Du, Hongqi; Fan, Wenna; Wang, Chengzhang

    2015-01-01

    Alfalfa (Medicago sativa L.) is one of the most widely cultivated perennial forage legumes worldwide. Fall dormancy is an adaptive character related to the biomass production and winter survival in alfalfa. The physiological, biochemical and molecular mechanisms causing fall dormancy and the related genes have not been well studied. In this study, we sequenced two standard varieties of alfalfa (dormant and non-dormant) at two time points and generated approximately 160 million high quality paired-end sequence reads using sequencing by synthesis (SBS) technology. The de novo transcriptome assembly generated a set of 192,875 transcripts with an average length of 856 bp representing about 165.1 Mb of the alfalfa leaf transcriptome. After assembly, 111,062 (57.6%) transcripts were annotated against the NCBI non-redundant database. A total of 30,165 (15.6%) transcripts were mapped to 323 Kyoto Encyclopedia of Genes and Genomes pathways. We also identified 41,973 simple sequence repeats, which can be used to generate markers for alfalfa, and 1,541 transcription factors were identified across 1,350 transcripts. Gene expression between dormant and non-dormant alfalfa at different time points were performed, and we identified several differentially expressed genes potentially related to fall dormancy. The Gene Ontology and pathways information were also identified. We sequenced and assembled the leaf transcriptome of alfalfa related to fall dormancy, and also identified some genes of interest involved in the fall dormancy mechanism. Thus, our research focused on studying fall dormancy in alfalfa through transcriptome sequencing. The sequencing and gene expression data generated in this study may be used further to elucidate the complete mechanisms governing fall dormancy in alfalfa.

  2. De Novo Characterization of Fall Dormant and Nondormant Alfalfa (Medicago sativa L.) Leaf Transcriptome and Identification of Candidate Genes Related to Fall Dormancy

    Science.gov (United States)

    Cheng, Ningning; Du, Hongqi; Fan, Wenna; Wang, Chengzhang

    2015-01-01

    Alfalfa (Medicago sativa L.) is one of the most widely cultivated perennial forage legumes worldwide. Fall dormancy is an adaptive character related to the biomass production and winter survival in alfalfa. The physiological, biochemical and molecular mechanisms causing fall dormancy and the related genes have not been well studied. In this study, we sequenced two standard varieties of alfalfa (dormant and non-dormant) at two time points and generated approximately 160 million high quality paired-end sequence reads using sequencing by synthesis (SBS) technology. The de novo transcriptome assembly generated a set of 192,875 transcripts with an average length of 856 bp representing about 165.1 Mb of the alfalfa leaf transcriptome. After assembly, 111,062 (57.6%) transcripts were annotated against the NCBI non-redundant database. A total of 30,165 (15.6%) transcripts were mapped to 323 Kyoto Encyclopedia of Genes and Genomes pathways. We also identified 41,973 simple sequence repeats, which can be used to generate markers for alfalfa, and 1,541 transcription factors were identified across 1,350 transcripts. Gene expression between dormant and non-dormant alfalfa at different time points were performed, and we identified several differentially expressed genes potentially related to fall dormancy. The Gene Ontology and pathways information were also identified. We sequenced and assembled the leaf transcriptome of alfalfa related to fall dormancy, and also identified some genes of interest involved in the fall dormancy mechanism. Thus, our research focused on studying fall dormancy in alfalfa through transcriptome sequencing. The sequencing and gene expression data generated in this study may be used further to elucidate the complete mechanisms governing fall dormancy in alfalfa. PMID:25799491

  3. [Dynamic change of Yulania sap flow before dormancy in response to environmental factors].

    Science.gov (United States)

    Zhu, Zhong-Long; Jia, Zhong-Kui; Ma, Lu-Yi; Wang, Xiao-Ling; Duan, Jie

    2012-09-01

    From September 26 to November 5, 2011, the sap flow of Yulania wufengensis trees including cold-resistance type (HK) and non cold-resistance type (HF), Y. 'Sunspire' (HY), and Yulania x soulangeana (EQ) which were introduced into Beijing four years before was monitored by Flow-32 stem heat balance sensor, and, in combining with the environmental factors monitored synchronically, the changes of the sap flow before dormancy and the environmental factors were analyzed, with the responses of the sap flow to the environmental factors investigated at the scales of 0.5 h and 1 day. The sap flow of the Yulanias trees before dormancy displayed an obvious trend of declining day by day. The environmental factors affecting the sap flow could be divided into two categories, i. e., meteorological index (MI) and soil index (SI). The sap flow of the Yulanias trees had a synchronous variation rhythm with MI, and declined in parallel to SI. The combined effect of MI and SI on the diurnal changes of the sap flow was 69% - 73%. At both 0.5 h and 1 day scales, the sap flow showed significantly correlations with total radiation (Rs), air vapor pressure deficit (D), air relative humidity (RH), air temperature (Ta), and wind speed (w). The sap flow showed no significant correlations with soil temperature (Ts) and soil water content (SWC) at 0. 5 h scale, but had significant correlations with Ts, SWC, and day length (Z) at 1 day scale (the correlation efficient was about 0.8). Only Rs, Z, and D were included into the model at 1 day scale, but almost all environmental factors (except SWC and Ts) were included in the model at 0.5 h scale. Except for HF type, the regression coefficients of the model for the Yulanias trees at 1 day scale (0.92-0.96) were larger than those at 0.5 h scale (0.77-0.87), and the correlations between the dynamic changes of sap flow and the environmental factor were consistent, which was in accord with the fact that the HF could not overwinter in Beijing but the

  4. Biosensors for detecting stress in developing embryos

    Science.gov (United States)

    Purdey, Malcolm S.; Saini, Avishkar; McLennan, Hanna J.; Pullen, Benjamin J.; Schartner, Erik P.; Sutton-McDowall, Melanie L.; Thompson, Jeremy G.; Monro, Tanya M.; Nicholls, Stephen J.; Abell, Andrew D.

    2016-12-01

    Reactive Oxygen Species (ROS) cause DNA damage and defective function in sperm and also affects the developmental competence of embryos. It is therefore critical to monitor ROS in sperm, oocytes and developing embryos. In particular, hydrogen peroxide (H2O2) is a ROS important to normal cell function and signalling as well as its role in oxidative stress. Here we report the development of a fluorescent sensor for H2O2 using carboxyperoxyfluor-1 (CPF1) in solution and attached to a glass slide or multi-mode optical fibre. CPF1 increases in fluorescence upon reaction with H2O2 to non-invasively detect H2O2 near developing embryos. These probes are constructed by immobilising CPF1 to the optical fibre tip a polyacrylamide layer. Also reported is a new dual optical fibre sensor for detecting both H2O2 and pH that is functional at biologically concentrations of H2O2 and can sense pH to 0.1 units. This research shows promise for the use of optical fibre sensors for monitoring the health of developing embryos. Furthermore, these sensors are applicable for use beyond embryos such as detecting stress in endothelial cells involved in cardiovascular dysfunction.

  5. Arabidopsis mitochondrial protein slow embryo development1 is essential for embryo development

    Energy Technology Data Exchange (ETDEWEB)

    Ju, Yan; Liu, Chunying; Lu, Wenwen; Zhang, Quan; Sodmergen, E-mail: sodmergn@pku.edu.cn

    2016-05-27

    The plant seeds formation are crucial parts in reproductive process in seed plants as well as food source for humans. Proper embryo development ensure viable seed formation. Here, we showed an Arabidopsis T-DNA insertion mutant slow embryo development1 (sed1) which exhibited retarded embryogenesis, led to aborted seeds. Embryo without SED1 developed slower compared to normal one and could be recognized at early globular stage by its white appearance. In later development stage, storage accumulated poorly with less protein and lipid body production. In vitro culture did not rescue albino embryo. SED1 encoded a protein targeted to mitochondria. Transmission electron microscopic analysis revealed that mitochondria developed abnormally, and more strikingly plastid failed to construct grana in time in sed1/sed1 embryo. These data indicated that SED1 is indispensable for embryogenesis in Arabidopsis, and the mitochondria may be involved in the regulation of many aspects of seed development. -- Highlights: •Arabidopsis SED1 is essential for embryo development. •The sed1 embryo accumulates less storage and has abnormal ultrastructure. •SED1 localizes to the mitochondrion.

  6. RECYCLING OF CATHETER FOR EMBRYO RECOVERY: A TOOL FOR COSTS REDUCTION IN EQUINE EMBRYO TRANSFER

    Directory of Open Access Journals (Sweden)

    Alberto Lopes Gusmao

    2010-06-01

    Full Text Available The embryo transfer is becoming a widespread practice.Most embryos are collected from spontaneous single ovulatingmares and result in 50% of embryo recovery, increasing the costsof production. To illustrate, the price of a catheter for embryosrecovery range from US$ 194.00 to US$ 250.00 (R$ 350.00 to R$450.00. Therefore, the aim of this work was to verify if catheterwith damaged balloon can be recuperated and reused withoutaltering its efficiency. For this study, two groups were used: acontrol group (GI, n=10, on which the nonsurgical recovery of theembryos of mares was performed with the catheter with originalballoon; and another group (GII, n=20, in which a restored catheterwas utilized. The mares of GI had an embryo recovery rate of60%, and GII mares had an embryo recovery rate of 55%. Therewas not statistical difference between groups I and II (P>0.05.Considering that the material used to restore the catheter costsUS$16.66 (R$30.00, this data show that the recuperation of thecatheters for embryo recovery in mares may reduce costs withoutcompromising the rates of embryo recovery.

  7. Embryo development and embryo transfer in the European mink (Mustela lutreola), an endangered mustelid species.

    Science.gov (United States)

    Amstislavsky, S; Kizilova, E; Ternovskaya, Y; Zudova, G; Lindeberg, H; Aalto, J; Valtonen, M

    2006-01-01

    The European mink is an endangered Mustelidae species and thus requires effective conservation measures, although little is known about reproduction in this species. In particular, preimplantation development has not been studied and, therefore, embryonic development and the growth of embryos was documented in the present study for European mink using light and fluorescent microscopy. Embryos develop in the oviducts and then migrate into the uterus on Day 6 post coitum (p.c.) at the morula stage. Embryos expanded as blastocysts from Day 7 until implantation on Day 12 p.c. Based on these findings, the use of embryo transfer for a conservation programme for the European mink was evaluated. Embryos were flushed from European mink resource females and transferred into the uterine horns of recipient hybrid females (honoriks and nohoriks). These hybrids were obtained by mating European polecat males with European mink females and vice versa. A total of 40 embryos was transferred and 20 live kits were born. The rates of pre- and postnatal survival were 50% and 70%, respectively. Both male and female offspring were lighter at birth in the embryo transfer group compared with naturally born controls, but there was no difference at 3 months of age.

  8. Toxicity of chlorine to zebrafish embryos

    Science.gov (United States)

    Kent, Michael L.; Buchner, Cari; Barton, Carrie; Tanguay, Robert L.

    2014-01-01

    Surface disinfection of fertilized fish eggs is widely used in aquaculture to reduce extraovum pathogens that may be released from brood fish during spawning, and this is routinely used in zebrafish (Danio rerio) research laboratories. Most laboratories use approximately 25 – 50 ppm unbuffered chlorine solution for 5 – 10 min. Treatment of embryos with chlorine has significant germicidal effects for many Gram-negative bacteria, viruses, and trophozoite stages of protozoa, it has reduced efficacy against cyst or spore stages of protozoa and certain Mycobacterium spp. Therefore, we evaluated the toxicity of unbufferred and buffered chlorine solution to embryos exposed at 6 or 24 hours post-fertilization (hpf) to determine if higher concentrations can be used for treating zebrafish embryos. Most of our experiments entailed using an outbred line (5D), with both mortality and malformations as endpoints. We found that 6 hpf embryos consistently were more resistant than 24 hpf embryos to the toxic effects of chlorine. Chlorine is more toxic and germicidal at lower pHs, and chlorine causes elevated pH. Consistent with this, we found that unbufferred chlorine solutions (pH ca 8–9) were less toxic at corresponding concentrations than solutions buffered to pH 7. Based on our findings here, we recommend treating 6 hpf embryos for 10 min and 24 hpf for 5 min with unbuffered chlorine solution at 100 ppm. One trial indicated that AB fish, a popular outbred line, are more susceptible to toxicity than 5Ds. This suggests that variability between zebrafish lines occurs, and researchers should evaluate each line or strain under their particular laboratory conditions for selection of the optimum chlorine treatment procedure. PMID:24429474

  9. Reduced reactivation from dormancy but maintained lineage choice of human mesenchymal stem cells with donor age.

    Directory of Open Access Journals (Sweden)

    Verena Dexheimer

    Full Text Available UNLABELLED: Mesenchymal stem cells (MSC are promising for cell-based regeneration therapies but up to date it is still controversial whether their function is maintained throughout ageing. Aim of this study was to address whether frequency, activation in vitro, replicative function, and in vitro lineage choice of MSC is maintained throughout ageing to answer the question whether MSC-based regeneration strategies should be restricted to younger individuals. MSC from bone marrow aspirates of 28 donors (5-80 years were characterized regarding colony-forming unit-fibroblast (CFU-F numbers, single cell cloning efficiency (SSCE, osteogenic, adipogenic and chondrogenic differentiation capacity in vitro. Alkaline phosphatase (ALP activity, mineralization, Oil Red O content, proteoglycan- and collagen type II deposition were quantified. While CFU-F frequency was maintained, SSCE and early proliferation rate decreased significantly with advanced donor age. MSC with higher proliferation rate before start of induction showed stronger osteogenic, adipogenic and chondrogenic differentiation. MSC with high osteogenic capacity underwent better chondrogenesis and showed a trend to better adipogenesis. Lineage choice was, however, unaltered with age. CONCLUSION: Ageing influenced activation from dormancy and replicative function of MSC in a way that it may be more demanding to mobilize MSC to fast cell growth at advanced age. Since fast proliferation came along with high multilineage capacity, the proliferation status of expanded MSC rather than donor age may provide an argument to restrict MSC-based therapies to certain individuals.

  10. Effects of different treatments on dormancy of Syagrus oleraces Becc palm seeds

    Directory of Open Access Journals (Sweden)

    Jefferson Fernando Naves Pinto

    2012-09-01

    Full Text Available The Guariroba Palm (Syagrus oleraces Becc is the only species known as producer of bitter palm heart, which is very appreciated in Goiânia cooking and can also be used in animal feeding and landscaping; however, it is little studied. The slow and uneven germination of seeds cause problems in the propagation of this species, thus complicating mainly the seedling production at a commercial scale. This study evaluated different treatments to reduce the dormancy state and consequently to speed up the germination period of guariroba palm seeds and looking for techniques of easy comprehension and application by small farmers. The experimental design was in completely randomized blocks with three replications in a 2 x 7 factorial arrangement; i.e, two levels for type of seeds (pulped and not pulped an seven different methods of seed treatment. In the second stage, the interference of coleobroca in the seed germination was quantified by counting the number of attacked seeds after seedling germination. The observed results showed that treatments under low temperatures caused a significant decrease in seed germination of guariroba and that non pulped seeds reduced the time required for germination. It was also evidenced that reducing humidity to 8% does not affect the germination of guariroba seeds and that the water absorption by the seeds was influenced directly by the time of immersion in the water glass, independently of pulp presence. The studied treatments were not effective in reduccing coleobroca attack.

  11. Garlic and H2O2 in overcoming dormancy on the vine “Cabernet Sauvignon”

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    Saavedra del Aguila Juan

    2015-01-01

    Full Text Available The objective of this experiment was to evaluate the effect of garlic extract, H2O2 and hydrogen cyanamide on dormancy break, budding and maturation of “Cabernet Sauvignon” in the Campaign Region – Brazil. In late winter 2014 and after drought pruning were performed spraying in the bud: T1 – distilled water (control; T2 – 3.0% of hydrogen cyanamide; T3 – 18.0% H2O2; and T4 – 3.0% garlic extract. It was evaluated in the field: the number of sprouted buds per plant, number of bunches per plant and weight of bunches per plant; and laboratory: on ripening, performed weekly from the color change of 360 berries per treatment for analyzes solids soluble – SS (Brix pH and titratable acidity – TA (% tartaric acid. It was observed that the vines of treatment T4 (3.0% garlic extract, showed higher percentage of buds sprouting (63 shoots plant−1. Already at the number of clusters and weight per plant, there were no statistical differences between all treatments. The results obtained in the laboratory to SS, pH and TA did not differ statistically for the four tested treatments.

  12. Innate immune system still works at diapause, a physiological state of dormancy in insects

    Energy Technology Data Exchange (ETDEWEB)

    Nakamura, Akihiro [Department of Reproductive Biology, National Center for Child Health and Development, 2-10-1 Okura, Setagaya, Tokyo 157-8535 (Japan); Miyado, Kenji, E-mail: kmiyado@nch.go.jp [Department of Reproductive Biology, National Center for Child Health and Development, 2-10-1 Okura, Setagaya, Tokyo 157-8535 (Japan); Takezawa, Youki; Ohnami, Naoko [Department of Reproductive Biology, National Center for Child Health and Development, 2-10-1 Okura, Setagaya, Tokyo 157-8535 (Japan); Sato, Masahiro [Section of Gene Expression Regulation, Frontier Science Research Center, Kagoshima University, 1-21-20 Korimoto, Kagoshima 890-0065 (Japan); Ono, Chihiro; Harada, Yuichirou; Yoshida, Keiichi; Kawano, Natsuko; Kanai, Seiya; Miyado, Mami; Umezawa, Akihiro [Department of Reproductive Biology, National Center for Child Health and Development, 2-10-1 Okura, Setagaya, Tokyo 157-8535 (Japan)

    2011-07-01

    Highlights: {yields} Two major types of cells are present in the body fluid isolated from the thoracic region of a diapausing pupa. {yields} Phagocytosis and encapsulation by these cells were observed when latex beads as foreign targets were microinjected into a pupa. {yields} Such behavior by these cells was still observed even when pupae were continuously chilled at 4 {sup o}C. {yields} Innate cellular reactions can work in diapausing insects in a dormant state. -- Abstract: Diapause is most often observed in insects and is a physiologically dormant state different from other types of dormancy, such as hibernation. It allows insects to survive in harsh environments or extend longevity. In general, larval, pupal, or adult non-diapausing insects possess an innate immune system preventing the invasion of microorganisms into their bodies; however, it is unclear whether this system works under the dormant condition of diapause. We here report the occurrence of innate cellular reactions during diapause using pupae of a giant silkmoth, Samia cynthia pryeri. Scanning electron microscopic analysis demonstrated the presence of two major types of cells in the body fluid isolated from the thoracic region of a pupa. Phagocytosis and encapsulation, characteristics of innate cellular reactions, by these cells were observed when latex beads as foreign targets were microinjected into the internal portion of a pupa. Such behavior by these cells was still observed even when pupae were continuously chilled at 4 {sup o}C. Our results indicate that innate cellular reactions can work in diapausing insects in a dormant state.

  13. Cell signaling mechanisms and metabolic regulation of germination and dormancy in barley seeds

    Directory of Open Access Journals (Sweden)

    Zhenguo Ma

    2017-12-01

    Full Text Available During germination of barley (Hordeum vulgare L. seeds, important morphological and physiological changes take place, including development of organs and tissues and activation of metabolic pathways. Germination and dormancy of seeds are regulated by abscisic acid, gibberellins, reactive oxygen species (ROS, reactive nitrogen species (RNS and several other factors. Activities of ascorbate–glutathione cycle enzymes, responsible for scavenging ROS, strongly increase. Catalase and superoxide dismutase activities, also scavenging ROS, decrease at the onset of seed germination and then increase. With the increase in aerobic metabolism after radicle protrusion, the activities of the fermentation enzymes lactate and alcohol dehydrogenase decline rapidly. The RNS-scavenging activity of S-nitrosoglutathione reductase decreases in the course of seed germination, in concert with elevation of nitric oxide production and protein nitrosylation. This activity supports the role of RNS in regulating seed germination. Transcription of various genes at different phases of seed germination exhibits phase-specific changes. During imbibition, genes involved in cell wall metabolism are highly expressed; in the middle phase of seed germination before radicle protrusion, genes involved in amino acid synthesis, protein synthesis, and transport and nucleic acid synthesis are upregulated significantly, and after radicle protrusion, genes involved in photosynthetic metabolism are induced. In summary, signal transduction and metabolic regulation of seed germination involve diverse reactions and complex regulation at different levels of metabolic organization. Keywords: Seed germination, Reactive oxygen species, Reactive nitrogen species, Signal transduction, Gene expression

  14. Breast cancer and amyloid bodies: is there a role for amyloidosis in cancer-cell dormancy?

    Directory of Open Access Journals (Sweden)

    Mizejewski GJ

    2017-04-01

    Full Text Available Gerald J Mizejewski Wadsworth Center, New York State Department of Health, Albany, NY, USA Abstract: Breast cancer and Alzheimer’s disease (AD are major causes of death in older women. Interestingly, breast cancer occurs less frequently in AD patients than in the general population. Amyloidosis, the aggregation of amyloid proteins to form amyloid bodies, plays a central role in the pathogenesis of AD and other human neuropathies by forming intracellular fibrillary proteins. Contrary to popular belief, amyloidosis is a common occurrence in mammalian cells, and has recently been reported to be a natural physiological process in response to environmental stress stimulations (such as pH and temperature extremes, hypoxia, and oxidative stress. Many proteins contain an intrinsic “amyloid-converting motif”, which acts in conjunction with a specific noncoding RNA to induce formation of proteinaceous amyloid bodies that are stored in intracellular bundles. In cancer cells such as breast and prostate, the process of amyloidosis induces cells to enter a dormant or resting stage devoid of cell division and proliferation. Therefore, cancer cells undergo growth cessation and enter a dormant stage following amyloidosis in the cell; this is akin to giving the cell AD to cease growth. Keywords: α-fetoprotein, noncoding RNA, amyloid bodies, dormancy, breast cancer, Alzheimer’s disease

  15. Latent Tuberculosis: Models, Computational efforts and the Pathogen's regulatory mechanisms during dormancy

    Directory of Open Access Journals (Sweden)

    Gesham eMagombedze

    2013-08-01

    Full Text Available Latent tuberculosis is a clinical syndrome that occurs after an individual has been exposed to the Mycobacterium tuberculosis (Mtb bacillus, the infection has been established and an immune response has been generated to control the pathogen and force it into a quiescent state. Mtb can exit this quiescent state where it is unresponsive to treatment and elusive to the immune response, and enter a rapid replicating state, hence causing infection reactivation. It remains a grey area to understand how the pathogen causes a persistent infection and it is unclear whether the organism will be in a slow replicating state or a dormant non-replicating state. The ability of the pathogen to adapt to changing host immune response mechanisms, in which it is exposed to hypoxia, low pH, nitric oxide (NO, nutrient starvation and several other anti-microbial effectors, is associated with a high metabolic plasticity that enables it to metabolise under these different conditions. Adaptive gene regulatory mechanisms are thought to coordinate how the pathogen changes their metabolic pathways through mechanisms that sense changes in oxygen tension and other stress factors, hence stimulating the pathogen to make necessary adjustments to ensure survival. Here, we review studies that give insights into latency/dormancy regulatory mechanisms that enable infection persistence and pathogen adaptation to different stress conditions. We highlight what mathematical and computational models can do and what they should do to enhance our current understanding of TB latency.

  16. Cyanogenic Glucosides and Derivatives in Almond and Sweet Cherry Flower Buds from Dormancy to Flowering

    Science.gov (United States)

    Del Cueto, Jorge; Ionescu, Irina A.; Pičmanová, Martina; Gericke, Oliver; Motawia, Mohammed S.; Olsen, Carl E.; Campoy, José A.; Dicenta, Federico; Møller, Birger L.; Sánchez-Pérez, Raquel

    2017-01-01

    Almond and sweet cherry are two economically important species of the Prunus genus. They both produce the cyanogenic glucosides prunasin and amygdalin. As part of a two-component defense system, prunasin and amygdalin release toxic hydrogen cyanide upon cell disruption. In this study, we investigated the potential role within prunasin and amygdalin and some of its derivatives in endodormancy release of these two Prunus species. The content of prunasin and of endogenous prunasin turnover products in the course of flower development was examined in five almond cultivars – differing from very early to extra-late in flowering time – and in one sweet early cherry cultivar. In all cultivars, prunasin began to accumulate in the flower buds shortly after dormancy release and the levels dropped again just before flowering time. In almond and sweet cherry, the turnover of prunasin coincided with increased levels of prunasin amide whereas prunasin anitrile pentoside and β-D-glucose-1-benzoate were abundant in almond and cherry flower buds at certain developmental stages. These findings indicate a role for the turnover of cyanogenic glucosides in controlling flower development in Prunus species. PMID:28579996

  17. Cyanogenic Glucosides and Derivatives in Almond and Sweet Cherry Flower Buds from Dormancy to Flowering

    Directory of Open Access Journals (Sweden)

    Jorge Del Cueto

    2017-05-01

    Full Text Available Almond and sweet cherry are two economically important species of the Prunus genus. They both produce the cyanogenic glucosides prunasin and amygdalin. As part of a two-component defense system, prunasin and amygdalin release toxic hydrogen cyanide upon cell disruption. In this study, we investigated the potential role within prunasin and amygdalin and some of its derivatives in endodormancy release of these two Prunus species. The content of prunasin and of endogenous prunasin turnover products in the course of flower development was examined in five almond cultivars – differing from very early to extra-late in flowering time – and in one sweet early cherry cultivar. In all cultivars, prunasin began to accumulate in the flower buds shortly after dormancy release and the levels dropped again just before flowering time. In almond and sweet cherry, the turnover of prunasin coincided with increased levels of prunasin amide whereas prunasin anitrile pentoside and β-D-glucose-1-benzoate were abundant in almond and cherry flower buds at certain developmental stages. These findings indicate a role for the turnover of cyanogenic glucosides in controlling flower development in Prunus species.

  18. A role for barley CRYPTOCHROME1 in light regulation of grain dormancy and germination.

    Science.gov (United States)

    Barrero, Jose M; Downie, A Bruce; Xu, Qian; Gubler, Frank

    2014-03-01

    It is well known that abscisic acid (ABA) plays a central role in the regulation of seed dormancy and that transcriptional regulation of genes encoding ABA biosynthetic and degradation enzymes is responsible for determining ABA content. However, little is known about the upstream signaling pathways impinging on transcription to ultimately regulate ABA content or how environmental signals (e.g., light and cold) might direct such expression in grains. Our previous studies indicated that light is a key environmental signal inhibiting germination in dormant grains of barley (Hordeum vulgare), wheat (Triticum aestivum), and Brachypodium distachyon and that this effect attenuates as after-ripening progresses further. We found that the blue component of the light spectrum inhibits completion of germination in barley by inducing the expression of the ABA biosynthetic gene 9-cis-epoxycarotenoid dioxygenase and dampening expression of ABA 8'-hydroxylase, thus increasing ABA content in the grain. We have now created barley transgenic lines downregulating the genes encoding the blue light receptors CRYTOCHROME (CRY1) and CRY2. Our results demonstrate that CRY1 is the key receptor perceiving and transducing the blue light signal in dormant grains.

  19. The effect of fire on the dormancy break of three annual legume seeds

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    Fabio Gresta

    2011-07-01

    Full Text Available Fire is a common phenomenon in the Mediterranean environment and strongly influences vegetal population dynamics through its impact on vegetation and the soil seed bank. Fire is able to break down the seed coat of hard-seeded legumes within the soil and trigger germination. To evaluate the effect of fire on the dormancy break in Medicago ciliaris, Medicago rugosa and Scorpiurus muricatus subsp. subvillosus, the seeds were placed at three different depths (surface, 25 mm and 50 mm and subjected to fires at two different intensities (high and low. As a control sample, a batch of seeds was buried at 25 mm for the duration of the trial and not subjected to fire. Soil temperatures during the fire were compared directly to stubble quantity and indirectly related to soil depth. The two Medicago species survived exposure to 90°C for a few minutes and displayed a significant increase in germination with exposure to high temperatures (over 70°C for several minutes. On the other hand, no germination occurred in Scorpiurus, irrespective of treatment. In conclusion, fire had a significant and positive effect in triggering germination of the Medicago species, but the dispersal strategies of these hard-seeded legumes are only partially interrupted by fire as a large number of seeds (>50% remained non-germinated in the soil.

  20. Ultra-late recurrences of gastro-intestinal carcinoma after primary resection: the mechanism of dormancy.

    Science.gov (United States)

    Janssens, J F; T'Syen, M; Verhaegen, S; Spaepen, K; Verbeeck, G

    2013-06-01

    Curative resection of limited gastro-intestinal carcinoma does not always mean curation with tumor-free long-term survival. We present two cases of ultra-late recurrence 14 years after initial treatment. In the first case a 50-year-old male underwent in 1997 a subtotal esophagectomy with tubulation of the stomach for a localized Barrett carcinoma. Postoperative staging showed a poorly differentiated adenocarcinoma, pT1N1 (stage IIB). In May 2011, 14 years after the initial resection, multiple bone metastases were diagnosed and a biopsy confirmed the poorly differentiated carcinoma with the same characteristics as the primary tumor. Investigations showed no evidence for a new primary tumor. The second case is a 52-year old man who underwent a low anterior resection for a small rectal cancer in 1997, histologically a well differentiated adenocarcinoma, stage IB (pT2NO). In December 2011 multiple metastases were diagnosed and a biopsy showed a metastasis from a mucinous carcinoma, suggestive for a colorectal carcinoma. There was also no evidence for a new primary tumor. Although the prognosis of limited esophageal and colorectal cancer is good, recurrence is always possible and an ultra-late recurrence may exceptionally occur. The mechanism of tumor dormancy is described.

  1. The expression of a Vp1-like gene and seed dormancy in Mesembryanthemum crystallinum.

    Science.gov (United States)

    Fukuhara, T; Bohnert, H J

    2000-08-01

    Seeds of the common ice plant (Mesembryanthemum crystallinum) germinate in distinct sub-populations over a time period of more than 4 weeks following imbibition. Distinguishing early (E)- and late (L)-germinating seeds is the expression of a homologue of the transcriptional activator VP1. The deduced amino acid sequence of ice plant VP1 (MVP1) is 39% identical (50% similar) to the sequence of the Arabidopsis VP1 homologue, ABI3. The amount of Mvp1 mRNA, transcribed from a single gene, is different in E and L seeds after water uptake. The levels of the Mvp1 transcripts are very low in immature and mature seeds and they increased during 6 days of imbibition. This expression profile of Mvp1 is different from known Vp1/ABI3-like genes in other plants. Cycloheximide (at 35 microM) abolishes the increase of Mvp1, and L seeds are turned into E seeds, which develop normally when the inhibitor is applied for a short time during imbibition. E seeds treated for the same time period are developmentally impaired and show no radicle elongation. We suggest that the presence and late disappearance of Mvp1 in L seeds is responsible for dormancy and after-ripening of late-germinating ice plant seeds.

  2. Comet assay on thawed embryos: An optimized technique to evaluate DNA damage in mouse embryos.

    Science.gov (United States)

    Rolland, L; Courbiere, B; Tassistro, V; Sansoni, A; Orsière, T; Liu, W; Di Giorgio, C; Perrin, J

    2017-10-01

    Our objective was to optimize the CA technique on mammal embryos. 1000 frozen 2-cell embryos from B6CBA mice were used. Based on a literature review, and after checking post-thaw embryo viability, the main outcome measures included: 1) comparison of the embryo recovery rate between 2 CA protocols (2 agarose layers and 3 agarose layers); 2) comparison of DNA damage by the CA on embryos with (ZP+) and without (ZP-) zona pellucida; and 3) comparison of DNA damage in embryos exposed to 2 genotoxic agents (H2O2 and simulated sunlight irradiation (SSI)). DNA damage was quantified by the % tail DNA. 1) The recovery rate was 3,3% (n=5/150) with the 2 agarose layers protocol and 71,3% (n=266/371) with the 3 agarose layers protocol. 2) DNA damage did not differ statistically significantly between ZP- and ZP+ embryos (12.60±2.53% Tail DNA vs 11.04±1.50 (p=0.583) for the control group and 49.23±4.16 vs 41.13±4.31 (p=0.182) for the H2O2 group); 3) H2O2 and SSI induced a statistically significant increase in DNA damage compared with the control group (41.13±4.31% Tail DNA, 36.33±3.02 and 11.04±1.50 (p<0.0001)). The CA on mammal embryos was optimized by using thawed embryos, by avoiding ZP removal and by the adjunction of a third agarose layer. Copyright © 2017 Elsevier Ltd. All rights reserved.

  3. Transcriptome analysis of embryo maturation in maize.

    Science.gov (United States)

    Teoh, Keat Thomas; Requesens, Deborah Vicuna; Devaiah, Shivakumar P; Johnson, Daniel; Huang, Xiuzhen; Howard, John A; Hood, Elizabeth E

    2013-02-04

    Maize is one of the most important crops in the world. With the exponentially increasing population and the need for ever increased food and feed production, an increased yield of maize grain (as well as rice, wheat and other grains) will be critical. Maize grain development is understood from the perspective of morphology, hormone responses, and storage reserve accumulation. This includes various studies on gene expression during embryo development and maturation but a global study of gene expression of the embryo has not been possible until recently. Transcriptome analysis is a powerful new tool that can be used to understand the genetic basis of embryo maturation. We undertook a transcriptomic analysis of normal maturing embryos at 15, 21 and 27 days after pollination (DAP), of one elite maize germplasm line that was utilized in crosses to transgenic plants. More than 19,000 genes were analyzed by this method and the challenge was to select subsets of genes that are vitally important to embryo development and maturation for the initial analysis. We describe the changes in expression for genes relating to primary metabolic pathways, DNA synthesis, late embryogenesis proteins and embryo storage proteins, shown through transcriptome analysis and confirmed levels of transcription for some genes in the transcriptome using qRT-PCR. Numerous genes involved in embryo maturation have been identified, many of which show changes in expression level during the progression from 15 to 27 DAP. An expected array of genes involved in primary metabolism was identified. Moreover, more than 30% of transcripts represented un-annotated genes, leaving many functions to be discovered. Of particular interest are the storage protein genes, globulin-1, globulin-2 and an unidentified cupin family gene. When expressing foreign proteins in maize, the globulin-1 promoter is most often used, but this cupin family gene has much higher expression and may be a better candidate for foreign gene

  4. Expression Analysis of the MdCIbHLH1 Gene in Apple Flower Buds and Seeds in the Process of Dormancy

    Directory of Open Access Journals (Sweden)

    Yiran Ren

    2016-03-01

    Full Text Available A bHLH transcription factor that is induced by low temperature was found in apple (Malus × domestica Borkh.. To understand the sequence characteristics of the gene, bioinformatics analysis was performed. Furthermore, gene expression patterns of the laminated apple seeds and lateral flower buds were analyzed during the period of dormancy release with semi-quantitative RT-PCR. Based on secondary structure predictions, the results showed that the MdCIbHLH1 protein structure mainly included α-helix and random coil, while β-sheet and extended strand content was less. Semi-quantitative RT-PCR analysis showed that the expression patterns of MdCIbHLH1 were similar in laminated apple seeds and lateral flower buds during the period of dormancy release. Before dormancy release, expression levels of MdCIbHLH1 were high and gradually decreased during the period of dormancy release. These results indicated that MdCIbHLH1 might play an important role during dormancy release in apple seeds and apple buds.

  5. Morphometric analysis of human embryos to predict developmental competence

    DEFF Research Database (Denmark)

    Ziebe, Søren

    2013-01-01

    Morphometric and morphokinetic approaches toward embryo quality assessment have for many years been difficult due to technical limitations. Today, with improvements in laboratory techniques and subsequent quality, we have a better understanding of the morphometric and kinetics of embryo development...

  6. Cryopreservation of embryos and oocytes in human assisted reproduction.

    Science.gov (United States)

    Konc, János; Kanyó, Katalin; Kriston, Rita; Somoskői, Bence; Cseh, Sándor

    2014-01-01

    Both sperm and embryo cryopreservation have become routine procedures in human assisted reproduction and oocyte cryopreservation is being introduced into clinical practice and is getting more and more widely used. Embryo cryopreservation has decreased the number of fresh embryo transfers and maximized the effectiveness of the IVF cycle. The data shows that women who had transfers of fresh and frozen embryos obtained 8% additional births by using their cryopreserved embryos. Oocyte cryopreservation offers more advantages compared to embryo freezing, such as fertility preservation in women at risk of losing fertility due to oncological treatment or chronic disease, egg donation, and postponing childbirth, and eliminates religious and/or other ethical, legal, and moral concerns of embryo freezing. In this review, the basic principles, methodology, and practical experiences as well as safety and other aspects concerning slow cooling and ultrarapid cooling (vitrification) of human embryos and oocytes are summarized.

  7. Using fertile couples as embryo donors: An ethical dilemma.

    Science.gov (United States)

    Alizadeh, Leila; Omani Samani, Reza

    2014-03-01

    The use of donated embryos has offered hope for infertile couples who have no other means to have children. In Iran, fertility centers use fertile couples as embryo donors. In this paper, the advantages and disadvantages of this procedure will be discussed. We conclude that embryo-donation should be performed with frozen embryos thus preventing healthy donors from being harmed by fertility drugs. There must be guidelines for choosing the appropriate donor families. In countries where commercial egg donation is acceptable, fertile couples can be procured as embryo donors thus fulfilling the possible shortage of good quality embryos. Using frozen embryos seems to have less ethical, religious and legal problems when compared to the use of fertile embryo donors.

  8. [Ectopic pregnancy following in vitro fertilization and embryo transfer].

    Science.gov (United States)

    Sudik, R; Fliess, F R; Bernt, W D; Meissner, J; Kunkel, S

    1984-01-01

    A report is given about one case of ectopic pregnancy after in vitro fertilization and transfer of three embryos. Possible causes of ectopic pregnancies following embryo transfer and conclusions are discussed.

  9. Advances in embryo culture platforms: novel approaches to improve preimplantation embryo development through modifications of the microenvironment.

    Science.gov (United States)

    Swain, J E; Smith, G D

    2011-01-01

    The majority of research aimed at improving embryo development in vitro has focused on manipulation of the chemical environment, examining details such as energy substrate composition and impact of various growth factors or other supplements. In comparison, relatively little work has been done examining the physical requirements of preimplantation embryos and the role culture platforms or devices can play in influencing embryo development. Electronic searches were performed using keywords centered on embryo culture techniques using PUBMED through June 2010 and references were searched for additional research articles. Various approaches to in vitro embryo culture that involve manipulations of the physical culture environment are emerging. Novel culture platforms being developed examine issues such as media volume and embryo spacing. Furthermore, methods to permit dynamic embryo culture with fluid flow and embryo movement are now available, and novel culture surfaces are being tested. Although several factors remain to be studied to optimize efficiency, manipulations of the embryo culture microenvironment through novel culture devices may offer a means to improve embryo development in vitro. Reduced volume systems that reduce embryo spacing, such as the well-of-the-well approach, appear beneficial, although more work is needed to verify the source of their true benefit in human embryos. Emerging microfluidic technology appears to be a promising approach. However, along with the work on specialized culture surfaces, more information is required to determine the impact on human embryo development.

  10. Sourcing human embryos for embryonic stem cell lines: Problems & perspectives

    Directory of Open Access Journals (Sweden)

    Rajvi H Mehta

    2014-01-01

    Full Text Available The ability to successfully derive human embryonic stem cells (hESC lines from human embryos following in vitro fertilization (IVF opened up a plethora of potential applications of this technique. These cell lines could have been successfully used to increase our understanding of human developmental biology, transplantation medicine and the emerging science of regenerative medicine. The main source for human embryos has been ′discarded′ or ′spare′ fresh or frozen human embryos following IVF. It is a common practice to stimulate the ovaries of women undergoing any of the assisted reproductive technologies (ART and retrieve multiple oocytes which subsequently lead to multiple embryos. Of these, only two or maximum of three embryos are transferred while the rest are cryopreserved as per the decision of the couple. In case a couple does not desire to ′cryopreserve′ their embryos then all the embryos remaining following embryo transfer can be considered ′spare′ or if a couple is no longer in need of the ′cryopreserved′ embryos then these also can be considered as ′spare′. But, the question raised by the ethicists is, "what about ′slightly′ over-stimulating a woman to get a few extra eggs and embryos? The decision becomes more difficult when it comes to ′discarded′ embryos. As of today, the quality of the embryos is primarily assessed based on morphology and the rate of development mainly judged by single point assessment. Despite many criteria described in the literature, the quality assessment is purely subjective. The question that arises is on the decision of ′discarding′ embryos. What would be the criteria for discarding embryos and the potential ′use′ of ESC derived from the ′abnormal appearing′ embryos? This paper discusses some of the newer methods to procure embryos for the derivation of embryonic stem cell lines which will respect the ethical concerns but still provide the source material.

  11. Embryo transfer and related technologies in sheep reproduction

    OpenAIRE

    Loi, Pasqualino; Ptak, Grazyna; Dattena, Maria; Ledda, Sergio; Naitana, Salvatore; Cappai, Pietro

    1998-01-01

    This paper reviews the status of embryo transfer and the major technologies applied to preimplantation of embryos in sheep. Embryo production from superovulated ewes is hindered by an unpredictable response to hormonal treatment. Progress in this area should be expected by an appropriated control of follicular development with gonadotropin-releasing hormone (GnRH) agonist or antagonist prior to gonadotrophin administration. Simple protocols for the cryopreservation of sheep embryos by vitrifi...

  12. Expressional regulation of PpDAM5 and PpDAM6, peach (Prunus persica) dormancy-associated MADS-box genes, by low temperature and dormancy-breaking reagent treatment.

    Science.gov (United States)

    Yamane, Hisayo; Ooka, Tomomi; Jotatsu, Hiroaki; Hosaka, Yukari; Sasaki, Ryuta; Tao, Ryutaro

    2011-06-01

    The present study investigated the expressional regulation of PpDAM5 and PpDAM6, two of the six peach (Prunus persica) dormancy-associated MADS-box genes, in relation to lateral bud endodormancy. PpDAM5 and PpDAM6 were originally identified as homologues of Arabidopsis SHORT VEGETATIVE PHASE/AGAMOUS-LIKE 24 identified in the EVERGROWING locus of peach. Furthermore, PpDAM5 and PpDAM6 have recently been suggested to be involved in terminal bud dormancy. In this study, seasonal expression analyses using leaves, stems, and lateral buds of high-chill and low-chill peaches in field conditions indicated that both genes were up-regulated during the endodormancy period and down-regulated with endodormancy release. Controlled environment experiments showed that the expression of both PpDAM5 and PpDAM6 were up-regulated by ambient cool temperatures in autumn, while they were down-regulated by the prolonged period of cold temperatures in winter. A negative correlation between expression levels of PpDAM5 and PpDAM6 and bud burst percentage was found in the prolonged cold temperature treatment. Application of the dormancy-breaking reagent cyanamide to endo/ecodormant lateral buds induced early bud break and down-regulation of PpDAM5 and PpDAM6 expression at the same time. These results collectively suggest that PpDAM5 and PpDAM6 may function in the chilling requirement of peach lateral buds through growth-inhibiting functions for bud break.

  13. Sexing bovine pre-implantation embryos using the polymerase ...

    African Journals Online (AJOL)

    The paper aims to present a bovine model for human embryo sexing. Cows were super-ovulated, artificially inseminated and embryos were recovered 7 days later. Embryo biopsy was performed; DNA was extracted from blastomeres and amplified using bovine-specific and bovine-Y-chromosomespecific primers, followed ...

  14. Bovine in-vitro embryo production and its contribution towards ...

    African Journals Online (AJOL)

    Mimi

    ... of the Kenyan livestock farmers and boost food security. It discusses the technical aspects of the procedures involved in the in-vitro production of bovine embryos and embryo transfer, with special reference to the application of the techniques in Kenya. MATERIALS AND METHODS. Production of embryos in the laboratory ...

  15. Endometrial preparation methods in frozen-thawed embryo transfer

    NARCIS (Netherlands)

    Groenewoud, E.R.

    2017-01-01

    One in six couples suffer from infertility, and many undergo treatment with in-vitro fertilization (IVF). Given that IVF often results in more embryos than can be transferred during one embryo transfer cryopreservation of the supernumerary embryos has been an important addition to IVF. In recent

  16. Retrograde tubal transfer of human embryos.

    Science.gov (United States)

    Risquez, F; Boyer, P; Rolet, F; Magnani, M; Guichard, A; Cedard, L; Zorn, J R

    1990-02-01

    This preliminary study was designed to evaluate retrograde cannulation of the Fallopian tubes up to the isthmo-interstitial junction using the new technique of tubal embryo stage transfer (TEST). Follicular aspiration was performed under the guidance of a vaginal ultrasound probe in 51 women treated with GnRH + HMG. The oocytes retrieved were inseminated in vitro with 50,000 motile spermatozoa and kept in Menezo B2 medium without serum, at 37 degrees C, in an atmosphere of air + 5% CO2. The eggs were checked 24 and 36 h after insemination. No fertilization occurred in 23 patients. Cleaved embryos were obtained in the 28 other patients. One to seven embryos at the 2-4-cell stage were transferred with the 'Baudelocque Black Catheter' (BBC) into one tube and spare embryos were frozen. Five pregnancies occurred after retrograde TEST, for a pregnancy rate of 9.8% per cycle and 17.9% per transfer. One patient has given birth to a normal full-term baby. One singleton and one twin pregnancy are ongoing (8 months in June 1989). The other two pregnancies were ectopic.

  17. Effects of fluoxetine on human embryo development

    NARCIS (Netherlands)

    Kaihola, Helena; Yaldir, Fatma G.; Hreinsson, Julius; Hornaeus, Katarina; Bergquist, Jonas; Olivier, Jocelien D. A.; Akerud, Helena; Sundstrom-Poromaa, Inger

    2016-01-01

    The use of antidepressant treatment during pregnancy is increasing, and selective serotonin reuptake inhibitors (SSRIs) are the most widely prescribed antidepressants in pregnant women. Serotonin plays a role in embryogenesis, and serotonin transporters are expressed in two-cell mouse embryos. Thus,

  18. Culture of Cells from Amphibian Embryos.

    Science.gov (United States)

    Stanisstreet, Martin

    1983-01-01

    Describes a method for in vitro culturing of cells from amphibian early embryos. Such cells can be used to demonstrate such properties of eukaryote cells as cell motility, adhesion, differentiation, and cell sorting into tissues. The technique may be extended to investigate other factors. (Author/JN)

  19. Genetic transformation of olive somatic embryos through ...

    African Journals Online (AJOL)

    Administrator

    2011-06-20

    Jun 20, 2011 ... Full Length Research Paper. Genetic transformation of olive somatic embryos through Agrobacterium tumefaciens and regeneration of transgenic plants. Mahboobeh Jafarzadeh-Bajestani 1#, Maryam Khodai-Kalaki 1#, Nasrin Motamed1*, Omidreza. Noorayin2. 1The University College of science, Faculty ...

  20. Transcervical Embryo recovery by transcervical technique in ...

    African Journals Online (AJOL)

    Vicente Freitas

    Laboratory of Physiology and Control of Reproduction, State University of Ceará - Faculty of Veterinary Science. Fortaleza - CE, 60.740-000, .... Data of recovered embryos were transformed to a log function and the means were compared by ANOVA followed by .... prostaglandin F2α and oxytocin. J. Anim. Sci. 76, 360-363.

  1. The endometrial factor in human embryo implantation

    NARCIS (Netherlands)

    Boomsma, C.M.

    2009-01-01

    The studies presented in this thesis aimed to explore the role of the endometrium in the implantation process. At present, embryo implantation is the major rate-limiting step for success in fertility treatment. Clinicians have sought to develop clinical interventions aimed at enhancing implantation

  2. Mapping selection within Drosophila melanogaster embryo's anatomy

    DEFF Research Database (Denmark)

    Salvador-Martínez, Irepan; Coronado-Zamora, Marta; Castellano, David

    2018-01-01

    We present a survey of selection across Drosophila melanogaster embryonic anatomy. Our approach integrates genomic variation, spatial gene expression patterns and development, with the aim of mapping adaptation over the entire embryo's anatomy. Our adaptation map is based on analyzing spatial gene...

  3. Ovarian hyperstimulation syndrome and prophylactic human embryo cryopreservation: analysis of reproductive outcome following thawed embryo transfer

    Directory of Open Access Journals (Sweden)

    Sills Eric

    2008-11-01

    Full Text Available Abstract Objective To review utilisation of elective embryo cryopreservation in the expectant management of patients at risk for developing ovarian hyperstimulation syndrome (OHSS, and report on reproductive outcome following transfer of thawed embryos. Materials and methods Medical records were reviewed for patients undergoing IVF from 2000–2008 to identify cases at risk for OHSS where cryopreservation was electively performed on all embryos at the 2 pn stage. Patient age, total number of oocytes retrieved, number of 2 pn embryos cryopreserved, interval between retrieval and thaw/transfer, number (and developmental stage of embryos transferred (ET, and delivery rate after IVF were recorded for all patients. Results From a total of 2892 IVF cycles undertaken during the study period, 51 IVF cases (1.8% were noted where follicle number exceeded 20 and pelvic fluid collection was present. Elective embryo freeze was performed as OHSS prophylaxis in each instance. Mean (± SD age of these patients was 32 ± 3.8 yrs. Average number of oocytes retrieved in this group was 23 ± 8.7, which after fertilisation yielded an average of 14 ± 5.7 embryos cryopreserved per patient. Thaw and ET was performed an average of 115 ± 65 d (range 30–377 d after oocyte retrieval with a mean of 2 ± 0.6 embryos transferred. Grow-out to blastocyst stage was achieved in 88.2% of cases. Delivery/livebirth rate was 33.3% per initiated cycle and 43.6% per transfer. Non-transferred blastocysts remained in cryostorage for 24 of 51 patients (46.1% after ET, with an average of 3 ± 3 blastocysts refrozen per patient. Conclusion OHSS prophylaxis was used in 1.8% of IVF cycles at this institution; no serious OHSS complications were encountered during the study period. Management based on elective 2 pn embryo cryopreservation with subsequent thaw and grow-out to blastocyst stage for transfer did not appear to compromise embryo viability or overall reproductive outcome. For

  4. Formation of planetary embryos from planetesimals

    Science.gov (United States)

    Rafikov, Roman Ravilevich

    This thesis is devoted to studying some aspects of the formation of terrestrial planets. Although it is currently widely accepted that terrestrial planets form by agglomeration of a large number of rocky or icy bodies called planetesimals there is still a number of unresolved issues hindering our understanding of this process. I concentrate my research on the dynamical interaction of planetesimal disk with the planetary embryos—precursors of protoplanets. I investigate the development of nonuniformities in the planetesimal disk using analytical techniques employing the methods of statistical mechanics, which is justified by the huge number of planetesimals under consideration. This treatment self-consistently accounts for the evolution of the planetesimal kinematic properties, which is coupled to spatial redistribution of planetesimals in the disk. Planetesimal-planetesimal and embryo- planetesimal interactions are studied in two different velocity regimes: when the average approach velocities of interacting bodies are dominated by their epicyclic motion (dispersion-dominated regime) and when they are dominated by the differential shear in the disk (shear- dominated regime). The intermediate regime is modeled by interpolation. I show that the embryo always tries to repel planetesimals away and produce a depression in planetesimal surface density around its semimajor axis, while the planetesimal-planetesimal scattering acts as a source of effective viscosity which opposes this tendency and tries to smooth any inhomogeneities in the disk. The mutual gravitational interaction between planetesimals also increases their epicyclic motion throughout the disk. Embryo-planetesimal interaction leads to the same dynamical effect but localized spatially in the narrow zone around the embryo's orbit. The formation of inhomogeneities and excitation of planetesimal epicyclic motion in the disk nearby strongly affects the accretion rate of the embryo. I demonstrate that the

  5. Variabilite du niveau de dormance des bourgeons vegetatifs suivant les types de rameau d'une couronne de noyer (Juglans regia L.); comparaison des cultivars Franquette et Pedro

    OpenAIRE

    Dreyer, Erwin; Mauget, Jean-Claude

    1986-01-01

    Une description détaillée de la dormance automno-hivernale des bourgeons de 2 cultivars de noyer, « Pedro» et « Franquette », a été réalisée au moyen de la technique des boutures de noeuds isolés. Cette étude a permis de montrer que chez ces 2 cultivars l’intensité de la dormance est très variable entre bourgeons d’un même arbre. Outre l’existence déjà connue de gradients de dormance le long des rameaux, le caractère fructifère ou végétatif de la pousse mais surtout son rythme d’allongeme...

  6. DORMANCY BREAKING OF OIL PALM SEED TENERA VARIETY BY SOAKING FOR A CERTAIN LENGTH OF TIME IN THE SULFURIC ACID SOLUTION

    Directory of Open Access Journals (Sweden)

    WAYAN SUENA

    2012-11-01

    Full Text Available The experiment aimed to know the effect of length of soaked time in sulfuric acid (H2SO4 solution to the dormancy breaking upon the oil palm seeds. The experiment show that soaking seeds for 12 and 10 minutes in the acid solution resulted dormancy breaking were reached after 61.3 days, while soaking seed for 2 minutes in the same solution breaking of dormancy was reached after 73.5 days. By soaked oil palm seeds in sulfuric acid solution gave highest germination percentage (80%, peak value of germination was 0.77%/day, by an average of 0.73%/day. So that, by soaked oil palm seed in sulfuric acid solution for 12 minutes was able to increase vigor, viability, rate of germination and growth uniformity.

  7. Seed Dormancy in Arabidopsis Requires Self-Binding Ability of DOG1 Protein and the Presence of Multiple Isoforms Generated by Alternative Splicing.

    Directory of Open Access Journals (Sweden)

    Kazumi Nakabayashi

    2015-12-01

    Full Text Available The Arabidopsis protein DELAY OF GERMINATION 1 (DOG1 is a key regulator of seed dormancy, which is a life history trait that determines the timing of seedling emergence. The amount of DOG1 protein in freshly harvested seeds determines their dormancy level. DOG1 has been identified as a major dormancy QTL and variation in DOG1 transcript levels between accessions contributes to natural variation for seed dormancy. The DOG1 gene is alternatively spliced. Alternative splicing increases the transcriptome and proteome diversity in higher eukaryotes by producing transcripts that encode for proteins with altered or lost function. It can also generate tissue specific transcripts or affect mRNA stability. Here we suggest a different role for alternative splicing of the DOG1 gene. DOG1 produces five transcript variants encoding three protein isoforms. Transgenic dog1 mutant seeds expressing single DOG1 transcript variants from the endogenous DOG1 promoter did not complement because they were non-dormant and lacked DOG1 protein. However, transgenic plants overexpressing single DOG1 variants from the 35S promoter could accumulate protein and showed complementation. Simultaneous expression of two or more DOG1 transcript variants from the endogenous DOG1 promoter also led to increased dormancy levels and accumulation of DOG1 protein. This suggests that single isoforms are functional, but require the presence of additional isoforms to prevent protein degradation. Subsequently, we found that the DOG1 protein can bind to itself and that this binding is required for DOG1 function but not for protein accumulation. Natural variation for DOG1 binding efficiency was observed among Arabidopsis accessions and contributes to variation in seed dormancy.

  8. Regulation of Wheat Seed Dormancy by After-Ripening Is Mediated by Specific Transcriptional Switches That Induce Changes in Seed Hormone Metabolism and Signaling

    Science.gov (United States)

    Kanno, Yuri; Jordan, Mark C.; Kamiya, Yuji; Seo, Mitsunori; Ayele, Belay T.

    2013-01-01

    Treatments that promote dormancy release are often correlated with changes in seed hormone content and/or sensitivity. To understand the molecular mechanisms underlying the role of after-ripening (seed dry storage) in triggering hormone related changes and dormancy decay in wheat (Triticum aestivum), temporal expression patterns of genes related to abscisic acid (ABA), gibberellin (GA), jasmonate and indole acetic acid (IAA) metabolism and signaling, and levels of the respective hormones were examined in dormant and after-ripened seeds in both dry and imbibed states. After-ripening mediated developmental switch from dormancy to germination appears to be associated with declines in seed sensitivity to ABA and IAA, which are mediated by transcriptional repressions of PROTEIN PHOSPHATASE 2C, SNF1-RELATED PROTEIN KINASE2, ABA INSENSITIVE5 and LIPID PHOSPHATE PHOSPHTASE2, and AUXIN RESPONSE FACTOR and RELATED TO UBIQUITIN1 genes. Transcriptomic analysis of wheat seed responsiveness to ABA suggests that ABA inhibits the germination of wheat seeds partly by repressing the transcription of genes related to chromatin assembly and cell wall modification, and activating that of GA catabolic genes. After-ripening induced seed dormancy decay in wheat is also associated with the modulation of seed IAA and jasmonate contents. Transcriptional control of members of the ALLENE OXIDE SYNTHASE, 3-KETOACYL COENZYME A THIOLASE, LIPOXYGENASE and 12-OXOPHYTODIENOATE REDUCTASE gene families appears to regulate seed jasmonate levels. Changes in the expression of GA biosynthesis genes, GA 20-OXIDASE and GA 3-OXIDASE, in response to after-ripening implicate this hormone in enhancing dormancy release and germination. These findings have important implications in the dissection of molecular mechanisms underlying regulation of seed dormancy in cereals. PMID:23437172

  9. Selection for low dormancy in annual ryegrass (Lolium rigidum) seeds results in high constitutive expression of a glucose-responsive α-amylase isoform

    Science.gov (United States)

    Goggin, Danica E.; Powles, Stephen B.

    2012-01-01

    Background and Aims α-Amylase in grass caryopses (seeds) is usually expressed upon commencement of germination and is rarely seen in dry, mature seeds. A heat-stable α-amylase activity was unexpectedly selected for expression in dry annual ryegrass (Lolium rigidum) seeds during targeted selection for low primary dormancy. The aim of this study was to characterize this constitutive activity biochemically and determine if its presence conferred insensitivity to the germination inhibitors abscisic acid and benzoxazolinone. Methods α-Amylase activity in developing, mature and germinating seeds from the selected (low-dormancy) and a field-collected (dormant) population was characterized by native activity PAGE. The response of seed germination and α-amylase activity to abscisic acid and benzoxazolinone was assessed. Using an alginate affinity matrix, α-amylase was purified from dry and germinating seeds for analysis of its enzymatic properties. Key Results The constitutive α-amylase activity appeared late during seed development and was mainly localized in the aleurone; in germinating seeds, this activity was responsive to both glucose and gibberellin. It migrated differently on native PAGE compared with the major activities in germinating seeds of the dormant population, but the enzymatic properties of α-amylase purified from the low-dormancy and dormant seeds were largely indistinguishable. Seed imbibition on benzoxazolinone had little effect on the low-dormancy seeds but greatly inhibited germination and α-amylase activity in the dormant population. Conclusions The constitutive α-amylase activity in annual ryegrass seeds selected for low dormancy is electrophoretically different from that in germinating seeds and its presence confers insensitivity to benzoxazolinone. The concurrent selection of low dormancy and constitutive α-amylase activity may help to enhance seedling establishment under competitive conditions. PMID:23002268

  10. An efficient method in breaking of dormancy from Bunium persicum (Boiss) Fedtsch seeds: a valuable herb of Middle East and Central Asia.

    Science.gov (United States)

    Emamipoor, Yousef; Maziah, Mahmood

    2014-08-01

    To develop a protocol for breaking of seed dormancy and increasing the seed germination rate of Bunium persicum. The seeds were treated with 3.1, 6.3, 12.5, 25, 50 and 100 µmol/L of benzyl aminopurine, gibberellic acid (GA3), thidiazuron (TDZ) and forchlorfenuron. Then, seeds were transferred to two different temperature conditions including room temperature (25 °C) and chilling temperature (2-5 °C). The treatment of moist seeds with chilling temperature (2-5 °C) broke seed dormancy and showed maximum germination, which was 54.7% after 60 d treatment. Also, the treatment of dry seeds with chilling temperature broke seed dormancy with 9.3% germination rate after 120 d. Treatment of seeds with different level of plant growth regulators showed that under moist-room condition, there was evidence of higher and lower seed germination rate: GA3 (100 µmol/L) with 46.7% and TDZ (50 µmol/L) with 6.67% respectively. In addition, the results showed that under moist-chilling condition, TDZ (6.3 µmol/L) with 53.3% seed germination rate had higher influence on breaking seed dormancy. Treatment of seeds with combination of TDZ and GA3 under moist-chilling condition revealed higher rate of breaking of seed dormancy when 6.3 µmol/L TDZ was combined with 100 µmol/L GA3, showing 93.7% germination rate. The effect of plant growth regulators coupled with chilling temperature on breaking of seed dormancy could provide a large number of seedlings while the long juvenile time which is the next restricting factor of plantation still remained. Thus, the subsequent growth of seedlings to provide a large number of corms is necessary for successful plantation.

  11. The fate of the mosaic embryo: Chromosomal constitution and development of Day 4, 5 and 8 human embryos

    NARCIS (Netherlands)

    M.A. Santos; G. Teklenburg (Gijs); N.S. Macklon (Nick); D. van Opstal (Diane); G.H. Schuring-Blom (Heleen); P-J. Krijtenburg (Pieter-Jaap); J. de Vreeden-Elbertse (Johanna); B.C.J.M. Fauser (Bart); E.B. Baart (Esther)

    2010-01-01

    textabstractBackground: Post-zygotic chromosome segregation errors are very common in human embryos after in vitro fertilization, resulting in mosaic embryos. However, the significance of mosaicism for the developmental potential of early embryos is unknown. We assessed chromosomal constitution and

  12. The joint influence of photoperiod and temperature during growth cessation and development of dormancy in white spruce (Picea glauca).

    Science.gov (United States)

    Hamilton, Jill A; El Kayal, Walid; Hart, Ashley T; Runcie, Daniel E; Arango-Velez, Adriana; Cooke, Janice E K

    2016-11-01

    Timely responses to environmental cues enable the synchronization of phenological life-history transitions essential for the health and survival of north-temperate and boreal tree species. While photoperiodic cues will remain persistent under climate change, temperature cues may vary, contributing to possible asynchrony in signals influencing developmental and physiological transitions essential to forest health. Understanding the relative contribution of photoperiod and temperature as determinants of the transition from active growth to dormancy is important for informing adaptive forest management decisions that consider future climates. Using a combination of photoperiod (long = 20 h or short = 8 h day lengths) and temperature (warm = 22 °C/16 °C and cool = 8 °C/4 °C day/night, respectively) treatments, we used microscopy, physiology and modeling to comprehensively examine hallmark traits of the growth-dormancy transition-including bud formation, growth cessation, cold hardiness and gas exchange-within two provenances of white spruce [Picea glauca (Moench) Voss] spanning a broad latitude in Alberta, Canada. Following exposure to experimental treatments, seedlings were transferred to favorable conditions, and the depth of dormancy was assessed by determining the timing and ability of spruce seedlings to resume growth. Short photoperiods promoted bud development and growth cessation, whereas longer photoperiods extended the growing season through the induction of lammas growth. In contrast, cool temperatures under both photoperiodic conditions delayed bud development. Photoperiod strongly predicted the development of cold hardiness, whereas temperature predicted photosynthetic rates associated with active growth. White spruce was capable of attaining endodormancy, but its release was environmentally determined. Dormancy depth varied substantially across experimental treatments suggesting that environmental cues experienced within one season could affect growth

  13. Somatic Embryos in Catharanthus roseus: A Scanning Electron Microscopic Study

    Directory of Open Access Journals (Sweden)

    Junaid ASLAM

    2014-06-01

    Full Text Available Catharanthus roseus (L. G. Don is an important medicinal plant as it contains several anti-cancerous compounds, like vinblastine and vincristine. Plant tissue culture technology (organogenesis and embryogenesis has currently been used in fast mass propagating raw materials for secondary metabolite synthesis. In this present communication, scanning electron microscopic (SEM study of somatic embryos was conducted and discussed. The embryogenic callus was first induced from hypocotyls of in vitro germinated seeds on which somatic embryos, differentiated in numbers, particularly on 2,4-D (1.0 mg/L Murashige and Skoog (MS was medium. To understand more about the regeneration method and in vitro formed embryos SEM was performed. The SEM study revealed normal somatic embryo origin and development from globular to heart-, torpedo- and then into cotyledonary-stage of embryos. At early stage, the embryos were clustered together in a callus mass and could not easily be detached from the parental tissue. The embryos were often long cylindrical structure with or without typical notch at the tip. Secondary embryos were also formed on primary embryo structure. The advanced cotyledonary embryos showed prominent roots and shoot axis, which germinated into plantlets. The morphology, structure and other details of somatic embryos at various stages were presented.

  14. Tissue densities in developing avian embryos. [under acceleration stresses

    Science.gov (United States)

    Smith, A. H.; Abbott, U. K.; Morzenti, A.

    1984-01-01

    The density changes in the components of the incubated egg, the embryo, and the embryo's body parts were measured in the course of 21 days of incubation. In the first two-thirds of the incubation period there is a sequence of increasing density among egg contents: amniotic fluid, embryo, yolk, and albumin. As a result, the embryo is located at the bottom of the amniotic fluid, but at the top of the albumin. This position provides the embryo with mechanical protection and a proximity to the egg's air cell. The observed density changes and the asymmetry of these changes among various body parts of the embryo suggest a functional relationship. The density distributions among the body parts are particularly important in gravitational investigations of embryogenesis since they will produce forces tending to dislocate parts of the embryo.

  15. Nucleolar changes in bovine nucleotransferred embryos.

    Science.gov (United States)

    Baran, V; Vignon, X; LeBourhis, D; Renard, J P; Fléchon, J E

    2002-02-01

    This study focused on nucleolar changes in bovine embryos reconstructed from enucleated mature oocytes fused with blastomeres of morulae or with cultured, serum unstarved bovine fetal skin fibroblasts (embryonic vs. somatic cloning). The nucleotransferred (NT) embryos were collected and fixed at time intervals of 1-2 h (early 1-cell stage), 10-15 h (late 1-cell stage), 22-24 h (2-cell stage), 37-38 h (4-cell stage), 40-41 h (early 8-cell stage), 47-48 h (late 8-cell stage), and 55 h (16-cell stage) after fusion. Immunocytochemistry by light and electron microscopy was used for structure-function characterization of nucleolar components. Antibodies against RNA, protein B23, protein C23, and fibrillarin were applied. In addition, DNA was localized by the terminal deoxynucleotidyl transferase (TdT) technique, and the functional organization of chromatin was determined with the nick-translation immunogold approach. The results show that fully reticulated (active) nucleoli observed in donor cells immediately before fusion as well as in the early 1-cell stage after fusion were progressively transformed into nucleolar bodies displaying decreasing numbers of vacuoles from the 2- to 4-cell stage in both types of reconstructed embryos. At the late 8-cell stage, morphological signs of resuming nucleolar activity were detected. Numerous new small vacuoles appeared, and chromatin blocks reassociated with the nucleolar body. During this period, nick-translation technique revealed numerous active DNA sites in the periphery of chromatin blocks associated with the nucleolar body. Fully reticulated nucleoli were again observed as early as the 16-cell stage of embryonic cloned embryos. In comparison, the embryos obtained by fetal cloning displayed a lower tendency to develop, mainly during the first cell cycle and during the period of presumed reactivation. Correlatively, the changes in nucleolar morphology (desegregation and rebuilding) were at least delayed in many somatic NT

  16. Vitrification of early-stage bovine and equine embryos.

    Science.gov (United States)

    Campos-Chillòn, L F; Suh, T K; Barcelo-Fimbres, M; Seidel, G E; Carnevale, E M

    2009-01-15

    The objectives of this study were to: (1) determine an optimal method and stage of development for vitrification of bovine zygotes or early embryos; and (2) use the optimal procedure for bovine embryos to establish equine pregnancies after vitrification and warming of early embryos. Initially, bovine embryos produced by in-vitro fertilization (IVF) were frozen and vitrified in 0.25mL straws with minimal success. A subsequent experiment was done using two vitrification methods and super open pulled straws (OPS) with 1- or 8-cell bovine embryos. In Method 1 (EG-O), embryos were exposed to 1.5M ethylene glycol (EG) for 5min, 7M ethylene glycol and 0.6M galactose for 30s, loaded in an OPS, and plunged into liquid nitrogen. In Method 2 (EG-DMSO), embryos were exposed to 1.1M ethylene glycol and 1.1M dimethyl sulfoxide (DMSO) for 3min, 2.5M ethylene glycol, 2.5M DMSO and 0.5M galactose for 30s, and loaded and plunged as for EG-O. Cryoprotectants were removed after warming in three steps. One- and eight-cell bovine embryos were cultured for 7 and 4.5 d, respectively, after warming, and control embryos were cultured without vitrification. Cleavage rates of 1-cell embryos were similar (P>0.05) for vitrified and control embryos, although the blastocyst rates for EG-O and control embryos were similar and higher (Pvitrification and warming. In summary, a successful method was established for vitrification of early-stage bovine embryos, and this method was used to establish equine pregnancies after vitrification and warming of 2- to 8-cell embryos produced by ICSI.

  17. Selecting embryos with the highest implantation potential using data mining and decision tree based on classical embryo morphology and morphokinetics.

    Science.gov (United States)

    Carrasco, Beatriz; Arroyo, Gemma; Gil, Yolanda; Gómez, Mª José; Rodríguez, Ignacio; Barri, Pedro N; Veiga, Anna; Boada, Montserrat

    2017-08-01

    The objective of this work was to determine which embryonic morphokinetic parameters up to D3 of in vitro development have predictive value for implantation for the selection of embryos for transfer in clinical practice based upon information generated from embryo transfers with known implantation data (KID). A total of 800 KID embryos (100% implantation rate (IR) per transfer and 0% IR per transfer) cultured in an incubator with Time-Lapse system were retrospectively analysed. Of them, 140 embryos implanted, whereas 660 did not. The analysis of morphokinetic parameters, together with the embryo morphology assessment on D3, enabled us to develop a hierarchical model that places the classical morphological score, the t4 and t8 morphokinetic values, as the variables with the best prognosis of implantation. In our decision tree, the classical morphological score is the most predictive parameter. Among embryos with better morphological scores, morphokinetics permits deselection of embryos with the lowest implantation potential.

  18. Echinoderm eggs and embryos: procurement and culture.

    Science.gov (United States)

    Foltz, Kathy R; Adams, Nikki L; Runft, Linda L

    2004-01-01

    The protocols outlined here hopefully will provide researchers with healthy, beautiful echinoderm oocytes, eggs, and embryos for experimental use. The large size of echinoderm oocytes and eggs, the ease with which they can be manipulated, and (in many species) their optical clarity, make them an ideal model system for studying not only the events specific to oocyte maturation and fertilization, but also for investigating more general questions regarding cell cycle regulation in an in vivo system. The quick rate at which development proceeds after fertilization to produce transparent embryos and larva makes the echinoderm an advantageous organism for studying deuterostome embryogenesis. Continued use of the echinoderms as model systems will undoubtedly uncover exciting answers to questions regarding fertilization, cell cycle regulation, morphogenesis, and how developmental events are controlled.

  19. Neurogenesis in zebrafish - from embryo to adult

    OpenAIRE

    Schmidt, R; Strähle, U; Scholpp, S.

    2013-01-01

    Neurogenesis in the developing central nervous system consists of the induction and proliferation of neural progenitor cells and their subsequent differentiation into mature neurons. External as well as internal cues orchestrate neurogenesis in a precise temporal and spatial way. In the last 20 years, the zebrafish has proven to be an excellent model organism to study neurogenesis in the embryo. Recently, this vertebrate has also become a model for the investigation of adult neurogenesis and ...

  20. Dormancy of 'Imperial Gala' apple and 'Hosui' pear tree buds in a region of low chill occurrence

    Directory of Open Access Journals (Sweden)

    Ruy Inácio Neiva de Carvalho

    2014-08-01

    Full Text Available The objective of this work was to evaluate the dormancy dynamic of Imperial Gala apple tree buds and Hosui pear tree buds in a region of low chill occurrence. Experiments were conducted between April and August in 2007 and 2008. Branches were collected every two weeks from an orchard at Porto Amazonas (Paraná State, Brazil. On the last sampling day, an additional set of branches was collected and refrigerated between 4°C and 7°C for 1,440 hours. Dormancy was evaluated using a biological test of single node cuttings isolated in growth chambers (GC at 25°C with 16 hours of light exposure. The number of chill hours (CH and chill units (CU for the region were recorded. The two species were evaluated in separate experiments. We used 11 completely randomized treatments with four replicas for each species. The peak of endodormancy for the Imperial Gala apple tree buds occurred in early June 2007 and from middle June to early July in 2008. The endodormancy of the Hosui pear tree buds oscillated between April and August in 2007 and peaked between June and early July in 2008.

  1. Predicted global warming scenarios impact on the mother plant to alter seed dormancy and germination behaviour in Arabidopsis.

    Science.gov (United States)

    Huang, Z; Footitt, S; Tang, A; Finch-Savage, W E

    2018-01-01

    Seed characteristics are key components of plant fitness that are influenced by temperature in their maternal environment, and temperature will change with global warming. To study the effect of such temperature changes, Arabidopsis thaliana plants were grown to produce seeds along a uniquely designed polyethylene tunnel having a thermal gradient reflecting local global warming predictions. Plants therefore experienced the same variations in temperature and light conditions but different mean temperatures. A range of seed-related plant fitness estimates were measured. There were dramatic non-linear temperature effects on the germination behaviour in two contrasting ecotypes. Maternal temperatures lower than 15-16 °C resulted in significantly greater primary dormancy. In addition, the impact of nitrate in the growing media on dormancy was shown only by seeds produced below 15-16 °C. However, there were no consistent effects on seed yield, number, or size. Effects on germination behaviour were shown to be a species characteristic responding to temperature and not time of year. Elevating temperature above this critical value during seed development has the potential to dramatically alter the timing of subsequent seed germination and the proportion entering the soil seed bank. This has potential consequences for the whole plant life cycle and species fitness. © 2017 John Wiley & Sons Ltd.

  2. Human Organ Chip Models Recapitulate Orthotopic Lung Cancer Growth, Therapeutic Responses, and Tumor Dormancy In Vitro

    Directory of Open Access Journals (Sweden)

    Bryan A. Hassell

    2017-10-01

    Full Text Available Here, we show that microfluidic organ-on-a-chip (organ chip cell culture technology can be used to create in vitro human orthotopic models of non-small-cell lung cancer (NSCLC that recapitulate organ microenvironment-specific cancer growth, tumor dormancy, and responses to tyrosine kinase inhibitor (TKI therapy observed in human patients in vivo. Use of the mechanical actuation functionalities of this technology revealed a previously unknown sensitivity of lung cancer cell growth, invasion, and TKI therapeutic responses to physical cues associated with breathing motions, which appear to be mediated by changes in signaling through epidermal growth factor receptor (EGFR and MET protein kinase. These findings might help to explain the high level of resistance to therapy in cancer patients with minimal residual disease in regions of the lung that remain functionally aerated and mobile, in addition to providing an experimental model to study cancer persister cells and mechanisms of tumor dormancy in vitro.

  3. Natural antisense transcripts are linked to the modulation of mitochondrial function and teliospore dormancy in Ustilago maydis.

    Science.gov (United States)

    Ostrowski, Lauren A; Saville, Barry J

    2017-03-01

    The basidiomycete smut fungus Ustilago maydis causes common smut of corn. This disease is spread through the production of teliospores, which are thick-walled dormant structures characterized by low rates of respiration and metabolism. Teliospores are formed when the fungus grows within the plant, and the morphological steps involved in their formation have been described, but the molecular events leading to dormancy are not known. In U. maydis, natural antisense transcripts (NATs) can function to alter gene expression and many NATs have increased levels in the teliospore. One such NAT is as-ssm1 which is complementary to the gene for the mitochondrial seryl-tRNA synthetase (ssm1), an enzyme important to mitochondrial function. The disruption of ssm1 leads to cell lysis, indicating it is also essential for cellular viability. To assess the function of as-ssm1, it was ectopically expressed in haploid cells, where it is not normally present. This expression led to reductions in growth rate, virulence, mitochondrial membrane potential and oxygen consumption. It also resulted in the formation of as-ssm1/ssm1 double-stranded RNA and increased ssm1 transcript levels, but no change in Ssm1 protein levels was detected. Together, these findings suggest a role for as-ssm1 in facilitating teliospore dormancy through dsRNA formation and reduction of mitochondrial function. © 2016 John Wiley & Sons Ltd.

  4. An Advanced Backcross Population through Synthetic Octaploid Wheat as a “Bridge”: Development and QTL Detection for Seed Dormancy

    Directory of Open Access Journals (Sweden)

    Zhang Dale

    2017-12-01

    Full Text Available The seed dormancy characteristic is regarded as one of the most critical factors for pre-harvest sprouting (PHS resistance. As a wild wheat relative species, Aegilops tauschii is a potential genetic resource for improving common wheat. In this study, an advanced backcross population (201 strains containing only Ae. tauschii segments was developed by means of synthetic octaploid wheat (hexaploid wheat Zhoumai 18 × Ae. tauschii T093. Subsequently, seed dormancy rate (Dor in the advanced backcross population was evaluated on the day 3, 5 and 7, in which 2 major QTLs (QDor-2D and QDor-3D were observed on chromosomes 2D and 3D with phenotypic variance explained values (PVEs of 10.25 and 20.40%, respectively. Further investigation revealed significant correlation between QDor-3D and Tamyb10 gene, while no association was found between the former and TaVp1 gene, implying that QDor-3D site could be of closer position to Tamyb10. The obtained quantitative trait locus sites (QTLs in this work could be applied to develop wheat cultivars with PHS resistance.

  5. Targeted mRNA Oxidation Regulates Sunflower Seed Dormancy Alleviation during Dry After-Ripening[C][W

    Science.gov (United States)

    Bazin, Jérémie; Langlade, Nicolas; Vincourt, Patrick; Arribat, Sandrine; Balzergue, Sandrine; El-Maarouf-Bouteau, Hayat; Bailly, Christophe

    2011-01-01

    After-ripening is the mechanism by which dormant seeds become nondormant during their dry storage after harvest. The absence of free water in mature seeds does not allow detectable metabolism; thus, the processes associated with dormancy release under these conditions are largely unknown. We show here that sunflower (Helianthus annuus) seed alleviation of dormancy during after-ripening is associated with mRNA oxidation and that this oxidation is prevented when seeds are maintained dormant. In vitro approaches demonstrate that mRNA oxidation results in artifacts in cDNA–amplified fragment length polymorphim analysis and alters protein translation. The oxidation of transcripts is not random but selective, and, using microarrays, we identified 24 stored mRNAs that became highly oxidized during after-ripening. Oxidized transcripts mainly correspond to genes involved in responses to stress and in cell signaling. Among them, protein phosphatase 2C PPH1, mitogen-activated protein kinase phosphatase 1, and phenyl ammonia lyase 1 were identified. We propose that targeted mRNA oxidation during dry after-ripening of dormant seeds could be a process that governs cell signaling toward germination in the early steps of seed imbibition. PMID:21642546

  6. Lemmas induce dormancy but help the seed of Leymus chinensis to resist drought and salinity conditions in Northeast China

    Directory of Open Access Journals (Sweden)

    Jixiang Lin

    2016-01-01

    Full Text Available Leymus chinensis is a dominant grass in the Songnen grassland of Northern China. The lower germination caused by the presence of lemmas has proved to be an obstacle for the use of the seeds of this plant by humans. However, it is still unknown if the lemmas have other ecological roles such as resisting drought and saline conditions. Three experiments were designed to investigate the ecological roles of the lemmas in Leymus chinensis seeds. The results showed that lemmas significantly improved the amount of water uptake and slowed down the dehydration rate of the seeds under dry conditions. Likewise, the lemmas induced seed dormancy, and removal of the lemmas improved the germination at all temperatures. Although germination percentage of the seeds without lemmas were higher than that of seeds with lemmas under salinity stress, the recovery and total percentage were significantly lower than the seeds with lemmas, especially at 400 mM stress. These results suggest that the lemmas play a vital function in water uptake, dehydration and salt tolerance during the germination stage of the seeds as a response to adverse environmental conditions. Although lemmas showed a dormancy effect, if we want to plant this species in salinity soil in Northeast China, the approach of removing the lemmas by artificial means and improving the seed germination percentage is not feasible.

  7. Human embryo cloning prohibited in Hong Kong.

    Science.gov (United States)

    Liu, Athena

    2005-12-01

    Since the birth of Dolly (the cloned sheep) in 1997, debates have arisen on the ethical and legal questions of cloning-for-biomedical-research (more commonly termed "therapeutic cloning") and of reproductive cloning using human gametes. Hong Kong enacted the Human Reproductive Technology Ordinance (Cap 561) in 2000. Section 15(1)(e) of this Ordinance prohibits the "replacing of the nucleus of a cell of an embryo with a nucleus taken from any other cell," i.e., nucleus substitution. Section 15(1)(f) prohibits the cloning of any embryo. The scope of the latter, therefore, is arguably the widest, prohibiting all cloning techniques such as cell nucleus replacement, embryo splitting, parthenogenesis, and cloning using stem cell lines. Although the Human Reproductive Technology Ordinance is not yet fully operative, this article examines how these prohibitions may adversely impact on basic research and the vision of the Hong Kong scientific community. It concludes that in light of recent scientific developments, it is time to review if the law offers a coherent set of policies in this area.

  8. Characterization of embryo-specific genes

    Energy Technology Data Exchange (ETDEWEB)

    Sung, R.

    1992-06-12

    The objective of the proposed research is to characterize the function and regulation of a set of embryonic genes which are expressed in the embryos, not in the plants. 22 cDNA clones were isolated from a cDNA library we constructed using mRNAS of -carrot somatic embryos. These cDNA clones identified mRNA species that are present in the somatic and zygotic embryos, but not in adult plants. The sequence of all 22cDNA clones were determined; genomic clones for three cDNA clones, DC8, DC59, and DC49 were isolated and gene sequences determined. DC8, DC49, and several other genes identified by the cDNA sequences belong to the category of late embryogenesis abundant protein genes, Lea. The function of these gens have not yet been determined, but they share common structural features, are regulated by ABA and are speculated to play a role in seed desiccation.

  9. Addition of ascorbate during cryopreservation stimulates subsequent embryo development.

    Science.gov (United States)

    Lane, Michelle; Maybach, Jeffery M; Gardner, David K

    2002-10-01

    Embryo development following cryopreservation is reduced compared with fresh embryos. One of the traumas that cryopreservation imparts on embryos is an increase in oxidative stress. Therefore, this study investigated the effects of the addition of the antioxidant ascorbate to the cryopreservation solutions on subsequent embryo development. Mouse embryos at the 2-cell and blastocyst stages were either slow-frozen or vitrified in solutions containing either no ascorbate or 0.1 or 0.5 mmol/l ascorbate. The effects on the levels of hydrogen peroxide and subsequent embryo development and physiology were assessed. Addition of ascorbate to the cryopreservation solutions reduced the levels of hydrogen peroxide in embryos. Furthermore, addition of 0.1 mmol/l ascorbate significantly enhanced inner cell mass development in blastocysts. Embryos cryopreserved with ascorbate had significantly lower levels of lactate dehydrogenase leakage, and increased rates of metabolism compared with those cryopreserved in the absence of ascorbate. The benefits of ascorbate were significantly greater in embryos that were slow-frozen compared with those that were vitrified. These data indicate that the addition of 0.1 mmol/l ascorbate to the cryopreservation solutions for the mammalian embryo would be of significant value.

  10. Cryopreservation of embryos of Lucilia sericata (Diptera: Calliphoridae).

    Science.gov (United States)

    Rajamohan, Arun; Rinehart, Joseph P; Leopold, Roger A

    2014-03-01

    Embryos of Lucilia (Phaenicia) sericata (Meigen) (Diptera Calliphoridae), the green blowfly, were successfully cryopreserved by vitrification in liquid nitrogen and stored for 8 yr. Embryos incubated at 19 degrees C for 17 h after oviposition were found to be the most appropriate stage to cryopreserve. Removal of the embryonic surface water was done using 2-propanol before the alkane treatment to permeabilize the embryo. Exposure to 2-propanol for > 10 s caused necrotic tissue damage in the embryos. Among the alkanes used, hexane was found to be a superior permeabilizing solvent compared with heptane or octane, with embryo hatching rates on par with the controls. Treatment with the vitrification solution for < 12 min was insufficient to vitrify the embryos. Treatment time in the solution beyond 15 min reduced embryo viability. However, the percentage of embryos vitrifying upon exposure to liquid nitrogen vapor remained constant after 12 min of treatment. Long-term storage was initiated in 2004, and the mean hatch percentage recorded then for the short-term cryopreserved embryos was 9.51%. When the long-term stored samples were retrieved in 2012, 8.47% of the embryos hatched, 66.36% larvae pupariated, and 36.96% of the pupae eclosed. Recent optimization of the technique has resulted in a hatch rate of 34.08 +/- 15.5%, of which 67.5% of the larvae pupariated and 72% of the pupae eclosed to normal flies.

  11. Cryopreservation of preimplantation embryos of cattle, sheep, and goats.

    Science.gov (United States)

    Youngs, Curtis R

    2011-08-05

    Preimplantation embryos from cattle, sheep, and goats may be cryopreserved for short- or long-term storage. Preimplantation embryos consist predominantly of water, and the avoidance of intracellular ice crystal formation during the cryopreservation process is of paramount importance to maintain embryo viability. Embryos are placed into a hypertonic solution (1.4 - 1.5 M) of a cryoprotective agent (CPA) such as ethylene glycol (EG) or glycerol (GLYC) to create an osmotic gradient that facilitates cellular dehydration. After embryos reach osmotic equilibrium in the CPA solution, they are individually loaded in the hypertonic CPA solution into 0.25 ml plastic straws for freezing. Embryos are placed into a controlled rate freezer at a temperature of -6°C. Ice crystal formation is induced in the CPA solution surrounding the embryo, and crystallization causes an increase in the concentration of CPA outside of the embryo, causing further cellular dehydration. Embryos are cooled at a rate of 0.5°C/min, enabling further dehydration, to a temperature of -34°C before being plunged into liquid nitrogen (-196°C). Cryopreserved embryos must be thawed prior to transfer to a recipient (surrogate) female. Straws containing the embryos are removed from the liquid nitrogen dewar, held in room temperature air for 3 to 5 sec, and placed into a 37°C water bath for 25 to 30 sec. Embryos cryopreserved in GLYC are placed into a 1 M solution of sucrose for 10 min for removal of the CPA before transfer to a recipient (surrogate) female. Embryos cryopreserved in EG, however, may be directly transferred to the uterus of a recipient.

  12. Differentiated dynamics of bud dormancy and growth in temperate fruit trees relating to bud phenology adaptation, the case of apple and almond trees

    Science.gov (United States)

    El Yaacoubi, Adnane; Malagi, Gustavo; Oukabli, Ahmed; Citadin, Idemir; Hafidi, Majida; Bonhomme, Marc; Legave, Jean-Michel

    2016-11-01

    Few studies have focused on the characterization of bud dormancy and growth dynamics for temperate fruit species in temperate and mild cropping areas, although this is an appropriate framework to anticipate phenology adaptation facing future warming contexts which would potentially combine chill declines and heat increases. To examine this issue, two experimental approaches and field observations were used for high- and low-chill apple cultivars in temperate climate of southern France and in mild climates of northern Morocco and southern Brazil. Low-chill almond cultivars offered an additional relevant plant material for comparison with apple in northern Morocco. Divergent patterns of dormancy and growth dynamics were clearly found in apple tree between southern France and southern Brazil. Divergences were less pronounced between France and Morocco. A global view outlined main differences in the dormancy chronology and intensity, the transition between endordormancy and ecodormancy and the duration of ecodormancy. A key role of bud rehydration in the transition period was shown. High-chill cultivars would be submitted in mild conditions to heterogeneous rehydration capacities linked to insufficient chill fulfillment and excessive forcing linked to high temperatures. This would favor bud competitions and consequently excessive flowering durations and weak flowering. Low chilling requirements in apple and almond would conversely confer biological capacities to tolerate superficial dormancy and abrupt transition from endordormancy to ecodormancy without important heterogeneous rehydration states within buds. It may also assume that low-chill cultivars can also tolerate high temperatures during ecodormancy as well as extended flowering durations.

  13. The effects of dormancy status on the endogenous contents and biological activities of jasmonic acid, n-(jasmonoyl)-isoleucine, and tuberonic acid in potato tubers

    Science.gov (United States)

    The effects of storage and dormancy progression on the endogenous contents and the growth-regulating activities of jasmonic acid (JA), jasmonoyl-isoleucine (JA-Ile), and tuberonic acid (TA) were determined in potato (Solanum tuberosum L. cv. Russet Burbank) minitubers and seed tubers over several ha...

  14. beta-1,3-Glucanase gene expression in low-hydrated seeds as a mechanism for dormancy release during tobacco after-ripening.

    Science.gov (United States)

    Leubner-Metzger, Gerhard

    2005-01-01

    An air-dry developmental state with low-hydrated tissues is a characteristic of most plant seeds. Seed dormancy is an intrinsic block of germination and can be released during after-ripening, that is air-dry storage of mature seeds. Both seed-covering layers, testa and endosperm, cause the coat-imposed dormancy of tobacco (Nicotiana tabacum). After-ripening and over-expression of class I beta-1,3-glucanase (betaGlu I) confer maternal effects on testa rupture and dormancy release. Very little is known about the molecular mechanisms of after-ripening and whether gene expression is possible in low-hydrated seeds. Transient, low-level betaGlu I transcription and translation was detected during tobacco seed after-ripening. (1)H NMR 2D micro-imaging showed uneven distribution of proton mobility in seeds. betaGlu I gene expression is associated spatially with the inner testa and temporally with the promotion of testa rupture. Local elevation in moisture content seems to permit local, low-level betaGlu I gene transcription and translation in the maternal tissues of air-dry, low-hydrated seeds. De novo gene expression is therefore proposed to be a novel molecular mechanism for the release of coat-imposed dormancy during oilseed after-ripening.

  15. Seed dormancy release in Arabidopsis Cvi by dry after-ripening, low temperature, nitrate and light shows common quantitative patterns of gene expression directed by environment specific sensing

    NARCIS (Netherlands)

    Finch-Savage, W.E.; Cadman, C.S.C.; Toorop, P.E.; Lynn, J.R.; Hilhorst, H.W.M.

    2007-01-01

    The depth of seed dormancy can be influenced by a number of different environmental signals, but whether a common mechanism underlies this apparently similar response has yet to be investigated. Full-genome microarrays were used for a global transcript analysis of Arabidopsis thaliana Cape Verde

  16. Propylthiouracil is teratogenic in murine embryos.

    Directory of Open Access Journals (Sweden)

    Valeria C Benavides

    Full Text Available BACKGROUND: Hyperthyroidism during pregnancy is treated with the antithyroid drugs (ATD propylthiouracil (PTU and methimazole (MMI. PTU currently is recommended as the drug of choice during early pregnancy. Yet, despite widespread ATD use in pregnancy, formal studies of ATD teratogenic effects have not been performed. METHODS: We examined the teratogenic effects of PTU and MMI during embryogenesis in mice. To span different periods of embryogenesis, dams were treated with compounds or vehicle daily from embryonic day (E 7.5 to 9.5 or from E3.5 to E7.5. Embryos were examined for gross malformations at E10.5 or E18.5 followed by histological and micro-CT analysis. Influences of PTU on gene expression levels were examined by RNA microarray analysis. RESULTS: When dams were treated from E7.5 to E9.5 with PTU, neural tube and cardiac abnormalities were observed at E10.5. Cranial neural tube defects were significantly more common among the PTU-exposed embryos than those exposed to MMI or vehicle. Blood in the pericardial sac, which is a feature indicative of abnormal cardiac function and/or abnormal vasculature, was observed more frequently in PTU-treated than MMI-treated or vehicle-treated embryos. Following PTU treatment, a total of 134 differentially expressed genes were identified. Disrupted genetic pathways were those associated with cytoskeleton remodeling and keratin filaments. At E 18.5, no gross malformations were evident in either ATD group, but the number of viable PTU embryos per dam at E18.5 was significantly lower from those at E10.5, indicating loss of malformed embryos. These data show that PTU exposure during embryogenesis is associated with delayed neural tube closure and cardiac abnormalities. In contrast, we did not observe structural or cardiac defects associated with MMI exposure except at the higher dose. We find that PTU exposure during embryogenesis is associated with fetal loss. These observations suggest that PTU has

  17. Demographic analysis of dormancy and survival in the terrestrial orchid Cypripedium reginae

    Science.gov (United States)

    Kery, Marc; Gregg, Katharine B.

    2004-01-01

    demographic analysis of plants with dormancy.

  18. Long bone development in the Japanese quail (Coturnix coturnixjaponica) embryos.

    Science.gov (United States)

    Ahmed, Yasser A; Soliman, Soha A

    2013-09-15

    The current study was undertaken to describe the main histological development stages of long bones (tibia and femur) from Japanese quail (Coturnix coturnix japonica) embryos. Whole Limbs or just tibia and femur of fifty Japanese quail embryos of different ages were fixed and embedded in paraffin or Spurr's resin. Paraffin and semi-thin, respectively, were undertaken and examined with light microscopy. Limb bud was established at day 5 of incubation. Mesenchymal cells differentiated into chondrocytes forming a cartilage template in the position of the future tibia and femur at day 6 of incubation. At day 7 of incubation, the cartilage template enlarged and had the shape and position of the future tibia and femur. At day 8, central chondrocytes underwent hypertrophy and were surrounded by a periosteal bone collar. Cellular and vascular invasion from the bone collar into the central zone of the cartilage template, cartilage resorption and formation of marrow tunnel and finally peripheral calcification was seen. Vascular cartilage canals penetrating the epiphysis were observed at day 9 and the canals gradually increased in thickness and number toward the hatching day. Articular epiphyseal growth cartilage with resting, proliferative and hypertrophic zones was clearly established by day 10 of incubation. After 17 days of incubation, the zonation of the articular epiphyseal cartilage were much clear, many cartilage canals were present within the epiphyses. In epiphyses of tibia but not femur, foci of chondrocytes hypertrophy were noticed close to the cartilage canals. The current study timed the main histological sequences of development of tibia and femur of embryonic quail.

  19. The Embryo Project: an integrated approach to history, practices, and social contexts of embryo research.

    Science.gov (United States)

    Maienschein, Jane; Laubichler, Manfred D

    2010-01-01

    This essay describes the approach and early results of the collaborative Embryo Project and its on-line encyclopedia (http://embryo.asu.edu). The project is based on a relational database that allows federated searches and inclusion of multiple types of objects targeted for multiple user groups. The emphasis is on the history and varied contexts of developmental biology, focusing on people, places, institutions, techniques, literature, images, and other aspects of study of embryos. This essay introduces the ways of working as well as the long-term goals of the project. We invite others to join the effort, both in this particular project and in joining together in digital collection, archiving, and knowledge generation at the borders of biology and history.

  20. Embryo quality and impact of specific embryo characteristics on ongoing implantation in unselected embryos derived from modified natural cycle in vitro fertilization

    NARCIS (Netherlands)

    Pelinck, Marie-Jose; Hoek, Annemieke; Simons, Arnold H. M.; Heineman, Maas Jan; van Echten-Arends, Janny; Arts, Eus G. J. M.

    Objective: To study the implantation potential of unselected embryos derived from modified natural cycle IVF according to their morphological characteristics. Design: Cohort study. Setting: Academic department of reproductive medicine. Patient(S): A series of 449 single embryo transfers derived from

  1. Estimation of the {beta}+ dose to the embryo resulting from {sup 18}F-FDG administration during early pregnancy

    Energy Technology Data Exchange (ETDEWEB)

    Zanotti-Fregonara, P.; Trebossen, R.; Maroy, R. [CEA, DSV, I2BM, SHFJ, LIME, Orsay (France); Champion, C. [Univ Paul Verlaine Metz, Inst Phys, Lab Phys Mol et Collis, Metz (France); Hindie, E. [Univ Paris 07, IUH, Ecole Doctorale B2T, Paris (France); Hindie, E. [Hop St Louis, AP-HP, Nucl Med Serv, F-75475 Paris 10 (France)

    2008-07-01

    Although {sup 18}F-FDG examinations are widely used, data are lacking on the dose to human embryo tissues in cases of exposure in early pregnancy. Although the photon component can easily be estimated from available data on the pharmacokinetics of {sup 18}F-FDG in female organs and from phantom measurements (considering the uterus as the target organ), the intensity of embryo tissue uptake, which is essential for deriving the {beta}+ dose, is not known. We report the case of a patient who underwent {sup 18}F-FDG PET/CT for tumor surveillance and who was later found to have been pregnant at the time of the examination(embryo age, 8 wk). Methods: The patient received 320 MBq of {sup 18}F-FDG. Imaging started with an unenhanced CT scan 1 h after the injection, followed by PET acquisition. PET images were used to compute the total number of {beta}+ emissions in embryo tissues per unit of injected activity, from standardized uptake value (SUV) measurements corrected for partial-volume effects. A Monte Carlo track structure code was then used to derive the {beta}+ self-dose and the {beta}+ cross-dose from amniotic fluid. The photon and CT doses were added to obtain the final dose received by the embryo. Results: The mean SUV in embryo tissues was 2.7, after correction for the partial-volume effect. The mean corrected SUV of amniotic fluid was 1.1. Monte Carlo simulation showed that the {beta}+ dose to the embryo (self-dose plus cross-dose from amniotic fluid) was 1.8 E-2 mGy per MBq of injected {sup 18}F-FDG. Based on MIRD data for the photon dose to the uterus, the estimated photon dose to the embryo was 1.5 E-2 mGy/MBq. Thus, the specific {sup 18}F-FDG dose to the embryo was 3.3 E-2 mGy/MBq (10.6 mGy in this patient). The CT scan added a further 8.3 mGy. Conclusion: The dose to the embryo is 3.3 E-2 mGy/MBq of {sup 18}F-FDG. The {beta}+ dose contributes 55% of the total dose. This value is higher than previous estimates in late nonhuman-primate pregnancies. (authors)

  2. Correlation between the cryosurvival, cell number and diameter in bovine in vitro produced embryos.

    Science.gov (United States)

    Kocyigit, Alper; Cevik, Mesut

    2016-10-01

    The selection of quality embryos is a prerequisite of cryopreservation process. Present study was conducted to examine the correlation between the diameter and cryotolerance, on the cell number of the cryopreserved embryos. The blastocyst stage embryos were collected at culture days 7-9, evaluated morphologically under a microscope and divided according to the diameter into three groups: Group 1; (larger than 150 μm), Group 2; (diameter of 100-150 μm), Group 3; (smaller than 100 μm). Blastocysts were vitrified-thawed using the classical vitrification method and then cultured in SOF medium drops at 24 h. Blastocysts were considered viable if they re-expanded or hatched from the zona pellucidae. Finally re-expanded blastocysts from the Group 1 and Group 2 to determine the differential count of cells in the ICM and TE. The re-expansion ability of blastocysts 100-150 μm in diameter (69.56%) was significantly higher than other groups (52.17 and 47.36%). The value of the correlation coefficient between the re-expansion rate and cell number of blastocysts in the group 2 (r = 0.784) tended to be higher than that in the group 1 (r = 0.512) and group 3 (r = 0.491) (p < 0.05). For ICM/total cell ratio yield group 2 embryos showed higher rate (0.28), compared to the other groups (0.19 and 0.16). In conclusion, the present study demonstrates that the correlation between diameter of embryos and their cryosurvival based on re-expansion ability and cell allocation. Copyright © 2016 Elsevier Inc. All rights reserved.

  3. Comparison between Conventional Blind Embryo Transfer and Embryo Transfer Based on Previously Measured Uterine Length

    Directory of Open Access Journals (Sweden)

    Nasrin Saharkhiz

    2014-11-01

    Full Text Available Background: Embryo transfer (ET is one of the most important steps in assisted reproductive technology (ART cycles and affected by many factors namely the depth of embryo deposition in uterus. In this study, the outcomes of intracytoplasmic sperm injection (ICSI cycles after blind embryo transfer and embryo transfer based on previously measured uterine length using vaginal ultrasound were compared. Materials and Methods: This prospective randomised clinical trial included one hundred and forty non-donor fresh embryo transfers during January 2010 to June 2011. In group I, ET was performed using conventional (blind method at 5-6cm from the external os, and in group II, ET was done at a depth of 1-1.5 cm from the uterine fundus based on previously measured uterine length using vaginal sonography. Appropriate statistical analysis was performed using Student’s t test and Chi-square or Fisher’s exact test. The software that we used was PASW statistics version 18. A p value <0.05 was considered statistically significant. Results: Chemical pregnancy rate was 28.7% in group I and 42.1% in group II, while the difference was not statistically significant (p=0.105. Clinical pregnancy, ongoing pregnancy and implantation rates for group I were 21.2%, 17.7%, and 12.8%, while for group II were 33.9%, 33.9%, and 22.1, respectively. In group I and group II, abortion rates were 34.7% and 0%, respectively, indicating a statistically significant difference (p<0.005. No ectopic pregnancy occurred in two groups. Conclusion: The use of uterine length measurement during treatment cycle in order to place embryos at depth of 1-1.5cm from fundus significantly increases clinical and ongoing pregnancy and implantation rates, while leads to a decrease in abortion rate (Registration Number: IRCT2014032512494N1.

  4. Effects of embryo-derived exosomes on the development of bovine cloned embryos.

    Science.gov (United States)

    Qu, Pengxiang; Qing, Suzhu; Liu, Ruiqi; Qin, Hongyu; Wang, Weiwei; Qiao, Fang; Ge, Hui; Liu, Jun; Zhang, Yong; Cui, Wei; Wang, Yongsheng

    2017-01-01

    The developmental competence of in vitro cultured (IVC) embryos is markedly lower than that of their in vivo counterparts, suggesting the need for optimization of IVC protocols. Embryo culture medium is routinely replaced three days after initial culture in bovine, however, whether this protocol is superior to continuous nonrenewal culture method under current conditions remains unclear. Using bovine somatic cell nuclear transfer (SCNT) embryos as the model, our results showed that compared with routine renewal treatment, nonrenewal culture system significantly improved blastocyst formation, blastocyst quality (increased total cell number, decreased stress and apoptosis, enhanced Oct-4 expression and ratio of ICM/TE), as well as following development to term. Existence and function of SCNT embryo-derived exosomes were then investigated to reveal the cause of impaired development induced by culture medium replacement. Exosomes were successfully isolated through differential centrifugation and identified by both electron microscopy and immunostaining against exosomal membrane marker CD9. Supplementation of extracted exosomes into freshly renewed medium significantly rescued not only blastocyst formation and quality (in vitro development), but also following growth to term (in vivo development). Notably, ratio of ICM/TE and calving rate were enhanced to a similar level as that in nonrenewal group. In conclusion, our results for the first time indicate that 1: bovine SCNT embryos can secrete exosomes into chemically defined culture medium during IVC; 2: secreted exosomes are essential for SCNT blastocyst formation, blastocyst quality, and following development to term; 3: removal of exosomes induced by culture medium replacement impairs SCNT embryo development, which can be avoided by nonrenewal culture procedure or markedly recovered by exosome supplementation.

  5. In vitro culture of individual mouse preimplantation embryos: the role of embryo density, microwells, oxygen, timing and conditioned media.

    Science.gov (United States)

    Kelley, Rebecca L; Gardner, David K

    2017-05-01

    Single embryo culture is suboptimal compared with group culture, but necessary for embryo monitoring, and culture systems should be improved for single embryos. Pronucleate mouse embryos were used to assess the effect of culture conditions on single embryo development. Single culture either before or after compaction reduced cell numbers (112.2 ± 3.1; 110.2 ± 3.5) compared with group culture throughout (127.0 ± 3.4; P media volume from 20 µl to 2 µl increased blastocyst cell numbers in single embryos cultured in 5% oxygen (84.4 ± 3.2 versus 97.8 ± 2.8; P Culture in microwell plates for the EmbryoScope and Primo Vision time-lapse systems changed cleavage timings and increased inner cell mass cell number (24.1 ± 1.0; 23.4 ± 1.2) compared with a 2 µl microdrop (18.4 ± 1.0; P media to single embryos increased hatching rate and blastocyst cell number (91.5 ± 4.7 versus 113.1 ± 4.4; P culture before or after compaction is therefore detrimental; oxygen, media volume and microwells influence single embryo development; and embryo-conditioned media may substitute for group culture. Copyright © 2017 Reproductive Healthcare Ltd. Published by Elsevier Ltd. All rights reserved.

  6. Vibrational properties characterization of mouse embryo during microinjection

    Directory of Open Access Journals (Sweden)

    Hedrih Anđelka N.

    2013-01-01

    Full Text Available To determine the vibration characteristics (natural frequencies and mode shapes of a mouse embryo during microinjection the modal analysis is used. The spherical mouse embryo 60 μm in diameter is modeled as elastic finite elements biostructure consisting of 6μm thick micromembrane and 38 μm in diameter nucleus. Embryo modeling and modal analysis were based on the use of the finite elements method in the modal analysis system of ANSYS software. The modal analysis was carried out for first six modes of embryo natural frequencies. The numerical analysis of dependence of embryo own frequencies on the boundary conditions and external loads are presented. The relevant illustrations of the typical variations of the shape, deformation and particle velocities of vibrating embryo are given. [Projekat Ministarstva nauke Republike Srbije, br. OI174001: Dynamics of hybrid systems with complex structures: Mechanics of materials

  7. Cutin fluorescence in early embryos of Pinus and Tsuga

    Directory of Open Access Journals (Sweden)

    Ewa Szczuka

    2014-01-01

    Full Text Available Embryos of Pinus nigra Arnold and Tsuga canadensis Carr. (Pinaceae at different stages of development were dissected from fresh, unfixed seeds and examined in a fluorescence microscope with 400 nm excitation light. The embryos of the investigated species showed cutin fluorescence after auramine 0 staining. At first the fluorescing cutin layer was formed on the apical part of the embryo with a well developed secondary suspensor, then it extended over the lateral surface of the embryo; the suspensor remained nonfluorescent. The fluorescing cutin layer occurred on the apical and side surface of the embryo, undergoing differentiation into the shoot axis and root initials. It is assumed that polarization and nutrition of the embryo may be influenced by presence of the cuticle.

  8. Globulin gene expression in embryos of maize viviparous mutants

    Energy Technology Data Exchange (ETDEWEB)

    Kriz, A.R.; Wallace, M.S.; Paiva, R. (Univ. of Illinois, Urbana (USA))

    1990-02-01

    Expression of genes encoding the major Zea mays embryo globulins was examined in the maize precocious germination viviparous (vp) mutants. Comparison of globulin protein profiles of precociously germinating mutant embryos with those of normally germinating mature embryos revealed substantial differences with respect to the proteins encoded by the Glb1 gene. Analysis of Glb1 transcript levels in vp/vp embryos suggests that these mutants do not fully switch from a program of embryo maturation to one of germination. These preliminary studies indicate that the vp mutants provide an excellent system for the study of embryo maturation in maize. We also provide evidence for the positive regulation of Glb1 expression by the plant growth regulator abscisic acid.

  9. Embryo sac development in some South African Lantana species (Verbenaceae

    Directory of Open Access Journals (Sweden)

    J. J. Spies

    1984-12-01

    Full Text Available Evidence that the South African Lantana camara L. complex only produces sexual embryo sacs is provided. It is shown that the archesporium occasionally divides mitotically and that both archesporia form tetrads. The chalazal megaspore of one tetrad and the micropylar megaspore of the second tetrad develop into Polygonum type embryo sacs. L. rugosa Thunb. also forms Polygonum type embryo sacs. The L. rugosa embryo sac has a much more densely packed cytoplasm, smaller vacuole and the position of the polar nuclei differs from that of the L. camara embryo sac. It is possible to distinguish between  L. camara and  L. rugosa on their embryo sac morphology alone.

  10. In vitro production of horse embryos: fundamental aspects

    OpenAIRE

    López Tremoleda, Jordi

    2003-01-01

    Developments in assisted reproduction have provided valuable tools for sub-fertility treatment and for selective breeding in animals. In horses, techniques such as artificial insemination and embryo transfer are used successfully to aid genetic progress but the commercial application of other assisted reproductive techniques, such as in vitro production of embryos (IVP), has been severely restricted by their low efficiency. The development of culture systems that can support embryo developmen...

  11. Prospective randomized comparison of two embryo culture systems: P1 medium by Irvine Scientific and the Cook IVF Medium.

    Science.gov (United States)

    Ben-Yosef, Dalit; Amit, Ami; Azem, Foad; Schwartz, Tamar; Cohen, Tania; Mei-Raz, Nava; Carmon, Ariela; Lessing, Joseph B; Yaron, Yuval

    2004-08-01

    To compare the efficacy of two commercially available in vitro fertilization (IVF) and embryo culture media systems: the glucose-free P1 Medium supplemented with 20% synthetic serum substitute (SSS) (Irvine Scientific), and the Cook IVF Medium (Cook, Australia). A prospective randomized study. Medical center-based IVF Unit affiliated to the Faculty of Medicine of Tel Aviv University. IVF patients were randomly assigned to either P1 Medium supplemented with 20% SSS (182 patients, 196 cycles) or Cook Medium (167 patients, 179 cycles). Fertilization rates were similar with both media (52.3 +/- 26.1 and 53.8 +/- 27.6, respectively). Likewise, no difference was found in morphological characteristics and grading of cultured embryos. However, a significantly higher proportion of the embryos incubated in the P1 Medium reached the four-cell stage on day 2 or the 6-cell stage on day 3 postfertilization, compared to those incubated in Cook Medium (54.3% vs. 41.9%, p < 0.0001). Clinical pregnancy and delivery rates were improved when oocytes and embryos were cultured in P1 Medium. Finally, Implantation rate was significantly higher in the P1 Medium Group (9.9% vs. 6%, respectively). Our results suggest that the P1 Medium may be associated with a higher embryo cleavage rate and improved implantation rates compared to the Cook IVF Medium.

  12. Thylacine 1 is expressed segmentally within the paraxial mesoderm of the Xenopus embryo and interacts with the Notch pathway.

    Science.gov (United States)

    Sparrow, D B; Jen, W C; Kotecha, S; Towers, N; Kintner, C; Mohun, T J

    1998-06-01

    The presomitic mesoderm of vertebrates undergoes a process of segmentation in which cell-cell interactions mediated by the Notch family of receptors and their associated ligands are involved. The vertebrate homologues of Drosophila &Dgr ; are expressed in a dynamic, segmental pattern within the presomitic mesoderm, and alterations in the function of these genes leads to a perturbed pattern of somite segmentation. In this study we have characterised Thylacine 1 which encodes a basic helix-loop-helix class transcription activator. Expression of Thylacine is restricted to the presomitic mesoderm, localising to the anterior half of several somitomeres in register with domains of X-Delta-2 expression. Ectopic expression of Thylacine in embryos causes segmentation defects similar to those seen in embryos in which Notch signalling is altered, and these embryos also show severe disruption in the expression patterns of the marker genes X-Delta-2 and X-ESR5 within the presomitic mesoderm. Finally, the expression of Thylacine is altered in embryos when Notch signalling is perturbed. These observations suggest strongly that Thylacine 1 has a role in the segmentation pathway of the Xenopus embryo, by interacting with the Notch signalling pathway.

  13. Mitigating phototoxicity during multiphoton microscopy of live Drosophila embryos in the 1.0-1.2 µm wavelength range.

    Directory of Open Access Journals (Sweden)

    Delphine Débarre

    Full Text Available Light-induced toxicity is a fundamental bottleneck in microscopic imaging of live embryos. In this article, after a review of photodamage mechanisms in cells and tissues, we assess photo-perturbation under illumination conditions relevant for point-scanning multiphoton imaging of live Drosophila embryos. We use third-harmonic generation (THG imaging of developmental processes in embryos excited by pulsed near-infrared light in the 1.0-1.2 µm range. We study the influence of imaging rate, wavelength, and pulse duration on the short-term and long-term perturbation of development and define criteria for safe imaging. We show that under illumination conditions typical for multiphoton imaging, photodamage in this system arises through 2- and/or 3-photon absorption processes and in a cumulative manner. Based on this analysis, we derive general guidelines for improving the signal-to-damage ratio in two-photon (2PEF/SHG or THG imaging by adjusting the pulse duration and/or the imaging rate. Finally, we report label-free time-lapse 3D THG imaging of gastrulating Drosophila embryos with sampling appropriate for the visualisation of morphogenetic movements in wild-type and mutant embryos, and long-term multiharmonic (THG-SHG imaging of development until hatching.

  14. Prolific shoot regeneration from immature embryo explants of sainfoin (Onobrychis viciifolia Scop.).

    Science.gov (United States)

    Ozcan, S; Sevimay, C S; Yildiz, M; Sancak, C; Ozgen, M

    1996-12-01

    Immature cotyledons and embryo axes of sainfoin were cultured on Murashige and Skoog (MS) media supplemented with various concentrations of 6-benzylaminopurine (BAP) and a-naphthaleneacetic acid (NAA) to induce adventitious shoot regeneration. The highest frequency of shoot regeneration occurred following an initial callus growth on a MS medium containing 0.5 mg/l BAP and 2 mg/l NAA. Immature embryo axes showed higher regeneration capacity than immature cotyledons, however, shoot elongation was best achieved on immature cotyledons. Regenerated shoots were excised and rooted in half strength MS medium with 1 mg/l indole-butyric acid (IBA) or 1 mg/l NAA. The rooted plantlets were finally transferred to compost.

  15. The Woman-Embryo Conflict in the Abortion Debate at the Parliament

    Directory of Open Access Journals (Sweden)

    Susana Rostagnol

    2008-05-01

    Full Text Available This article analyzes the woman-embryo conflict discussed by the Uruguayan Senate during the debates on abortion legalization in October and November 2007. Its aim is to show the underlying notions, which are classified as those that promote the ‘patrimonial control over the body’ and those that promote autonomy. From that perspective, it analyzes the abstract or concrete standpoint given to abortion in the Senators arguments. Then, it discusses the personhood assigned to zef (zygote-embryo-fetus based on biomedical arguments. It also discusses the attribute of moral person given/or not to the pregnant woman. Finally it shows that abortion is basically a fact that influences directly in the organization of social relations.

  16. Morphogenesis in sea urchin embryos: linking cellular events to gene regulatory network states

    Science.gov (United States)

    Lyons, Deidre; Kaltenbach, Stacy; McClay, David R.

    2013-01-01

    Gastrulation in the sea urchin begins with ingression of the primary mesenchyme cells (PMCs) at the vegetal pole of the embryo. After entering the blastocoel the PMCs migrate, form a syncitium, and synthesize the skeleton of the embryo. Several hours after the PMCs ingress the vegetal plate buckles to initiate invagination of the archenteron. That morphogenetic process occurs in several steps. The non-skeletogenic cells produce the initial inbending of the vegetal plate. Endoderm cells then rearrange and extend the length of the gut across the blastocoel to a target near the animal pole. Finally, cells that will form part of the midgut and hindgut are added to complete gastrulation. Later, the stomodeum invaginates from the oral ectoderm and fuses with the foregut to complete the archenteron. In advance of, and during these morphogenetic events an increasingly complex gene regulatory network controls the specification and the cell biological events that conduct the gastrulation movements. PMID:23801438

  17. Breaking seed dormancy in smooth loofah (Luffa cylindrica (L. M. Roem. using scarification and dry heat treatment

    Directory of Open Access Journals (Sweden)

    Sajee Chaodumrikul

    2016-03-01

    Full Text Available Hard seed dormancy is a common problem with smooth loofah seed. Scarification, clipping and dry heat were used to break dormancy in smooth loofah seed at the Department of Horticulture, Kasetsart University, Bangkok, Thailand. A completely randomized design with 20 treatments was used involving: untreated seed (control, clipping, scarifying by scarifier at 40, 70 and 100 revolutions per minute (rpm for 1 min, and dry heat at 60 °C, 70 °C and 80 °C for 1–5 h. After breaking dormancy, seed germination was tested in four replicates, with 50 seeds per replicate. The thickness of the seed coat was measured under a digital microscope. The results showed that clipped seeds gave the highest germination (100% and decreased mean germination time (3.58 d. Scarified seed using a scarifier at 70 and 100 rpm for 1 min resulted in germination rates of 67.0–75.5%, which was higher than for seeds scarified at 40 rpm. The dry heat-treated seeds at 60 °C for 3–5 h and at 70 °C for 2–5 h had germination of 71.0–80.5%. The outer layer of seed coat scarified at 100 rpm for 1 min was thinner than those of un-scarified seed samples. Dry heat had no effect on the seed coat thickness, but affected cells of the inner seed coat as the sclerenchymous cells showed disordered characteristics and were non-uniform and seemed to have been torn off. Dry heat treatment and scarification significantly improved germination compared to the control treatment. However, 80% germination may not be considered as an effective method at a commercial scale where 100% germination is needed. Further investigation of more accessions that may have different seed coat thicknesses may be needed.

  18. Air bubble migration is a random event post embryo transfer.

    Science.gov (United States)

    Confino, E; Zhang, J; Risquez, F

    2007-06-01

    Air bubble location following embryo transfer (ET) is the presumable placement spot of embryos. The purpose of this study was to document endometrial air bubble position and migration following embryo transfer. Multicenter prospective case study. Eighty-eight embryo transfers were performed under abdominal ultrasound guidance in two countries by two authors. A single or double air bubble was loaded with the embryos using a soft, coaxial, end opened catheters. The embryos were slowly injected 10-20 mm from the fundus. Air bubble position was recorded immediately, 30 minutes later and when the patient stood up. Bubble marker location analysis revealed a random distribution without visible gravity effect when the patients stood up. The bubble markers demonstrated splitting, moving in all directions and dispersion. Air bubbles move and split frequently post ET with the patient in the horizontal position, suggestive of active uterine contractions. Bubble migration analysis supports a rather random movement of the bubbles and possibly the embryos. Standing up changed somewhat bubble configuration and distribution in the uterine cavity. Gravity related bubble motion was uncommon, suggesting that horizontal rest post ET may not be necessary. This report challenges the common belief that a very accurate ultrasound guided embryo placement is mandatory. The very random bubble movement observed in this two-center study suggests that a large "window" of embryo placement maybe present.

  19. Preimplantation death of xenomitochondrial mouse embryo harbouring bovine mitochondria

    Science.gov (United States)

    Kawahara, Manabu; Koyama, Shiori; Iimura, Satomi; Yamazaki, Wataru; Tanaka, Aiko; Kohri, Nanami; Sasaki, Keisuke; Takahashi, Masashi

    2015-01-01

    Mitochondria, cellular organelles playing essential roles in eukaryotic cell metabolism, are thought to have evolved from bacteria. The organization of mtDNA is remarkably uniform across species, reflecting its vital and conserved role in oxidative phosphorylation (OXPHOS). Our objectives were to evaluate the compatibility of xenogeneic mitochondria in the development of preimplantation embryos in mammals. Mouse embryos harbouring bovine mitochondria (mtB-M embryos) were prepared by the cell-fusion technique employing the haemagglutinating virus of Japan (HVJ). The mtB-M embryos showed developmental delay at embryonic days (E) 3.5 after insemination. Furthermore, none of the mtB-M embryos could implant into the maternal uterus after embryo transfer, whereas control mouse embryos into which mitochondria from another mouse had been transferred developed as well as did non-manipulated embryos. When we performed quantitative PCR (qPCR) of mouse and bovine ND5, we found that the mtB-M embryos contained 8.3% of bovine mitochondria at the blastocyst stage. Thus, contamination with mitochondria from another species induces embryonic lethality prior to implantation into the maternal uterus. The heteroplasmic state of these xenogeneic mitochondria could have detrimental effects on preimplantation development, leading to preservation of species-specific mitochondrial integrity in mammals. PMID:26416548

  20. Dilemmas encountered with preimplantation diagnosis of aneuploidy in human embryos.

    Science.gov (United States)

    Allan, John; Edirisinghe, Rohini; Anderson, Jasen; Jemmott, Rodney; Nandini, A V; Gattas, Michael

    2004-04-01

    An increased embryo aneuploidy rate is associated with advancing maternal age. Preimplantation genetic diagnosis (PGD) using fluorescence in situ hybridisation (FISH) coupled with in vitro fertilisation (IVF)/embryo biopsy provides a powerful tool to improve the take home baby rates for this poor prognostic group. To report the preliminary findings of a PGD study for aneuploidy screening and to discuss the dilemmas encountered. Preimplantation genetic diagnosis was offered in egg pick up-PGD and frozen embryo transfer-PGD cycles. Embryo biopsy was carried out on day 3 and FISH was used to detect chromosomal abnormalities. The outcome of 75 patients, 100 treatment cycles; 62 egg pick up-PGD and 38 frozen embryo transfer-PGD are presented. The embryo biopsy rate, blastomere survival, presence of nuclei and successful FISH rates for egg pick-up and frozen embryo transfer cycles were similar giving a chromosomal abnormality rate of 57.5 and 51.2% for the respective treatment group. The positive pregnancy, clinical pregnancy and implantation rates were, for egg pick up-PGD 22.7, 13.6 and 21.1% and for frozen embryo transfer-PGD 13.8, 10.3 and 10.0%, respectively. Preimplantation genetic diagnosis coupled with IVF treatment seems to give satisfactory pregnancy rates. The high embryo aneuploidy rates, chromosomal mosaicism and other issues have presented significant ethical and management dilemmas for our physicians and patients alike. These issues highlight the importance of skillful pretreatment counselling for patients considering PGD.

  1. Cryopreservation of somatic embryos of paradise tree (Melia azedarach L.).

    Science.gov (United States)

    Scocchi, Adriana; Vila, Silvia; Mroginski, Luis; Engelmann, Florent

    2007-01-01

    In paradise tree (Melia azedarach L.), immature zygotic embryos sampled from immature fruits are the starting material for the production of somatic embryos. These somatic embryos are employed for freezing experiments. Immature fruits could be stored at 25 degrees C for up to 80 days without impairing the embryogenic potential of zygotic embryos, which represents a four-fold increase in immature fruit storage duration, compared with previous studies. Among the three cryopreservation techniques tested for freezing paradise tree somatic embryos, namely desiccation, encapsulation-dehydration and pregrowth-dehydration, only encapsulation-dehydration and pregrowth-dehydration led to successful results. The optimal protocol was the following: i) somatic embryos (encapsulated or not) pretreated in liquid Murashige & Skoog medium with daily increasing sucrose concentration (0.5 M/0.75 M/1.0 M); ii) dehydrated with silica gel to 21 - 26% moisture content (fresh weight basis), for encapsulation-dehydration, or to 19% moisture content, for pregrowth-dehydration; iii) frozen at 1 degree C/min from 20 degrees C to -30 degrees C with a programmable freezing apparatus; iv) rapid immersion in liquid nitrogen. The highest recovery achieved was 36% with encapsulation-dehydration and 30% with pregrowth-dehydration. Regrowth of frozen embryos was direct in most cases, as secondary embryogenesis originating from the root pole was observed on only around 10% of cryopreserved somatic embryos. Plants recovered from cryopreserved embryos presented the same phenotypic traits as non-frozen control plants.

  2. In vitro production of embryos in South American camelids.

    Science.gov (United States)

    Trasorras, V; Giuliano, S; Miragaya, M

    2013-01-10

    Studies in reproductive biotechnology techniques have been minimal in South American camelids (SAC). Complex reproductive characteristics of these species contribute to slow progress. Nevertheless, some techniques, such as in vitro fertilization, intracytoplasmic sperm injection and nuclear transfer have been applied and have produced advances in knowledge on embryo environment and in vitro conditions necessary for development. Embryo production may have a high impact in both domestic and wild camelids population. Studies addressed to improve in vitro embryo production and oocyte collection could be a potential key to develop IVF and embryo production as a routine procedure in camelids. Copyright © 2012 Elsevier B.V. All rights reserved.

  3. Neurogenesis in zebrafish - from embryo to adult.

    Science.gov (United States)

    Schmidt, Rebecca; Strähle, Uwe; Scholpp, Steffen

    2013-02-21

    Neurogenesis in the developing central nervous system consists of the induction and proliferation of neural progenitor cells and their subsequent differentiation into mature neurons. External as well as internal cues orchestrate neurogenesis in a precise temporal and spatial way. In the last 20 years, the zebrafish has proven to be an excellent model organism to study neurogenesis in the embryo. Recently, this vertebrate has also become a model for the investigation of adult neurogenesis and neural regeneration. Here, we summarize the contributions of zebrafish in neural development and adult neurogenesis.

  4. Obtention of somatic embryos of Parajubaea cocoides Burret from immature zygotic embryos

    Directory of Open Access Journals (Sweden)

    Verónica Sánchez

    2015-01-01

    Full Text Available Cumbé coconut palm (Parajubaea cocoides Burret is an ornamental species endemic of Ecuador. It is threatened by environmental and socioeconomic factors. Your sexual propagation by seed, is not effective. Tissue culture can become an alternative and within this, somatic embryogenesis. The objective of this research was to obtain somatic embryos in semi-solid and liquid media culture from immature zygotic embryos. The explants were collected from mature plants and fruits were placed to form calli in culture medium with different concentrations of 2,4-D and activated carbon. Callus with embryogenic structures were used to form embryos in semisolid medium with BAP and kinetin and in liquid culture medium with BAP. The results showed that in treatments without activated carbon or low concentrations of 2,4-D no callus were formed. With 60 mg l-1 2,4-D and 1 g l-1 activated charcoal, friable callus were obtained. It was possible to obtain somatic embryos in semisolid and liquid culture medium, with higher number in liquid. The results provide the basis for propagating this species by somatic embryogenesis. Key words: calli, ornamental, growth regulators, palm

  5. Excised Embryo Rambutan (Nephelium Lappaceum L.) Dan Kepekaannya Terhadap Pengeringan*[desiccation Sensitivity of Rambutan (Nephelium Lappaceum L.) Excised Embryo

    OpenAIRE

    Soetisna, Usep; Zebua, Lisye Iriana

    2005-01-01

    A study on desiccation sensitivity of rambutan (Nephelium lappaceum L.)excised embryo has been conducted.Excised embryos were desiccated into target moisture content of 30%, 25%, 20%, 15% and 10% respectively.Results shown that the critical level for moisture content was 20% with 60% viability and 7.431% per etmal growth rate and 929ms electric conduction Further study is needed as to investigate on how long the embryo will withstand subsequent storage treatments.

  6. Phytohemagglutinin facilitates the aggregation of blastomere pairs from Day 5 donor embryos with Day 4 host embryos for chimeric bovine embryo multiplication.

    Science.gov (United States)

    Simmet, Kilian; Reichenbach, Myriam; Reichenbach, Horst-Dieter; Wolf, Eckhard

    2015-12-01

    Multiplication of bovine embryos by the production of aggregation chimeras is based on the concept that few blastomeres of a donor embryo form the inner cell mass (ICM) and thus the embryo proper, whereas cells of a host embryo preferentially contribute to the trophectoderm (TE), the progenitor cells of the embryonic part of the placenta. We aggregated two fluorescent blastomeres from enhanced green fluorescent protein (eGFP) transgenic Day 5 morulae with two Day 4 embryos that did not complete their first cleavage until 27 hours after IVF and tested the effect of phytohemagglutinin-L (PHA) on chimeric embryo formation. The resulting blastocysts were characterized by differential staining of cell lineages using the TE-specific factor CDX2 and confocal laser scanning microscopy to facilitate the precise localization of eGFP-positive cells. The proportions of blastocyst development of sandwich aggregates with (n = 99) and without PHA (n = 46) were 85.9% and 54.3% (P multiplication of genetically valuable donor embryos. Copyright © 2015 Elsevier Inc. All rights reserved.

  7. Genetic Screening for EMS-Induced Maize Embryo-Specific Mutants Altered in Embryo Morphogenesis.

    Science.gov (United States)

    Brunelle, Dale C; Clark, Janice K; Sheridan, William F

    2017-11-06

    We have previously identified embryo-specific (emb) mutations that resulted in maize kernels containing abnormal embryos with normal-appearing endosperm among the progeny of active Robertson's Mutator stocks. Our rationale for the mutant screen described here is that it should be possible to produce ethyl methane sulfonate (EMS)-induced emb mutations at a frequency higher than that obtained by transposon mutagenesis and with greater ease. This proved to be the case when we screened for mutations that are embryo-specific among progeny of materials generated with EMS-treated pollen. The EMS-induced emb mutation frequency reported here is nearly three times the 4.5% we obtained with the transposable element stocks. The 45 mutants reported here were all tested for germination capacity and nearly all were lethal. The embryo phenotypes of 34 mutations were examined by dissection of the mature embryos. All were found to be retarded in development and morphologically abnormal. Half of the mutants in this group were blocked in the proembryo and transition stages. They likely include mutations in nuclear genes coding for plastid proteins. The other 17 are mainly blocked in the coleoptilar stage, or in later stages with a low frequency. This group likely includes mutations in genes regulating the completion of shoot apical meristem (SAM) development and accompanying morphogenetic events. Most of the complementation tests using 19 of the mutations in 35 unique combinations complimented each other, except for two pairs of mutations with similar phenotypes. Our results provide additional evidence for the presence of many emb loci in the maize genome. Copyright © 2017 Brunelle et al.

  8. Studies of In Vitro Embryo Culture of Guppy (Poecilia reticulata).

    Science.gov (United States)

    Liu, LiLi; Lee, Ki-Young

    2014-09-01

    Different with other fishes, the guppies (Poecilia reticulata) is ovoviviparity, which retain their fertilized eggs within the follicle throughout gestation. The synchronously growing diplotene oocytes store nutrients in droplets and yolk, before their maturation and fertilization. The lecithotrophic strategy of development entails the provisioning of embryos with resources from the maternal yolk deposit rather than from a placenta, it allows the extracorporeal culture of guppy embryo. Studies on their early development of live bearers like the guppy including lineage tracing and genetic manipulations, have been limited. Therefore, to optimize conditions of embryo in vitro culture, explanted embryos from pregnant females were incubated in embryo medium (L-15 medium, supplemented with 5, 10, 15, 20% fetal bovine serum, respectively). We investigated whether the contents of FBS in vitro culture medium impact the development of embryos, and whether they would hatch in vitro. Our study found that in 5% of FBS of the medium, although embryos developed significantly slower in vitro than in the ovary, it was impossible to exactly quantify the developmental delay in culture, due to the obvious spread in developmental stage within each batch of eggs, and embryos can only be maintained until the early-eyed. And although in culture with 20% FBS the embryos can sustain rapid development of early stage, but cannot be cultured for the entire period of their embryonic development and ultimately died. In the medium with 10% and 15% FBS, the embryos seems well developed, even some can continue to grow after follicle ruptures until it can be fed. We also observed that embryonic in these two culture conditions were significantly different in development speed, in 15% it is faster than 10%. But 10% FBS appears to be more optimizing condition than 15% one on development process of embryos and survival rate to larvae stage.

  9. Cryopreservation of coffee zygotic embryos: dehydration and osmotic rehydration

    Directory of Open Access Journals (Sweden)

    Maísa de Siqueira Pinto

    Full Text Available ABSTRACT Conservation of plant genetic resources is important to prevent genetic erosion. Seed banks are the most common method of ex situ conservation; however, coffee seeds can not be stored by conventional methods. Cryopreservation is a viable alternative for long-term conservation of species that produce intermediate or recalcitrant seeds, as coffee. The aim of this work was to cryopreserve Coffea arabica L. cv Catuaí Vermelho IAC 144 zygotic embryos, and analyse the effects of dehydration prior cryopreservation and osmotic rehydration after thawing, in embryos germination and seedlings formation after cryopreservation. Prior to cryopreservation, different dehydration times (0, 15, 30, 60 and 120 min were tested. Dehydrated embryos were cryopreserved in liquid nitrogen for 1 hour, and after thawing were rehydrated by osmotic solutions. Dehydrated and non-cryopreserved embryos were also analysed. The test with 2,3,5 triphenyl tetrazolium chloride (TTC was used to evaluate the embryos viability. Non-dehydrated embryos did not survive after freezing. Embryos that were dehydrated until 20% of the moisture content did not germinate when osmotic rehydration was not performed. In contrast, cryopreserved embryos with the same moisture content presented 98% germination when they were rehydrated slowly in osmotic solution. According to tetrazolium tests, embryos presented maximum viability (75% after dehydration for 60 minutes (23% moisture content. Therefore, coffee zygotic embryos (Coffea arabica L. cv. Catuaí Vermelho can be successfully cryopreserved using physical dehydration in silica gel for 60 minutes (23% moisture content, followed by osmotic rehydration after thawing. This method allowed a germination of 98% of cryopreserved zygotic embryos.

  10. Precocious germination and its regulation in embryos of triticale caryopses

    Directory of Open Access Journals (Sweden)

    Stanisław Weidner

    2014-01-01

    Full Text Available Triticale var. Lasko embryos, isolated from grain gathered at milk ripeness, the beginning of wax ripeness and at full ripeness, were allowed to germinate for 48 h on agar with glucose. The highest incorporation of tritiated adenosine into polyribosomal RNA during germination was found in the ribosome fractions from embryos of grain gathered at full ripeness, lower incorporation was in preparations from embryos of milk ripe grain and the lowest in preparations from embryos of wax ripe grain. Different tendencies were observed in respect to the synthesis of ribosomal proteins. The highest incorporation of 14C-amino acids into ribosomal proteins was found in preparations of ribosome fractions from embryos of milk ripe grain, lower in preparations of embryos from fully ripe grain, the lowest in preparations of embryos from wax ripe grain. ABA (10-4 M completely inhibited the external symptoms of germination of immature embryos, while its inhibition of the synthesis of polyribosomal RNA and ribosomal proteins was greater the more mature the embryos that were germinated. The greatest stimulation of precocious germination by exogenous BA and GA3 was demonstrated in the least mature embryos isolated from milk ripe grain. Under the influence of both stimulators, an increase of the proportion of polyribosomes in the total ribosome fraction occurred in this sample, as did a rise in the intensity of ribosomal protein synthesis. The incorporation of 3H-adenosine into polyribosomal RNA, however, was lower than in the control sample. The results obtained suggest that the regulation of precocious germination of triticale embryos by phyto-hormones is not directly related to transcription.

  11. Macroevolutionary developmental biology: Embryos, fossils, and phylogenies.

    Science.gov (United States)

    Organ, Chris L; Cooper, Lisa Noelle; Hieronymus, Tobin L

    2015-10-01

    The field of evolutionary developmental biology is broadly focused on identifying the genetic and developmental mechanisms underlying morphological diversity. Connecting the genotype with the phenotype means that evo-devo research often considers a wide range of evidence, from genetics and morphology to fossils. In this commentary, we provide an overview and framework for integrating fossil ontogenetic data with developmental data using phylogenetic comparative methods to test macroevolutionary hypotheses. We survey the vertebrate fossil record of preserved embryos and discuss how phylogenetic comparative methods can integrate data from developmental genetics and paleontology. Fossil embryos provide limited, yet critical, developmental data from deep time. They help constrain when developmental innovations first appeared during the history of life and also reveal the order in which related morphologies evolved. Phylogenetic comparative methods provide a powerful statistical approach that allows evo-devo researchers to infer the presence of nonpreserved developmental traits in fossil species and to detect discordant evolutionary patterns and processes across levels of biological organization. © 2015 Wiley Periodicals, Inc.

  12. Tracking individual nanodiamonds in Drosophila melanogaster embryos

    CERN Document Server

    Simpson, David A; Kowarsky, Mark; Zeeshan, Nida F; Barson, Michael S J; Hall, Liam; Yan, Yan; Kaufmann, Stefan; Johnson, Brett C; Ohshima, Takeshi; Caruso, Frank; Scholten, Robert; Saint, Robert B; Murray, Michael J; Hollenberg, Lloyd C L

    2013-01-01

    Tracking the dynamics of fluorescent nanoparticles during embryonic development allows insights into the physical state of the embryo and, potentially, molecular processes governing developmental mechanisms. In this work, we investigate the motion of individual fluorescent nanodiamonds micro-injected into Drosophila melanogaster embryos prior to cellularisation. Fluorescence correlation spectroscopy and wide-field imaging techniques are applied to individual fluorescent nanodiamonds in blastoderm cells during stage 5 of development to a depth of ~40 \\mu m. The majority of nanodiamonds in the blastoderm cells during cellularisation exhibit free diffusion with an average diffusion coefficient of (6 $\\pm$ 3) x 10$^{-3}$ \\mu m$^2$/s, (mean $\\pm$ SD). Driven motion in the blastoderm cells was also observed with an average velocity of 0.13 $\\pm$ 0.10 \\mu m/s (mean $\\pm$ SD) \\mu m/s and an average applied force of 0.07 $\\pm$ 0.05 pN (mean $\\pm$ SD). Nanodiamonds in the periplasm between the nuclei and yolk were also...

  13. The factors affecting the outcome of frozen–thawed embryo transfer cycle

    Directory of Open Access Journals (Sweden)

    Mahnaz Ashrafi

    2011-06-01

    Conclusion: Protocol type, gonadotrophin preparations, fresh-cycle outcome, endometrial thickness and the numbers of obtained oocytes, embryos, and high-quality thawed embryos transferred are the factors affecting pregnancy outcome of frozen–thawed embryo transfer.

  14. Final Report

    Energy Technology Data Exchange (ETDEWEB)

    Gurney, Kevin R. [Arizona Univ., Mesa, AZ (United States)

    2015-01-12

    This document constitutes the final report under DOE grant DE-FG-08ER64649. The organization of this document is as follows: first, I will review the original scope of the proposed research. Second, I will present the current draft of a paper nearing submission to Nature Climate Change on the initial results of this funded effort. Finally, I will present the last phase of the research under this grant which has supported a Ph.D. student. To that end, I will present the graduate student’s proposed research, a portion of which is completed and reflected in the paper nearing submission. This final work phase will be completed in the next 12 months. This final workphase will likely result in 1-2 additional publications and we consider the results (as exemplified by the current paper) high quality. The continuing results will acknowledge the funding provided by DOE grant DE-FG-08ER64649.

  15. Final Report

    Energy Technology Data Exchange (ETDEWEB)

    DeTar, Carleton [P.I.

    2012-12-10

    This document constitutes the Final Report for award DE-FC02-06ER41446 as required by the Office of Science. It summarizes accomplishments and provides copies of scientific publications with significant contribution from this award.

  16. Principles guiding embryo selection following genome-wide haplotyping of preimplantation embryos.

    Science.gov (United States)

    Dimitriadou, Eftychia; Melotte, Cindy; Debrock, Sophie; Esteki, Masoud Zamani; Dierickx, Kris; Voet, Thierry; Devriendt, Koen; de Ravel, Thomy; Legius, Eric; Peeraer, Karen; Meuleman, Christel; Vermeesch, Joris Robert

    2017-03-01

    How to select and prioritize embryos during PGD following genome-wide haplotyping? In addition to genetic disease-specific information, the embryo selected for transfer is based on ranking criteria including the existence of mitotic and/or meiotic aneuploidies, but not carriership of mutations causing recessive disorders. Embryo selection for monogenic diseases has been mainly performed using targeted disease-specific assays. Recently, these targeted approaches are being complemented by generic genome-wide genetic analysis methods such as karyomapping or haplarithmisis, which are based on genomic haplotype reconstruction of cell(s) biopsied from embryos. This provides not only information about the inheritance of Mendelian disease alleles but also about numerical and structural chromosome anomalies and haplotypes genome-wide. Reflections on how to use this information in the diagnostic laboratory are lacking. We present the results of the first 101 PGD cycles (373 embryos) using haplarithmisis, performed in the Centre for Human Genetics, UZ Leuven. The questions raised were addressed by a multidisciplinary team of clinical geneticist, fertility specialists and ethicists. Sixty-three couples enrolled in the genome-wide haplotyping-based PGD program. Families presented with either inherited genetic variants causing known disorders and/or chromosomal rearrangements that could lead to unbalanced translocations in the offspring. Embryos were selected based on the absence or presence of the disease allele, a trisomy or other chromosomal abnormality leading to known developmental disorders. In addition, morphologically normal Day 5 embryos were prioritized for transfer based on the presence of other chromosomal imbalances and/or carrier information. Some of the choices made and principles put forward are specific for cleavage-stage-based genetic testing. The proposed guidelines are subject to continuous update based on the accumulating knowledge from the implementation of

  17. The association between embryo quality and perinatal outcome of singletons born after single embryo transfers: a pilot study.

    Science.gov (United States)

    Oron, Galia; Son, Weon-Young; Buckett, William; Tulandi, Togas; Holzer, Hananel

    2014-07-01

    Does the quality of a single transferred embryo have an effect on the pregnancy outcome? After adjusting for confounding maternal variables, poor embryo quality was not associated with adverse obstetric or perinatal outcome in this small pilot study. Embryo quality is a major predictor of the success of in vitro fertilization treatment and studies have demonstrated a strong association between embryo morphology, implantation and clinical pregnancy rates. However, the association with obstetric and perinatal outcomes has not been evaluated. This single center, retrospective cohort study included 1541 fresh single embryo transfers (SETs) using non-donor oocytes in women ≤40 years between December 2008 and 2012. We compared the cycle outcome and singleton live births resulting from the transfer of a single fresh good quality (Grade 2) embryo with those resulting from the transfer of a single poor quality (fair, Grade 3 or poor, Grade 4) embryo in the cleavage or blastocyst stages. The cycle outcome parameters were biochemical pregnancy and clinical intrauterine pregnancy. The pregnancy outcomes were live birth, miscarriages and stillbirths after 20 weeks of gestation. Among the live births, perinatal outcome parameters included birthweight, small for gestational age, preterm delivery, pre-eclampsia, placental abruption and neonatal complications. Covariates were maternal age, body mass index, smoking status, parity and gender of the baby. There were 1193 good quality SETs and 348 poor quality embryo transfers. SETs performed during the study period resulted in 563 pregnancies and 440 singleton births. There was a higher clinical pregnancy rate (41.5%) and live birth rate (32.3%) in the good quality embryo transfer group compared with that in the poor quality transfer group (19.2 and 15.5%, respectively; P quality embryo. Multivariable logistic regression analyses for pregnancy complications revealed no increased risk of maternal or neonatal complications with the

  18. Successful pregnancies from vitrified embryos in the dromedary camel: Avoidance of a possible toxic effect of sucrose on embryos.

    Science.gov (United States)

    Herrid, M; Billah, M; Skidmore, J A

    2017-12-01

    Successful embryo cryopreservation facilitates the wider application of assisted reproduction technologies and also provides a useful method for gene banking of valuable genetics. Unfortunately attempts to establish an effective cryopreservation protocol for camelid embryos have been unsuccessful. In the current study, a modified vitrification protocol with three steps was investigated, whereby embryos were exposed to solutions containing increasing amounts of glycerol and ethylene glycol for fixed time periods. Embryos were then loaded into an Open Pull Straw (OPS) and plunged directly into liquid nitrogen for storage. Three experiments were designed to investigate the effect of 1) artificial shrinkage (AS) of embryos, 2) the addition of sucrose to the vitrification solutions, and 3) the replacement of sucrose by galactose in the warming solution, on the outcome of vitrification. The results showed that neither AS of hatched embryos prior to vitrification, nor the addition of sucrose into vitrification solutions improves the outcome of vitrification, while replacement of sucrose with galactose in warming solution increases the survival and developmental rates of vitrified embryos in culture. Transfer of vitrified embryos that were warmed in galactose resulted in a pregnancy rate of 42.8% per embryo or 46.1% per recipient. Collectively, these results suggest a possible species-specific toxic effect of sucrose on camel embryos, and that avoiding its use either in vitrification or warming solution is critical for establishing an effective protocol. This study may also be applicable to the vitrification of embryos of other camelid species including alpaca and llamas. Copyright © 2017 Elsevier B.V. All rights reserved.

  19. Embryo rescue of crosses between diploid and tetraploid grape ...

    African Journals Online (AJOL)

    ajl yemi

    2011-12-19

    Dec 19, 2011 ... tetraploid grapes can be a good way to obtain new triploid germplasm. However, there exists a severe mating obstacle in crosses between diploid and tetraploid grape. The embryo rescue technique may prevent the early stage abortion of triploid young embryo, so triploid plants can be produced (Pan et al., ...

  20. Sexing bovine pre-implantation embryos using the polymerase ...

    African Journals Online (AJOL)

    Yomi

    2012-03-06

    Mar 6, 2012 ... can also be applied to human embryos, using different primers, designed for human DNA. Key words: sexing, embryo, PCR, bovine. INTRODUCTION. In vitro fertilization represents nowadays a modern assisted reproductive technology that can be applied to couples with fertility problems that make natural ...

  1. The role of growth regulators, embryo age and genotypes on ...

    African Journals Online (AJOL)

    One of the most important problem of tomato breeders is lengthy seed to seed cycle in a breeding program. In vitro techiques provide a lot of advantages for breeders. The objective of this work was to determine the effect of growth regulators and immature embryo age on embryo germination and rapid generation ...

  2. Factors affecting conception rates in cattle following embryo transfer ...

    African Journals Online (AJOL)

    Embryo Transfer Technology (ETT) plays an important role in improving productivity of dairy cattle (Bos indicus). Embryo Transfer Technology allows top quality female livestock to improve a herd or flock in much the same way that artificial insemination has allowed greater use of superior sires. The technology hastens ...

  3. Fruit, seed and embryo development of different cassava (Manihot ...

    African Journals Online (AJOL)

    Fruit, seed and embryo developments of different cassava (Manihot esculenta Crantz) genotypes, as well as embryo rescue, were investigated. The fruits of three genotypes after uncontrolled open pollination presented the same progressive development with similar sizes at different stages. There are large differences in ...

  4. In vitro bulblet regeneration from immature embryos of Muscari ...

    African Journals Online (AJOL)

    A high frequency bulblet regeneration was achieved for endemic and endangered ornamental plant Muscari azureum using immature embryos. Immature embryos of M. azureum were cultured on callus induction medium consisting of N6 mineral salts and vitamins, 400 mg/L casein + 40 g/L sucrose + 2 g/l L-proline, 2 mg/L ...

  5. Plant regeneration from immature embryos of Kenyan maize inbred ...

    African Journals Online (AJOL)

    Field grown, self pollinated maize genotypes were planted in KARI (Kiboko and Kabete) research stations between January 2004 and May 2005. Immature maize embryos from twelve parental inbred lines and their respective single cross hybrids were evaluated for their ability form callus, somatic embryos and subsequent ...

  6. Mouse embryos cultured in amniotic fluid | Oettle | South African ...

    African Journals Online (AJOL)

    One thousand mouse embryos were collected over a period of 6 weeks·and randomly assigned to either amniotic fluid aspirated during routine amniocentesis from normal 16 weeks pregnant patients or Earle's medium. The embryos were cultured for 72 hours at 37°C in 5% carbon dioxide in air. Osmolarity, pH, partial ...

  7. Laser-assisted vitrification of large equine embryos.

    Science.gov (United States)

    Scherzer, J; Davis, C; Hurley, D J

    2011-12-01

    The major difficulty in providing the benefits of embryo cryopreservation for equine agriculture is the mismatch between the optimal embryo age for collection from the mare (7-8 days after ovulation was detected) and the optimal age for freezing under current methods (6.5 days after ovulation). To overcome this limitation, we tested a method to enhance penetration of cryopreservative across the capsule and trophoblast of day 7 and 8 embryos combined with rapid freezing by vitrification. Six small embryos (laser system used to create a small opening in the embryonic capsule and trophectoderm. All embryos were vitrified using a CryoLeaf freezing support. After recovery from freezing and embryo transfer, three of four small untreated embryos (300 μm in diameter, 44%) resulted in a vesicle as detected by ultrasonography approximately one week after transfer. However, only one recipient mare was still pregnant on day 23, and she delivered a live foal. Further investigation is required to determine why most of the embryos in this experiment were lost between day 13 and day 23 of gestation. © 2011 Blackwell Verlag GmbH.

  8. Induction of microspore-derived embryos by anther culture in ...

    African Journals Online (AJOL)

    Five pepper genotypes (A71, A269, A313, A109 and A74) and four different culture media were tested in this study carried out at the University of Çukurova, Turkey. The anthers were cultured at different periods in order to optimize the frequency of embryo production. Moreover, the embryos that were unable to complete ...

  9. Early embryo development in Fucus distichus is auxin sensitive

    Science.gov (United States)

    Basu, Swati; Sun, Haiguo; Brian, Leigh; Quatrano, Ralph L.; Muday, Gloria K.

    2002-01-01

    Auxin and polar auxin transport have been implicated in controlling embryo development in land plants. The goal of these studies was to determine if auxin and auxin transport are also important during the earliest stages of development in embryos of the brown alga Fucus distichus. Indole-3-acetic acid (IAA) was identified in F. distichus embryos and mature tissues by gas chromatography-mass spectroscopy. F. distichus embryos accumulate [(3)H]IAA and an inhibitor of IAA efflux, naphthylphthalamic acid (NPA), elevates IAA accumulation, suggesting the presence of an auxin efflux protein complex similar to that found in land plants. F. distichus embryos normally develop with a single unbranched rhizoid, but growth on IAA leads to formation of multiple rhizoids and growth on NPA leads to formation of embryos with branched rhizoids, at concentrations that are active in auxin accumulation assays. The effects of IAA and NPA are complete before 6 h after fertilization (AF), which is before rhizoid germination and cell division. The maximal effects of IAA and NPA are between 3.5 and 5 h AF and 4 and 5.5 h AF, respectively. Although, the location of the planes of cell division was significantly altered in NPA- and IAA-treated embryos, these abnormal divisions occurred after abnormal rhizoid initiation and branching was observed. The results of this study suggest that auxin acts in the formation of apical basal patterns in F. distichus embryo development.

  10. Epigenetics and chromosome segregation in human pre-implantation embryos

    NARCIS (Netherlands)

    C. van de Werken (Christine)

    2015-01-01

    markdownabstractAbstract Chapter 1 Currently, the average pregnancy rate per embryo transfer after in vitro fertilization (IVF) is around 32%. In order to achieve better results in the future, we need to gain knowledge on all aspects of the treatment, including pre-implantation embryo

  11. The role of auxin signaling in early embryo pattern formation

    NARCIS (Netherlands)

    Smit, Margot E.; Weijers, Dolf

    2015-01-01

    Pattern formation of the early Arabidopsis embryo generates precursors to all major cell types, and is profoundly controlled by the signaling molecule auxin. Here we discuss recent milestones in our understanding of auxin-dependent embryo patterning. Auxin biosynthesis, transport and response

  12. Storage oil breakdown during embryo development of Brassica napus (L.).

    Science.gov (United States)

    Chia, Tansy Y P; Pike, Marilyn J; Rawsthorne, Stephen

    2005-05-01

    In this study it is shown that at least 10% of the major storage product of developing embryos of Brassica napus (L.), triacylglycerol, is lost during the desiccation phase of seed development. The metabolism of this lipid was studied by measurements of the fate of label from [1-(14)C]decanoate supplied to isolated embryos, and by measurements of the activities of enzymes of fatty acid catabolism. Measurements on desiccating embryos have been compared with those made on embryos during lipid accumulation and on germinating seedlings. Enzymes of beta-oxidation and the glyoxylate cycle, and phosphoenolpyruvate carboxykinase were present in embryos during oil accumulation, and increased in activity and abundance as the seeds matured and became desiccated. Although the activities were less than those measured during germination, they were at least comparable to the in vivo rate of fatty acid synthesis in the embryo during development. The pattern of labelling, following metabolism of decanoate by isolated embryos, indicated a much greater involvement of the glyoxylate cycle during desiccation than earlier in oil accumulation, and showed that much of the (14)C-label from decanoate was released as CO(2) at both stages. Sucrose was not a product of decanoate metabolism during embryo development, and therefore lipid degradation was not associated with net gluconeogenic activity. These observations are discussed in the context of seed development, oil yield, and the synthesis of novel fatty acids in plants.

  13. Lack of carbon air filtration impacts early embryo development.

    Science.gov (United States)

    Munch, Erika M; Sparks, Amy E; Duran, Hakan E; Van Voorhis, Bradley J

    2015-07-01

    To assess human fertilization and preimplantation embryo development in the presence and in the absence of carbon filtration This is a retrospective cohort analysis of fresh, controlled ovarian hyperstimulation cycles as well as previously cryopreserved pronuclear stage embryo transfer cycles in a single IVF center. Embryo development and cycle-based outcomes were compared among three groups: 1) when carbon filtration was present, 2) when carbon filtration was absent, and 3) when carbon filtration had been restored. A total of 524 fresh cycles and 156 cryopreserved embryo cycles were analyzed. Fertilization, cleavage, and blastocyst conversion rates for fresh cycles all declined during the period of absent carbon filtration and recovered after the restoration of carbon filtration. Cryopreserved embryos that were thawed and cultured during the period of absent filtration did not have changes in cleavage or blastocyst conversion rates compared to periods where carbon filtration was present. Clinical pregnancy and live birth rates were unchanged among the three time periods. The absence of carbon filtration in an IVF laboratory air handler is associated with poor fertilization and early embryo development for fresh cycles. Because development of previously frozen pronuclear stage embryos was unaffected, the lack of carbon filtration may preferentially affect embryos in the peri-fertilization period. Carbon filtration is an integral part to a successful human in-vitro fertilization laboratory.

  14. Effects of LeY glycan expression on embryo implantation.

    Science.gov (United States)

    Gu, J; Sui, L-L; Cui, D; Ma, Y-N; Zhu, C-Y; Kong, Y

    2016-08-01

    To investigate the correlation between LeY glycan expression and embryo implantation. Uterine epithelial cells before implantation were transfected with FUT1siRNA to inhibit FUT1 (the gene encoding the key enzyme of LeY synthesis) expression and treated with 10 ng/ml leukemia inhibitory factor (LIF). Murine embryo implantation model in vitro was prepared by late blastocysts with identical morphology and treated uterine epithelial cells co-culture. Using RT-PCR, dot blot and observation of embryo attachment to analyze FUT1 gene expression and LeY synthesis of uterine epithelial cells and studied further the correlation of LeY expression level and embryo implantation. FUT1 gene expression and LeY synthesis declined after cells were transfected with FUT1siRNA, and LIF promoted FUT1 expression and LeY synthesis. After expression of FUT1 gene was inhibited, attachment rate of embryos lowered, but LIF up-regulated FUT1 expression and increased the attachment rate of embryos. These results indicated regulating FUT1 expression affected LeY synthesis, and then LeY regulated the recognition and attachment of uterus-embryo and participates in embryo implantation further.

  15. The development of ovary in quail's embryo | Rong | African Journal ...

    African Journals Online (AJOL)

    The results showed that when embryo was hatched for 4 days, lots of primordial germ cells (PGCs) clustered in the region where gonad would be formed. On the 5th day of hatching, the gonad of the embryo began to be formed and exhibited the feature of ovary or testis. On the 7th hatching day, the right ovary began to ...

  16. Development of the ventral body wall in the human embryo

    NARCIS (Netherlands)

    Mekonen, Hayelom K.; Hikspoors, Jill P. J. M.; Mommen, Greet; Köhler, S. Eleonore; Lamers, Wouter H.

    2015-01-01

    Migratory failure of somitic cells is the commonest explanation for ventral body wall defects. However, the embryo increases ~ 25-fold in volume in the period that the ventral body wall forms, so that differential growth may, instead, account for the observed changes in topography. Human embryos

  17. Closure of the vertebral canal in human embryos and fetuses

    NARCIS (Netherlands)

    Mekonen, Hayelom K.; Hikspoors, Jill P. J. M.; Mommen, Greet; Kruepunga, Nutmethee; Köhler, S. Eleonore; Lamers, Wouter H.

    2017-01-01

    The vertebral column is the paradigm of the metameric architecture of the vertebrate body. Because the number of somites is a convenient parameter to stage early human embryos, we explored whether the closure of the vertebral canal could be used similarly for staging embryos between 7 and 10weeks of

  18. Optimal developmental stage for vitrification of parthenogenetically activated porcine embryos

    DEFF Research Database (Denmark)

    Li, Rong; Li, Juan; Liu, Ying

    2012-01-01

    -lapse monitored for 24 h or analyzed by diffential staining. After warming, the embryos had to be cultured for at least 8 h before their survival rates were stabilized. Both the survival rate and 8 h and the hatching rate at 24 h of Day 4 embryos were significantly higher than those vitrified on Day5 or Day 6 (P...

  19. Chromosomal mosaicism in human preimplantation embryos : a systematic review

    NARCIS (Netherlands)

    van Echten-Arends, Jannie; Mastenbroek, Sebastiaan; Sikkema-Raddatz, Birgit; Korevaar, Johanna C.; Heineman, Maas Jan; van der Veen, Fulco; Repping, Sjoerd

    2011-01-01

    BACKGROUND: Although chromosomal mosaicism in human preimplantation embryos has been described for almost two decades, its exact prevalence is still unknown. The prevalence of mosaicism is important in the context of preimplantation genetic screening in which the chromosomal status of an embryo is

  20. Superovulation and embryo recovery in Boer goats treated with ...

    African Journals Online (AJOL)

    Lehloenya

    semen were performed 36 h and 48 h following CIDR removal and the embryos surgically flushed six days after the second AI. The oestrous response, onset- and ..... Increased embryo development and metabolism following short term storage of bovine IVP blastocysts at 25 ºC in EmcareTM compared to ovum culture.