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Sample records for bud dormancy entrance

  1. Identification of genes associated with growth cessation and bud dormancy entrance using a dormancy-incapable tree mutant

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    Reighard Gregory L

    2010-02-01

    Full Text Available Abstract Background In many tree species the perception of short days (SD can trigger growth cessation, dormancy entrance, and the establishment of a chilling requirement for bud break. The molecular mechanisms connecting photoperiod perception, growth cessation and dormancy entrance in perennials are not clearly understood. The peach [Prunus persica (L. Batsch] evergrowing (evg mutant fails to cease growth and therefore cannot enter dormancy under SD. We used the evg mutant to filter gene expression associated with growth cessation after exposure to SD. Wild-type and evg plants were grown under controlled conditions of long days (16 h/8 h followed by transfer to SD (8 h/16 h for eight weeks. Apical tissues were sampled at zero, one, two, four, and eight weeks of SD and suppression subtractive hybridization was performed between genotypes at the same time points. Results We identified 23 up-regulated genes in the wild-type with respect to the mutant during SD exposure. We used quantitative real-time PCR to verify the expression of the differentially expressed genes in wild-type tissues following the transition to SD treatment. Three general expression patterns were evident: one group of genes decreased at the time of growth cessation (after 2 weeks in SD, another that increased immediately after the SD exposure and then remained steady, and another that increased throughout SD exposure. Conclusions The use of the dormancy-incapable mutant evg has allowed us to reduce the number of genes typically detected by differential display techniques for SD experiments. These genes are candidates for involvement in the signalling pathway leading from photoperiod perception to growth cessation and dormancy entrance and will be the target of future investigations.

  2. Bud dormancy in apple trees after thermal fluctuations

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    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.

  3. Temperature Characteristics of Dormancy Development of Terminal and Lateral Buds in Paulownia

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    LIUZhen; LIGuangtao; WANGYanmei; JIANGXiaoping

    2004-01-01

    In order to probe the death reason of terminal buds and carry out trunk extension by using lateral buds, the temperature characteristics of dormancy development of terminal and lateral buds in Paulownia tomentosa xp. fortunei 33 were investigated by raising cutting branches on different date at 25℃ and 15℃. The results were as follows:①The death reason of terminal buds and the first pair of lateral buds was itselfe cological adapting strategy, not the injury of early frost and freezing; ② The lateral buds 2, 3 and 4 had obtained the feature of winter dormancy, and could survive from cold winter, and widen its possible temperature range of sprouting to lower temperature by experiencing winter chilling; ③The lateral buds 2, 3 and 4 could sprout at the same time in spring, but it was difficult to sprout for other lateral buds; ④ The sprouting of upper lateral buds could restrict the sprouting of lower lateral buds at 25℃, but not at 15℃.

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

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    Castède, Sophie; Campoy, José Antonio; Le Dantec, Loïck; Quero-García, José; Barreneche, Teresa; Wenden, Bénédicte; Dirlewanger, Elisabeth

    2015-01-01

    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.

  5. 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.

  6. Symplastic connection is required for bud outgrowth following dormancy in potato (Solanum tuberosum L.) tubers.

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    Viola, Roberto; Pelloux, Jérôme; van der Ploeg, Anke; Gillespie, Trudi; Marquis, Nicola; Roberts, Alison G; Hancock, Robert D

    2007-08-01

    To gain greater insight into the mechanism of dormancy release in the potato tuber, an investigation into physiological and biochemical changes in tuber and bud tissues during the transition from bud dormancy (immediately after harvest) to active bud growth was undertaken. Within the tuber, a rapid shift from storage metabolism (starch synthesis) to reserve mobilization within days of detachment from the mother plant suggested transition from sink to source. Over the same period, a shift in the pattern of [U-(14)C]sucrose uptake by tuber discs from diffuse to punctate accumulation was consistent with a transition from phloem unloading to phloem loading within the tuber parenchyma. There were no gross differences in metabolic capacity between resting and actively growing tuber buds as determined by [U-(14)C]glucose labelling. However, marked differences in metabolite pools were observed with large increases in starch and sucrose, and the accumulation of several organic acids in growing buds. Carboxyfluorescein labelling of tubers clearly demonstrated strong symplastic connection in actively growing buds and symplastic isolation in resting buds. It is proposed that potato tubers rapidly undergo metabolic transitions consistent with bud outgrowth; however, growth is initially prevented by substrate limitation mediated via symplastic isolation.

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

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    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.

  8. Identification of differentially expressed genes associated with bud dormancy release in tree peony (Paeonia suffruticosa) by suppression subtractive hybridization

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    HUANG Xin; ZHENG Guo-sheng; DAI Si-lan; GAI Shu-peng

    2008-01-01

    A subtractive cDNA library was developed to study genes associated with bud dormancy release in tree peonies. In order to identify genes that are highly expressed in buds released from dormancy, 588 clones were examined by differential screening. Of these, 185 clones were selected to be sequenced. A total of 37 unique sequences were obtained of which only 31 sequences have matches in the NCBI database or the Arabidopsis thaliana protein database. Semi-quantitative RT-PCR was used to confirm further the expression profiles for 12 transcripts identified within the subtraetive cDNA library. Gene ontology analyses indicated that many of the different genes identified have unknown or hypothetical functions while it is speculated that other genes play different molecular roles. In our study, genes involved in bud dormancy release were growth-related or stress-responsive, while low-temperature-induced ribosomal proteins may also play a role in bud dormancy release. Our results provide interesting information for further understanding of the molecular mechanism of bud dormancy release in tree peonies.

  9. 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.

  10. Differentiated dynamics of bud dormancy and growth in temperate fruit trees relating to bud phenology adaptation, the case of apple and almond trees

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    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.

  11. Differentiated dynamics of bud dormancy and growth in temperate fruit trees relating to bud phenology adaptation, the case of apple and almond trees

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    El Yaacoubi, Adnane; Malagi, Gustavo; Oukabli, Ahmed; Citadin, Idemir; Hafidi, Majida; Bonhomme, Marc; Legave, Jean-Michel

    2016-04-01

    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.

  12. The involvement of mitochondrial phosphate transporter in accelerating bud dormancy release during chilling treatment of tree peony (Paeonia suffruticosa).

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    Huang, Xin; Zhu, Wei; Dai, Silan; Gai, Shupeng; Zheng, Guosheng; Zheng, Chengchao

    2008-09-01

    A cDNA clone was isolated from tree peony (Paeonia suffruticosa) subtractive cDNA library of burst buds and characterized with regard to its sequence, expression in response to chilling treatment during the release of bud dormancy, and its function in transgenic Arabidopsis thaliana. The clone, designated as PsMPT, contains 1,615 nucleotides with an open reading frame of 1,119 nucleotides, and the deduced amino acid sequence shows high homology with mitochondrial phosphate transporters (MPTs) from various organisms. The mRNA accumulation of PsMPT in tree peony was strongly induced by chilling treatment during the release of bud dormancy. When the treated plants were transferred to normal growth conditions, the level of PsMPT transcripts induced by sufficient chilling could be maintained high, whereas that induced by insufficient chilling decreased sharply. The transgenic Arabidopsis plants that overexpress PsMPT showed rapid growth and earlier flowering than wild-type plants. ATP contents in the transgenic plants were much higher than that in wild-type plants through various developmental stages. Together, these results suggest that the product of PsMPT is a MPT and might play an important role during the release of bud dormancy in tree peony.

  13. Changes in aquaporin gene expression and magnetic resonance imaging of water status in peach tree flower buds during dormancy.

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    Yooyongwech, Suravoot; Horigane, Akemi K; Yoshida, Mitsuru; Yamaguchi, Masami; Sekozawa, Yoshihiro; Sugaya, Sumiko; Gemma, Hiroshi

    2008-11-01

    The movement of cellular water accompanies changes in growth within dormant buds. To further understand this process, accumulation of tonoplast deltaTIP1 and plasma membrane PIP2 aquaporin transcripts was measured by quantitative reverse transcriptase-polymerase chain reaction and the water dynamics in dormant peach (Prunus persica L.) flower buds was studied by magnetic resonance imaging. Proton density (PD), spin-spin relaxation time (T(2)) and apparent diffusion coefficient (ADC) were used to observe water dynamics during dormancy. The expression of deltaTIP1 and PIP2 aquaporins, PD and T(2) in the upper part of the bud including primordia, in the basal part of the bud and the bud trace increased earlier in the low-chill cultivar 'Coral' than in the high-chill cultivar 'Kansuke Hakuto,' reflecting the difference in timing for the end of endodormancy in the two cultivars. deltaTIP1 mRNA accumulated mainly in the basal part of the bud, whereas PIP2 mRNA was detected mainly in the upper part. These findings may reflect the activation of inter- and intracell communication through membrane transport properties of aquaporins resulting in a gradual increase in water content to that required for bud activity at the end of endodormancy. An apparent decrease in the expression of deltaTIP1 and PIP2 mRNAs was, however, observed in late winter in some portions of the buds of both cultivars just before sprouting.

  14. Transcriptomic analysis of the underground renewal buds during dormancy transition and release in 'Hangbaishao' peony (Paeonia lactiflora.

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    Jiaping Zhang

    Full Text Available Paeonia lactiflora is one of the most famous species of herbaceous peonies with gorgeous flowers. Bud dormancy is a crucial developmental process that allows P. lactiflora to survive unfavorable environmental conditions. However, little information is available on the molecular mechanism of the bud dormancy in P. lactiflora. We performed de novo transcriptome sequencing using the Illumina RNA sequencing platform for the underground renewal buds of P. lactiflora 'Hangbaishao' to study the molecular mechanism underlying its bud dormancy transition (the period from endodormancy to ecodormancy and release (the period from ecodormancy to bud elongation and sprouting. Approximately 300 million high-quality clean reads were generated and assembled into 207,827 (mean length = 828 bp and 51,481 (mean length = 1250 bp unigenes using two assembly methods named "Trinity" and "Trinity+PRICE", respectively. Based on the data obtained by the latter method, 32,316 unigenes were annotated by BLAST against various databases. Approximately 1,251 putative transcription factors were obtained, of which the largest number of unique transcripts belonged to the basic helix-loop-helix protein (bHLH transcription factor family, and five of the top ten highly expressed transcripts were annotated as dehydrin (DHN. A total of 17,705 simple sequence repeat (SSR motifs distributed in 13,797 sequences were obtained. The budbreak morphology, levels of indole-3-acetic acid (IAA and abscisic acid (ABA, and activities of guaiacol peroxidase (POD and catalase (CAT were observed. The expression of 20 interested unigenes, which annotated as DHN, heat shock protein (HSP, histone, late elongated hypocotyl (LHY, and phytochrome (PHY, and so on, were also analyzed. These studies were based on morphological, physiological, biochemical, and molecular levels and provide comprehensive insight into the mechanism of dormancy transition and release in P. lactiflora. Transcriptome dataset can be

  15. Dormancy of 'Imperial Gala' apple and 'Hosui' pear tree buds in a region of low chill occurrence

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    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.

  16. An electron microscopic-cytochemical localization of plasma membrane Ca2+-ATPase activity in poplar apical bud cells during the induction of dormancy by short-day photoperiods

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    Plasma membrane (PM) Ca2+-ATPasc activity in poplar apical bud meristematic cells during short-day (SD)-induced dormancy development was examined by a cerium precipitation EM-cytochemical method. Ca2+-ATPase activity, indicated by the status of cerium phosphate precipitated grains, was localized mainly on the interior face (cytoplasmic side) of the PM when plants were grown under long days and reached a deep dormancy. A few reaction products were also observed on the nuclear envelope. When plant buds were developing dormancy after 28 to 42 d of SD exposure, almost no reaction products were present on the interior face of the PM. In contrast, a large number of cerium phosphate precipitated grains were distributed on the exterior face of the PM. After 70 d of SD exposure, when buds had developed a deep dormancy, the reaction products of Ca2+-ATPase activity again appeared on the interior face of the PM. The results seemed suggesting that two kinds of Ca2+-ATPases may be present on the PM during the SD-induced dormancy in poplar.One is the Ca2+-pumping ATPase, which is located on the interior face of the PM, for maintaining and restoring the Ca2+homeostasis. The other might be an ecto-Ca2+-ATPase, which is located on the exterior face of the PM, for the exocytosis of cell wall materials as suggested by the fact of the cell wall thickening during the dormancy development in poplar.

  17. ptr-MIR169 is a posttranscriptional repressor of PtrHAP2 during vegetative bud dormancy period of aspen (Populus tremuloides) trees

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    Potkar, Rewati; Recla, Jill [School of Forest Resources and Environmental Science, Michigan Technological University, 1400 Townsend Drive, Houghton, MI 49931 (United States); Busov, Victor, E-mail: vbusov@mtu.edu [School of Forest Resources and Environmental Science, Michigan Technological University, 1400 Townsend Drive, Houghton, MI 49931 (United States)

    2013-02-15

    Highlights: ► We show a novel microRNA-mediated mechanism for control of bud dormancy in trees. ► ptr-MIR169a and PtrHAP2–5 gene showed inverse expression during dormancy period. ► The PtrHAP2–5 decline in abundance correlated with high ptr-MIR169a levels. ► PtrHAP2–5 cleavage occurred at the miR169 site during PtrHAP2–5 transcript decline. ► Our results show that miR169 attenuates PtrHAP2–5 transcript during dormancy. -- Abstract: Dormancy is a mechanism evolved in woody perennial plants to survive the winter freezing and dehydration stress via temporary suspension of growth. We have identified two aspen microRNAs (ptr-MIR169a and ptr-MIR169h) which were highly and specifically expressed in dormant floral and vegetative buds. ptr-MIR169a and its target gene PtrHAP2–5 showed inverse expression patterns during the dormancy period. ptr-MIR169a transcript steadily increased through the first half of the dormancy period and gradually declined with the approach of active growing season. PtrHAP2–5 abundance was higher in the beginning of the dormancy period but rapidly declined thereafter. The decline of PtrHAP2–5 correlated with the high levels of ptr-MIR169a accumulation, suggesting miR169-mediated attenuation of the target PtrHAP2–5 transcript. We experimentally verified the cleavage of PtrHAP2–5 at the predicted miR169a site at the time when PtrHAP2–5 transcript decline was observed. HAP2 is a subunit of a nuclear transcription factor Y (NF-Y) complex consisting of two other units, HAP3 and HAP5. Using digital expression profiling we show that poplar HAP2 and HAP5 are preferentially detected in dormant tissues. Our study shows that microRNAs play a significant and as of yet unknown and unstudied role in regulating the timing of bud dormancy in trees.

  18. Respiratory Metabolism Changes During Dormancy Induction of Grape Buds%葡萄冬芽自然休眠诱导期间的呼吸代谢变化

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    王海波; 王孝娣; 史祥宾; 王宝亮; 郑晓翠; 刘凤之

    2015-01-01

    [Objective]The changes of respiratory rate and respiratory pathway during the dormancy induction period, and the relationship between respiration and dormancy induction of grape bud were studied for the purpose of laying a theoretical foundation for the control technology of dormancy such as no-dormancy culture and promote early autumn cultivation, and solve the problem of the annual supply of fresh grapes.[Method]The experiment was undertaken in typeⅡlow carbon high energy saving greenhouse in trial demonstration garden area. Three-year-old high chilling requirement grape V. vinifera-V. labrusca cv. ‘Summer Black’ and low chilling requirement grape V. vinifera cv.‘Jingmi’ were used as test material and‘Beta’ as rootstock. Respiration inhibitors and oxygen electrode were used for determination of the respiratory rate and respiratory pathway changes in grape buds, combined with single bud cuttings sand culture method to define the natural dormancy induction process, and to investigate the changes of respiratory metabolism during dormancy in grape buds. [Result] The starting and ending time of dormancy induction of low chilling requirement grape cultivar was later and depth of dormancy was shallower than high chilling requirement grape V. vinifera-V. labrusca cv. ‘Summer Black’. Change tendency of total respiratory rate of different chilling requirement grape cultivars had the similar single peak curves, the maximum total respiratory rate appeared at the end of dormancy induction. The total respiratory rate and the increase amplitude of low chilling requirement grape bud was significantly lower than high chilling requirement grape bud at the end of the dormancy induction. During the dormancy induction period, the activity of different respiratory pathways at the oxidation substrate level and the electron transport level changed obviously, and the change trend was basically identical which closely related with its natural dormancy process. The

  19. An electron microscopic—cytochemical localization of plasma membrane Ca2+—ATPase activity in poplar apical bud cells during the induction of dormancy by short—day photoperiods

    Institute of Scientific and Technical Information of China (English)

    JIANLINGCHENG; JIHONGLI; 等

    2000-01-01

    Plasma membrane(PM) Ca2+-ATPase activity in poplar apical bud meristematic cells during short-day(SD)-induced dormancy development was examined by a cerium precipitation EM-cytochemical method.Ca2+-ATPase activity,indicated by the status of cerium phosphate precipitated grains,was localized mainly on the interior face(cytoplasmic side) of the PM when plants were grown under long days and reached a deep dormancy.A few reaction products were also observed on the nuclear envelope.When plant buds were developing dormancy after 28 to 42 d of SD exposure,almost no reaction products were present on the interior face of the PM.In contrast,a large number of cerium phosphate precipitated grains were distributed on the exterior face of the PM.After 70 d of SD exposure,when buds had developed a deep dormancy,the reaction products of Ca2+-ATPase activity again appeared on the interior face of the PM.The results seemed suggesting that two kinds of Ca2+-ATP ases may be present on the PM during the SD-induced dormancy in poplar.One is the Ca2+-pumping ATPase,which is located on the interior face of the PM,for maintaining and restoring the Ca2+ homeostasis.The other might be and ecto-Ca2+-ATPase,which is located on the exterior face of the PM,for the exocytosis of cell wall materials as suggested by the fact of the cell wall thickening during the dormancy development in poplar.

  20. 多年生植物的芽休眠及调控机理研究进展%Progress in Research on Bud Dormancy and Its Regulation Mechanisms in Perennial Plants

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    王新超; 马春雷; 杨亚军

    2011-01-01

    芽休眠是一种有益的生物学特性,能够使多年生植物避开不利的环境条件,使种群在不利环境条件下得以生存.综述了多年生植物芽休眠的机制及其调控的研究进展.芽休眠是一个受多个因素和多种基因综合调控的复杂生命现象,其形成和解除受到光照、温度、水分等外界环境因素的影响和调控.在这个过程中,植物体内的激素、糖类、多胺和Ca2+等信号分子以及抗氧化酶类和能量代谢酶类等发生一系列的变化与之相适应.这些变化是在相应的基因表达调控下实现的,这些基因涉及到光、温响应基因,水分响应基因,能量代谢基因,胁迫响应基因,激素相关基因,以及MADS-box转录因子等,它们构成一个复杂的凋控网络,共同控制着芽休眠的形成与解除.结合研究课题提出今后芽休眠机制的研究方向以及在农业上的应用前景.%Bud dormancy can help perennial plants in avoiding or resisting environmental stresses. With this adaptation stratedgy, the species survive and the population persists through the harsh seasons. Recent research on bud dormancy and its regulation mechanism was summarized and reviewed. It was concluded that bud dormancy as a complex biological phenomenon, was controlled by many factors and genes. The changes of environment factors such as light, temperature and water would affect and regulate the formation and release of bud dormancy. During this procedure, the inside physiological changes happened, including changes of signal substances, e. G. Hormone, carbohydrate, polyamine, Ca2+, and some antioxidase and energy metabolism-related enzymes. These changes were regulated by the corresponding genes, such as light- and temperature-corresponding genes, water corresponding genes, energy metabolism-related genes, stress-related genes, hormone-related genes, and MADS-box transcription factors, which constituted complex gene regulatory network and regulate the

  1. 光周期对油桃芽休眠诱导及呼吸代谢的影响%Effects of Photoperiod on Dormancy Induction and Respiration of Nectarine Buds

    Institute of Scientific and Technical Information of China (English)

    谭钺; 李玲; 李冬梅; 陈修德; 李瑾; 高东升

    2012-01-01

    The effect of photoperiod on the bud respiration based on substrate level during dormancy induction were studied with 'Shuguang' nectarine (Prunus persica var. nectariana cv. Shuguang) using oxygen-electrode system and respiratory inhibitors. The results showed that the total respiration of both leaf and blossom buds presented single peak curves during dormancy induction. On the substrate level, the tricarboxylic acid cycle (TCA) slightly decreased but still kept at a high level while the pentose phosphate pathway (PPP) increased during the whole period. Short-day radiation brought the buds into dormancy earlier and accelerated its deepening while long-day radiation had opposing effects. Relevant respiration was also advanced by short-day radiation treatment. Long-day radiation delayed the dormancy and had opposite influences on respiration. Fig 4, Tab 1, Ref24%以‘曙光’(Prunus persica var.nectariana cv.Shuguang)油桃为试材,研究光周期对油桃芽休眠诱导进程以及对芽内底物水平的呼吸代谢运行的影响.结果表明:短日照使油桃芽提前进入休眠诱导,并促进休眠迅速加深,而长日照使休眠延迟.整个休眠诱导期内,叶芽和花芽的总呼吸速率先升高后降低.在底物水平上,随着休眠诱导的进行,三羧酸循环(TCA)略有下降,但仍维持高位运行,磷酸戊糖途径(PPP)在总呼吸中比例持续上升.短日照诱导相关的呼吸代谢变化提前出现,而长日照对相关呼吸代谢的变化具有推迟作用.

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

    Directory of Open Access Journals (Sweden)

    Anne Y Fennell

    2015-11-01

    Full Text Available 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 (2h 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 genes associated with C3HC4-TYPE RING FINGER, NAC

  3. 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

  4. Effect of hydrogen cyanamide (HC) on release of floral bud dormancy, endogenous hormone and carbohydrate in Pyrus pyrifolia cv. Cuiguan%氰胺对‘翠冠’梨花芽休眠解除及内源激素和碳水化合物含量的影响

    Institute of Scientific and Technical Information of China (English)

    刘冬峰; 陈露露; 李国鹏; 王涛; 滕元文

    2013-01-01

    Bud dormancy is an adaptive developmental process for perennial deciduous fruit trees to survive under the adverse environmental conditions,which is released when both the chilling requirement and growth temperature are achieved.Prolonged dormancy is considered to be the major obstacle to economic production of temperate fruits in warm winter regions.In Southern China,due to warm winter temperature,dormancy release becomes a major factor for production of Pyrus pyrifolia cv.Cuiguan.The irregular blossoming and delayed flowering behavior present in this crop may cause negative influence on pear industry of this region.In view of limiting factor in particular regions,the need for artificial means to compensate for lack of natural chilling for maintaining economic production of pear crop.Chemicals likewise hydrogen cyanamide (HC) and thiourea is widely used to overcome the bud release problem of insufficient chilling for deciduous fruits.P.pyrifolia is a good early maturing cultivar and commercially grown in the region of Southern China.Now,Hydrogen cyanamide (HC) was used as a dormancy breaking agent for P.pyrifolia.Different concentration of hydrogen cyanamide (HC) was used to release floral buds from dormancy and duration of dormancy releasing periods of buds,to analyze the variation in endogenous hormones and carbohydrates. Survey was made during the phenological periods including floral bud breaking,flowering and fruit maturing and investigation were made by enzyme-linked immunosorbent assay (ELISA) for the occurrence of changes in endogenous hormone contents including gibberellin (GA3),abscisic acid (ABA) and zeatin riboside (ZR) and the data was recorded for carbohydrate conversion between starch and soluble sugar in floral bud. Data regarding phenological phase were analysed statistically.Results presented indicated that higher concentration of hydrogen cyanamide treatment (2 %) was significantly proved better for early bud break and also in florescence period

  5. Variações do conteúdo de glucose, frutose e sorbitol em gemas e ramos de macieira durante a dormência Variations of glucose, frutose and sorbitol content in buds and stems of apple tree during the dormancy period

    Directory of Open Access Journals (Sweden)

    Ruy Inacio Neiva de Carvalho

    2006-12-01

    Full Text Available O objetivo deste trabalho foi determinar as variações do conteúdo de glucose, frutose e sorbitol em gemas e ramos de um ano de macieira durante o período de dormência. Os ramos da cultivar "Imperial Gala" foram coletados em Porto Amazonas-PR, em intervalos de 21 dias, de abril a agosto (19/04, 10/05, 31/05, 21/06, 12/07, 02/08 e 23/08, e receberam ou não tratamento com frio suplementar de 1.440 horas à temperatura de 4 a 7°C. As análises dos carboidratos foram realizadas em gemas e porções de ramos adjacentes às primeiras por cromatografia líquida de alta eficiência (HPLC. Ocorreu um acúmulo de glucose, frutose e sorbitol nas gemas de macieira durante a dormência. O acúmulo de glucose e frutose nos ramos aconteceu até o início de agosto quando, em seguida, houve redução, enquanto o sorbitol decresceu até junho e, em seguida, elevou-se até o final de agosto. O tratamento com frio ao longo da dormência modificou as variações dos conteúdos de carboidratos nas gemas e ramos de macieira.This research was aimed at evaluating the variations of glucose, frutose and sorbitol content in one year old buds and stems of apple trees during the dormancy period. The stems of cv. Imperial Gala were collected in Porto Amazonas, Parana State, Brazil, at intervals of 21 days from April to August (April 19th, May 10th, May 31st, June 21st, July 12th, August 2nd and August 23rd and were treated or not with 1,440 hours of chill (4 to 7°C. The carbohydrates were analysed in buds and stem tissues close to buds by high performance liquid chromatography (HPLC. There was an increase of glucose, frutose and sorbitol content in apple tree buds during the dormancy. An increase of glucose and frutose content in stems occured until August 2nd followed by a significative reduction, while the sorbitol content decreased until June 21st followed by an increase until August 31st. The chill treatment during the dormancy period modified the variations of

  6. Effects of Temperature and Several Chemicals on Metabolic Changes During Dormancy Release in NJ72 Nectarine

    Institute of Scientific and Technical Information of China (English)

    YUAN Zhi-you; LI Xian-li; LI Ling-hao; HAN Xing-guo; YAN Tian-li

    2003-01-01

    Poor, delayed and ununiform budbreak is a major problem for peaches in greenhouse. To clari-fy the mechanism of breaking bud dormancy in nectarines, the effect of temperature and three dormancy-breaking agents on metabolic changes during dormancy release in two-year old NJ72 nectarine (Prunus persicaL. Batch) was investigated. The result showed temperature and chemicals affected the budbreak and the me-tabolism of NJ72 nectarine during dormancy. Endogeneons peroxide content in buds increased soon after lowtemperature treatment. Meanwhile, catalase activity was also shown to increase significantly at low temperature treatment, coincided with increase of the activity of peroxidase and superoxide dismntase. The rate of res-piration in flower buds increased at low temperature during dormancy. The rate of the pentose phosphate path-way increased, while the rate of the Embden-Meyerhof pathway decreased and the rate of triearboxlic acid cycle changed little. Glucose 6-phosphate dehydrogenase activity increased at low temperature during dormancy.At the same time we found an accumulation of peroxide after treatment with dormancy-breaking chemicals. Inflower buds treated with dormancy-breaking agents, thiourca, KNO3 and NH4 NO3, catalase activity was in-hibited soon after treatment, whereas peroxidase activity increased, and the changes of superoxide dismutaseremained little. In this study, it was found that the rates of respiration in flower buds increased by chemicalssprays during dormancy. The activity of glucose 6-phosphate dehydrogenase, the key enzyme in the pentosephosphate pathway (PPP), increased by spraying with dormancy-breaking agents, concomitantly with the ac-tivatlon of the pentose phosphate pathway.

  7. Dinâmica do conteúdo de monossacarídeos em gemas e ramos de dois anos de macieira durante a endodormência Dynamics of monosaccharides content in two year old buds and stems of apple tree during the dormancy period

    Directory of Open Access Journals (Sweden)

    Ruy Inacio Neiva de Carvalho

    2006-08-01

    Full Text Available O objetivo do trabalho foi determinar as variações do conteúdo de glucose, frutose e sorbitol em gemas e ramos de dois anos de macieira que receberam ou não frio suplementar durante o período de dormência. Os ramos da cultivar Imperial Gala foram coletados em Porto Amazonas-PR, região de baixa ocorrência de frio, em intervalos de 21 dias, de abril a agosto, e receberam ou não tratamento com frio suplementar de 1.440 horas, à temperatura de 4 a 7°C. As análises dos monossacarídeos foram realizadas em gemas e porções de ramos adjacentes a elas por cromatografia líquida de alta eficiência (HPLC. Houve acúmulo de glucose e frutose em gemas de macieira de abril a agosto, e este aumento foi estimulado pelo tratamento com 1.440 horas de frio. O conteúdo de glucose e frutose nos ramos adjacentes às gemas elevou-se de abril ao início de agosto, com posterior queda no final de agosto e o tratamento com frio antecipou esta dinâmica. O conteúdo de sorbitol em gemas e ramos de macieira oscilou de abril a agosto, e sua dinâmica foi alterada pelo frio.The objective of this work was to evaluate the variation of glucose, fructose and sorbitol content in two year old buds and stems of apple trees during the dormancy period. Stems of cv. Imperial Gala were collected in Porto Amazonas, Parana State, Brazil, a region of low chill occurence, at intervals of 21 days from April to August and were treated or not with 1,440 hours of chill (4 to 7°C. The monosaccharides were analysed in buds and stem tissues close to buds by high performance liquid chromatography (HPLC. There was an increase of glucose and fructose content in buds from April to August and it was stimulated by the chill treatment. The glucose and fructose content in stems increased from April to August 2nd followed by a reduction in August 23rd and the chill treatment advanced this dynamics. The sorbitol content in buds and stems of apple tree oscillated from April to August and

  8. Dormancy in sweet cherry (Prunus avium L. under Mediterranean climatic conditions

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    Ahmed Mahhou

    2007-01-01

    Full Text Available It is admitted that the lack of winter chilling is a limiting factor for the cultivation of temperate fruit trees in warm climates. Nevertheless, the characteristics of dormancy in sweet cherry under such conditions are still not fully understood. Therefore, and in order to contribute to the elucidation of these mechanisms, the objective of this work is to evaluate the dormancy of sweet cherry (Prunus avium L. under the Mediterranean conditions of Meknes region (Morocco. Evaluation of dormancy behaviour of four varieties was made on the basis of a biological test, known as the « single node cuttings », and histological dissections of flower buds at the time of bud break. The variations of mean time to bud break (MTB were interpreted in terms of the evolution of growth capacity of the buds. The lack of cold affected tree phenological development. The evolution of dormancy in cherry buds showed three phases with variable levels of inertia: the first and third phases being of similar intensity and duration while the second phase was of a high level of inertia (endo-dormancy. The correlative inhibitions of the leaves imposed on the buds continued up to the arrival of continuous low temperatures. The delay in the decrease of inertia reveals insufficient chilling accumulation causing incomplete release from dormancy and low bud break percentage in the orchard. Histological observations showed that vascular connection of flower buds was established during bud break stage. However, flowers showed certain abnormalities, ie low pollen production and malformations of pistils, which limit the possibilities of pollination.

  9. Dinâmica da dormência de gemas de dois anos de macieira 'Imperial Gala' em região de baixa ocorrência de frio Dormancy dynamics of two year old buds of 'Imperial Gala' apple tree in a region of low chill occurence

    Directory of Open Access Journals (Sweden)

    Ruy Inacio Neiva de Carvalho

    2004-12-01

    Full Text Available O objetivo deste trabalho foi determinar a dinâmica da dormência de gemas em ramos de dois anos de macieira 'Imperial Gala' com ou sem frio suplementar durante o outono e inverno, cultivadas em Porto Amazonas - PR, região de baixa ocorrência de frio. Os ramos foram coletados em intervalos de 21 dias, de abril a agosto (19-04, 10-05, 31-05, 21-06, 12-07, 02-08 e 23-08 e receberam ou não tratamento com frio suplementar de 1.440 horas, à temperatura de 4 a 7° C. A avaliação da dormência foi realizada pelo teste biológico de estacas de nós isolados (temperatura de 25° C e fotoperíodo de 16 horas por meio dos parâmetros: tempo médio para brotação (TMB, velocidade de brotação (VB, taxa final de brotação (TF, taxa de brotações vigorosas (TBV e tempo médio para aparecimento de folhas abertas (TMFA. A dormência mais intensa de gemas de dois anos ocorre no final de maio, com oscilações até o início de agosto. A aplicação de 1.440 horas de frio suplementar de 4 a 7° C altera a dinâmica da dormência das gemas de dois anos, reduzindo o seu tempo médio de brotação. Uma vez propiciada a brotação de gemas não-dormentes de dois anos, as mesmas possuem boa capacidade para se desenvolver.This work aims to evaluate the dormancy dynamics of two year old apple tree buds with or without supplementary chill during autumn and winter, in a region of low chill occurence. The stems were collected in Porto Amazonas, Parana State, Brazil, at intervals of 21 days from April to August (April 19th, May 10th, May 31st, June 21st, July 12th, August 2nd and August 23rd and were either treated or not with 1,440 hours of chill (4 to 7° C. The evaluation of dormancy was observed through the biological test of single node cuttings under controlled conditions (25° C and long days of 16 hours by the following parameters: average time for budburst (TMB, velocity of budburst (VB, final rate of budburst (TF, rate of vigorous budburst (TBV and

  10. Dinâmica da dormência de gemas de macieira 'Imperial Gala' durante o outono e inverno em região de baixa ocorrência de frio Dormancy dynamics of 'Imperial Gala' apple tree buds during autumn and winter in a region of low chill occurrence

    Directory of Open Access Journals (Sweden)

    Ruy Inacio Neiva de Carvalho

    2004-04-01

    Full Text Available O objetivo deste trabalho foi determinar a dinâmica da dormência de gemas de um ano de macieira 'Imperial Gala' com ou sem frio suplementar durante o outono e o inverno, cultivadas em região de baixa ocorrência de frio. Os ramos foram coletados em Porto Amazonas-PR, em intervalos de 21 dias, de abril a agosto (19-04, 10-05, 31-05, 21-06, 12-07, 02-08 e 23-08 e receberam ou não tratamento com frio suplementar de 1.440 horas à temperatura de 4 a 7° C. A avaliação da dormência foi realizada pelo teste biológico de estacas de nós isolados (temperatura de 25° C e fotoperíodo de 16 horas por meio dos parâmetros: tempo médio para brotação (TMB, velocidade de brotação (VB, taxa final de brotação (TF, taxa de brotações vigorosas (TBV e tempo médio para aparecimento de folhas abertas (TMFA. A dormência mais intensa das gemas de um ano ocorreu em 12 de julho. A aplicação de 1.440 horas de frio suplementar de 4 a 7° C foi efetivo para a redução do tempo médio de brotação das gemas. A utilização da variável TBV nos testes de estacas de nós isolados foi uma importante forma de avaliação da capacidade real de desenvolvimento da gema, diminuindo-se a interferência do corte da estaca como estimulador de início de desenvolvimento.This work aimed to evaluate the dormancy dynamics of one year old apple tree buds with or without supplementary chill during autumn and winter, in a region of low chill occurence. The stems were collected in Porto Amazonas, Parana State, Brazil, at intervals of 21 days from April to August (04/19, 05/10, 05/31, 06/21, 07/12, 08/02 and 08/23 and were treated or not with 1,440 hours of chill (4 to 7° C. The evaluation of dormancy was observed by the biological test of single node cuttings under controlled conditions (25° C and long days of 16 hours by following parameters: average time for budburst (TMB, velocity of budburst (VB, final rate of budburst (TF, rate of vigorous budburst (TBV and

  11. Respiratory Response of Dormant Nectarine Floral Buds on Chilling Deficiency

    Institute of Scientific and Technical Information of China (English)

    TAN Yue; GAO Dong-sheng; LI Ling; CHEN Xiu-de; XU Ai-hong

    2010-01-01

    Changes in main biochemical respiratory pathways in dormant nectarine floral buds were studied with nectarine trees (Prunus persica.var,nectariana cv.Shuguang) in order to determine the function of respiration in dormancy release.Oxygen-electrode system and respiratory inhibitors were used to measure total respiratory rates and rates of respiratory pathways.Results showed that chilling deficiency blocked the transition of respiratory mode,and made buds stay in a state of high level pentose phosphate pathway (PPP) and low level tricarboxylic acid cycle (TCA).The decline of PPP and activation of TCA occurred synchronously with the release of dormancy.In addition,the inhibition of PPP stimulated a respiration increase related with TCA.It could be concluded that the function of PPP activation in dormancy release might be limited and PPP declination inducing TCA activation might be part of respiration mode transition mechanism during bud sprouting.

  12. [Bud population dynamics of Phragmites australis in heterogeneous habitats of Northeast grassland, China].

    Science.gov (United States)

    2015-02-01

    To adapt ecological environment, typical clonal plants can occur continuously by means of buds. The changes in the bud bank and bud flow in the heterogeneous habitats become the foundation for deep understanding the characteristics of vegetative propagation. By sampling soil from the unit area, a comparative analysis was performed for rhizome bud population dynamics of Phragmites australis community in both meadow soil and saline-alkali soil habitats in meadow grassland of Northeast China. The one-age class rhizome buds formed in the current year were used as input, with the other age classes rhizome buds as output, counting the dormancy buds and death buds. The results showed that the storage, input, output, dormancy, death and the input rates of P. australis rhizome bud populations in meadow soil habitat were significantly higher than that in saline-alkali habitat. There was no significant difference in output rate between the two habitats. The dormant rate in saline-alkali habitat was significantly greater than that in meadow soil habitat. The death rates remained at relatively low levels in both, less than 2%. With the going of growing season, the input buds and input rate of bud bank increased in the two habitats, while the output buds remained relatively stable. The output rate increased first and decreased later, the dormancy buds and dormant rate decreased. Bud bank and bud flow were positively related to soil moisture, soil organic matter and soil available nitrogen content. However, they were negatively related to soil pH value and soil available phosphorus content. Bud bank and bud flow had a similar seasonal variation. Constantly for both habitats, P. australis populations generated new rhizome buds supplied to the bud bank and kept a stable output to maintain their vegetative propagation.

  13. Dinâmica da dormência de gemas de videira e quivizeiro em região de baixa ocorrência de frio Dormancy dynamics of grape and kiwi tree buds in a region of low chill occurrence

    Directory of Open Access Journals (Sweden)

    Luiz Antonio Biasi

    2010-12-01

    Full Text Available O objetivo desta pesquisa foi determinar a dinâmica da dormência de gemas de videira cv. Niagara Branca e de quivizeiro cv. Bruno, em região de baixa ocorrência de frio. Os experimentos foram realizados nos anos de 2007 e 2008, com coletas de ramos a cada duas semanas, em pomares localizados em Pinhais-PR. Na última coleta, um grupo adicional de ramos foi coletado e mantido em refrigerador a temperatura de 4 a 7º C, por 1.440 horas. A avaliação da dormência foi realizada por meio do teste biológico de estacas de nós isolados em sala de crescimento, à temperatura de 25º C e fotoperíodo de 16 horas. Foi realizada a quantificação de horas de frio (HF e de unidades de frio (UF ocorridas na região. As duas espécies foram avaliadas como experimentos distintos. O delineamento experimental adotado foi o completamente casualizado, com doze tratamentos em 2007 e onze tratamentos em 2008, ambos com quatro repetições e dez estacas por unidade experimental. A endodormência de gemas de quivizeiro 'Bruno' instala-se a partir de abril e atinge maior intensidade do final de maio à segunda metade de junho. A saída da endodormência pode ocorrer naturalmente até o fim de agosto, mas com variações entre os anos. A endodormência de gemas de videira 'Niagara Branca' instala-se em abril e mantém-se intensa até maio. A saída natural da endodormência ocorre da metade de agosto ao início de setembro.The objective of this work was to evaluate the dormancy dynamic of 'Niagara Branca' grape and 'Bruno' kiwi tree buds in a region of low chill occurrence. The experiments were carried out in 2007 and 2008 through cut branches every two weeks in orchards in Pinhais-PR. In the last date, an additional group of stems was collected and maintained in a refrigerator at temperature of 4 to 7º C by 1440 hours. The evaluation of dormancy was observed by the biological test of single node cuttings into a growth room with temperature of 25º C and

  14. Arenavirus Budding

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    Shuzo Urata

    2011-01-01

    Full Text Available Several arenaviruses cause hemorrhagic fever disease in humans and pose a significant public health concern in their endemic regions. On the other hand, the prototypic arenavirus LCMV is a superb workhorse for the investigation of virus-host interactions and associated disease. The arenavirus small RING finger protein called Z has been shown to be the main driving force of virus budding. The budding activity of Z is mediated by late (L domain motifs, PT/SAP, and PPXY, located at the C-terminus of Z. This paper will present the current knowledge on arenavirus budding including the diversity of L domain motifs used by different arenaviruses. We will also discuss how improved knowledge of arenavirus budding may facilitate the development of novel antiviral strategies to combat human pathogenic arenaviruses.

  15. Photosynthetic leaf area modulates tiller bud outgrowth in sorghum.

    Science.gov (United States)

    Kebrom, Tesfamichael H; Mullet, John E

    2015-08-01

    Shoot branches or tillers develop from axillary buds. The dormancy versus outgrowth fates of buds depends on genetic, environmental and hormonal signals. Defoliation inhibits bud outgrowth indicating the role of leaf-derived metabolic factors such as sucrose in bud outgrowth. In this study, the sensitivity of bud outgrowth to selective defoliation was investigated. At 6 d after planting (6 DAP), the first two leaves of sorghum were fully expanded and the third was partially emerged. Therefore, the leaves were selectively defoliated at 6 DAP and the length of the bud in the first leaf axil was measured at 8 DAP. Bud outgrowth was inhibited by defoliation of only 2 cm from the tip of the second leaf blade. The expression of dormancy and sucrose-starvation marker genes was up-regulated and cell cycle and sucrose-inducible genes was down-regulated during the first 24 h post-defoliation of the second leaf. At 48 h, the expression of these genes was similar to controls as the defoliated plant recovers. Our results demonstrate that small changes in photosynthetic leaf area affect the propensity of tiller buds for outgrowth. Therefore, variation in leaf area and photosynthetic activity should be included when integrating sucrose into models of shoot branching.

  16. Seed dormancy and germination

    NARCIS (Netherlands)

    Bentsink, L.; Koornneef, M.

    2002-01-01

    Arabidopsis possesses dormancy, as is the case for many other plant species, which is controlled by environmental factors such as light, temperature and time of dry storage as well as by genetic factors. The use of genetics and molecular genetics in Arabidopsis is starting to shed light on some aspe

  17. Epidemiology and effective control of Altenaria altenata, causal agent of dead (dormant) flower bud disease of pear

    NARCIS (Netherlands)

    Wenneker, M.; Joosten, N.N.; Anbergen, R.H.N.; Vink, P.; Bruggen, van A.S.

    2011-01-01

    Dead flower buds are a common phenomenon in pear culture in The Netherlands, Belgium and Mediterranean countries. Disease cases are also reported from South America. The disease is characterized by a partial or complete necrosis of flower buds during tree dormancy. The disease progresses during wint

  18. 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

  19. 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..

    Directory of Open Access Journals (Sweden)

    Gulshan Kumar

    Full Text Available 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

  20. 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

  1. Alanine aminotransferase controls seed dormancy in barley

    Science.gov (United States)

    Sato, Kazuhiro; Yamane, Miki; Yamaji, Nami; Kanamori, Hiroyuki; Tagiri, Akemi; Schwerdt, Julian G.; Fincher, Geoffrey B.; Matsumoto, Takashi; Takeda, Kazuyoshi; Komatsuda, Takao

    2016-01-01

    Dormancy allows wild barley grains to survive dry summers in the Near East. After domestication, barley was selected for shorter dormancy periods. Here we isolate the major seed dormancy gene qsd1 from wild barley, which encodes an alanine aminotransferase (AlaAT). The seed dormancy gene is expressed specifically in the embryo. The AlaAT isoenzymes encoded by the long and short dormancy alleles differ in a single amino acid residue. The reduced dormancy allele Qsd1 evolved from barleys that were first domesticated in the southern Levant and had the long dormancy qsd1 allele that can be traced back to wild barleys. The reduced dormancy mutation likely contributed to the enhanced performance of barley in industrial applications such as beer and whisky production, which involve controlled germination. In contrast, the long dormancy allele might be used to control pre-harvest sprouting in higher rainfall areas to enhance global adaptation of barley. PMID:27188711

  2. Mechanisms of Metastatic Tumor Dormancy

    Directory of Open Access Journals (Sweden)

    Mary Osisami

    2013-09-01

    Full Text Available Tumor metastasis can occur years after an apparent cure due to a phenomenon known as metastatic tumor dormancy; in which tumor masses or individual tumor cells are growth restricted for extended periods of time. This period of dormancy is induced and maintained by several mechanisms, including: (1 Tumor microenvironment factors such as cytokine expression, immunosurveillance and angiogenesis; (2 Metastasis suppressor gene activity; and (3 Cancer therapeutics. Disseminated tumor cells (DTC are the key cells that result in dormant tumors. However, many challenges exist towards isolating DTCs for mechanistic studies. The main DTC that may represent the dormant cell is the cancer stem cells (CSC as they have a slow proliferation rate. In addition to limited knowledge regarding induction of tumor dormancy, there are large gaps in knowledge regarding how tumors escape from dormancy. Emerging research into cancer stem cells, immunotherapy, and metastasis suppressor genes, may lead to new approaches for targeted anti-metastatic therapy to prevent dormancy escape. Overall, an enhanced understanding of tumor dormancy is critical for better targeting and treatment of patients to prevent cancer recurrence.

  3. A molecular framework for seasonal growth-dormancy regulation in perennial plants.

    Science.gov (United States)

    Shim, Donghwan; Ko, Jae-Heung; Kim, Won-Chan; Wang, Qijun; Keathley, Daniel E; Han, Kyung-Hwan

    2014-01-01

    The timing of the onset and release of dormancy impacts the survival, productivity and spatial distribution of temperate horticultural and forestry perennials and is mediated by at least three main regulatory programs involving signal perception and processing by phytochromes (PHYs) and PHY-interacting transcription factors (PIFs). PIF4 functions as a key regulator of plant growth in response to both external and internal signals. In poplar, the expression of PIF4 and PIF3-LIKE1 is upregulated in response to short days, while PHYA and PHYB are not regulated at the transcriptional level. Integration of light and environmental signals is achieved by gating the expression and transcriptional activity of PIF4. During this annual cycle, auxin promotes the degradation of Aux/IAA transcriptional repressors through the SKP-Cullin-F-boxTIR1 complex, relieving the repression of auxin-responsive genes by allowing auxin response factors (ARFs) to activate the transcription of auxin-responsive genes involved in growth responses. Analyses of transcriptome changes during dormancy transitions have identified MADS-box transcription factors associated with endodormancy induction. Previous studies show that poplar dormancy-associated MADS-box (DAM) genes PtMADS7 and PtMADS21 are differentially regulated during the growth-dormancy cycle. Endodormancy may be regulated by internal factors, which are specifically localized in buds. PtMADS7/PtMADS21 may function as an internal regulator in poplar. The control of flowering time shares certain regulatory hierarchies with control of the dormancy/growth cycle. However, the particularities of different stages of the dormancy/growth cycle warrant comprehensive approaches to identify the causative genes for the entire cycle. A growing body of knowledge also indicates epigenetic regulation plays a role in these processes in perennial horticultural and forestry plants. The increased knowledge contributes to better understanding of the dormancy

  4. 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

  5. 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.

  6. Dormancy and growth vigour of seed potatoes.

    NARCIS (Netherlands)

    Ittersum, van M.K.

    1992-01-01

    Dormancy is an important property of seed potatoes. Seed tubers planted too soon after their harvest do not produce plants because of dormancy, or produce low yields because of poor growth vigour. Potato tubers from the same cultivar vary in their duration of dormancy. The first aim of the research

  7. Dormancy break with garlic extract and hydrogen peroxide in rootstock vine ‘SO4’

    Directory of Open Access Journals (Sweden)

    Aguilla Juan Saavedra del

    2016-01-01

    Full Text Available A synthetic product is used to help overcome dormancy of the buds of vines in tropical and sub-tropical climate, but the product currently available in Brazil has the highest level of toxicity to humans. The objective was to study some alternatives to break the dormancy of the buds of the rootstock vine ‘SO4’. The sprayed treatments were: T1 = water (control; T2 = hydrogen cyanamide (3%; T3 = garlic (33% and; T4 = Hydrogen Peroxide – H2O2 – (3%. The cuttings were immersed in a indole acetic acid (IAA of 5 ppm for 15 seconds and placed in plastic bags (19 cm× 5 cm× 8 cm with 50% sand + 50% commercial substrate (H. Decker® . After 04 months, were evaluated: percentage of live cuttings, aerial part height (cm, length of roots (cm and dry matter of aerial parts and root (g. Regarding the roots, root dry weight and dry matter of aerial parts, stood out the cuttings treated with H2O2 at a concentration of 3% (T4. In the present work conditions, preliminarily concluded that H2O2 at a concentration of 3% can assist in breaking dormancy of the buds of the roostock vine ‘SO4’.

  8. Chilling privation during dormancy period and carbohydrate mobilization in Japanese pear trees

    Directory of Open Access Journals (Sweden)

    Anderson Carlos Marafon

    2011-08-01

    Full Text Available The flower bud abortion is one of the main problems that limit commercial pear (Pyrus pyrifolia production in the southern region of Brazil. Insufficient chilling during the dormancy period is known as the main factor of this problem. One of the hypotheses to explain this problem is that the starch mobilization and carbohydrate fluxes to the buds are impeded when mild temperatures occurred during winter. This study compared the total soluble sugars (TSS and reducing sugars (RS concentrations, the cell wall acid invertase (CWAI - EC 3.2.1.26 and sucrose-phosphate synthase (SPS - EC 2.4.1.14 activities in wood of branches and floral buds of Japanese pear trees cv. Housui, grafted on Pyrus calleryana and submitted to chilling conditions during the dormancy period. Treatments were: (i natural conditions; (ii continuous artificial chilling; (iii alternating temperatures, and (iv total chilling privation. TSS and RS contents, as well as CWAI and SPS activities in tissues of branches that received insufficient chilling were lower than those that received sufficient chilling during winter. The starch concentration was superior in wood tissues of branches kept under chilling privation. The chilling privation disturbs carbohydrate mobilization in pear trees, reducing the sucrose synthesis capacity in wood tissues (source and sucrose importation by the floral buds (sink.

  9. Escape from Tumor Cell Dormancy

    Science.gov (United States)

    2012-10-01

    can be followed for weeks to months, the process of seeding, dormancy and emergence can be followed. 15. SUBJECT TERMS breast cancer, metastasis...format that is functional in all aspects (sturdy, stable, and physiologically relevant) is a multi-step process involving integration of desirable...covalently bonded to the filter material surface or that penetrate into the filter during gelation and form physical links around filter structures

  10. Free amino acids in the xylem sap of pear trees during dormancy

    Directory of Open Access Journals (Sweden)

    Anderson Carlos Marafon

    2016-01-01

    Full Text Available ABSTRACT: Storage and remobilization are considered key processes for the effective use of nitrogen in temperate fruit trees. As dormancy begins, storage proteins are synthesized, coinciding with a reduction in the levels of free amino acids. Consequently, as dormancy breaks, these storage proteins are degraded, and an increase in the concentrations of amino acids occurs, in order to support new growth. The objective of this study was to evaluate water content of different vegetative tissues (buds, bark, and bole wood, volume of xylem sap, and free amino acid concentrations of xylem sap, during winter dormancy of Hosui Japanese pear trees (VL. Plant material was obtained from the Embrapa Temperate Climate experimental orchard at Pelotas, in the state of Rio Grande do Sul, Brazil. Xylem sap was extracted from the branches with the aid of a vacuum pump, and the free amino acids were determined by gas chromatography, using the EZ kit: Faast GC/FID (Phenomenex. Water content of buds, as well as the volume of sap and concentrations of both aspartic acid and asparagine, substantially increased over time, reaching maximum values in the phase preceding sprouting.

  11. Coordinated Expression of FLOWERING LOCUS T and DORMANCY ASSOCIATED MADS-BOX-Like Genes in Leafy Spurge.

    Directory of Open Access Journals (Sweden)

    Xinyuan Hao

    Full Text Available Leafy spurge (Euphorbia esula L. is a noxious perennial weed that produces underground adventitious buds, which are crucial for generating new vegetative shoots following periods of freezing temperatures or exposure to various control measures. It is also capable of flowering and producing seeds, but requires vernalization in some cases. DORMANCY ASSOCIATED MADS-BOX (DAM genes have been proposed to play a direct role in the transition to winter-induced dormancy and maintenance through regulation of the FLOWERING LOCUS T (FT gene, which also is likely involved in the vernalization process. To explore the regulation of FT and DAM during dormancy transitions in leafy spurge, the transcript accumulation of two previously cloned DAM splice variants and two different previously cloned FT genes was characterized. Under long-photoperiods (16 h light, both DAM and FT transcripts accumulate in a diurnal manner. Tissue specific expression patterns indicated the tissues with high DAM expression had low FT expression and vice versa. DAM expression is detected in leaves, stems, shoot tips, and crown buds. FT transcripts were detected mainly in leaves and flowers. Under dormancy inducing conditions, DAM and FT genes had an inverse expression pattern. Additionally, chromatin immunoprecipitation assays were performed using DAM-like protein specific antibodies to demonstrate that DAM or related proteins likely bind to cryptic and/or conserved CArG boxes in the promoter regions of FT genes isolated from endodormant crown buds. These results are consistent with the hypothesis that DAM proteins play a crucial role in leafy spurge dormancy transition and maintenance, potentially by negatively regulating the expression of FT.

  12. 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.

  13. 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...... in ‘Titania’. Since ‘Narve Viking’ has a higher chilling requirement than ‘Titania’, this indicates that, in high-chillingrequiring genotypes, dormancy responses may temper the effect of warming on spring phenology. Winter Warming significantly reduced fruit yield the following summer in both cultivars...... at elevated temperature showed decreased levels of sucrose in stems of both cultivars and flower buds of ‘Narve Viking’, which, in buds, was associated with increased concentrations of glucose and fructose. Hence, winter warming influences carbohydrate metabolism, but it remains to be elucidated whether...

  14. English for common entrance

    CERN Document Server

    Kossuth, Kornel

    2013-01-01

    Succeed in the exam with this revision guide, designed specifically for the brand new Common Entrance English syllabus. It breaks down the content into manageable and straightforward chunks with easy-to-use, step-by-step instructions that should take away the fear of CE and guide you through all aspects of the exam. - Gives you step-by-step guidance on how to recognise various types of comprehension questions and answer them. - Shows you how to write creatively as well as for a purpose for the section B questions. - Reinforces and consolidates learning with tips, guidance and exercises through

  15. What Are Taste Buds?

    Science.gov (United States)

    ... your taste buds for letting you appreciate the saltiness of pretzels and the sweetness of ice cream. ... allow you to experience tastes that are sweet, salty, sour, and bitter. How exactly do your taste ...

  16. Latitudinal variation in sensitivity of flower bud formation to high temperature in Japanese Taraxacum officinale.

    Science.gov (United States)

    Yoshie, Fumio

    2014-05-01

    Control of flowering time plays a key role in the successful range expansion of plants. Taraxacum officinale has expanded throughout Japan during the 110 years after it was introduced into a cool temperate region. The present study tested a hypothesis that there is a genetic difference in the bud formation time in relation to temperature along latitudinal gradient of T. officinale populations. In Experiment 1, plants from three populations at different latitudes (26, 36, and 43°N) were grown at three temperatures. Time to flower bud appearance did not significantly differ among the three populations when plants were grown at 14 °C, whereas it increased with increasing latitude when grown at 19 and 24 °C. Rosette diameter was not different among the populations, indicating that the variation in bud formation time reflected a difference in genetic control rather than size variation. The latitudinal variation in bud appearance time was confirmed by Experiment 2 in which plants from 17 population were used. In Experiment 3, the size of plants that exhibited late-flowering was studied to test a hypothesis that the variation in flowering time reflects dormancy of vegetative growth, but the late-flowering plants were found to continue growth, indicating that vegetative dormancy was not the cause of the variation. The results clearly indicate that the degree of suppression of flower bud formation at high temperature decreases with latitude from north to south, which is under genetic control.

  17. Respiratory Response of Dormant Nectarine Vegetative Buds to High Temperature Stress

    Institute of Scientific and Technical Information of China (English)

    TAN Yue; LI Ling; LENG Chuan-yuan; LI Dong-mei; CHEN Xiu-de; GAO Dong-sheng

    2013-01-01

    High temperature stress (HT) is efficient in breaking endo-dormancy of perennial trees. The effects of HT (50°C) on the respiration of dormant nectarine (Prunus persica var. nectariana cv. Shuguang) vegetative buds were evaluated in the research. We found that bud respiration was transiently inhibited by HT and the pentose phosphate pathway (PPP) and the cytochrome C pathway (CYT) were significantly affected. On the substrate level, PPP was activated in the HT-treated buds compared with the control group. However, the activation did mot occur until hours after HT treatment. The tricarboxylic acid cycle (TCA) in both the HT-treated buds and in the control group proceeded at a low level most of the time compared with total respiration. On the electron transfer level, CYT was transiently inhibited by HT but became significantly active in the later stage. CYT operation in the control group exhibited an attenuation process. The alternative pathway (ALT) fluctuated both in the HT-treated samples and in the control. The results suggest that the temporary CYT inhibition and the following PPP activation may be involved in HT-induced bud dormancy release and budburst mechanisms.

  18. 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.

  19. EARLY ENTRANCE COPRODUCTION PLANT

    Energy Technology Data Exchange (ETDEWEB)

    John S. Abughazaleh; Mushtaq Ahmed; Ashok Anand; John H. Anderson; Charles Benham; Fred D. Brent; Thomas E. Chance; William K. Davis; Raymond F. Drnevich; Larry Hall; Ming He; Stephen A. Lang; Jimmy O. Ong; Sarah J. Patel; George Potoczniak; Adela G. Sanchez; Charles H. Schrader; Lalit S. Shah; Phil J. Shires; Rae Song

    2000-10-26

    The overall objective of this project is the three phase development of an Early Entrance Coproduction Plant (EECP) which produces at least one product from at least two of the following three categories: (1) electric power (or heat), (2) fuels, and (3) chemicals. The objective is to have these products produced by technologies capable of using synthesis gas derived from coal and/or other carbonaceous feedstock. The objective of Phase I is to determine the feasibility and define the concept for the EECP located at a specific site and to develop a Research, Development, and Testing Plan (RD and T) for implementation in Phase II. The objective of Phase II is to implement the RD and T as outlined in the Phase I RD and T Plan to enhance the development and commercial acceptance of coproduction technology that produces high-value products, particularly those that are critical to our domestic fuel and power requirements. The project will resolve critical knowledge and technology gaps on the integration of gasification and downstream processing to coproduce some combination of power, fuels, and chemicals from coal and other feedstocks. The objective of Phase III is to develop an engineering design package and a financing plan for an EECP located at a specific site. The project's intended result is to provide the necessary technical, economic, and environmental information that will be needed to move the EECP forward to detailed design, construction, and operation by industry.

  20. EARLY ENTRANCE COPRODUCTION PLANT

    Energy Technology Data Exchange (ETDEWEB)

    Mushtaq Ahmed; John H. Anderson; Charles Benham; Earl R. Berry; Fred Brent; Belma Demirel; Ming He; Troy Raybold; Manuel E. Quintana; Lalit S. Shah; Kenneth A. Yackly

    2003-06-09

    The overall objective of this project is the three phase development of an Early Entrance Coproduction Plant (EECP) which produces at least one product from at least two of the following three categories: (1) electric power (or heat), (2) fuels, and (3) chemicals. The objective is to have these products produced by technologies capable of using synthesis gas derived from coal and/or other carbonaceous feedstocks. The objectives of Phase I were to determine the feasibility and define the concept for the EECP located at a specific site; develop a Research, Development, and Testing (RD&T) Plan for implementation in Phase II; and prepare a Preliminary Project Financing Plan. The objective of Phase II is to implement the work as outlined in the Phase I RD&T Plan to enhance the development and commercial acceptance of coproduction technology that produces high-value products, particularly those that are critical to our domestic fuel and power requirements. The project will resolve critical knowledge and technology gaps on the integration of gasification and downstream processing to coproduce some combination of power, fuels, and chemicals from coal and/or other carbonaceous feedstocks. The objective of Phase III is to develop an engineering design package and a financing and testing plan for an EECP located at a specific site. The project's intended result is to provide the necessary technical, economic, and environmental information needed by industry to move the EECP forward to detailed design, construction, and operation.

  1. EARLY ENTRANCE COPRODUCTION PLANT

    Energy Technology Data Exchange (ETDEWEB)

    John S. Abughazaleh; Mushtaq Ahmed; Ashok Anand; John H. Anderson; Charles Benham; Fred D. Brent; Thomas E. Chance; William K. Davis; Raymond F. Drnevich; Larry Hall; Ming He; Stephen A. Lang; David Mintner; Wendy Moore; Jimmy O. Ong; George Potoczniak; Adela G. Sanchez; Charles H. Schrader; Lalit S. Shah; Kalapi D. Sheth; Phil J. Shires; Rae Song

    2001-05-17

    The overall objective of this project is the three-phase development of an Early Entrance Coproduction Plant (EECP) that produces at least one product from at least two of the following three categories: Electric power (or heat); Fuels; and Chemicals. The objective is to have these products produced by technologies capable of using synthesis gas derived from coal and/or some other carbonaceous feedstock, such as petroleum coke. The objective of Phase I was to determine the feasibility and define the concept for the EECP located at a specific site and to develop a Research, Development, and Testing (RD and T) Plan for implementation in Phase II. This objective has now been accomplished. A specific site, Motiva Refinery in Port Arthur, Texas, has been selected as the location best suited for the EECP. The accomplishments of Phase I are discussed in detail in this Phase I Concept Report. A RD and T Plan and a preliminary project financing plan have been developed and are submitted separately from this report.

  2. Dormancy Breaking in Ormosia arborea Seeds

    OpenAIRE

    Edilma Pereira Gonçalves; Franklim Sales de Jesus Soares; Sérgio dos Santos Silva; Débora de Souza Tavares; Jeandson Silva Viana; Brenda Colleen Clifton Cardoso

    2011-01-01

    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 imm...

  3. Phylogenetic analysis and molecular evolution of the dormancy associated MADS-box genes from peach

    Directory of Open Access Journals (Sweden)

    Abbott Albert G

    2009-06-01

    Full Text Available Abstract Background Dormancy associated MADS-box (DAM genes are candidates for the regulation of growth cessation and terminal bud formation in peach. These genes are not expressed in the peach mutant evergrowing, which fails to cease growth and enter dormancy under dormancy-inducing conditions. We analyzed the phylogenetic relationships among and the rates and patterns of molecular evolution within DAM genes in the phylogenetic context of the MADS-box gene family. Results The peach DAM genes grouped with the SVP/StMADS11 lineage of type II MIKCC MADS-box genes. Phylogenetic analyses suggest that the peach SVP/StMADS11-like gene family, which contains significantly more members than annual model plants, expanded through serial tandem gene duplication. We found evidence of strong purifying selection acting to constrain functional divergence among the peach DAM genes and only a single codon, located in the C-terminal region, under significant positive selection. Conclusion Because all DAM genes are expressed in peach and are subjected to strong purifying selection we suggest that the duplicated genes have been maintained by subfunctionalization and/or neofunctionalization. In addition, this pattern of selection suggests that the DAM genes are important for peach growth and development.

  4. EARLY ENTRANCE COPRODUCTION PLANT

    Energy Technology Data Exchange (ETDEWEB)

    David Storm; Govanon Nongbri; Steve Decanio; Ming He; Lalit Shah; Charles Schrader; Earl Berry; Peter Ricci; Belma Demirel; Charles Benham; Mark Bohn

    2004-01-12

    The overall objective of this project is the three phase development of an Early Entrance Coproduction Plant (EECP) which uses petroleum coke to produce at least one product from at least two of the following three categories: (1) electric power (or heat), (2) fuels, and (3) chemicals using ChevronTexaco's proprietary gasification technology. The objective of Phase I is to determine the feasibility and define the concept for the EECP located at a specific site; develop a Research, Development, and Testing (RD&T) Plan to mitigate technical risks and barriers; and prepare a Preliminary Project Financing Plan. The objective of Phase II is to implement the work as outlined in the Phase I RD&T Plan to enhance the development and commercial acceptance of coproduction technology. The objective of Phase III is to develop an engineering design package and a financing and testing plan for an EECP located at a specific site. The project's intended result is to provide the necessary technical, economic, and environmental information needed by industry to move the EECP forward to detailed design, construction, and operation. The partners in this project are Texaco Energy Systems LLC or TES (a subsidiary of ChevronTexaco), General Electric (GE), Praxair, and Kellogg Brown & Root (KBR) in addition to the U.S. Department of Energy (DOE). TES is providing gasification technology and Fischer-Tropsch (F-T) technology developed by Rentech, Inc., GE is providing combustion turbine technology, Praxair is providing air separation technology, and KBR is providing engineering. During Phase I, a design basis for the Fischer-Tropsch Synthesis section was developed based on limited experience with the specified feed gas and operating conditions. The objective of this Task in Phase II RD&T work was to confirm the performance of the F-T reactor at the set design conditions. Although much of the research, development, and testing work were done by TES outside of this project, several

  5. EARLY ENTRANCE COPRODUCTION PLANT

    Energy Technology Data Exchange (ETDEWEB)

    John Anderson; Charles Schrader

    2004-01-26

    In 1999, the U. S. Department of Energy (DOE) awarded a Cooperative Agreement to Texaco Energy Systems Inc. to provide a preliminary engineering design of an Early Entrance Coproduction Plant (EECP). Since the award, continuous and diligent work has been undertaken to achieve the design of an economical facility that makes strides toward attaining the goal of DOE's Vision 21 Program. The objective of the EECP is to convert coal and/or petroleum coke to power while coproducing transportation fuels, chemicals, and useful utilities such as steam. This objective is being pursued in a three-phase effort through the partnership of the DOE with prime contractor Texaco Energy Systems, LLC. (TES), the successor to Texaco Energy Systems, Inc. The key subcontractors to TES include General Electric (GE), Praxair, and Kellogg Brown and Root. ChevronTexaco provided gasification technology and Rentech Inc.'s Fischer-Tropsch (F-T) technology that has been developed for non-natural gas sources. GE provided gas turbine technology for the combustion of low energy content gas. Praxair provided air separation technology and KBR provided engineering to integrate the facility. A conceptual design was completed in Phase I and the report was accepted by the DOE in May 2001. The Phase I work identified risks and critical research, development, and testing that would improve the probability of technical success of the EECP. The objective of Phase II was to mitigate the risks by executing research, development, and testing. Results from the Phase II work are the subject of this report. As the work of Phase II concluded, it became evident that sufficient, but not necessarily complete, technical information and data would be available to begin Phase III - Preliminary Engineering Design. Work in Phase II requires additional technical development work to correctly apply technology at a specific site. The project's intended result is to provide the necessary technical, economic, and

  6. Garlic and H2O2 in overcoming dormancy on the vine “Cabernet Sauvignon”

    Directory of Open Access Journals (Sweden)

    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.

  7. Morphological characterization and gene expression profiling during bud development in a tropical perennial, Litchi chinensis Sonn.

    Directory of Open Access Journals (Sweden)

    Huifeng Zhang

    2016-10-01

    Full Text Available Tropical evergreen perennials undergo recurrent flush growth, and their terminal buds alternate between growth and dormancy. In sharp contrast to intensive studies on bud development in temperate deciduous trees, there is little information about bud development regulation in tropical trees. In this study, litchi (Litchi chinensis Sonn. was used as a model tropical perennial for morphological characterization and transcriptomic analysis of bud development. Litchi buds are naked with apical meristem embraced by rudimentary leaves, which are brown at dormant stage (Stage I. They swell and turn greenish as buds break (Stage II, and as growth accelerates, the rudimentary leaves elongate and open exposing the inner leaf primodia. With the outgrowth of the needle-like leaflets, bud growth reaches a maximum (Stage III. When leaflets expand, bud growth cease with the abortion of the rudimentary leaves at upper positions (Stage IV. Then buds turn brown and reenter dormant status. Budbreak occurs again when new leaves become hard green. Buds at four stages (Stage I to IV were collected for respiration measurements and in-depth RNA sequencing. Respiration rate was lowest at Stage I and highest at Stage II, decreasing towards growth cessation. RNA sequencing obtained over 5 Gb data from each of the bud samples and de novo assembly generated a total of 59999 unigenes, 40119 of which were annotated. Pair-wise comparison of gene expression between stages, gene profiling across stages, GO/KEGG enrichment analysis, and the expression patterns of 17 major genes highlighted by principal component (PC analysis displayed significant changes in stress resistance, hormone signal pathways, circadian rhythm, photosynthesis, cell division, carbohydrate metabolism, programmed cell death during bud development, which might be under epigenetic control involving chromatin methylation. The qPCR results of 8 selected unigenes with high PC scores agreed with the RPKM values

  8. EARLY ENTRANCE COPRODUCTION PLANT

    Energy Technology Data Exchange (ETDEWEB)

    Charles Benham; Mark Bohn; John Anderson; Earl Berry; Fred Brent; Ming He; Randy Roberts; Lalit Shah; Marjan Roos

    2003-09-15

    The 1999 U. S. Department of Energy (DOE) award to Texaco Energy Systems Inc. (presently Texaco Energy Systems LLC, a subsidiary of ChevronTexaco) was made to provide a Preliminary Engineering Design of an Early Entrance Coproduction Plant (EECP). Since the award presentation, work has been undertaken to achieve an economical concept design that makes strides toward the DOE Vision 21 goal. The objective of the EECP is to convert coal and/or petroleum coke to electric power plus transportation fuels, chemicals and useful utilities such as steam. The use of petroleum coke was added as a fuel to reduce the cost of feedstock and also to increase the probability of commercial implementation of the EECP concept. This objective has been pursued in a three phase effort through the partnership of the DOE with prime contractor Texaco Energy Systems LLC and subcontractors General Electric (GE), Praxair, and Kellogg Brown and Root (KBR). ChevronTexaco is providing gasification technology and Rentech's Fischer-Tropsch technology that has been developed for non-natural gas feed sources. GE is providing gas turbine technology for the combustion of low energy content gas. Praxair is providing air separation technology, and KBR is providing engineering to integrate the facility. The objective of Phase I was to determine the feasibility and define the concept for the EECP located at a specific site; develop a Research, Development, and Testing (RD&T) Plan to mitigate technical risks and barriers; and prepare a Preliminary Project Financing Plan. The objective of Phase II is to implement the work as outlined in the Phase I RD&T Plan to enhance the development and commercial acceptance of coproduction technology. The objective of Phase III is to develop an engineering design package and a financing and testing plan for an EECP located at a specific site. Phase I Preliminary Concept Report was completed in 2000. The Phase I Preliminary Concept Report was prepared based on making

  9. EARLY ENTRANCE COPRODUCTION PLANT

    Energy Technology Data Exchange (ETDEWEB)

    John Anderson; Mark Anselmo; Earl Berry; Mark Bohn; Roko Bujas; Ming He; Ken Kwik; Charles H. Schrader; Lalit Shah; Dennis Slater; Donald Todd; Don Wall

    2003-08-21

    The overall objective of this project is the three phase development of an Early Entrance Coproduction Plant (EECP) which uses petroleum coke to produce at least one product from at least two of the following three categories: (1) electric power (or heat), (2) fuels, and (3) chemicals using ChevronTexaco's proprietary gasification technology. The objective of Phase I is to determine the feasibility and define the concept for the EECP located at a specific site; develop a Research, Development, and Testing (RD&T) Plan to mitigate technical risks and barriers; and prepare a Preliminary Project Financing Plan. The objective of Phase II is to implement the work as outlined in the Phase I RD&T Plan to enhance the development and commercial acceptance of coproduction technology. The objective of Phase III is to develop an engineering design package and a financing and testing plan for an EECP located at a specific site. The project's intended result is to provide the necessary technical, economic, and environmental information needed by industry to move the EECP forward to detailed design, construction, and operation. The partners in this project are Texaco Energy Systems LLC (TES), a subsidiary of ChevronTexaco, General Electric (GE), Praxair, and Kellogg Brown & Root (KBR) in addition to the U.S. Department of Energy (DOE). TES is providing gasification technology and Fischer-Tropsch (F-T) technology developed by Rentech, Inc. GE is providing combustion turbine technology, Praxair is providing air separation technology, and KBR is providing engineering. Each of the EECP subsystems were assessed for technical risks and barriers. A plan was identified to mitigate the identified risks (Phase II RD&T Plan, October 2000). The RD&T Plan identified catalyst/wax separation as a potential technical and economic risk. To mitigate risks to the proposed EECP, Phase II RD&T included tests of an alternative (to Rentech's Dynamic Settler) primary catalyst

  10. EARLY ENTRANCE COPRODUCTION PLANT

    Energy Technology Data Exchange (ETDEWEB)

    Fred D. Brent; Lalit Shah; Earl Berry; Charles H. Schrader; John Anderson; Ming He; James F. Stevens; Centha A. Davis; Michael Henley; Jerome Mayer; Harry Tsang; Jimell Erwin; Jennifer Adams; Michael Tillman; Chris Taylor; Marjan J. Roos; Robert F. Earhart

    2004-01-27

    The overall objective of this project is the three phase development of an Early Entrance Coproduction Plant (EECP) which uses petroleum coke to produce at least one product from at least two of the following three categories: (1) electric power (or heat), (2) fuels, and (3) chemicals using ChevronTexaco's proprietary gasification technology. The objective of Phase I is to determine the feasibility and define the concept for the EECP located at a specific site; develop a Research, Development, and Testing (RD&T) Plan to mitigate technical risks and barriers; and prepare a Preliminary Project Financing Plan. The objective of Phase II is to implement the work as outlined in the Phase I RD&T Plan to enhance the development and commercial acceptance of coproduction technology. The objective of Phase III is to develop an engineering design package and a financing and testing plan for an EECP located at a specific site. The project's intended result is to provide the necessary technical, economic, and environmental information needed by industry to move the EECP forward to detailed design, construction, and operation. The partners in this project are Texaco Energy Systems LLC or TES (a subsidiary of ChevronTexaco), General Electric (GE), Praxair, and Kellogg Brown & Root (KBR) in addition to the U.S. Department of Energy (DOE). TES is providing gasification technology and Fischer-Tropsch (F-T) technology developed by Rentech, GE is providing combustion turbine technology, Praxair is providing air separation technology, and KBR is providing engineering. Each of the EECP subsystems was assessed for technical risks and barriers. A plan was developed to mitigate the identified risks (Phase II RD&T Plan, October 2000). The potential technical and economic risks to the EECP from Task 2.5 can be mitigated by demonstrating that the end-use products derived from the upgrading of the F-T synthesis total liquid product can meet or exceed current specifications for the

  11. Are seed dormancy and persistence in soil related?

    NARCIS (Netherlands)

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

    2003-01-01

    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 betwe

  12. Sucrose is an early modulator of the key hormonal mechanisms controlling bud outgrowth in Rosa hybrida.

    Science.gov (United States)

    Barbier, François; Péron, Thomas; Lecerf, Marion; Perez-Garcia, Maria-Dolores; Barrière, Quentin; Rolčík, Jakub; Boutet-Mercey, Stéphanie; Citerne, Sylvie; Lemoine, Remi; Porcheron, Benoît; Roman, Hanaé; Leduc, Nathalie; Le Gourrierec, José; Bertheloot, Jessica; Sakr, Soulaiman

    2015-05-01

    Sugar has only recently been identified as a key player in triggering bud outgrowth, while hormonal control of bud outgrowth is already well established. To get a better understanding of sugar control, the present study investigated how sugar availability modulates the hormonal network during bud outgrowth in Rosa hybrida. Other plant models, for which mutants are available, were used when necessary. Buds were grown in vitro to manipulate available sugars. The temporal patterns of the hormonal regulatory network were assessed in parallel with bud outgrowth dynamics. Sucrose determined bud entrance into sustained growth in a concentration-dependent manner. Sustained growth was accompanied by sustained auxin production in buds, and sustained auxin export in a DR5::GUS-expressing pea line. Several events occurred ahead of sucrose-stimulated bud outgrowth. Sucrose upregulated early auxin synthesis genes (RhTAR1, RhYUC1) and the auxin efflux carrier gene RhPIN1, and promoted PIN1 abundance at the plasma membrane in a pPIN1::PIN1-GFP-expressing tomato line. Sucrose downregulated both RwMAX2, involved in the strigolactone-transduction pathway, and RhBRC1, a repressor of branching, at an early stage. The presence of sucrose also increased stem cytokinin content, but sucrose-promoted bud outgrowth was not related to that pathway. In these processes, several non-metabolizable sucrose analogues induced sustained bud outgrowth in R. hybrida, Pisum sativum, and Arabidopsis thaliana, suggesting that sucrose was involved in a signalling pathway. In conclusion, we identified potential hormonal candidates for bud outgrowth control by sugar. They are central to future investigations aimed at disentangling the processes that underlie regulation of bud outgrowth by sugar.

  13. EARLY ENTRANCE COPRODUCTION PLANT

    Energy Technology Data Exchange (ETDEWEB)

    Fred D. Brent; Lalit Shah; Earl Berry; Charles H. Schrader; John Anderson; J. Erwin; Matthew G. Banks; Terry L. Ullman

    2004-01-12

    The overall objective of this project is the three phase development of an Early Entrance Coproduction Plant (EECP) which uses petroleum coke to produce at least one product from at least two of the following three categories: (1) electric power (or heat), (2) fuels, and (3) chemicals using ChevronTexaco's proprietary gasification technology. The objective of Phase I is to determine the feasibility and define the concept for the EECP located at a specific site; develop a Research, Development, and Testing (RD&T) Plan to mitigate technical risks and barriers; and prepare a Preliminary Project Financing Plan. The objective of Phase II is to implement the work as outlined in the Phase I RD&T Plan to enhance the development and commercial acceptance of coproduction technology. The objective of Phase III is to develop an engineering design package and a financing and testing plan for an EECP located at a specific site. The project's intended result is to provide the necessary technical, economic, and environmental information needed by industry to move the EECP forward to detailed design, construction, and operation. The partners in this project are Texaco Energy Systems LLC or TES (a subsidiary of ChevronTexaco), General Electric (GE), Praxair, and Kellogg Brown & Root (KBR) in addition to the U.S. Department of Energy (DOE). TES is providing gasification technology and Fischer-Tropsch (F-T) technology developed by Rentech, GE is providing combustion turbine technology, Praxair is providing air separation technology, and KBR is providing engineering. Each of the EECP subsystems was assessed for technical risks and barriers. A plan was developed to mitigate the identified risks (Phase II RD&T Plan, October 2000). Phase II RD&T Task 2.6 identified as potential technical risks to the EECP the fuel/engine performance and emissions of the F-T diesel fuel products. Hydrotreating the neat F-T diesel product reduces potentially reactive olefins, oxygenates, and acids

  14. EARLY ENTRANCE COPRODUCTION PLANT

    Energy Technology Data Exchange (ETDEWEB)

    Fred D. Brent; Lalit Shah; Earl Berry; Charles H. Schrader; John Anderson; J. Erwin; Matthew G. Banks; Terry L. Ullman

    2004-01-12

    The overall objective of this project is the three phase development of an Early Entrance Coproduction Plant (EECP) which uses petroleum coke to produce at least one product from at least two of the following three categories: (1) electric power (or heat), (2) fuels, and (3) chemicals using ChevronTexaco's proprietary gasification technology. The objective of Phase I is to determine the feasibility and define the concept for the EECP located at a specific site; develop a Research, Development, and Testing (RD&T) Plan to mitigate technical risks and barriers; and prepare a Preliminary Project Financing Plan. The objective of Phase II is to implement the work as outlined in the Phase I RD&T Plan to enhance the development and commercial acceptance of coproduction technology. The objective of Phase III is to develop an engineering design package and a financing and testing plan for an EECP located at a specific site. The project's intended result is to provide the necessary technical, economic, and environmental information needed by industry to move the EECP forward to detailed design, construction, and operation. The partners in this project are Texaco Energy Systems LLC or TES (a subsidiary of ChevronTexaco), General Electric (GE), Praxair, and Kellogg Brown & Root (KBR) in addition to the U.S. Department of Energy (DOE). TES is providing gasification technology and Fischer-Tropsch (F-T) technology developed by Rentech, GE is providing combustion turbine technology, Praxair is providing air separation technology, and KBR is providing engineering. Each of the EECP subsystems was assessed for technical risks and barriers. A plan was developed to mitigate the identified risks (Phase II RD&T Plan, October 2000). Phase II RD&T Task 2.6 identified as potential technical risks to the EECP the fuel/engine performance and emissions of the F-T diesel fuel products. Hydrotreating the neat F-T diesel product reduces potentially reactive olefins, oxygenates, and acids

  15. On dormancy strategies in tardigrades.

    Science.gov (United States)

    Guidetti, Roberto; Altiero, Tiziana; Rebecchi, Lorena

    2011-05-01

    In this review we analyze the dormancy strategies of metazoans inhabiting "hostile to life" habitats, which have a strong impact on their ecology and in particular on the traits of their life history. Tardigrades are here considered a model animal, being aquatic organisms colonizing terrestrial habitats. Tardigrades evolved a large variety of dormant stages that can be ascribed to diapause (encystment, cyclomorphosis, resting eggs) and cryptobiosis (anhydrobiosis, cryobiosis, anoxibiosis). In tardigrades, diapause and cryptobiosis can occur separately or simultaneously, consequently the adoption of one adaptive strategy is not necessarily an alternative to the adoption of the other. Encystment and cyclomorphosis are characterized by seasonal cyclic changes in morphology and physiology of the animals. They share several common features and their evolution is strictly linked to the molting process. A bet-hedging strategy with different patterns of egg hatching time has been observed in a tardigrade species. Four categories of eggs have been identified: subitaneous, delayed-hatching, abortive and diapause resting eggs, which needs a stimulus to hatch (rehydration after a period of desiccation). Cryptobiotic tardigrades are able to withstand desiccation (anhydrobiosis) and freezing (cryobiosis) at any stage of their life-cycle. This ability involves a complex array of factors working at molecular (bioprotectans), physiological and structural levels. Animal survival and the accumulation of molecular damage are related to the time spent in the cryptobiotic state, to the abiotic parameters during the cryptobiotic state, and to the conditions during initial and final phases of the process. Cryptobiosis evolved independently at least two times in tardigrades, in eutardigrades and in echiniscoids. Within each evolutionary line, the absence of cryptobiotic abilities is more related to selective pressures to local habitat adaptation than to phylogenetic relationships. The

  16. Science for common entrance physics

    CERN Document Server

    Pickering, WR

    2015-01-01

    Cover everything required for the 13+ Common Entrance Physics exam with clearly presented content, lively illustrations and challenging end-of-chapter questions. This challenging and stimulating Science course has been reviewed by the ISEB subject editor and covers the content of both Levels 1 and 2 of the 13+ Physics exam. Designed for pupils in Years 7 and 8, it is an indispensable resource that lays the foundations for Common Entrance success. - Explores every Level 1 and 2 topic with clear explanations and examples - Includes topic-based exercises and extension questions - Builds on p

  17. Dormancy cycling in seeds: mechanisms and regulation

    NARCIS (Netherlands)

    Claessens, S.M.C.

    2012-01-01

    The life cycle of most plants starts, and ends, at the seed stage. In most species mature seeds are shed and dispersed on the ground. At this stage of its life cycle the seed may be dormant and will, by definition, not germinate under favourable conditions (Bewley, 1997). Seasonal dormancy cycling

  18. 47 CFR 69.110 - Entrance facilities.

    Science.gov (United States)

    2010-10-01

    ... 47 Telecommunication 3 2010-10-01 2010-10-01 false Entrance facilities. 69.110 Section 69.110... Computation of Charges § 69.110 Entrance facilities. (a) A flat-rated entrance facilities charge expressed in... that use telephone company facilities between the interexchange carrier or other person's point...

  19. Science for common entrance physics : answers

    CERN Document Server

    Pickering, W R

    2015-01-01

    This book contains answers to all exercises featured in the accompanying textbook Science for Common Entrance: Physics , which covers every Level 1 and 2 topic in the ISEB 13+ Physics Common Entrance exam syllabus. - Clean, clear layout for easy marking. - Includes examples of high-scoring answers with diagrams and workings. - Suitable for ISEB 13+ Mathematics Common Entrance exams taken from Autumn 2017 onwards. Also available to purchase from the Galore Park website www.galorepark.co.uk :. - Science for Common Entrance: Physics. - Science for Common Entrance: Biology. - Science for Common En

  20. Regulation of Metastatic Breast Cancer Dormancy

    Science.gov (United States)

    2015-09-01

    important knowledge gap we have developed an all-human hepatic bioreactor . In this award period we have established that the hepatic bioreactor is...functional for 30 days by functional and injury markers (BUN, AST, ALT, CYP). We have generated micrometastases in the bioreactor and determined that...breast cancer cell lines enter spontaneous dormancy in the bioreactor . We have also completed pilot experiments in mouse models for spontaneous

  1. 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.

  2. Dormancy: Illuminating How a Microbial Sleeping Beauty Awakens.

    Science.gov (United States)

    Sawers, R Gary

    2016-11-07

    Nitrogen limitation induces dormancy in the cyanobacterium Synechocystis. During dormancy, the bacterium neither photosynthesizes nor divides, yet it maintains low-level metabolic activity. A new study shows how provision of a nitrogen source initiates a regimented genetic program that initially kick-starts metabolism and ultimately photosynthesis.

  3. Development of the Relationship between Angiogenesis and Tumor Dormancy

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    Tumor dormancy, a complex and still poorly understood phenomenon, has been defined by the long-term persistence of occult cancer cells during tumor progression. Recurrence and metastasis may occur just because of an activation of a small portion of the tumor cells. In our view, sustained angiogenesis is considered essential in triggering invasive tumor growth. Here we analyze the correlation between angiogenesis and tumor dormancy, the establishment of tumor dormancy models, the imaging strategies and the new biomarkers for dececting microscopic tumors before or during the angiogenic switch. It imperative to understand the role of angiogenesis in tumor dormancy, as this will accelerate the development of anti-angiogenesis techniques to induce dormancy and/or eradicate dormant disease.

  4. Mathematics for common entrance three (extension) answers

    CERN Document Server

    Alexander, Serena

    2015-01-01

    This book contains answers to all exercises featured in the accompanying textbook Mathematics for Common Entrance Three (Extension) , which provides essential preparation for Level 3 of the ISEB 13+ Mathematics exam, as well as for CASE and other scholarship exams. - Clean, clear layout for easy marking. - Includes examples of high-scoring answers with diagrams and workings. Also available to purchase from the Galore Park website www.galorepark.co.uk :. - Mathematics for Common Entrance Three (Extension). - Mathematics for Common Entrance One. - Mathematics for Common Entrance One Answers. - M

  5. Perception of photoperiod in individual buds of mature trees regulates leaf-out.

    Science.gov (United States)

    Zohner, Constantin M; Renner, Susanne S

    2015-12-01

    Experimental data on the perception of day length and temperature in dormant temperate zone trees are surprisingly scarce. In order to investigate when and where these environmental signals are perceived, we carried out bagging experiments in which buds on branches of Fagus sylvatica, Aesculus hippocastanum and Picea abies trees were exposed to natural light increase or kept at constant 8-h days from December until June. Parallel experiments used twigs cut from the same trees, harvesting treated and control twigs seven times and then exposing them to 8- or 16-h days in a glasshouse. Under 8-h days, budburst in Fagus outdoors was delayed by 41 d and in Aesculus by 4 d; in Picea, day length had no effect. Buds on nearby branches reacted autonomously, and leaf primordia only reacted to light cues in late dormancy after accumulating warm days. Experiments applying different wavelength spectra and high-resolution spectrometry to buds indicate a phytochrome-mediated photoperiod control. By demonstrating local photoperiodic control of buds, revealing the time when these signals are perceived, and showing the interplay between photoperiod and chilling, this study contributes to improved modelling of the impact of climate warming on photosensitive species.

  6. Dormancy and germination: How does the crop seed decide?

    Science.gov (United States)

    Shu, K; Meng, Y J; Shuai, H W; Liu, W G; Du, J B; Liu, J; Yang, W Y

    2015-11-01

    Whether seeds germinate or maintain dormancy is decided upon through very intricate physiological processes. Correct timing of these processes is most important for the plants life cycle. If moist conditions are encountered, a low dormancy level causes pre-harvest sprouting in various crop species, such as wheat, corn and rice, this decreases crop yield and negatively impacts downstream industrial processing. In contrast, a deep level of seed dormancy prevents normal germination even under favourable conditions, resulting in a low emergence rate during agricultural production. Therefore, an optimal seed dormancy level is valuable for modern mechanised agricultural systems. Over the past several years, numerous studies have demonstrated that diverse endogenous and environmental factors regulate the balance between dormancy and germination, such as light, temperature, water status and bacteria in soil, and phytohormones such as ABA (abscisic acid) and GA (gibberellic acid). In this updated review, we highlight recent advances regarding the molecular mechanisms underlying regulation of seed dormancy and germination processes, including the external environmental and internal hormonal cues, and primarily focusing on the staple crop species. Furthermore, future challenges and research directions for developing a full understanding of crop seed dormancy and germination are also discussed.

  7. Stratification requirements for seed dormancy alleviation in a wetland weed.

    Science.gov (United States)

    Boddy, Louis G; Bradford, Kent J; Fischer, Albert J

    2013-01-01

    Echinochloaoryzicola(syn.E. phyllopogon) is an exotic weed of California rice paddies that has evolved resistance to multiple herbicides. Elimination of seedlingsthroughcertain weed control methods can limit the spread of this weed, but is contingent on accurate predictions of germination and emergence timing, which are influenced by seed dormancy levels.In summer annuals, dormancy can often be relieved through stratification, a period of prolonged exposure to cold and moist conditions.We used population-based threshold models to quantify the effects of stratification on seed germination of four E. Oryzicola populations at a range of water potential (Ψ) and oxygen levels. We also determined how stratification temperatures, moisture levels and durations contributed to dormancy release. Stratification released dormancy by decreasing base Ψ and hydrotimerequired for germination and by eliminating any germination sensitivity to oxygen. Stratification also increased average germination rates (GR), which were used as a proxy for relative dormancy levels. Alternating temperatures nearly doubled GR in all populations, indicating that seeds could be partially dormant despite achieving high final germination percentages. Stratification at Ψ = 0 MPa increased GR compared to stratification at lower water potentials, demonstrating that Ψ contributed to regulating dormancy release. Maximum GR occurred after 2-4 weeks of stratification at 0 MPa; GR were often more rapid for herbicide-resistant than for herbicide-susceptible seeds, implying greater dormancy in the latter. Manipulation of field conditions to promote dormancy alleviation of E. oryzicola seeds might improve the rate and uniformity of germination for seed bank depletion through seedling weed control. Our results suggest field soil saturation in winter would contribute towards E. oryzicola dormancy release and decrease the time to seedling emergence.

  8. Candidate cave entrances on Mars

    Science.gov (United States)

    Cushing, Glen E.

    2012-01-01

    This paper presents newly discovered candidate cave entrances into Martian near-surface lava tubes, volcano-tectonic fracture systems, and pit craters and describes their characteristics and exploration possibilities. These candidates are all collapse features that occur either intermittently along laterally continuous trench-like depressions or in the floors of sheer-walled atypical pit craters. As viewed from orbit, locations of most candidates are visibly consistent with known terrestrial features such as tube-fed lava flows, volcano-tectonic fractures, and pit craters, each of which forms by mechanisms that can produce caves. Although we cannot determine subsurface extents of the Martian features discussed here, some may continue unimpeded for many kilometers if terrestrial examples are indeed analogous. The features presented here were identified in images acquired by the Mars Odyssey's Thermal Emission Imaging System visible-wavelength camera, and by the Mars Reconnaissance Orbiter's Context Camera. Select candidates have since been targeted by the High-Resolution Imaging Science Experiment. Martian caves are promising potential sites for future human habitation and astrobiology investigations; understanding their characteristics is critical for long-term mission planning and for developing the necessary exploration technologies.

  9. The Relation Between Endogenous Hormones and Late-Germination in Buds of Avrolles Apple

    Institute of Scientific and Technical Information of China (English)

    QIN Dong; WANG Jin-zheng; GUO Jian-min; ZHAI Heng

    2009-01-01

    In order to provide the physiological bases for selecting late-germination cultivars that can avoid late frost damage,the very late-germination variety Avrolles (Malus domestica) was used to study the relation between the dynamic changes and balance of endogenous hormones and germination time.The concentrations of endogenous GA3,ABA,IAA,and ZR were determined in buds of Avrolles and Judeline (Malus domestica) from dormancy releasing to germination by capillary electrophoresis.The dynamic changes of endogenous hormones concentration in buds of Avrolles and Judeline were similar; but the magnitude and time of the change were significantly different between the two varieties,especially for GA3.GA3 concentration increased with dormancy releasing,then decreased,and increased again before germination in the two varieties.GA3 concentration in Avrolles was 1.72 times that in Judeline at the first peak,the gap increased to 2.22 times at germination.ZR concentration exhibited a continuous increase trend,but it decreased sharply before germination.ZR accumulation in Avrolles took 36 days longer than in Judeline,the peak value was 44% higher than in Judeline.Before germination,ZR concentration in Avrolles was 2.12 times that in Judeline.The differences between IAA and ABA concentration were relatively small in the two varieties,while the ratios of GA3/ABA and (GA3 + IAA + ZR)/ABA in Avrolles were 2.08 and 1.58 times those in Judeline,respectively.The germination of apple bud was regulated by the endogenous hormones.For the late-germination apple Avrolles,its germination requires higher concentration of GA3 and ZR,which leads to the high ratios of GA3/ABA and (GA3 + IAA + ZR)/ABA.

  10. Budding of Walnut ( Juglans regia L.

    Directory of Open Access Journals (Sweden)

    Majlind Kasmi

    2013-09-01

    Full Text Available The walnut is classified as a strategic species for human nutrition and is included in the FAO’s list of priority plants. Walnut, (Juglans regia L. propagation is more difficult, compared to most fruit species. Due to walnut heterozygosity, propagation by seeds does not lead to inheritance of all the characteristics of certain varieties. That is the reason why propagation technologies are being improved worldwide. The purpose of this experiment was to increase the success of inoculation of the walnut budding var. Franquete. Methods such as the patch budding and chip budding have been employed during the experiment. To establish the most appropriate season of inoculation, June budding on 28 June (with buds taken in the current season, autumn budding on 28 August (with buds taken in the current season and spring budding on 28 May (with buds collected from the winter dormant period, were tested. As rootstocks for the June and August budding, the seedlings of Juglans regia L. of the current year's growth have been employed. For the spring inoculation the one year old scions have been used. Patch budding resulted the most successful method for walnuts. However, the success of the method of patch budding depends on the season of inoculation. An 80 % of successful inoculation was achieved by June budding (on 28 June. Furthermore, cutting off the leaf 20 days before the buds being taken for budding, led to even higher results reaching 87% of successful inoculation. According to the results of the present study, the June budding of the patch method seems to be the best solution for the production of grafted young walnut trees.

  11. Overcoming dormancy in seeds of cotton-silk tree

    OpenAIRE

    Irinaldo Lima do Nascimento

    2012-01-01

    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,...

  12. 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.

  13. 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.

  14. Do university entrance exams predict academic achievement?

    OpenAIRE

    Häkkinen, Iida

    2004-01-01

    The study examines which factors predict academic performance at university and compares the predictive values of subject-related entrance exams and indicators of past school performance. The results show that in the fields of engineering and social sciences entrance exams predict both graduation and the number of study credits better than past performance. In education past school performance is a better predictor of graduation. Changing the admission rule to school grades would affect the a...

  15. Review of Tumor Dormancy Therapy Using Traditional Oriental Herbal Medicine

    Directory of Open Access Journals (Sweden)

    Lee Jong-Ho

    2013-03-01

    Full Text Available Objective: Standard cancer therapy prolongs survival, but can be detrimental to the quality of life, compromise the immune system, and leave residual disease that can cause recurrence years or decades in the future. Tumor dormancy therapy is a novel therapeutic approach that may improve these shortcomings, promote quality of life, and prolong survival. The aim of this study was to analyze studies on dormancy therapy, especially studies using traditional Oriental herbal medicine, so as to evaluate the efficacy of dormancy therapy with traditional oriental herbal medicine. Methods: We conducted a systematic literature review using Scientific and Technical Information Integration Services (NDSL, PubMed, and RISS. We searched for clinical reports, papers, and books related to tumor metastasis, recurrence, immunotherapy, tumor dormancy, and traditional oriental herbal medicine with anticancer effects. Seventy-nine (79 experimental and clinical articles in both Korean and English were reviewed. This study was conducted from March 1, 2012 to May 31, 2012. Results: This approach, Tumor dormancy therapy, rather than seeking to remove the tumor, includes combination of low-dose chemotherapy, immunotherapy, immunosurveillance, and other methods to stabilize tumor growth and to enhance the host is immunity against disseminated tumor cells and thus to manage cancer as a chronic disease while maintaining quality of life. In particular, integrative use of Oriental herbal medicine has been shown to induce or maintain tumor dormancy, increase the effectiveness of conventional chemotherapy, improve quality of life, and prolong survival. Conclusion: Tumor dormancy therapy is a promising novel therapeutic approach that may be especially effective with Oriental herbal medicine. Further research is needed to determine its potential mechanisms and therapeutic applications.

  16. Entrance C - Meyrin site: new access conditions

    CERN Multimedia

    2013-01-01

    Entrance C on the Meyrin site, which drivers of motorised vehicles can use Mondays to Fridays from 7 a.m. to 9 a.m. and from 5 p.m. to 7 p.m., has been altered to include a turnstile to allow cyclists and pedestrians to use their access card to get in and out of the site from 6 a.m. until 10 p.m.   The following video illustrates how to use the new turnstile: A new type of entrance gate fitted with a number plate reader similar to that installed at the entrance to the Prévessin site should, once fully tested, allow drivers of motorised vehicles to access the site. For the time being, the conditions of use of Entrance C remain unchanged. Further information on the entry into force of new arrangements will be issued in due course. For further information about CERN entrances: CERN opening hours CERN control access GS Department

  17. Seed dormancy in Acer: Endogenous germination inhibitors and dormancy in Acer pseudoplatanus L.

    Science.gov (United States)

    Webb, D P; Wareing, P F

    1972-06-01

    Dormant seeds of Acer pseudoplatanus L. contain two zones of inhibition on paper chromatograms in "10:1:1" as detected by the lettuce and cress seed germination, and the wheat coleoptile bioassays. One zone at Rf 0.6-0.8 was partitioned into ethyl acetate at acid pH and was shown to contain ABA by its behaviour on GLC and isomerization under ultra-violet light. The other zone at Rf 0.9 was detected only in the germination bioassays and was partitioned into ethyl acetate over a range of pH indicating the presence of one or more neutral compounds.The inhibitors present in the embryo of dormant sycamore seeds inhibited the germination of non-dormant sycamore seeds at relatively low concentrations. A comparison with the effects of application of exogenous ABA indicated that endogenous ABA could not solely account for the inhibitory activity of seed extracts, which appeared to be due partly to the presence of ABA and partly to that of neutral compounds present in the embryo. Leaching treatments that removed dormancy led to a decrease in the level of inhibitors present mainly in the basic fraction. The exogenous application of kinetin to dormant sycamore seeds increased germination whereas gibberellic acid had no effect. Similar responses were obtained with lettuce seeds inhibited by the basic fraction of dormant sycamore seeds.It is suggested that an inhibitor-cytokinin interaction may be involved in the dormancy of sycamore seeds.

  18. Germination and Dormancy in Annual Halophyte Juncus ranarius Song & Perr.

    Directory of Open Access Journals (Sweden)

    Jeremi KOŁODZIEJEK

    2015-12-01

    Full Text Available The effects of cold stratification and gibberellic acid (GA3 on dormancy breaking for seeds of the annual halophyte species Juncus ranarius were tested. Germination percentage and recovery responses of salt stressed seeds were also tested. Freshly collected seeds germinated slowly under all incubation conditions. Thus, the seeds of J. ranarius have physiological dormancy, e.g. they are water permeable, have a fully developed embryo and require cold stratification to come out of dormancy. Furthermore, promotion of germination by GA3 after-ripening in dry storage also indicated that these seeds have non-deep physiological dormancy. In general, the higher the GA3 concentration, the more germination occurred within the studied range. Juncus ranarius demonstrated a germination preference for light. The highest germination percentage and rate of germination were recorded under constant light conditions at 22 °C after 24 weeks of cold stratification. In saline solutions, the highest percentage of germination was obtained at 25 mM L-1 NaCl, and further increase in salinity resulted in a gradual decrease in germination. However, ungerminated seeds were not damaged by salt, showing a high level of recovery. The greater the reduction in salinity, the better the germination rate became. It was concluded that dormancy could be completely broken by cold stratification, indicating spring germination. Juncus ranarius can grow well at lower NaCl concentrations under constant light conditions at 22 °C.

  19. Heterogeneity of dormancy in apple embryos. [Pyrus malus

    Energy Technology Data Exchange (ETDEWEB)

    Christine, B.; Camille, B.

    1986-04-01

    This study concerns the heterogeneity of embryo dormancy with the aim of investigating a possible relationship between chlorophyllogenesis and dormancy. Dormant embryos of Pyrus malus L. cv. Golden delicious were cultivated on water-agar (agar 6 g/l). They were placed flat with one cotyledon in contact with the medium. After 6 days of culture at 23/sup 0/C under fluorescent light the non-germinated embryos (99% of the total) were classified in three main categories on the basis of the state of greening of their cotyledons. By application of partial dormancy releasing treatments (chilling, anaerobiosis, GA/sub 7/), it was shown that the three categories of embryos were characterized by different depths of dormancy. Germination was most difficult for the embryos which were non pigmented after the initial culture, whereas high germination percentages were rapidly reached by embryos exhibiting high degree of greening. Evaluation of ABA by radioimmunoassay shows that the three categories of embryos also differ in their ABA and ABA-GE levels. A good correlation was thus observed between depth of dormancy and levels of ABA and ABA-GE.

  20. 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.

  1. Mechanisms of seed dormancy in an annual population of Zostera marina (eelgrass) from the Netherlands)

    NARCIS (Netherlands)

    Harrison, P.G.

    1991-01-01

    Mechanisms of dormancy of seeds from an annual population of the seagrass Zostera marina L. (eelgrass) in the SW Netherlands were investigated in the laboratory. Both physiological dormancy (a requirement for reduced salinity for germination) and physical dormancy (imposed by the seed coat) existed

  2. Analysis of natural allelic variation at seed dormancy loci of Arabidopsis thaliana

    NARCIS (Netherlands)

    Alonso-Blanco, C.; Bentsink, L.; Hanhart, C.J.; Vries, de M.H.C.; Koornneef, M.

    2003-01-01

    Arabidopsis accessions differ largely in their seed dormancy behavior. To understand the genetic basis of this intraspecific variation we analyzed two accessions: the laboratory strain Landsberg erecta (Ler) with low dormancy and the strong-dormancy accession Cape Verde Islands (Cvi). We used a quan

  3. Cellular Factors Required for Lassa Virus Budding

    OpenAIRE

    Urata, Shuzo; Noda, Takeshi; Kawaoka, Yoshihiro; Yokosawa, Hideyoshi; Yasuda, Jiro

    2006-01-01

    It is known that Lassa virus Z protein is sufficient for the release of virus-like particles (VLPs) and that it has two L domains, PTAP and PPPY, in its C terminus. However, little is known about the cellular factor for Lassa virus budding. We examined which cellular factors are used in Lassa virus Z budding. We demonstrated that Lassa Z protein efficiently produces VLPs and uses cellular factors, Vps4A, Vps4B, and Tsg101, in budding, suggesting that Lassa virus budding uses the multivesicula...

  4. Whole-Transcriptome Analysis of Differentially Expressed Genes in the Vegetative Buds, Floral Buds and Buds of Chrysanthemum morifolium.

    Directory of Open Access Journals (Sweden)

    Hua Liu

    Full Text Available Chrysanthemum morifolium is an important floral crop that is cultivated worldwide. However, due to a lack of genomic resources, very little information is available concerning the molecular mechanisms of flower development in chrysanthemum.The transcriptomes of chrysanthemum vegetative buds, floral buds and buds were sequenced using Illumina paired-end sequencing technology. A total of 15.4 Gb of reads were assembled into 91,367 unigenes with an average length of 739 bp. A total of 43,137 unigenes showed similarity to known proteins in the Swissprot or NCBI non-redundant protein databases. Additionally, 25,424, 24,321 and 13,704 unigenes were assigned to 56 gene ontology (GO categories, 25 EuKaryotic Orthologous Groups (KOG categories, and 285 Kyoto Encyclopedia of Genes and Genomes (KEGG pathways, respectively. A total of 1,876 differentially expressed genes (DEGs (1,516 up-regulated, 360 down-regulated were identified between vegetative buds and floral buds, and 3,300 DEGs (1,277 up-regulated, 1,706 down-regulated were identified between floral buds and buds. Many genes encoding important transcription factors (e.g., AP2, MYB, MYC, WRKY, NAC and CRT as well as proteins involved in carbohydrate metabolism, protein kinase activity, plant hormone signal transduction, and the defense responses, among others, were considerably up-regulated in floral buds. Genes involved in the photoperiod pathway and flower organ determination were also identified. These genes represent important candidate genes for molecular cloning and functional analysis to study flowering regulation in chrysanthemum.This comparative transcriptome analysis revealed significant differences in gene expression and signaling pathway components between the vegetative buds, floral buds and buds of Chrysanthemum morifolium. A wide range of genes was implicated in regulating the phase transition from vegetative to reproductive growth. These results should aid researchers in the study of

  5. Coordination of seed dormancy and germination processes by MYB96.

    Science.gov (United States)

    Lee, Kyounghee; Seo, Pil Joon

    2015-01-01

    The transition between seed dormancy and germination is an important stage that initiates plant life cycle. Hormonal balances of abscisic acid (ABA) and gibberellin (GA) contribute to determining the proper timing to germinate. Here, we demonstrate that the R2R3-type MYB96 transcription factor, a key ABA signaling mediator, coordinates seed dormancy and germination processes through distinct downstream events. This transcription factor controls ABA-INSENSITIVE 4 (ABI4) expression to inhibit seed germination by suppressing breakdown of lipid reserves in embryo. In addition, it also induces seed dormancy by stimulating ABA biosynthesis in an ABI4-independent manner. We propose that MYB96 integrates a multitude of environmental stress signals and acts as a master regulator in the determination of timing for seed germination.

  6. HIV Pol inhibits HIV budding and mediates the severe budding defect of Gag-Pol.

    Directory of Open Access Journals (Sweden)

    Xin Gan

    Full Text Available The prevailing hypothesis of HIV budding posits that the viral Gag protein drives budding, and that the Gag p6 peptide plays an essential role by recruiting host-cell budding factors to sites of HIV assembly. HIV also expresses a second Gag protein, p160 Gag-Pol, which lacks p6 and fails to bud from cells, consistent with the prevailing hypothesis of HIV budding. However, we show here that the severe budding defect of Gag-Pol is not caused by the absence of p6, but rather, by the presence of Pol. Specifically, we show that (i the budding defect of Gag-Pol is unaffected by loss of HIV protease activity and is therefore an intrinsic property of the Gag-Pol polyprotein, (ii the N-terminal 433 amino acids of Gag and Gag-Pol are sufficient to drive virus budding even though they lack p6, (iii the severe budding defect of Gag-Pol is caused by a dominant, cis-acting inhibitor of budding in the HIV Pol domain, and (iv Gag-Pol inhibits Gag and virus budding in trans, even at normal levels of Gag and Gag-Pol expression. These and other data support an alternative hypothesis of HIV budding as a process that is mediated by the normal, non-viral pathway of exosome/microvesicle biogenesis.

  7. Repellence of the red bud borer (Resseliella oculiperda) to grafted apple trees by impregnation of budding tape with essential oils

    NARCIS (Netherlands)

    Tol, van R.W.H.M.; Linden, van der A.; Swarts, H.J.; Visser, J.H.

    2007-01-01

    The red bud borer Resseliella oculiperda (Rübs.) is a pest insect of apple trees when rootstocks are grafted with scion buds by shield budding. The female midges are attracted to the wounds of the grafted buds where they lay their eggs. The larvae feed on the cambium and destroy the buds completely

  8. Mathematics for common entrance one answers

    CERN Document Server

    Alexander, Serena

    2015-01-01

    Enables efficient assessment of pupils' performance at Levels 1 and 2 of the ISEB 13+ Common Entrance syllabus. Clear layout saves time marking work and identifies areas requiring further attention. Includes diagrams and working where necessary, to demonstrate how to present high-scoring answers in Level 1 and 2 exams

  9. Mathematics for common entrance two answers

    CERN Document Server

    Alexander, Serena

    2015-01-01

    Enables efficient assessment of pupils' performance at Levels 1 and 2 of the ISEB 13+ Common Entrance syllabus. Clear layout saves time marking work and identifies areas requiring further attention. Includes diagrams and working where necessary, to demonstrate how to present high-scoring answers in Level 1 and 2 exams.

  10. Supercalculators and University Entrance Calculus Examinations.

    Science.gov (United States)

    Hong, Ye Yoon; Thomas, Mike; Kiernan, Christine

    2000-01-01

    Investigates whether the use of computer algebra systems could provide a significant advantage to students taking standard university entrance calculus examinations. Indicates that supercalculators would probably provide a significant advantage, particularly for lower-achieving students. Demonstrates that it is possible to write questions in which…

  11. 30 CFR 18.37 - Lead entrances.

    Science.gov (United States)

    2010-07-01

    ... against loosening. (d) Compressed packing material shall be in contact with the cable jacket for a length... cable jacket and the nominal inside diameter of the packing material shall not exceed 1/32-inch, based... § 18.37 Lead entrances. (a) Insulated cable(s), which must extend through an outside wall of...

  12. An Entrance Region Mass Transfer Experiment.

    Science.gov (United States)

    Youngquist, G. R.

    1979-01-01

    This paper describes an experiment designed to reveal the consequences of the development of a concentration boundary layer. The rate of a mass transfer limited electrochemical reaction is measured and used to obtain the dependence of average Sherwood number on Reynolds number and entrance length. (Author/BB)

  13. Mapping and Analysis of Quantitative Trait Loci Controlling Seed Dormancy in Rice

    Institute of Scientific and Technical Information of China (English)

    JIANG Ling; ZHANG Wen-wei; ZHAI Hu-qu; WAN Jian-min

    2005-01-01

    Seed dormancy is one of the most important traits related to the rice grain quality and seeds application, because it is associated with pre-harvest sprouting, resulting in a downgrading of quality and severe limitations in end-use application.The recent development of DNA markers and linkage maps of rice has made possible mapping of individual genes associated with complex seed dormancy traits, analyzing the genetics effects of individual genes and genotype-byenvironment interactions. Up to now, numerous quantitative trait loci (QTLs) associated with seed dormancy in rice have been identified and mapped in the molecular genetic map by different populations. In this review, we focus on the genetic base of seed dormancy in rice, especially compare QTLs controlling seed dormancy reported up to now, analyze the expression and stability of QTLs controlling seed dormancy, and discuss the present problems. Finally we show a new pathway to further research on seed dormancy.

  14. Epicotyl morphophysiological dormancy in seeds of Lilium polyphyllum (Liliaceae)

    Indian Academy of Sciences (India)

    Anurag Dhyani; Shyam S Phartyal; B P Nautiyal; M C Nautiyal

    2013-03-01

    Dormancy-breaking and seed germination studies in genus Lilium reveal that the majority of Lilium spp. studied have an underdeveloped embryo at maturity, which grows inside the seed before the radicle emerges. Additionally, the embryo, radicle or cotyledon has a physiological component of dormancy; thus, Lilium seeds have morphophysiological dormancy (MPD). A previous study suggested that seeds of Lilium polyphyllum have MPD but the study did not investigate the development of the embryo, which is one of the main criteria to determine MPD in seeds. To test this hypothesis, we investigated embryo growth and emergence of radicles and epicotyls in seeds over a range of temperatures. At maturity, seeds had underdeveloped embryos which developed fully at warm temperature within 6 weeks. Immediately after embryo growth, radicles also emerged at warm temperatures. However, epicotyls failed to emerge soon after radicle emergence. Epicotyls emerged from > 90% seeds with an emerged radicle only after they were subjected to 2 weeks of cold moist stratification. The overall temperature requirements for dormancy-breaking and seed germination indicate a non-deep simple epicotyl MPD in L. polyphyllum.

  15. 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

  16. 49 CFR 236.534 - Entrance to equipped territory; requirements.

    Science.gov (United States)

    2010-10-01

    ... 49 Transportation 4 2010-10-01 2010-10-01 false Entrance to equipped territory; requirements. 236... Entrance to equipped territory; requirements. Where trains are not required to stop at the entrance to equipped territory, except when leaving yards and stations and speed until entering equipped territory...

  17. Alteration of PHYA expression change circadian rhythms and timing of bud set in Populus.

    Science.gov (United States)

    Kozarewa, Iwanka; Ibáñez, Cristian; Johansson, Mikael; Ogren, Erling; Mozley, David; Nylander, Eva; Chono, Makiko; Moritz, Thomas; Eriksson, Maria E

    2010-05-01

    In many temperate woody species, dormancy is induced by short photoperiods. Earlier studies have shown that the photoreceptor phytochrome A (phyA) promotes growth. Specifically, Populus plants that over-express the oat PHYA gene (oatPHYAox) show daylength-independent growth and do not become dormant. However, we show that oatPHYAox plants could be induced to set bud and become cold hardy by exposure to a shorter, non-24 h diurnal cycle that significantly alters the relative position between endogenous rhythms and perceived light/dark cycles. Furthermore, we describe studies in which the expression of endogenous Populus tremula x P. tremuloides PHYTOCHROME A (PttPHYA) was reduced in Populus trees by antisense inhibition. The antisense plants showed altered photoperiodic requirements, resulting in earlier growth cessation and bud formation in response to daylength shortening, an effect that was explained by an altered innate period that leads to phase changes of clock-associated genes such as PttCO2. Moreover, gene expression studies following far-red light pulses show a phyA-mediated repression of PttLHY1 and an induction of PttFKF1 and PttFT. We conclude that the level of PttPHYA expression strongly influences seasonally regulated growth in Populus and is central to co-ordination between internal clock-regulated rhythms and external light/dark cycles through its dual effect on the pace of clock rhythms and in light signaling.

  18. Entrance Effects in Microchannel Gas Flow

    Institute of Scientific and Technical Information of China (English)

    T. Lewandowski; S. Jebauer; J. Czerwinska; P. Doerffer

    2009-01-01

    Motivation of this work has its origin in the boundary layer control for aeronautics and turbomachinery. For that purpose boundary layer can be modified by perforated plates with holes of specific sizes. The questions which rise in such configuration are related to the existence of optimal size of the holes and the influence of microscale phenomena on the global flow patterns. This paper concentrates on the issue of the entrance effects on the micro-channel flow. It is shown that mass flow rate is only insignificantly influenced by slip effects. Global parameters such as pressure difference and geometrical shape in more pronounced way alter flow behavior. In this paper we concentrate on the numerical investigation of the microchannel flow for Kn < 0.01 and Re < 500. The channel length is finite. Hence, entrance and outlet effects on microchannel flow can be studied.

  19. 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

  20. 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.

  1. A Cellular Automaton Model for Tumor Dormancy: Emergence of a Proliferative Switch

    CERN Document Server

    Chen, Duyu; Torquato, Salvatore

    2014-01-01

    Malignant cancers that lead to fatal outcomes for patients may remain dormant for very long periods of time. Although individual mechanisms such as cellular dormancy, angiogenic dormancy and immunosurveillance have been proposed, a comprehensive understanding of cancer dormancy and the "switch" from a dormant to a proliferative state still needs to be strengthened from both a basic and clinical point of view. Computational modeling enables one to explore a variety of scenarios for possible but realistic microscopic dormancy mechanisms and their predicted outcomes. The aim of this paper is to devise such a predictive computational model of dormancy with an emergent "switch" behavior. Specifically, we generalize a previous cellular automaton (CA) model for proliferative growth of solid tumor that now incorporates a variety of cell-level tumor-host interactions and different mechanisms for tumor dormancy, for example the effects of the immune system. Our new CA rules induce a natural "competition" between the tu...

  2. SUBSTRATES UTILIZATION TO ASSESS ROOTEDNESS CAPACITY AND VIABILITY BUDS AT SOME GRAPE VARIETIES

    Directory of Open Access Journals (Sweden)

    Gheorghe Cristian Popescu

    2013-12-01

    Full Text Available The cultivated grapevine (Vitis vinifera L. is a fruit crop of enormous economic importance with over eight million hectares planted in vineyards worldwide. Table grapes and wines represent a considerable share of the economy in many grape and wine-producing countries. During the dormant, due to low temperatures and how to prepare grape for entrance in winter time, wood annual increases and buds may be adversely affected. The way how the vines passed by dormant period can affect the buds and wood viability and rooting ability of vine cuttings. In this study were tested on different culture substrates vine cuttings belonging to a noble variety and a hybrid vines: Merlot and Isabella. Noble grapes are a term used to describe the international variety of grapes that are most recognizable for the top quality wine they produce. In this paper was determinate total dry matter of vine cuttings, humidity of biological material, vine cuttings rooting capacity and viability status buds cuttings placed on three nutritional substrates.

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

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    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.

  4. Proteomics and posttranslational proteomics of seed dormancy and germination.

    Science.gov (United States)

    Rajjou, Loïc; Belghazi, Maya; Catusse, Julie; Ogé, Laurent; Arc, Erwann; Godin, Béatrice; Chibani, Kamel; Ali-Rachidi, Sonia; Collet, Boris; Grappin, Philippe; Jullien, Marc; Gallardo, Karine; Job, Claudette; Job, Dominique

    2011-01-01

    The seed is the dispersal unit of plants and must survive the vagaries of the environment. It is the object of intense genetic and genomic studies because processes related to seed quality affect crop yield and the seed itself provides food for humans and animals. Presently, the general aim of postgenomics analyses is to understand the complex biochemical and molecular processes underlying seed quality, longevity, dormancy, and vigor. Due to advances in functional genomics, the recent past years have seen a tremendous progress in our understanding of several aspects of seed development and germination. Here, we describe the proteomics protocols (from protein extraction to mass spectrometry) that can be used to investigate several aspects of seed physiology, including germination and its hormonal regulation, dormancy release, and seed longevity. These techniques can be applied to the study of both model plants (such as Arabidopsis) and crops.

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

    Science.gov (United States)

    2016-07-01

    formulate two graduate level lectures- advanced immunology and molecular biology of cancer - related to cancer dormancy. 2) As an invited speaker, Dr...Department of Microbiology & Immunology and Massey Cancer Center, Virginia Commonwealth University, Richmond, VA 23298, USA. Corresponding Author: Masoud...Toor,†,** Harry D. Bear,†,§ and Masoud H. Manjili*,†,2 *Department of Microbiology and Immunology , †Massey Cancer Center, and Departments of

  6. Macrophage Function in Early Dissemination and Dormancy of Breast Cancer

    Science.gov (United States)

    2015-09-01

    of Oncological Sciences, The Immunology Institute, Tisch Cancer Institute, Mount Sinai School of Medicine, New York, NY, USA 3Department of...cell 13, 58-68. Joyce, J. A., and Pollard, J. W. (2009). Microenvironmental regulation of metastasis. Nature reviews Cancer 9, 239-252. Kaplan, R. N...AWARD NUMBER: W81XWH-14-1-0365 TITLE: Macrophage Functions in Early Dissemination and Dormancy of Breast Cancer PRINCIPAL INVESTIGATOR: Nina

  7. Senescence, dormancy and tillering in perennial C4 grasses.

    Science.gov (United States)

    Sarath, Gautam; Baird, Lisa M; Mitchell, Robert B

    2014-03-01

    Perennial, temperate, C4 grasses, such as switchgrass and miscanthus have been tabbed as sources of herbaceous biomass for the production of green fuels and chemicals based on a number of positive agronomic traits. Although there is important literature on the management of these species for biomass production on marginal lands, numerous aspects of their biology are as yet unexplored at the molecular level. Perenniality, a key agronomic trait, is a function of plant dormancy and winter survival of the below-ground parts of the plants. These include the crowns, rhizomes and meristems that will produce tillers. Maintaining meristem viability is critical for the continued survival of the plants. Plant tillers emerge from the dormant crown and rhizome meristems at the start of the growing period in the spring, progress through a phase of vegetative growth, followed by flowering and eventually undergo senescence. There is nutrient mobilization from the aerial portions of the plant to the crowns and rhizomes during tiller senescence. Signals arising from the shoots and from the environment can be expected to be integrated as the plants enter into dormancy. Plant senescence and dormancy have been well studied in several dicot species and offer a potential framework to understand these processes in temperate C4 perennial grasses. The availability of latitudinally adapted populations for switchgrass presents an opportunity to dissect molecular mechanisms that can impact senescence, dormancy and winter survival. Given the large increase in genomic and other resources for switchgrass, it is anticipated that projected molecular studies with switchgrass will have a broader impact on related species.

  8. 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.

  9. Hormonal Regulation of Dormancy in Developing Sorghum Seeds.

    Science.gov (United States)

    Steinbach, H. S.; Benech-Arnold, R. L.; Sanchez, R. A.

    1997-01-01

    The role of abscisic acid (ABA) and gibberellic acid (GA) in determining the dormancy level of developing sorghum (Sorghum bicolor [L.] Moench.) seeds from varieties presenting contrasting preharvest sprouting behavior (Redland B2, susceptible; IS 9530, resistant) was investigated. Panicles from both varieties were sprayed soon after pollination with fluridone or paclobutrazol to inhibit ABA and GA synthesis, respectively. Fluridone application to the panicles increased germinability of Redland B2 immature caryopses, whereas early treatment with paclobutrazol completely inhibited germination of this variety during most of the developmental period. Incubating caryopses in the presence of 100 [mu]M GA4+7 overcame the inhibitory effect of paclobutrazol, but also stimulated germination of seeds from other treatments. IS 9530 caryopses presented germination indices close to zero until physiological maturity (44 d after pollination) in control and paclobutrazol-treated particles. However, fluridone-treated caryopses were released from dormancy earlier than control and paclobutrazol-treated caryopses. Incubation in the presence of GA4+7 stimulated germination of caryopses from all treatments. Our results support the proposition that a low dormancy level (which is related to a high preharvest sprouting susceptibility) is determined not only by a low embryonic sensitivity to ABA, but also by a high GA content or sensitivity.

  10. 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.

  11. Methods for overcoming dormancy of Parkinsonia aculeata L. seeds

    Directory of Open Access Journals (Sweden)

    Pollyanna Freire Montenegro Agra

    2015-06-01

    Full Text Available The Parkinsonia aculeata L seeds have tegumentary dormancy, which makes them last for a long period in the seed bank of the earth so that their germination occurs in favorable conditions. Our aim was to evaluate the influence of pregermination treatments for overcoming the dormancy of P. aculeata seeds. The seeds were submitted to the following treatments: sample – intact seeds (T1; mechanical scarification with water sandpaper no. 80, followed by room temperature water soaking for 12 and 24 hours (T3 e T4, respectively; immersion in sulfuric acid for 5, 10, 15 and 20 minutes (T5, T6, T7 e T8, respectively; immersion in water in 60ºC, 70ºC, 80ºC and 90ºC for one minute (T9, T10, T11 e T12, respectively. The characteristics evaluated were: percentage of emergence, emergence first count, emergence speed index, height and dry weight of seedlings. In the treatments that involved immersion in water in 60ºC, 70ºC, 80ºC and 90ºC, a low percentage of emergence was obtained. The P. aculeate seeds tegumentary dormancy is overcome with maximum efficiency by the mechanical scarification with sandpaper, suggesting that, in natural environment the movement of contraction and expansion of the soil results in a mechanical scarification of the tegument of the seeds, thus, allowing a high percentage of germination with distribution as time passes.

  12. Shrinkage of ipsilateral taste buds and hyperplasia of contralateral taste buds following chorda tympani nerve transection

    Institute of Scientific and Technical Information of China (English)

    Yi-ke Li; Juan-mei Yang; Yi-bo Huang; Dong-dong Ren; Fang-lu Chi

    2015-01-01

    The morphological changes that occur in the taste buds after denervation are not well under-stood in rats, especially in the contralateral tongue epithelium. In this study, we investigated the time course of morphological changes in the taste buds following unilateral nerve transection. The role of the trigeminal component of the lingual nerve in maintaining the structural integrity of the taste buds was also examined. Twenty-four Sprague-Dawley rats were randomly divided into three groups:control, unilateral chorda tympani nerve transection and unilateral chorda tympani nerve transection+lingual nerve transection. Rats were allowed up to 42 days of re-covery before being euthanized. The taste buds were visualized using a cytokeratin 8 antibody. Taste bud counts, volumes and taste receptor cell numbers were quantiifed and compared among groups. No signiifcant difference was detected between the chorda tympani nerve transection and chorda tympani nerve transection+lingual nerve transection groups. Taste bud counts, vol-umes and taste receptor cell numbers on the ipsilateral side all decreased signiifcantly compared with control. On the contralateral side, the number of taste buds remained unchanged over time, but they were larger, and taste receptor cells were more numerous postoperatively. There was no evidence for a role of the trigeminal branch of the lingual nerve in maintaining the structural integrity of the anterior taste buds.

  13. Shrinkage of ipsilateral taste buds and hyperplasia of contralateral taste buds following chorda tympani nerve transection

    Directory of Open Access Journals (Sweden)

    Yi-ke Li

    2015-01-01

    Full Text Available The morphological changes that occur in the taste buds after denervation are not well understood in rats, especially in the contralateral tongue epithelium. In this study, we investigated the time course of morphological changes in the taste buds following unilateral nerve transection. The role of the trigeminal component of the lingual nerve in maintaining the structural integrity of the taste buds was also examined. Twenty-four Sprague-Dawley rats were randomly divided into three groups: control, unilateral chorda tympani nerve transection and unilateral chorda tympani nerve transection + lingual nerve transection. Rats were allowed up to 42 days of recovery before being euthanized. The taste buds were visualized using a cytokeratin 8 antibody. Taste bud counts, volumes and taste receptor cell numbers were quantified and compared among groups. No significant difference was detected between the chorda tympani nerve transection and chorda tympani nerve transection + lingual nerve transection groups. Taste bud counts, volumes and taste receptor cell numbers on the ipsilateral side all decreased significantly compared with control. On the contralateral side, the number of taste buds remained unchanged over time, but they were larger, and taste receptor cells were more numerous postoperatively. There was no evidence for a role of the trigeminal branch of the lingual nerve in maintaining the structural integrity of the anterior taste buds.

  14. Entrance Length and Turbulence Transition in Microflows

    Science.gov (United States)

    Wereley, Steve; Lee, Sangyoup; Gui, Lichuan

    2002-11-01

    Since microfabrication techniques are typically planar processes, microchannel flows typically have significant predevelopment due to the upstream reservoir having the same height as the microchannel. The main concerns of the current study are categorized into finding the effects of typical microchannel geometry on the velocity entrance length in the laminar flow regime and providing the turbulence transitional Reynolds number range using the details of the velocity profile rather than global measurements of pressure drop. A rectangular micro-channel of aspect ratio 2.65 and the hydraulic diameter 380 um was used in this study. Micro particle image velocimetry measurement was performed to measure the velocity profiles. The entrance length is found to be reduced by about 45number occurs between 2100 and 2900-comparable to macroscale observations. Finally a new technique is proposed to measure the turbulence intensity of a flow directly from the PIV correlation function peak width. This new technique provides results comparable to traditional means of calculating turbulence intensity but is particularly useful in measuring microflows where the seeding density can be very low.

  15. Oxytocin signaling in mouse taste buds.

    Directory of Open Access Journals (Sweden)

    Michael S Sinclair

    Full Text Available BACKGROUND: The neuropeptide, oxytocin (OXT, acts on brain circuits to inhibit food intake. Mutant mice lacking OXT (OXT knockout overconsume salty and sweet (i.e. sucrose, saccharin solutions. We asked if OXT might also act on taste buds via its receptor, OXTR. METHODOLOGY/PRINCIPAL FINDINGS: Using RT-PCR, we detected the expression of OXTR in taste buds throughout the oral cavity, but not in adjacent non-taste lingual epithelium. By immunostaining tissues from OXTR-YFP knock-in mice, we found that OXTR is expressed in a subset of Glial-like (Type I taste cells, and also in cells on the periphery of taste buds. Single-cell RT-PCR confirmed this cell-type assignment. Using Ca2+ imaging, we observed that physiologically appropriate concentrations of OXT evoked [Ca2+]i mobilization in a subset of taste cells (EC50 approximately 33 nM. OXT-evoked responses were significantly inhibited by the OXTR antagonist, L-371,257. Isolated OXT-responsive taste cells were neither Receptor (Type II nor Presynaptic (Type III cells, consistent with our immunofluorescence observations. We also investigated the source of OXT peptide that may act on taste cells. Both RT-PCR and immunostaining suggest that the OXT peptide is not produced in taste buds or in their associated nerves. Finally, we also examined the morphology of taste buds from mice that lack OXTR. Taste buds and their constituent cell types appeared very similar in mice with two, one or no copies of the OXTR gene. CONCLUSIONS/SIGNIFICANCE: We conclude that OXT elicits Ca2+ signals via OXTR in murine taste buds. OXT-responsive cells are most likely a subset of Glial-like (Type I taste cells. OXT itself is not produced locally in taste tissue and is likely delivered through the circulation. Loss of OXTR does not grossly alter the morphology of any of the cell types contained in taste buds. Instead, we speculate that OXT-responsive Glial-like (Type I taste bud cells modulate taste signaling and afferent

  16. LITERACY SENSES: WRITING IN VESTIBULAR (ENTRANCE EXAMS

    Directory of Open Access Journals (Sweden)

    Victoria Wilson da Costa Coelho

    2015-10-01

    Full Text Available The aim of this paper is to pose a reflection on explicit or underlying literacy practices in a literacy event such as the Brazilian university entrance exams (vestibular using, as an object of study, the essays written during that event. We aim to understand the educated writing culture, or Brazilian literacy, in its very extreme, that is, the end of High School, based on Bakhtin’s theory of enunciation. Despite pedagogical measures focused on elaborate (argumentative writing in view of college assessment exams and ENEM (National High School Exam, we know how unsatisfactory its results still are, in terms of the school literacy practices, which still remains to be sufficiently reflected on. It is also worth highlighting that we understand writing (school writing more as a set of social practices than as a set of skills alone.

  17. Regulation of seed dormancy by abscisic acid and DELAY OF Germination 1

    NARCIS (Netherlands)

    Dekkers, S.J.W.; Bentsink, L.

    2015-01-01

    Physiological dormancy has been described as a physiological inhibiting mechanism that prevents radicle emergence. It can be caused by the embryo (embryo dormancy) as well as by the structures that cover the embryo. One of its functions is to time plant growth and reproduction to the most optimal se

  18. 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...

  19. 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 an

  20. Grain dormancy and light quality effects on germination in the model grass Brachypodium distachyon.

    Science.gov (United States)

    Barrero, José M; Jacobsen, John V; Talbot, Mark J; White, Rosemary G; Swain, Stephen M; Garvin, David F; Gubler, Frank

    2012-01-01

    • Lack of grain dormancy in cereal crops such as barley and wheat is a common problem affecting farming areas around the world, causing losses in yield and quality because of preharvest sprouting. Control of seed or grain dormancy has been investigated extensively using various approaches in different species, including Arabidopsis and cereals. However, the use of a monocot model plant such as Brachypodium distachyon presents opportunities for the discovery of new genes related to grain dormancy that are not present in modern commercial crops. • In this work we present an anatomical description of the Brachypodium caryopsis, and we describe the dormancy behaviour of six common diploid Brachypodium inbred genotypes. We also study the effect of light quality (blue, red and far-red) on germination, and analyse changes in abscisic acid levels and gene expression between a dormant and a non-dormant Brachypodium genotype. • Our results indicate that different genotypes display high natural variability in grain dormancy and that the characteristics of dormancy and germination are similar to those found in other cereals. • We propose that Brachypodium is an ideal model for studies of grain dormancy in grasses and can be used to identify new strategies for increasing grain dormancy in crop species.

  1. 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...

  2. Two Faces of One Seed: Hormonal Regulation of Dormancy and Germination.

    Science.gov (United States)

    Shu, Kai; Liu, Xiao-dong; Xie, Qi; He, Zu-hua

    2016-01-01

    Seed plants have evolved to maintain the dormancy of freshly matured seeds until the appropriate time for germination. Seed dormancy and germination are distinct physiological processes, and the transition from dormancy to germination is not only a critical developmental step in the life cycle of plants but is also important for agricultural production. These processes are precisely regulated by diverse endogenous hormones and environmental cues. Although ABA (abscisic acid) and GAs (gibberellins) are known to be the primary phytohormones that antagonistically regulate seed dormancy, recent findings demonstrate that another phytohormone, auxin, is also critical for inducing and maintaining seed dormancy, and therefore might act as a key protector of seed dormancy. In this review, we summarize our current understanding of the sophisticated molecular networks involving the critical roles of phytohormones in regulating seed dormancy and germination, in which AP2-domain-containing transcription factors play key roles. We also discuss the interactions (crosstalk) of diverse hormonal signals in seed dormancy and germination, focusing on the ABA/GA balance that constitutes the central node.

  3. Capturing blocked-entrance binaural signals from open-entrance recordings

    DEFF Research Database (Denmark)

    Hammershøi, Dorte; Hoffmann, Pablo F.; Olesen, Søren Krarup

    2008-01-01

    interfering the individual's hearing and doing. In this work we propose a strategy for the recording of binaural audio with minimal hearing interference, and for transforming these recordings to blocked-entrance versions that are more suitable for analysis and reproduction of binaural audio in a more general...... context. To this purpose, equalization filters are derived from the ratio between blocked and open ear canal transfer functions. Different transfer-function measuring techniques and inverse filtering methods are evaluated....

  4. 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

    2013-06-25

    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.

  5. Persuasive Ways to Change Entrance Use of Buildings

    NARCIS (Netherlands)

    Boer, de Johannes; Heylen, Dirk K.J.; Teeuw, Wouter B.

    2014-01-01

    People tend to use the same door every time they enter and exit a building. When certain entrances are widely preferred over others, congestion can occur. This paper describes two interventions to persuade visitors to use another entrance. The first intervention used sensory deprivation (darkness),

  6. Molecular Determinants and Clinical Implications of Breast Cancer Dormancy

    Science.gov (United States)

    2014-12-01

    repair mediates resistance of hair follicle bulge stem cells to DNA-damage- induced cell death. Nat Cell Biol 2010; 12: 572–582. 7. Chiruvella KK1...dormancy-mediated recurrence and malignancy which may serve as important diagnosis biomarkers and therapeutic targets for breast cancer recurrence...populations. In this assay, BamHI-cleaved pCSCMV-tdTomato was used as a target for NHEJ and pEGFP-C1 as a control plasmid. Briefly, MCF7 cells were

  7. Temperature requirements differ for the two stages of seed dormancy break in Aegopodium podagraria (Apiaceae), a species with deep complex morphophysiological dormancy.

    Science.gov (United States)

    Phartyal, Shyam S; Kondo, Tetsuya; Baskin, Jerry M; Baskin, Carol C

    2009-06-01

    Only a few studies have considered the possibility that low temperature requirements may vary among stages of dormancy break in seeds with morphophysiological dormancy (MPD). We show that this lack of consideration in previous studies on seed dormancy and germination of Aegopodium podagraria might explain the low germination percentages and/or the relatively long periods of incubation needed for germination. Under natural temperatures, embryos began to grow in September and were fully elongated by late December; most growth occurred when the average daily mean temperature was about 10°C. Radicles emerged under snow in late winter, and cotyledons emerged after snowmelt in early spring. In laboratory experiments, 100% of the embryos grew to full length at both 0 and 5°C, whereas 0°C was much more effective than 5°C in overcoming the physiological dormancy in seeds after embryos were fully elongated. Following radicle emergence, cotyledons emerged readily in a wide range of temperatures ≥5°C. GA(3) did not substitute for the low temperature requirement for dormancy break. Seed dormancy in A. podagraria fits Nikolaeva's formula for deep complex MPD, i.e., C(3)B-C(3). Better germination of seeds pretreated at 0° than at 5°C has practical implications for cultivating this species.

  8. Identification and Quality Assessment of Chrysanthemum Buds by CE Fingerprinting

    Directory of Open Access Journals (Sweden)

    Xiaoping Xing

    2015-01-01

    Full Text Available A simple and efficient fingerprinting method for chrysanthemum buds was developed with the aim of establishing a quality control protocol based on biochemical makeup. Chrysanthemum bud samples were successively extracted by water and alcohol. The fingerprints of the chrysanthemum buds samples were obtained using capillary electrophoresis and electrochemical detection (CE-ED employing copper and carbon working electrodes to capture all of the chemical information. 10 batches of chrysanthemum buds were collected from different regions and various factories to establish the baseline fingerprint. The experimental data of 10 batches electropherogram buds by CE were analyzed by correlation coefficient and the included angle cosine methods. A standard chrysanthemum bud fingerprint including 24 common peaks was established, 12 from each electrode, which was successfully applied to identify and distinguish between chrysanthemum buds from 2 other chrysanthemum species. These results demonstrate that fingerprint analysis can be used as an important criterion for chrysanthemum buds quality control.

  9. Mechanisms of frost adaptation and freeze damage in grapevine buds

    OpenAIRE

    Badulescu Valle, Radu Virgil

    2002-01-01

    Mechanisms of frost hardening in compound (latent) buds of the grapevine cultivar ?Bacchus? were tested with different methods during three winters. The investigated parameters were LTE/HTE (low temperature exotherm/high temperature exotherm), water content, starch, sugar- and anions combination and bud histology. Water content from wood and buds was determined regularly every 2 weeks from March 1998 until Mai 2000. The lowest water content in wood and buds (about 40 %) was found ...

  10. 高温和单氰胺对油桃休眠花芽呼吸代谢的影响%Effects of high temperature and hydrogen cyanamide on dormant nectarine' s floral bud respiratory metabolism

    Institute of Scientific and Technical Information of China (English)

    谭钺; 冷传远; 李玲; 徐臣善; 陈修德; 高东升

    2012-01-01

    以3年生盆栽‘曙光’油桃为材料,研究油桃自然休眠过程中50℃高温和单氰胺对花芽呼吸代谢的影响.结果表明:高温和单氰胺均可以打破油桃的自然休眠,导致休眠花芽呼吸代谢显著下降,其呼吸代谢的衰减可持续数小时.主要呼吸途径三羧酸循环(TCA)和磷酸戊糖途径(PPP)的运行均受到影响.未经破眠处理的花芽TCA和PPP均呈衰减趋势,而高温和单氰胺诱导了早期呼吸衰减结束后PPP的迅速活化.高温还表现出对TCA恢复的诱导,而单氰胺在96 h内未表现出这种作用.在高温和单氰胺打破自然休眠的机制中,呼吸衰减和随后出现的PPP活化可能是重要的组成部分.%Taking 3-year old potted ' Shuguang' nectarine (Prunus persica var. nectariana cv. Shuguang) as test material, this paper studied the effects of high temperature (50℃ , HT) and hydrogen cyanamide (HC) on the floral bud respiratory metabolism of the tree during its natural dormancy. Both HT and HC could break the natural dormancy of the tree, and lead to a significant decrease in the respiratory metabolism of floral buds for several hours. The main respiratory pathways, tricarboxylic acid cycle (TCA) and pentose phosphate pathway (PPP) , were affected. For the buds not received dormancy-breaking treatments, both the TCA and the PPP decreased, while treating with HT and HC induced a rapid recovery of PPP after the early respiratory attenuation. HT also induced the recovery of TCA, but HC did not show this effect in 96 hours. Therefore, respiratory attenuation and the following PPP activation could be the important part in the floral bud respiratory mechanism of HT- and HC-induced dormancy release.

  11. Bipolar budding in yeasts - an electron microscope study

    NARCIS (Netherlands)

    Kreger-van Rij, N.J.W.; Veenhuis, M.

    1971-01-01

    Bud formation in yeasts with bipolar budding was studied by electron microscopy of thin sections. Budding in yeasts of the species Saccharomycodes ludwigii, Hanseniaspora valbyensis and Wickerhamia fluorescens resulted in concentric rings of scar ridges on the wall of the mother cell. The wall betwe

  12. Seed Dormancy in Red Rice (Oryza sativa) (IX. Embryo Fructose-2,6-Bisphosphate during Dormancy Breaking and Subsequent Germination).

    Science.gov (United States)

    Footitt, S.; Cohn, M. A.

    1995-04-01

    Fructose-2,6-bisphosphate (Fru-2,6-bisP) was evaluated as a potential marker for the dormancy-breaking phase or the germination phase before pericarp splitting in red rice (Oryza sativa). During 4 h of imbibition at 30[deg]C, Fru-2,6-bisP of dehulled dormant and nondormant seeds increased to 0.26 and 0.38 pmol embryo-1, respectively. In nondormant seeds, embryo Fru-2,6-bisP content remained stable until the onset of pericarp splitting (12 h) and increased rapidly thereafter. In dormant seeds, Fru-2,6-bisP declined to 0.09 pmol embryo-1 at 24 h. Embryo Fru-2,6-bisP was correlated with O2 uptake of dormant and nondormant seeds. A 24-h exposure of dehulled, water-imbibed, dormant seeds to treatments yielding >90% germination (sodium nitrite [4 mM], propionic acid [22 mM], methyl propionate [32 mM], propanol [75 mM], and propionaldehyde [40 mM]) led to changes in embryo Fru-2,6-bisP that were unrelated to the final germination percentages. Furthermore, a 2-h pulse of propionaldehyde increased Fru-2,6-bisP 4-fold but did not break dormancy. Whereas nitrite and propionaldehyde increased Fru-2,6-bisP to 0.33 pmol embryo-1 after 2 h of contact, propionic acid and methyl propionate did not increase Fru-2,6-bisP above the untreated control. In all cases, further increases in Fru-2,6-bisP occurred after pericarp splitting. However, the plateau Fru-2,6-bisP attained during chemical contact was inversely correlated with elapsed time to 30% germination (r = -0.978). Therefore, although Fru-2,6-bisP is not a universal marker for dormancy release, its rapid increase during nitrite and propionaldehyde treatments suggests that events associated with dormancy breaking can occur within 2 h of chemical treatment.

  13. 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.

  14. Treatments to break the dormancy of Cassia fistula L. seeds

    Directory of Open Access Journals (Sweden)

    Paulo Alexandre Fernandes Rodrigues de Melo

    2013-11-01

    Full Text Available Cassia fistula L. (Fabaceae – Caesalpinioidea is a forest species that is propagated by seeds. To promote the production of seedlings of C. fistula it is necessary to break the natural dormancy of its seeds, which is caused by the seed tegument that is impermeable to water. The goal of this study was to establish a pre-germination treatment for germinating C. fistula seeds. The seeds were subjected to the following treatments: control – intact seeds (T1; mechanical scarification with sandpaper nº 80 on the side of the seed (T2; mechanical scarification with sandpaper nº 80, followed by immersion in water, at room temperature, for 12 and 24 hours (T3 and T4, respectively; immersion in sulfuric acid for 1, 5, 10, 15, and 20 min (T5, T6, T7, T8 and T9, respectively; and immersion in water at 100°C until cool (T10. We evaluated the percentage of emergence, first count emergence, emergence speed index, and the length and dry mass of the seedlings. The treatment that involved immersion in water at 100°C did not break the dormancy of the seeds. The highest percentage of emergence was for the treatment that scarified the side of the seeds with sandpaper nº 80.

  15. Synchronization of the Budding Yeast Saccharomyces cerevisiae.

    Science.gov (United States)

    Foltman, Magdalena; Molist, Iago; Sanchez-Diaz, Alberto

    2016-01-01

    A number of model organisms have provided the basis for our understanding of the eukaryotic cell cycle. These model organisms are generally much easier to manipulate than mammalian cells and as such provide amenable tools for extensive genetic and biochemical analysis. One of the most common model organisms used to study the cell cycle is the budding yeast Saccharomyces cerevisiae. This model provides the ability to synchronise cells efficiently at different stages of the cell cycle, which in turn opens up the possibility for extensive and detailed study of mechanisms regulating the eukaryotic cell cycle. Here, we describe methods in which budding yeast cells are arrested at a particular phase of the cell cycle and then released from the block, permitting the study of molecular mechanisms that drive the progression through the cell cycle.

  16. Historical bathymetric changes near the entrance to Grays Harbor, Washington

    Energy Technology Data Exchange (ETDEWEB)

    Burch, T.L.; Sherwood, C.R. [Battelle/Marine Sciences Lab., Sequim, WA (United States)

    1992-12-01

    Large changes in the distribution of sediment near the entrance to Grays Harbor, Washington, have occurred since the long rock jetties were built to confine flow. Spits to the north and south of the entrance have grown, the entrance channel has deepened, and the outer bar has eroded and moved offshore. The shorelines of North Beach and South Beach have experienced significant amounts of both erosion and accretion since the jetties were constructed around the turn of the century. Recently, the erosion rate at South Beach has increased and, because Half Moon Bay is growing at the expense of the shoreward side of Point Chehalis, the vegetated portion of the spit is now less than 350 ft wide at the narrowest section. The US Army Corps of Engineers, Seattle District, requested that Battelle/Marine Sciences Laboratory evaluate long-term trends in erosion near the entrance to Grays Harbor.

  17. Crab Orchard National Wildlife Refuge : Entrance Fee Plan

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — The Emergency Wetlands Resources Act of 1986 authorizes the Fish and Wildlife Service to collect entrance fees within selected units of the National Wildlife Refuge...

  18. Obscured phylogeny and possible recombinational dormancy in Escherichia coli

    Directory of Open Access Journals (Sweden)

    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.

  19. 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.

  20. 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

    Pre-harvest sprouting results in significant economic loss for the grain industry around the world. Lack of adequate seed dormancy is the major reason for pre-harvest sprouting in the field under wet weather conditions. Although this trait is governed by multiple genes it is also highly heritable....... 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...

  1. 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.

  2. Development and standardization of a simple technique for breaking seed dormancy in sunflower (Helianthus annuus L.)

    OpenAIRE

    Maiti R.K.; Vidyasagar P; Shahapur S.C.; Ghosh S.K.; Seiler G.J.

    2006-01-01

    Seed dormancy causes a great problem in efficient seed production of sunflower. Attempts have been made to develop simple techniques for breaking seed dormancy. In the first experiment, different techniques were evaluated using treatments such as a growth regulator, Ethrel, priming (water soaking followed by 2-3 days drying in shade), chemicals such as acetone (CH3COCH3), and potassium nitrate (KNO3) which showed the most promise. To confirm these findings, several treatments (25% acetone, 0....

  3. 低温对芦笋萌芽及其激素含量的影响%Effect of Low Temperature on Bud Break and Changes of Endogenous Hormones of Asparagus

    Institute of Scientific and Technical Information of China (English)

    苗金龙; 乜兰春; 石立哲; 高飞; 贾丽丽

    2011-01-01

    以芦笋'Applo'为试材,在河北保定研究了低温对其萌芽及内源激素含量变化的影响.结果表明:自然条件下,芦笋在10月30日保温,仍可迅速萌芽生长;但11月14日和11月29日保温,萌芽数和采笋数显著减少;而在12月14日或之后保温,萌芽数与10月30日保温无显著差异,采笋数显著多于10月30日保温.说明芦笋在低温作用下一旦进入休眠阶段,需要满足一定的低温积累量,才能在保温后恢复正常生长.不同低温处理表明,2℃30 d或5℃45 d可满足'Applo'对低温的需求.芦笋在经历自然低温和低温处理过程中,鳞芽中GA3、IAA、ZR含量相对稳定,ABA含量先上升后又迅速下降,ABA含量变化与与芦笋休眠及休眠解除有密切关系.%Three-year-old plants of ‘Applo' were used to study the effect of low temperature on bud break and changes of endogenous hormones in bud of asparagus (Asparagus officinalis Linn) . The results showed that asparagus plant showed rapid bud break and spear growth when it was incubated on Oct. 30.But when it was incubated on Nov. 14 or 29, bud break and spear harvest decreased. While when it was incubated on Dec. 14 or later, the bud break had no difference with that incubated on Oct. 30, but spear harvest increased. These results suggested that once asparagus plants underwent the period of dormancy induced by the chilling in winter, they needed sufficient chilling duration to restore the activity of bud break and spear growth. The experiment of different low temperature treatment revealed that 2 ℃ 30 d or 5 ℃ 45 d could sastify the chilling duration of‘Applo'. During natural or treated chilling period, the content of GA3, IAA and ZR in bud of asparagus was relatively stable, but the content of ABA increased during dormancy stage, and then decreased rapidly to a lower level. The changes of ABA content had close relationship with dormancy and dormancy-breaking of asparagus.

  4. Mechanism of supercooling in flower bud of Camellia oleifea

    Institute of Scientific and Technical Information of China (English)

    苏维埃; 潘良文

    1995-01-01

    It is the first time for MRI to be used in the research of flower buds supercooling. Directobservation on freezing course of living flower buds of Camellia yuhsienensis by MRI and tissue browning test showed that freezing order of the flower organs is bud axis, scale, petal, pistil and stamen. It is coincident with the direction of ice development from bud axes to flower organs upwards. The corresponding results from MRI and freezing-fixation showed that the water translocation from flower organs to axes and scales is carried on in the course of bud freezing. ’H spectral measurement of NMR was used to follow the decrease of unfrozen water in the buds during the cooling.

  5. Identification of an amphipathic helix important for the formation of ectopic septin spirals and axial budding in yeast axial landmark protein Bud3p.

    Science.gov (United States)

    Guo, Jia; Gong, Ting; Gao, Xiang-Dong

    2011-03-08

    Correct positioning of polarity axis in response to internal or external cues is central to cellular morphogenesis and cell fate determination. In the budding yeast Saccharomyces cerevisiae, Bud3p plays a key role in the axial bud-site selection (axial budding) process in which cells assemble the new bud next to the preceding cell division site. Bud3p is thought to act as a component of a spatial landmark. However, it is not clear how Bud3p interacts with other components of the landmark, such as the septins, to control axial budding. Here, we report that overexpression of Bud3p causes the formation of small septin rings (∼1 µm in diameter) and arcs aside from previously reported spiral-like septin structures. Bud3p closely associates with the septins in vivo as Bud3p colocalizes with these aberrant septin structures and forms a complex with two septins, Cdc10p and Cdc11p. The interaction of Bud3p with the septins may involve multiple regions of Bud3p including 1-858, 850-1220, and 1221-1636 a.a. since they all target to the bud neck but exhibit different effects on septin organization when overexpressed. In addition, our study reveals that the axial budding function of Bud3p is mediated by the N-terminal region 1-858. This region shares an amphipathic helix (850-858) crucial for bud neck targeting with the middle portion 850-1103 involved in the formation of ectopic septin spirals and rings. Interestingly, the Dbl-homology domain located in 1-858 is dispensable for axial bud-site selection. Our findings suggest that multiple regions of Bud3p ensure efficient targeting of Bud3p to the bud neck in the assembly of the axial landmark and distinct domains of Bud3p are involved in axial bud-site selection and other cellular processes.

  6. Taxonomy Icon Data: Budding yeast [Taxonomy Icon

    Lifescience Database Archive (English)

    Full Text Available Budding yeast Saccharomyces cerevisiae Saccharomyces_cerevisiae_L.png Saccharomyces_cerevisiae_NL.png Saccha...romyces_cerevisiae_S.png Saccharomyces_cerevisiae_NS.png http://biosciencedbc.jp/ta...xonomy_icon/icon.cgi?i=Saccharomyces+cerevisiae&t=L http://biosciencedbc.jp/taxonomy_icon/icon.cgi?i=Saccharomyces...+cerevisiae&t=NL http://biosciencedbc.jp/taxonomy_icon/icon.cgi?i=Saccharomyces...+cerevisiae&t=S http://biosciencedbc.jp/taxonomy_icon/icon.cgi?i=Saccharomyces+cerevisiae&t=NS http://togodb.biosciencedbc.jp/togodb/view/taxonomy_icon_comment_en?species_id=216 ...

  7. Regeneration of Blue Honeysuckle via Dormant Axillary Buds

    Institute of Scientific and Technical Information of China (English)

    QU Guiqin; HUANG Longshuang; HUO Junwei

    2008-01-01

    The optimum medium for dormant axillary buds culture of blue honeysuckle was screened according to the growth rate and elongation rate by inoculating the buds on culture medium with various 6-BA and iron-salt concentration. About 35 days, the stretched stem buds were divided into strong root system after inoculated on 1/2 MS+1.0 mg·L-1 IBA rooting medium. Amount of qualified tissue-cultured young plants could be obtained by the stretched stem buds reproduction.

  8. Development Correlations of the Buds of Grapevine (Vitis vinifera L.

    Directory of Open Access Journals (Sweden)

    Liliana ROTARU

    2010-06-01

    Full Text Available The development characteristics of different buds of the grapevine are mainly related by stimulation and/or inhibition effects, the action of which is still inexplicable. The present study examines the development dynamics of the buds of a one-year old branch after excision of different buds and the application of ?-naphtyl acetic acid (ANA, as well as the growth capacity of each bud individually. We verified the effects of acrotony cited previously by various researchers. These effects are due to different developmental characteristics of which could to lay the groundwork for the improvement of different productions methods.

  9. Overexpression of CONSTANS homologs CO1 and CO2 fails to alter normal reproductive onset and fall bud set in woody perennial poplar.

    Directory of Open Access Journals (Sweden)

    Chuan-Yu Hsu

    Full Text Available CONSTANS (CO is an important flowering-time gene in the photoperiodic flowering pathway of annual Arabidopsis thaliana in which overexpression of CO induces early flowering, whereas mutations in CO cause delayed flowering. The closest homologs of CO in woody perennial poplar (Populus spp. are CO1 and CO2. A previous report showed that the CO2/FLOWERING LOCUS T1 (FT1 regulon controls the onset of reproduction in poplar, similar to what is seen with the CO/FLOWERING LOCUS T (FT regulon in Arabidopsis. The CO2/FT1 regulon was also reported to control fall bud set. Our long-term field observations show that overexpression of CO1 and CO2 individually or together did not alter normal reproductive onset, spring bud break, or fall dormancy in poplar, but did result in smaller trees when compared with controls. Transcripts of CO1 and CO2 were normally most abundant in the growing season and rhythmic within a day, peaking at dawn. Our manipulative experiments did not provide evidence for transcriptional regulation being affected by photoperiod, light intensity, temperature, or water stress when transcripts of CO1 and CO2 were consistently measured in the morning. A genetic network analysis using overexpressing trees, microarrays, and computation demonstrated that a majority of functionally known genes downstream of CO1 and CO2 are associated with metabolic processes, which could explain their effect on tree size. In conclusion, the function of CO1 and CO2 in poplar does not appear to overlap with that of CO from Arabidopsis, nor do our data support the involvement of CO1 and CO2 in spring bud break or fall bud set.

  10. Predicting Siltation in Entrance Channel Based on Wind Conditions

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    The siltation induced by wind waves in an entrance channel is one of the prime factors influencing the operation efficiency of a port. It is necessary to predict the siltation accurately for dredging and ship operation passing through the entrance of the port. However, it is difficult to apply the traditional method to predicting entrance siltation because of its complex computational procedure and lacking the data of ocean dynamic elements in the specified sea area. From the view of energy conservation, a direct relationship between wind conditions and sediment deposition can be founded. On the basis of the above methodology, an empirical formula expressed by wind conditions for forecasting the siltation in the entrance channel is set up. The wind conditions are easily obtained from the local meteorological stations or weather maps, so the formula established in this paper is more convenient and practical than the traditional method. A case study is provided, in which the emopirical formula is calibrated and verified utilizing the measured wind and siltation conditions in the entrance channel of the port. Comparisons between computed values and measured data show satisfactory agreement.

  11. Optimal shape of entrances for a frictionless nanochannel

    Science.gov (United States)

    Belin, Christophe; Joly, Laurent; Detcheverry, François

    2016-09-01

    The nearly frictionless flow of water in narrow carbon nanotubes is a genuine nanofluidic phenomenon with many prospects of applications in membrane technology. When inner dissipation is vanishing, the limiting factor to high flux lies in the viscous dissipation occurring at the tube mouth. As shown by Gravelle et al. [Gravelle, Joly, Detcheverry, Ybert, Cottin-Bizonne, and Bocquet, Proc. Natl. Acad. Sci. USA 110, 16367 (2013), 10.1073/pnas.1306447110], these so-called end effects can be reduced by adding a conical entrance. In this work, we take a step further and search for the optimal entrance shape. We use finite element calculations to compute the hydrodynamic resistance of a frictionless tube with superellipse-shaped entrances and propose an approximate analytical model. If perfect slip applies on its wall, an optimal entrance which is only 10 tube radii in length is sufficient to reduce end effects by an order of magnitude, a performance almost three times better than the optimal cone. In the case of partial slip, the resistance decreases with the entrance length before reaching a plateau at an optimal length controlled by liquid-solid slip. Our results are discussed in connection with biological and artificial systems.

  12. Tumor budding in upper gastrointestinal carcinomas

    Directory of Open Access Journals (Sweden)

    Viktor Hendrik Koelzer

    2014-08-01

    Full Text Available The basis of personalized medicine in oncology is the prediction of an individual’s risk of relapse and death from disease. The presence of tumor budding (TB at the tumor-host interface of gastrointestinal cancers has been recognized as a hallmark of unfavorable disease biology. TB is defined as the presence of dedifferentiated cells or small clusters of up to five cells at the tumor invasive front and can be observed in aggressive carcinomas of the esophagus, stomach, pancreas, ampulla, colon and rectum. Presence of TB reproducibly correlates with advanced tumor stage, frequent lymphovascular invasion, nodal and distant metastasis. The UICC has officially recognized TB as additional independent prognostic factor in cancers of the colon and rectum. Recent studies have also characterized TB as a promising prognostic indicator for clinical management of esophageal squamous cell carcinoma, adenocarcinoma of the gastro-esophageal junction and gastric adenocarcinoma. However, several important issues have to be addressed for application in daily diagnostic practice: 1 Validation of prognostic scoring systems for tumor budding in large, multi-center studies 2 Consensus on the optimal assessment method 3 Inter-observer reproducibility. This review provides a comprehensive analysis of TB in cancers of the upper gastrointestinal tract including critical appraisal of perspectives for further study.

  13. Molecular mechanism of arenavirus assembly and budding.

    Science.gov (United States)

    Urata, Shuzo; Yasuda, Jiro

    2012-10-10

    Arenaviruses have a bisegmented negative-strand RNA genome, which encodes four viral proteins: GP and NP by the S segment and L and Z by the L segment. These four viral proteins possess multiple functions in infection, replication and release of progeny viruses from infected cells. The small RING finger protein, Z protein is a matrix protein that plays a central role in viral assembly and budding. Although all arenaviruses encode Z protein, amino acid sequence alignment showed a huge variety among the species, especially at the C-terminus where the L-domain is located. Recent publications have demonstrated the interactions between viral protein and viral protein, and viral protein and host cellular protein, which facilitate transportation and assembly of viral components to sites of virus egress. This review presents a summary of current knowledge regarding arenavirus assembly and budding, in comparison with other enveloped viruses. We also refer to the restriction of arenavirus production by the antiviral cellular factor, Tetherin/BST-2.

  14. Molecular Mechanism of Arenavirus Assembly and Budding

    Directory of Open Access Journals (Sweden)

    Shuzo Urata

    2012-10-01

    Full Text Available Arenaviruses have a bisegmented negative-strand RNA genome, which encodes four viral proteins: GP and NP by the S segment and L and Z by the L segment. These four viral proteins possess multiple functions in infection, replication and release of progeny viruses from infected cells. The small RING finger protein, Z protein is a matrix protein that plays a central role in viral assembly and budding. Although all arenaviruses encode Z protein, amino acid sequence alignment showed a huge variety among the species, especially at the C-terminus where the L-domain is located. Recent publications have demonstrated the interactions between viral protein and viral protein, and viral protein and host cellular protein, which facilitate transportation and assembly of viral components to sites of virus egress. This review presents a summary of current knowledge regarding arenavirus assembly and budding, in comparison with other enveloped viruses. We also refer to the restriction of arenavirus production by the antiviral cellular factor, Tetherin/BST-2.

  15. Electrochemical regulation of budding yeast polarity.

    Directory of Open Access Journals (Sweden)

    Armin Haupt

    2014-12-01

    Full Text Available Cells are naturally surrounded by organized electrical signals in the form of local ion fluxes, membrane potential, and electric fields (EFs at their surface. Although the contribution of electrochemical elements to cell polarity and migration is beginning to be appreciated, underlying mechanisms are not known. Here we show that an exogenous EF can orient cell polarization in budding yeast (Saccharomyces cerevisiae cells, directing the growth of mating projections towards sites of hyperpolarized membrane potential, while directing bud emergence in the opposite direction, towards sites of depolarized potential. Using an optogenetic approach, we demonstrate that a local change in membrane potential triggered by light is sufficient to direct cell polarization. Screens for mutants with altered EF responses identify genes involved in transducing electrochemical signals to the polarity machinery. Membrane potential, which is regulated by the potassium transporter Trk1p, is required for polarity orientation during mating and EF response. Membrane potential may regulate membrane charges through negatively charged phosphatidylserines (PSs, which act to position the Cdc42p-based polarity machinery. These studies thus define an electrochemical pathway that directs the orientation of cell polarization.

  16. Seed dormancy and germination in Jeffersonia dubia (Berberidaceae) as affected by temperature and gibberellic acid.

    Science.gov (United States)

    Rhie, Y H; Lee, S Y; Kim, K S

    2015-03-01

    The genus Jeffersonia, which contains only two species, has a trans-Atlantic disjunct distribution. The aims of this study were to determine the requirements for breaking dormancy and germination of J. dubia seeds and to compare its dormancy characteristics with those of the congener in eastern North America. Ripe seeds of J. dubia contain an underdeveloped embryo and were permeable to water. In nature, seeds were dispersed in May, while embryos began to grow in September, and were fully elongated by late November. Germination started in March of the next year, and seeds emerged as seedlings soon after germination. In laboratory experiments, incubation at high temperatures (25 °C, 25/15 °C) for at least 8 weeks was required to initiate embryo growth, while a transfer to moderate temperatures (20/10 °C, 15/6 °C) was needed for the completion of embryo growth. At least 8 weeks at 5 °C was effective in overcoming physiological dormancy and for germination in seeds after the embryos had fully elongated. Thus, both high and low temperatures were essential to break dormancy. Gibberellic acid (GA3 ) treatment could substitute for the high temperature requirement, but not for the low temperature requirement. Based on the dormancy-breaking requirements, it is confirmed that the seeds have deep simple morphophysiological dormancy. This dormancy type is similar to that of seeds of the eastern North American species J. diphylla. Although seeds require 10-11 months from seed dispersal to germination in nature, under controlled conditions they required only 3 months after treatment with 1000 mg·l(-1) GA3 , followed by incubation at 15/6 °C. This represents practical knowledge for propagation of these plants from seed.

  17. Traffic disruption at Entrance B -TRAM- related work

    CERN Multimedia

    Infrastructure and General Services Department

    2010-01-01

    Due to work being carried out for the TRAM we inform you that vehicles coming from Geneva will be prohibited from turning left into Entrance B. This restriction will be in place for approx. 10 weeks*) starting from Monday 30 August 2010. You are highly recommended to enter CERN through Entrance A during this period even though a diversion will be put in place to allow access to CERN from Entrance B (as shown in the attached sketch). In addition, approx. 20 car parking spaces will be temporarily unavailable at the western end of the flags car park. We thank you in advance for your kind understanding. ______________ *) The exact end date of the work will be communicated in due course. GS-SEM Group

  18. Prévessin site – Pedestrian and cycle entrances

    CERN Document Server

    GS-IS

    2013-01-01

      A second entrance for pedestrians and cyclists on Route du Maroc will be opened and the existing entrance on Chemin du Moulin des Ponts will be re-opened: - for the period 2 April to 31 October 2013, - from 7.00 a.m. to 9.00 a.m. and from 5.00 p.m. to 7.00 p.m. on working days (Monday to Friday). IMPORTANT: all users must show their access cards to the security guard as a matter of course when passing through the gates, both on entering and leaving the site.

  19. 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.

  20. Comparative genomics of the dormancy regulons in mycobacteria.

    Science.gov (United States)

    Gerasimova, Anna; Kazakov, Alexey E; Arkin, Adam P; Dubchak, Inna; Gelfand, Mikhail S

    2011-07-01

    In response to stresses, Mycobacterium cells become dormant. This process is regulated by the DosR transcription factor. In Mycobacterium tuberculosis, the dormancy regulon is well characterized and contains the dosR gene itself and dosS and dosT genes encoding DosR kinases, nitroreductases (acg; Rv3131), diacylglycerol acyltransferase (DGAT) (Rv3130c), and many universal stress proteins (USPs). In this study, we apply comparative genomic analysis to characterize the DosR regulons in nine Mycobacterium genomes, Rhodococcus sp. RHA1, Nocardia farcinica, and Saccharopolyspora erythraea. The regulons are highly labile, containing eight core gene groups (regulators, kinases, USPs, DGATs, nitroreductases, ferredoxins, heat shock proteins, and the orthologs of the predicted kinase [Rv2004c] from M. tuberculosis) and 10 additional genes with more restricted taxonomic distribution that are mostly involved in anaerobic respiration. The largest regulon is observed in M. marinum and the smallest in M. abscessus. Analysis of large gene families encoding USPs, nitroreductases, and DGATs demonstrates a mosaic distribution of regulated and nonregulated members, suggesting frequent acquisition and loss of DosR-binding sites.

  1. Cell to cell signalling during vertebrate limb bud development

    NARCIS (Netherlands)

    Panman, Lia

    2004-01-01

    Communication between cells is essential during embryonic development. The vertebrate limb bud provides us a model to study signalling interactions between cells during patterning of embryonic tissues and organogenesis. In chapter 1 I give an introduction about limb bud development that is focussed

  2. 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

  3. Changes in the biochemical composition and enzyme activity during dormancy release of Cyclocarya paliurus seeds

    Institute of Scientific and Technical Information of China (English)

    Fang Sheng-zuo; Wang Jia-yuan

    2007-01-01

    Cyclocarya paliurus is only propagated from seeds which have pronounced dormancy. Overcoming seed dormancy is an important component of efficient and cost-effective seedling production of Cyclocarya paliurus. Changes in biochemical composition and enzyme activity were investigated during dormancy release. The activities of all the studied enzymes in the stratified seeds increased significantly, compared to those in the control samples. Of the enzymes examined, the activities of protease increased the most (413.8%), followed by peroxidase (278.7%), lipase (161.0%), glucose-6-phosphate dehydrognase (149.1%) and amylase (60.6%) after 8 months of stratification. Crude fat and protein constituted the bulk of the storage reserves in mature seeds of C. paliurus. Compared with the seeds before stratification, about 45% of the starch, 46% of the protein and 11% of the crude fat were depleted during dormancy release of C. paliurus seeds, while the soluble sugar content was enhanced by 101.5% in the germinating seeds. Correlation analysis showed, during dormancy release of C. paliurus seeds, a close positive relationship between POD and G6PDH activity as well as soluble sugar content and amylase activity, while there was a significant negative relationship between storage substances and their related enzyme activities.

  4. [Effects of photoperiod on photosynthesis and PSII performance in peach during dormancy induction].

    Science.gov (United States)

    Li, Dong-Mei; Tan, Qiu-Ping; Gao, Dong-Sheng; Chen, Xiu-De; Li, Ling

    2014-07-01

    Long-day and short-day photoperiods were set artificially, with natural condition as the control, to examine photosynthetic parameters and chlorophyll fluorescence transient kinetics of 6-year-old 'Chunjie' peach cultivar (Prunus persica cv. Chunjie), and to investigate the effects of photoperiod on photosynthesis of the northern deciduous fruit trees. The tree advanced into the dormancy induction period under the short-day condition, and delayed under the long-day condition. In the dormancy induction period, the leaf net photosynthetic rate (Pn) and stomatal conductance (g(s)) decreased, and the intercellular CO2 concentration (Ci) increased, suggesting that the Pn decreased because of non-stomatal limitation. Maximum quantum yield for primary photochemistry (PhiPo, or Fv/Fm), potential activity (Fv/Fo), probability that a trapped exciton moved an electron into the electron transport chain beyond Q(A)-(Psi(o)) and performance index on absorption basis (Pl(ABS)) decreased in the dormancy induction period, suggesting that the electron transport capacity of photosynthetic electron transport chain was inhibited, possibly due to the damage to downstream electron transport chain (after Q(A)- acceptor) of PS II reaction center. Long-day photoperiod improved Pn in the dormancy induction period, and reduced the range of decline in PI(ABS) and the injured degree of photosystem. Short-day photoperiod deepened and accelerated the damage to photosynthetic apparatus significantly. The induced effect of photoperiod was associated with the dormancy processes.

  5. Budding yeast for budding geneticists: a primer on the Saccharomyces cerevisiae model system.

    Science.gov (United States)

    Duina, Andrea A; Miller, Mary E; Keeney, Jill B

    2014-05-01

    The budding yeast Saccharomyces cerevisiae is a powerful model organism for studying fundamental aspects of eukaryotic cell biology. This Primer article presents a brief historical perspective on the emergence of this organism as a premier experimental system over the course of the past century. An overview of the central features of the S. cerevisiae genome, including the nature of its genetic elements and general organization, is also provided. Some of the most common experimental tools and resources available to yeast geneticists are presented in a way designed to engage and challenge undergraduate and graduate students eager to learn more about the experimental amenability of budding yeast. Finally, a discussion of several major discoveries derived from yeast studies highlights the far-reaching impact that the yeast system has had and will continue to have on our understanding of a variety of cellular processes relevant to all eukaryotes, including humans.

  6. 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.

  7. Breaking tuber dormancy in Helianthus tuberosus L. and interspecific hybrids of Helianthus annuus L. x Helianthus tuberosus

    Science.gov (United States)

    Helianthus tuberosus L. tubers are dormant from the late fall to the following spring. In the wild, tuber dormancy is broken after exposure to winter cold, resulting in sprouting and shoot development in the spring when environmental conditions are favorable. The dormancy period typically limits H. ...

  8. Measuring mitotic spindle dynamics in budding yeast

    Science.gov (United States)

    Plumb, Kemp

    In order to carry out its life cycle and produce viable progeny through cell division, a cell must successfully coordinate and execute a number of complex processes with high fidelity, in an environment dominated by thermal noise. One important example of such a process is the assembly and positioning of the mitotic spindle prior to chromosome segregation. The mitotic spindle is a modular structure composed of two spindle pole bodies, separated in space and spanned by filamentous proteins called microtubules, along which the genetic material of the cell is held. The spindle is responsible for alignment and subsequent segregation of chromosomes into two equal parts; proper spindle positioning and timing ensure that genetic material is appropriately divided amongst mother and daughter cells. In this thesis, I describe fluorescence confocal microscopy and automated image analysis algorithms, which I have used to observe and analyze the real space dynamics of the mitotic spindle in budding yeast. The software can locate structures in three spatial dimensions and track their movement in time. By selecting fluorescent proteins which specifically label the spindle poles and cell periphery, mitotic spindle dynamics have been measured in a coordinate system relevant to the cell division. I describe how I have characterised the accuracy and precision of the algorithms by simulating fluorescence data for both spindle poles and the budding yeast cell surface. In this thesis I also describe the construction of a microfluidic apparatus that allows for the measurement of long time-scale dynamics of individual cells and the development of a cell population. The tools developed in this thesis work will facilitate in-depth quantitative analysis of the non-equilibrium processes in living cells.

  9. Decellularized Tooth Bud Scaffolds for Tooth Regeneration.

    Science.gov (United States)

    Zhang, W; Vazquez, B; Oreadi, D; Yelick, P C

    2017-01-01

    Whole tooth regeneration approaches currently are limited by our inability to bioengineer full-sized, living replacement teeth. Recently, decellularized organ scaffolds have shown promise for applications in regenerative medicine by providing a natural extracellular matrix environment that promotes cell attachment and tissue-specific differentiation leading to full-sized organ regeneration. We hypothesize that decellularized tooth buds (dTBs) created from unerupted porcine tooth buds (TBs) can be used to guide reseeded dental cell differentiation to form whole bioengineered teeth, thereby providing a potential off-the-shelf scaffold for whole tooth regeneration. Porcine TBs were harvested from discarded 6-mo-old pig jaws, and decellularized by successive sodium dodecyl sulfate/Triton-X cycles. Four types of replicate implants were used in this study: 1) acellular dTBs; 2) recellularized dTBs seeded with porcine dental epithelial cells, human dental pulp cells, and human umbilical vein endothelial cells (recell-dTBs); 3) dTBs seeded with bone morphogenetic protein (BMP)-2 (dTB-BMPs); and 4) freshly isolated nondecellularized natural TBs (nTBs). Replicate samples were implanted into the mandibles of host Yucatan mini-pigs and grown for 3 or 6 mo. Harvested mandibles with implanted TB constructs were fixed in formalin, decalcified, embedded in paraffin, sectioned, and analyzed via histological methods. Micro-computed tomography (CT) analysis was performed on harvested 6-mo samples prior to decalcification. All harvested constructs exhibited a high degree of cellularity. Significant production of organized dentin and enamel-like tissues was observed in dTB-recell and nTB implants, but not in dTB or dTB-BMP implants. Micro-CT analyses of 6-mo implants showed the formation of organized, bioengineered teeth of comparable size to natural teeth. To our knowledge, these results are the first to describe the potential use of dTBs for functional whole tooth regeneration.

  10. Getting Interpersonal on a University Entrance Exam Impromptu Writing Task

    Science.gov (United States)

    Myskow, Gordon; Gordon, Kana

    2012-01-01

    This article explores the types of audience engagement strategies used by a Japanese secondary school student in an after school course preparing for a high-stakes impromptu academic writing task on a university entrance exam. The study uses appraisal theory--the branch of Systemic Functional Linguistics (SFL) concerned with the patterning of…

  11. Analysis of Genomic DNA Methylation during Chilling Induced Endo-dormancy Release by Methylation Sensitive Amplified Polymorphism (MSAP) Technology in Tree Peony (Paeonia suffruticosa)%低温解除牡丹休眠进程中基因组DNA甲基化敏感扩增多态性(MSAP)分析

    Institute of Scientific and Technical Information of China (English)

    盖树鹏; 张风; 张玉喜; 郑国生

    2012-01-01

    DNA methylation is an important component of the epigenetic network, and it plays a very important role in regulating gene expression. This paper aims to analyze the variation of methylation patterns during chilling induced endo-dormancy release process in tree peony(Paeoraa suffruticosa), which will help to isolate and identify methylation regulating genes during dormancy release. The morphological changes of Luhehong enduring 0, 6, 12, 18 and 24 d of 4℃ chilling were observed to ascertain the stages of dormancy after transferred to greenhouse (18~22 ℃ /10~18℃, 8 h light/ 16 h-dark cycle). The accumulation of chilling had a significant effect on the percentage of buds break and also florescence. As the amount of chilling accumulation increased, the percentage of bud break and florescence increased with faster germination. When exposed to less than 18 d of chilling, the percentage of bud break and flower was low, but after 18 d nearly 100% of the buds broke and finally flowered, and no difference between 18 and 24 d of chilling (P>0.05). Therefore, physiological status of flower bud receivingless than 18 d chilling fulfilling was defined as endo-dormancy, and that receiving more than 18 d chilling treatment was designated as eco-dormancy. DNA methylation patterns were subsequently analyzed by methylation sensitive amplified polymorphism (MSAP) technology with 32 pairs of primer combination with EcoR I and Hpa II Imsp I. Totally, 3 181 bands were amplified, averaging 99.4 bands per primers pair. The results showed that the level of methylation in dormancy buds was extraordinary high, and all exceeded 60% , among which hemi-methylation was dominant. The levels of hemi-methylation and fully methylation fluctuated during chilling duration. However, the level of total DNA methylation was down-regulated during bud dormancy release except a peak at 18 d chilling, and the methylation levels of 0, 6, 12, 18 and 24 d chilling were 78.6%, 76.3%, 74%, 79%, and 61

  12. Combining drought survival via summer dormancy and annual biomass productivity in Dactylis glomerata L.

    Directory of Open Access Journals (Sweden)

    Rajae eKallida

    2016-02-01

    Full Text Available Under Mediterranean climates, the best strategy to produce rain-fed fodder crops is to develop perennial drought resistant varieties. Summer dormancy present in native germplasm has been shown to confer a high level of survival under severe drought. Nevertheless it has also been shown to be negatively correlated with annual biomass productivity. The aim of this study was to analyse the correlations between summer dormancy and annual biomass productivity related traits and to identify quantitative trait loci (QTL for these traits in a progeny of a summer dormant cocksfoot parent (Kasbah and a summer active parent (Medly. A total of 283 offspring and the parents were phenotyped for summer dormancy, plant growth rate and heading date in Morocco and for maximum leaf elongation rate (LERm in France. The individuals were genotyped with a total of 325 markers including 59 AFLP, 64 SSR and 202 DArT markers. The offspring exhibited a large quantitative variation for all measured traits. Summer dormancy showed a negative correlation with both plant growth rate (-0.34 p<0.005 and LERm (-0.27 p<0.005. However, genotypes with both a high level of summer dormancy and a high level of plant growth rate were detected in the progeny. One genetic map per parent was built with a total length of 377 and 423 cM for Kasbah and Medly, respectively. Both different and co-localised QTL for summer dormancy and plant growth rate were identified. These results demonstrate that it should be possible to create summer dormant cocksfoot varieties with a high annual biomass productivity.

  13. 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.

  14. Combining Drought Survival via Summer Dormancy and Annual Biomass Productivity in Dactylis glomerata L.

    Science.gov (United States)

    Kallida, Rajae; Zhouri, Latifa; Volaire, Florence; Guerin, Adrien; Julier, Bernadette; Shaimi, Naima; Fakiri, Malika; Barre, Philippe

    2016-01-01

    Under Mediterranean climates, the best strategy to produce rain-fed fodder crops is to develop perennial drought resistant varieties. Summer dormancy present in native germplasm has been shown to confer a high level of survival under severe drought. Nevertheless it has also been shown to be negatively correlated with annual biomass productivity. The aim of this study was to analyze the correlations between summer dormancy and annual biomass productivity related traits and to identify quantitative trait loci (QTL) for these traits in a progeny of a summer dormant cocksfoot parent (Kasbah) and a summer active parent (Medly). A total of 283 offspring and the parents were phenotyped for summer dormancy, plant growth rate (PGR) and heading date in Morocco and for maximum leaf elongation rate (LERm) in France. The individuals were genotyped with a total of 325 markers including 59 AFLP, 64 SSR, and 202 DArT markers. The offspring exhibited a large quantitative variation for all measured traits. Summer dormancy showed a negative correlation with both PGR (-0.34 p < 0.005) and LERm (-0.27 p < 0.005). However, genotypes with both a high level of summer dormancy and a high level of PGR were detected in the progeny. One genetic map per parent was built with a total length of 377 and 423 cM for Kasbah and Medly, respectively. Both different and co-localized QTL for summer dormancy and PGR were identified. These results demonstrate that it should be possible to create summer dormant cocksfoot varieties with a high annual biomass productivity. PMID:26904054

  15. 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

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

    Directory of Open Access Journals (Sweden)

    Erwann eArc

    2013-03-01

    Full Text Available 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.

  17. Seed dormancy cycling in Arabidopsis: chromatin remodelling and regulation of DOG1 in response to seasonal environmental signals.

    Science.gov (United States)

    Footitt, Steven; Müller, Kerstin; Kermode, Allison R; Finch-Savage, William E

    2015-02-01

    The involvement of chromatin remodelling in dormancy cycling in the soil seed bank (SSB) is poorly understood. Natural variation between the winter and summer annual Arabidopsis ecotypes Cvi and Bur was exploited to investigate the expression of genes involved in chromatin remodelling via histone 2B (H2B) ubiquitination/de-ubiquitination and histone acetylation/deacetylation, the repressive histone methyl transferases CURLY LEAF (CLF) and SWINGER (SWN), and the gene silencing repressor ROS1 (REPRESSOR OF SILENCING1) and promoter of silencing KYP/SUVH4 (KRYPTONITE), during dormancy cycling in the SSB. ROS1 expression was positively correlated with dormancy while the reverse was observed for CLF and KYP/SUVH4. We propose ROS1 dependent repression of silencing and a sequential requirement of CLF and KYP/SUVH4 dependent gene repression and silencing for the maintenance and suppression of dormancy during dormancy cycling. Seasonal expression of H2B modifying genes was correlated negatively with temperature and positively with DOG1 expression, as were histone acetyltransferase genes, with histone deacetylases positively correlated with temperature. Changes in the histone marks H3K4me3 and H3K27me3 were seen on DOG1 (DELAY OF GERMINATION1) in Cvi during dormancy cycling. H3K4me3 activating marks remained stable along DOG1. During relief of dormancy, H3K27me3 repressive marks slowly accumulated and accelerated on exposure to light completing dormancy loss. We propose that these marks on DOG1 serve as a thermal sensing mechanism during dormancy cycling in preparation for light repression of dormancy. Overall, chromatin remodelling plays a vital role in temporal sensing through regulation of gene expression.

  18. 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

  19. A permeability barrier surrounds taste buds in lingual epithelia.

    Science.gov (United States)

    Dando, Robin; Pereira, Elizabeth; Kurian, Mani; Barro-Soria, Rene; Chaudhari, Nirupa; Roper, Stephen D

    2015-01-01

    Epithelial tissues are characterized by specialized cell-cell junctions, typically localized to the apical regions of cells. These junctions are formed by interacting membrane proteins and by cytoskeletal and extracellular matrix components. Within the lingual epithelium, tight junctions join the apical tips of the gustatory sensory cells in taste buds. These junctions constitute a selective barrier that limits penetration of chemosensory stimuli into taste buds (Michlig et al. J Comp Neurol 502: 1003-1011, 2007). We tested the ability of chemical compounds to permeate into sensory end organs in the lingual epithelium. Our findings reveal a robust barrier that surrounds the entire body of taste buds, not limited to the apical tight junctions. This barrier prevents penetration of many, but not all, compounds, whether they are applied topically, injected into the parenchyma of the tongue, or circulating in the blood supply, into taste buds. Enzymatic treatments indicate that this barrier likely includes glycosaminoglycans, as it was disrupted by chondroitinase but, less effectively, by proteases. The barrier surrounding taste buds could also be disrupted by brief treatment of lingual tissue samples with DMSO. Brief exposure of lingual slices to DMSO did not affect the ability of taste buds within the slice to respond to chemical stimulation. The existence of a highly impermeable barrier surrounding taste buds and methods to break through this barrier may be relevant to basic research and to clinical treatments of taste.

  20. Characterization of Septin Ultrastructure in Budding Yeast Using Electron Tomography

    Science.gov (United States)

    Bertin, Aurélie; Nogales, Eva

    2015-01-01

    Summary Septins are essential for the completion of cytokinesis. In budding yeast, Saccharomyces cerevisiae, septins are located at the bud neck during mitosis and are closely connected to the inner plasma membrane. In vitro, yeast septins have been shown to self-assemble into a variety of filamentous structures, including rods, paired filaments, bundles and rings [1–3]. Using electron tomography of freeze-substituted section and cryo-electron tomography of frozen sections, we determined the three dimensional organization of the septin cytoskeleton in dividing budding yeast with molecular resolution [4,5]. Here we describe the detailed procedures used for our characterization of the septin cellular ultrastructure. PMID:26519309

  1. Seed dormancy and germination in three Crocus ser. Verni species (Iridaceae): implications for evolution of dormancy within the genus.

    Science.gov (United States)

    Carta, A; Probert, R; Moretti, M; Peruzzi, L; Bedini, G

    2014-11-01

    The aim of this work was to examine whether seed ecophysiological traits in three closely related Crocus species were associated with ecological niche differentiation and species divergence. Seeds of the temperate tetraploid cytotype of Crocus neapolitanus, the sub-Mediterranean C. etruscus and the Mediterranean C. ilvensis were placed either on agar in the laboratory under different periods of simulated seasonal conditions or in nylon mesh bags buried outdoors to examine embryo growth, radicle and shoot emergence. In agreement with the phenology observed outdoors, in the laboratory embryos required a cool temperature (ca. 10 °C) to grow to full size (embryo length:seed length, E:S ratio ca. 0.75) but only after seeds received a warm stratification; radicle emergence then followed immediately (November). Shoot emergence is a temporally separated phase (March) that was promoted by cold stratification in C. neapolitanus while in the other two species this time lag was attributed to a slow continuous developmental process. These species have similar embryo growth and radicle phenology but differ in their degree of epicotyl dormancy, which is related to the length of local winter. Conclusions from laboratory experiments that only consider root emergence could be misleading; evaluating the phenology of both root and shoot emergence should be considered in order to demonstrate ecologically meaningful differences in germination behaviour and to develop effective propagation protocols. Although these taxa resulted from recent speciation processes, the outcomes suggest an early onset of adaptation to local ecological factors and that phylogeny may represent a significant constraint in the evolution and expression of seed traits in Crocus.

  2. Mechanical feedback stabilizes budding yeast morphogenesis

    Science.gov (United States)

    Banavar, Samhita; Trogdon, Michael; Petzold, Linda; Campas, Otger

    Walled cells have the ability to remodel their shape while sustaining an internal turgor pressure that can reach values up to 10 atmospheres. This requires a tight and simultaneous regulation of cell wall assembly and mechanochemistry, but the underlying mechanisms by which this is achieved remain unclear. Using the growth of mating projections in budding yeast (S. cerevisiae) as a motivating example, we have developed a theoretical description that couples the mechanics of cell wall expansion and assembly via a mechanical feedback. In the absence of a mechanical feedback, cell morphogenesis is inherently unstable. The presence of a mechanical feedback stabilizes changes in cell shape and growth, and provides a mechanism to prevent cell lysis in a wide range of conditions. We solve for the dynamics of the system and obtain the different dynamical regimes. In particular, we show that several parameters affect the stability of growth, including the strength of mechanical feedback in the system. Finally, we compare our results to existing experimental data.

  3. Micropropagation of Helleborus through axillary budding.

    Science.gov (United States)

    Beruto, Margherita; Viglione, Serena; Bisignano, Alessandro

    2013-01-01

    Helleborus genus, belonging to the Ranunculaceae family, has 20 species of herbaceous perennial flowering plants. The commercial exploitation of this plant is dependent on the selection and propagation of appropriate lines. High propagation rate could be accomplished by using a suitable tissue culture method enabling the rapid introduction of valuable selections in the market. However, in vitro cultivation of Helleborus is still very difficult. Thereby the development of reliable in vitro propagation procedures is crucial for future production systems. Axillary buds cultured on agar-solidified Murashige and Skoog medium supplemented with 1 mg/L benzyladenine, 0.1 mg/L β-naphthoxyacetic acid, and 2 mg/L isopentenyl adenine develop shoots after 16 weeks of culture under 16 h light regime, 50-60 μmol/s/m(2), and 19 ± 1°C. The multiplication rate ranges from 1.4 to 2.1. However, the genotype and the number of subcultures affect the efficiency of the micropropagation process. The rooting of shoots is about 80% in solidified MS medium containing 1 mg/L 1-naphthaleneacetic acid and 3 mg/L indole-3-butyric acid. The described protocol provides information which can contribute to the commercial production of Helleborus plants.

  4. Flower Bud Differentiation in Quercus suber L.

    Directory of Open Access Journals (Sweden)

    Maria Carolina Varela

    2016-06-01

    Full Text Available Background and Purpose: Cork oak (Quercus suber L. is one of the most important forest species growing in the Western Mediterranean region. This investigation intends to assess the timing of flowering differentiation of cork oak and contribute to the deepening of the knowledge about the process of the sexual reproduction of the species. Materials and Methods: In 2010 four trees were selected (9, 14, 24, 25 from a plot of 25 trees located at Quinta da Serra, Portugal. A total of 240 buds were collected from these four trees, on three days (8, 14 and 23 March, from 4 branches per tree and 5 positions per branch for the assessment of meristem differentiation. Results: Meristem differentiation analysed on the sampling days revealed there were only vegetative structures by 8 March; a few male and female primordia on 14 March; and fully differentiated reproductive structures on 23 March. Conclusions: Flowering sex determination of cork oak occurs about one month before the flowering onset.

  5. Grapevine bud break prediction for cool winter climates

    Science.gov (United States)

    Nendel, Claas

    2010-05-01

    Statistical analysis of bud break data for grapevine ( Vitis vinifera L. cvs. Riesling and Müller-Thurgau) at 13 sites along the northern boundary of commercial grapevine production in Europe revealed that, for all investigated sites, the heat summation method for bud break prediction can be improved if the starting date for the accumulation of heat units is specifically determined. Using the coefficient of variance as a criterion, a global minimum for each site can be identified, marking the optimum starting date. Furthermore, it was shown that the application of a threshold temperature for the heat summation method does not lead to an improved prediction of bud break. Using site-specific parameters, bud break of grapevine can be predicted with an accuracy of ± 2.5 days. Using average parameters, the prediction accuracy is reduced to ± 4.5 days, highlighting the sensitivity of the heat summation method to the quality and the representativeness of the driving temperature data.

  6. Apoptosis at inflection point in liquid culture of budding yeasts.

    Directory of Open Access Journals (Sweden)

    Toshiyuki Hagiwara

    Full Text Available Budding yeasts are highly suitable for aging studies, because the number of bud scars (stage proportionally correlates with age. Its maximum stages are known to reach at 20-30 stages on an isolated agar medium. However, their stage dynamics in a liquid culture is virtually unknown. We investigate the population dynamics by counting scars in each cell. Here one cell division produces one new cell and one bud scar. This simple rule leads to a conservation law: "The total number of bud scars is equal to the total number of cells." We find a large discrepancy: extremely fewer cells with over 5 scars than expected. Almost all cells with 6 or more scars disappear within a short period of time in the late log phase (corresponds to the inflection point. This discrepancy is confirmed directly by the microscopic observations of broken cells. This finding implies apoptosis in older cells (6 scars or more.

  7. Factors influencing axillary shoot proliferation and adventitious budding in cedar.

    Science.gov (United States)

    Renau-Morata, Begoña; Ollero, Javier; Arrillaga, Isabel; Segura, Juan

    2005-04-01

    We developed procedures for in vitro cloning of Cedrus atlantica Manetti and C. libani A. Rich explants from juvenile and mature plants. Explant size was one determinant of the frequency of axillary bud break in both species. Shoot tips and nodal explants mainly developed calli, whereas bud sprouting occurred in defoliated microcuttings cultured on a modified Murashige and Skoog medium without growth regulators. Isolation and continuous subculture of sprouted buds on the same medium allowed cloning of microcuttings from C. atlantica and C. libani seedlings and bicentennial C. libani trees, thus providing a desirable alternative for multiplying mature trees that have demonstrated superior characteristics. We also report adventitious bud differentiation from isolated embryos of C. atlantica. Neither auxin treatments nor other methods tested, including infection with Agrobacterium rhizogenes, were effective in inducing root initiation.

  8. Tolerance of budding yeast Saccharomyces cerevisiae to ultra high pressure

    Science.gov (United States)

    Shibata, M.; Torigoe, M.; Matsumoto, Y.; Yamamoto, M.; Takizawa, N.; Hada, Y.; Mori, Y.; Takarabe, K.; Ono, F.

    2014-05-01

    Our studies on the tolerance of plants and animals against very high pressure of several GPa have been extended to a smaller sized fungus, the budding yeast Saccharomyces cerevisiae. Several pieces of budding yeast (dry yeast) were sealed in a small teflon capsule with a liquid pressure medium fluorinate, and exposed to 7.5 GPa by using a cubic anvil press. The pressure was kept constant for various duration of time from 2 to 24 h. After the pressure was released, the specimens were brought out from the teflon capsule, and they were cultivated on a potato dextrose agar. It was found that the budding yeast exposed to 7.5 GPa for up to 6 h showed multiplication. However, those exposed to 7.5 GPa for longer than 12 h were found dead. The high pressure tolerance of budding yeast is a little weaker than that of tardigrades.

  9. Functional cell types in taste buds have distinct longevities.

    Directory of Open Access Journals (Sweden)

    Isabel Perea-Martinez

    Full Text Available Taste buds are clusters of polarized sensory cells embedded in stratified oral epithelium. In adult mammals, taste buds turn over continuously and are replenished through the birth of new cells in the basal layer of the surrounding non-sensory epithelium. The half-life of cells in mammalian taste buds has been estimated as 8-12 days on average. Yet, earlier studies did not address whether the now well-defined functional taste bud cell types all exhibit the same lifetime. We employed a recently developed thymidine analog, 5-ethynil-2'-deoxyuridine (EdU to re-evaluate the incorporation of newly born cells into circumvallate taste buds of adult mice. By combining EdU-labeling with immunostaining for selected markers, we tracked the differentiation and lifespan of the constituent cell types of taste buds. EdU was primarily incorporated into basal extragemmal cells, the principal source for replenishing taste bud cells. Undifferentiated EdU-labeled cells began migrating into circumvallate taste buds within 1 day of their birth. Type II (Receptor taste cells began to differentiate from EdU-labeled precursors beginning 2 days after birth and then were eliminated with a half-life of 8 days. Type III (Presynaptic taste cells began differentiating after a delay of 3 days after EdU-labeling, and they survived much longer, with a half-life of 22 days. We also scored taste bud cells that belong to neither Type II nor Type III, a heterogeneous group that includes mostly Type I cells, and also undifferentiated or immature cells. A non-linear decay fit described these cells as two sub-populations with half-lives of 8 and 24 days respectively. Our data suggest that many post-mitotic cells may remain quiescent within taste buds before differentiating into mature taste cells. A small number of slow-cycling cells may also exist within the perimeter of the taste bud. Based on their incidence, we hypothesize that these may be progenitors for Type III cells.

  10. Search for entrance channel effects in compound nuclear formation

    CERN Document Server

    Maj, A; Herskind, B; Bracco, A; Camera, F; Hagemann, G; Varmette, P

    1999-01-01

    The entrance channel effect was studied for the decay of sup 1 sup 7 sup 0 W formed in fusion reactions with different beam-target combinations. The average number of emitted neutrons suggest a lower effective excitation energy in the (alpha,xn) decay channel when more mass-symmetric reaction is used, especially at the highest angular momenta. The results are in qualitative agreement with predictions of the dissipative fusion model.

  11. A buckling mechanism for ESCRT-III budding

    CERN Document Server

    Lenz, Martin; Joanny, Jean-François

    2009-01-01

    The ESCRT-III protein complex binds to the membrane of eukaryotic cells, causing it to bud into long tubes. Here we propose that this budding is akin to a buckling instability. We analyze the linear stability of flat ESCRT-III-dressed membranes and account for the formation of long tubes. We study strongly deformed dressed membranes and their bifurcation diagram numerically. Our mechanism is compatible with reasonable in vivo parameter values and we propose an experiment allowing its validation.

  12. Entrance channel effect in the incomplete fusion reactions

    Directory of Open Access Journals (Sweden)

    Singh B.P.

    2011-10-01

    Full Text Available In the present work the effect of various entrance channel parameters on incomplete fusion strength and the reaction dynamics in 12C+159Tb system at energies ≈ 4-7MeV/A have been investigated by measuring the excitation functions of individual reaction channels. Experimental excitation functions have been analyzed in the framework of compound nucleus decay using statistical model code PACE4. Analysis of data suggests the production of xn/pxn-channels via complete fusion of 12C with 159Tb, as these are found to be well reproduced by PACE4 predictions, while, a significant enhancement in the excitation functions of α-emitting channels has been observed over the theoretical ones. This enhancement has been attributed due to incomplete fusion. For better insight into the underlying dynamics, fraction of incomplete fusion to the total fusion has been deduced and compared with 16O+159Tb and other nearby systems as a function of various entrance channel parameters. The fraction of incomplete fusion has been found to be sensitive to the projectile type, energy and entrance-channel mass-asymmetry.

  13. An increase in pectin methyl esterase activity accompanies dormancy breakage and germination of yellow cedar seeds.

    Science.gov (United States)

    Ren, C; Kermode, A R

    2000-09-01

    Pectin methyl esterase (PME) (EC 3.1.1.11) catalyzes the hydrolysis of methylester groups of cell wall pectins. We investigated the role of this enzyme in dormancy termination and germination of yellow cedar (Chamaecyparis nootkatensis [D. Don] Spach) seeds. PME activity was not detected in dormant seeds of yellow cedar but was induced and gradually increased during moist chilling; high activity coincided with dormancy breakage and germination. PME activity was positively correlated to the degree of dormancy breakage of yellow cedar seeds. The enzyme produced in different seed parts and in seeds at different times during moist chilling, germination, and early post-germinative growth consisted of two isoforms, both basic with isoelectric points of 8.7 and 8.9 and the same molecular mass of 62 kD. The pH optimum for the enzyme was between 7.4 and 8.4. In intact yellow cedar seeds, activities of the two basic isoforms of PME that were induced in embryos and in megagametophytes following dormancy breakage were significantly suppressed by abscisic acid. Gibberellic acid had a stimulatory effect on the activities of these isoforms in embryos and megagametophytes of intact seeds at the germinative stage. We hypothesize that PME plays a role in weakening of the megagametophyte, allowing radicle emergence and the completion of germination.

  14. 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 6-benz

  15. TBK1 Regulates Prostate Cancer Dormancy through mTOR Inhibition

    Directory of Open Access Journals (Sweden)

    Jin Koo Kim

    2013-09-01

    Full Text Available The mechanisms that regulate hematopoietic stem cell (HSC dormancy and self-renewal are well established and are largely dependent on signals emanating from the HSC niche. Recently, we found that prostate cancer (PCa cells target the HSC niche in mouse bone marrow (BM during metastasis. Little is known, however, as to how the HSC niche may regulate dormancy in cancer cells. In this study, we investigated the effects of TANK binding kinase 1 (TBK1 on PCa dormancy in the BM niche. We found that binding with niche osteoblasts induces the expression of TBK1 in PCa cells PC3 and C4-2B. Interestingly, TBK1 interacts with mammalian target of rapamycin (mTOR and inhibits its function. Rapamycin, an mTOR inhibitor, induces cell cycle arrest of PCa cells and enhances chemotherapeutic resistance of PCa cells. As a result, the knockdown of TBK1 decreases PCa stem-like cells and drug resistance in vitro and in vivo. Taken together, these results strongly indicate that TBK1 plays an important role in the dormancy and drug resistance of PCa.

  16. 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 undetectab

  17. A role for jasmonates in the release of dormancy by cold stratification in wheat.

    Science.gov (United States)

    Xu, Qian; Truong, Thy T; Barrero, Jose M; Jacobsen, John V; Hocart, Charles H; Gubler, Frank

    2016-05-01

    Hydration at low temperatures, commonly referred to as cold stratification, is widely used for releasing dormancy and triggering germination in a wide range of species including wheat. However, the molecular mechanism that underlies its effect on germination has largely remained unknown. Our previous studies showed that methyl-jasmonate, a derivative of jasmonic acid (JA), promotes dormancy release in wheat. In this study, we found that cold-stimulated germination of dormant grains correlated with a transient increase in JA content and expression of JA biosynthesis genes in the dormant embryos after transfer to 20 (o)C. The induction of JA production was dependent on the extent of cold imbibition and precedes germination. Blocking JA biosynthesis with acetylsalicylic acid (ASA) inhibited the cold-stimulated germination in a dose-dependent manner. In addition, we have explored the relationship between JA and abscisic acid (ABA), a well-known dormancy promoter, in cold regulation of dormancy. We found an inverse relationship between JA and ABA content in dormant wheat embryos following stratification. ABA content decreased rapidly in response to stratification, and the decrease was reversed by addition of ASA. Our results indicate that the action of JA on cold-stratified grains is mediated by suppression of two key ABA biosynthesis genes, TaNCED1 and TaNCED2.

  18. 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

  19. Dormancy of the barley grain is correlated with gibberellic Acid responsiveness of the isolated aleurone layer.

    Science.gov (United States)

    Schuurink, R C; Sedee, N J; Wang, M

    1992-12-01

    The relationship between barley grain dormancy and gibberellic acid (GA(3)) responsiveness of aleurone layers has been investigated. Barley (Hordeum distichum L. cvs Triumph and Kristina) grains were matured under defined conditions in a phytotron. Grains of Triumph plants grown under long-day/warm conditions had lower dormancy levels than grains of plants grown under short-day/cool conditions. Aleurone layers isolated from grains of long-day Triumph plants secreted more alpha-amylase and had a higher responsiveness to GA(3) as measured by alpha-amylase secretion. Storage of the grains increased both the percentage of germination and the responsiveness of the aleurone to GA(3). Use of different sterilization methods to break dormancy confirmed the correlation between germination percentage and aleurone layer GA(3) responsiveness. The response of embryoless Triumph grains to GA(3) was lower than that of the isolated aleurone layers, suggesting a role of the starchy endosperm in regulating the GA(3) response of the aleurone layer. Grains of the cultivar Kristina harvested from short day- and long day-grown plants lacked dormancy, and their isolated aleurone layers had a similar responsiveness to GA(3) as measured by alpha-amylase secretion. The data indicate that the physiological state of the aleurone layers contributes to the percentage germination of the grains.

  20. Correlation Between Parents and F1 and Combining Ability of Parents on Seed Dormancy in indica Rice (Oryza sativa)

    Institute of Scientific and Technical Information of China (English)

    XU Bao-qin; LU Zuo-mei

    2009-01-01

    Dormancy indices of hulled and dehulled seeds were investigated by using 19 cytoplasmic male sterile (CMS) lines, 9 restorer lines and their 109 F1 hybrids of indica hybrid rice. The seeds of each F1 and the parents were harvested on 35 days after flowering. Combining ability was analyzed in 25 combinations made by 5 CMS lines and 5 restorer lines (North Carolina II mating design). The seed dormancy index of F1 was positively and highly significantly correlated with those of their parents and mid-parent value. Out of the 109 combinations, 82 combinations showed mid-parent heterosis, and 43 heterobeltiosis. Seed dormancy indices of F1s and their parents declined dramatically in dehulled seeds compared with hulled seeds, indicating that the hull played an important role in seed dormancy. However, the trends were similar in hulled seeds and dehulled seeds in terms of relationships between the seed dormancy indicices in F1 and their parents. The influence of hull on seed dormancy mainly depended on F1 genotype, not on the hull from maternal parent. The variances of general combining ability (GCA) in female and male parents occupied 59.2% and 31.1% of total variance, respectively. The variance of specific combining ability (SCA) in combinations occupied 9.7% of total variance, indicating that gene additive effects were principal. Among the 5 CMS lines, II112A had the highest GCA effect for seed dormancy, followed by D62A. Among the 5 restorer lines, IR112 had the highest GCA effect for seed dormancy, followed by 2786. These lines are elite parental materials for breeding F1 hybrid rice with stronger seed dormancy.

  1. Dormancy Characteristics and the Method for Breaking seed Dormancy in Lonicera japonica%忍冬种子休眠特性及破眠方法研究

    Institute of Scientific and Technical Information of China (English)

    李建军; 贾国伦; 李博; 李静云; 杨丽

    2012-01-01

    Using honeysuckle seed as materials,this article aimed at exploring the dormancy characteristics of honeysuckle seeds and screening effective methods to break dormancy and the optimum matrix. The results showed that the seed size and quality had significantly difference between different honeysuckle germplasms. The embryo rate rose from 41. 57% to 53. 07% before and after low temperature treatment, indicating that the low temperature promoted honeysuckle seeds dormancy breaking. The bibulous rate of seeds rapidly increased from G to 52. 35% after 0 - 2 days seed soaking,indicating that skin had no obvious absorbent obstacles Abrasive paper friction can promote the broking dormancy of honeysuckle seeds and 0. 3 - 0. 7 g/L gibberellin solution also can promote the broken dormancy of honeysuckle seeds,the germination percentage with abrasive paper friction+0. 5 g/L gibberellin gave the best result of 68. 30% emergence perentage. The germination rate with vermiculite mix pine needle soil (1 : 1) was 10%,being the optimum matrix for the growth of honeysuckle seeds.%以忍冬种子为材料,研究忍冬种子休眠特性并筛选打破休眠的方法以及发芽最佳基质.结果表明,不同忍冬品种种子大小和质量存在显著性差异;低温处理前后忍冬种子胚率从41.57%上升到53.07%,说明低温具有破眠作用;浸种0~2 d种子吸水率由0快速上升到52.35%,说明种皮无明显吸水障碍;砂纸摩擦和0.3~0.7 g/L赤霉素均可促进忍冬种子破眠,其中砂纸摩擦+0.5g/L赤霉素处理种子发芽率为68.30%,效果最佳;蛭石+松针土(体积比为1∶1)发芽率为10%,是种子发芽最适基质.

  2. Substation interference on gas entrance of industrial plants

    Energy Technology Data Exchange (ETDEWEB)

    Freire, Paulo Edmundo; Giacommelo, Claudinei [PAIOL Engenharia, Paulinia, SP (Brazil)

    2009-12-19

    Industrial plants often have medium or high voltage electrical power entrance and also gas feeders. Often the main substation is located near the gas entrance, in the utilities area. When the occurrence of a phase to ground short-circuit in the substation, the pipeline and gas entrance that serves the plant may be exposed to high voltage soil potential, of the order of a few kilovolts, due to resistive coupling with the substation ground mesh. The consequences of this situation are reflected in various risks, with emphasis on: damage to the protective coating of the duct, due to the increased soil potential, in excess of its dielectric supportability (typically on the order of 5 kV); spread of potentially hazardous to duct exposed parts (valves, measuring place etc.); and damage to cathodic protection system components, as rectifier and insulating joins at gas entrance. This paper presents the investigations conducted in a factory that has a 69 kV main substation very close to the gas entrance, the order of a few meters away. The substation phase to ground short-circuit current is 7 kA, what causes a 9 kV soil potential near the gas pipe. It is presented the methodology for modeling the various elements involved in this process, the results of simulations made, arrangements been taken to reduce soil potential next to the duct to levels below 5 kV, and the measures for people and insulating joins protection. It is important to note that such problems usually will be solved with measures involving the entire grounding system of the industrial complex and also close to the duct (outside the industrial plant). The gas distribution companies should require from customers where this situation occurs, to ensure safety for people who have access to elements of its network, and for the integrity of their own ducts and cathodic protection components. The computer simulations developed for this work were made with the software Auto Grid, developed by the Canadian company Safe

  3. Developing a biomimetic tooth bud model.

    Science.gov (United States)

    Smith, Elizabeth E; Zhang, Weibo; Schiele, Nathan R; Khademhosseini, Ali; Kuo, Catherine K; Yelick, Pamela C

    2017-01-08

    A long-term goal is to bioengineer, fully functional, living teeth for regenerative medicine and dentistry applications. Biologically based replacement teeth would avoid insufficiencies of the currently used dental implants. Using natural tooth development as a guide, a model was fabricated using post-natal porcine dental epithelial (pDE), porcine dental mesenchymal (pDM) progenitor cells, and human umbilical vein endothelial cells (HUVEC) encapsulated within gelatin methacrylate (GelMA) hydrogels. Previous publications have shown that post-natal DE and DM cells seeded onto synthetic scaffolds exhibited mineralized tooth crowns composed of dentin and enamel. However, these tooth structures were small and formed within the pores of the scaffolds. The present study shows that dental cell-encapsulated GelMA constructs can support mineralized dental tissue formation of predictable size and shape. Individually encapsulated pDE or pDM cell GelMA constructs were analysed to identify formulas that supported pDE and pDM cell attachment, spreading, metabolic activity, and neo-vasculature formation with co-seeded endothelial cells (HUVECs). GelMa constructs consisting of pDE-HUVECS in 3% GelMA and pDM-HUVECs within 5% GelMA supported dental cell differentiation and vascular mineralized dental tissue formation in vivo. These studies are the first to demonstrate the use of GelMA hydrogels to support the formation of post-natal dental progenitor cell-derived mineralized and functionally vascularized tissues of specified size and shape. These results introduce a novel three-dimensional biomimetic tooth bud model for eventual bioengineered tooth replacement teeth in humans. Copyright © 2017 John Wiley & Sons, Ltd.

  4. Mild temperatures on bud breaking dormancy in peaches Temperaturas amenas na superação da dormência de pessegueiros

    Directory of Open Access Journals (Sweden)

    Geraldo Chavarria

    2009-10-01

    Full Text Available The search for low chill cultivars for peach production in areas with low chill accumulation (temperatures below 7.2°C has stimulated studies about the higher temperatures effects on low chill cultivars. The objective of this research was to evaluate the influence of mild temperatures on flowering and leafing of 'Turmalina' and 'Ágata' cultivars with low and medium low chilling requirements, respectively. Plants obtained by grafting flower twigs in the autumn, after the grafting, were submitted to chilling treatments (150, 250, 350, 500 and 672 hours at three temperature levels (5°C, 10°C and 15°C. After the end of the treatments, the plants had been taken to greenhouse (20°C±5°C and evaluated weekly. The results showed that satisfactory flower and leaf development occur even at temperatures as high as 15°C for a period of 150 hours, in 'Turmalina' peach. Temperatures of 10°C for a period equal or superior to 350 hours promote satisfactory leafing in 'Ágata' peach. Temperatures of 10°C and 15°C cause earlier development of flowers and leaves in both cultivars when compared to 5°C.A busca por cultivares pessegueiro com baixa necessidade em frio para regiões com pouco acúmulo de frio (temperaturas abaixo de 7,2°C tem estimulado estudos sobre o efeito de altas temperaturas sobre cultivares de baixa necessidade de frio. O objetivo desta pesquisa foi avaliar a influência de temperaturas amenas na floração e brotação da 'Turmalina' e 'Ágata', duas cultivares com baixa e média necessidade de frio, respectivamente. Plantas obtidas por enxertia no outono foram submetidas a tratamentos de frio (150, 250, 350, 500 e 672 horas em três níveis de temperatura (5°C, 10°C e 15°C. Após os tratamentos, estas plantas foram colocadas em casa de vegetação a temperatura de 20°C±5°C e avaliadas semanalmente. Conclui-se que temperatura de até 15°C por um período de 150 horas é capaz de resultar em floração e brotação satisfatórias para a cultivar 'Turmalina'. Temperaturas de 10°C por um período igual ou superior a 350 horas promovem brotação satisfatória na cultivar 'Ágata'. Temperaturas de 10°C e 15°C comparadas a 5°C causam antecipação da floração e brotação e ambas cultivares.

  5. EnTranCe to the second life of gas : EnTranCe as source of innovation and human resources

    NARCIS (Netherlands)

    Aué, Jan-jaap; Gemert, Wim van; Martinus, Gerard

    2015-01-01

    The living lab EnTranCe provides a platform for open innovations. Stakeholders from large industry, SME’s, government and the research community team up to work on the future of the European energy system, with gas in a pivotal role. An important element of the innovation strength of EnTranCe is tha

  6. Advances in Understanding Seed Dormancy at the Whole-seed Level:An Ecological, Biogeographical and Phylogenetic Perspective

    Institute of Scientific and Technical Information of China (English)

    BASKIN Carol C; BASKIN Jerry M

    2008-01-01

    Following a brief account of the early foundations of seed germination ecology sensu lato, some historical and recent developments pertaining to the ecology, biogeography and phylogeny of seed dormancy are discussed.

  7. Loads on Entrance Platforms for Offshore Wind Turbines

    DEFF Research Database (Denmark)

    Frigaard, Peter; Andersen, Thomas Lykke; Ramirez, Jorge Robert Rodriguez;

    2010-01-01

    The present paper gives an overview of the performed large scale tests in GWK, Hannover for studying wave run-up generated forces on wind turbine entrance platforms. The run-up height and velocity was measured by use of high speed video recordings supplemented by some wave gauges mounted...... at the pile. Hereafter, the run-up generated impact forces were measured on two types of grates and a solid plate. The pressure distribution was also measured for the solid plate. In addition to this the wave generated backfilling of an initial scour hole and the strength of the backfilling soil was studied...

  8. Prévessin site: Pedestrian and cycle entrance

    CERN Multimedia

    2015-01-01

    The entrance to the Prévessin site for pedestrians and cyclists on Chemin du Moulin des Ponts will be re-opened: from 7 April to 30 October 2015, from 7.00 a.m. to 9.00 a.m. and from 5.00 p.m. to 7.00 p.m. on working days (Monday to Friday).   IMPORTANT: all users must show their access cards to the security guard as a matter of course when passing through the gates, both on entering and leaving the site.

  9. Prévessin site – Pedestrian and cycle entrances

    CERN Multimedia

    GS-DI

    2014-01-01

    Entrances for pedestrians and cyclists on Route du Maroc and on Chemin du Moulin des Ponts, in Prévessin, will be re-opened:   from 7 April to 31 October 2014, from 7.00 a.m. to 9.00 a.m. and from 5.00 p.m. to 7.00 p.m. on working days (Monday to Friday).   IMPORTANT: all users must show their access cards to the security guard as a matter of course when passing through the gates, both on entering and leaving the site.

  10. Electron tomography reveals the steps in filovirus budding.

    Directory of Open Access Journals (Sweden)

    Sonja Welsch

    2010-04-01

    Full Text Available The filoviruses, Marburg and Ebola, are non-segmented negative-strand RNA viruses causing severe hemorrhagic fever with high mortality rates in humans and nonhuman primates. The sequence of events that leads to release of filovirus particles from cells is poorly understood. Two contrasting mechanisms have been proposed, one proceeding via a "submarine-like" budding with the helical nucleocapsid emerging parallel to the plasma membrane, and the other via perpendicular "rocket-like" protrusion. Here we have infected cells with Marburg virus under BSL-4 containment conditions, and reconstructed the sequence of steps in the budding process in three dimensions using electron tomography of plastic-embedded cells. We find that highly infectious filamentous particles are released at early stages in infection. Budding proceeds via lateral association of intracellular nucleocapsid along its whole length with the plasma membrane, followed by rapid envelopment initiated at one end of the nucleocapsid, leading to a protruding intermediate. Scission results in local membrane instability at the rear of the virus. After prolonged infection, increased vesiculation of the plasma membrane correlates with changes in shape and infectivity of released viruses. Our observations demonstrate a cellular determinant of virus shape. They reconcile the contrasting models of filovirus budding and allow us to describe the sequence of events taking place during budding and release of Marburg virus. We propose that this represents a general sequence of events also followed by other filamentous and rod-shaped viruses.

  11. Electron tomography reveals the steps in filovirus budding.

    Science.gov (United States)

    Welsch, Sonja; Kolesnikova, Larissa; Krähling, Verena; Riches, James D; Becker, Stephan; Briggs, John A G

    2010-04-29

    The filoviruses, Marburg and Ebola, are non-segmented negative-strand RNA viruses causing severe hemorrhagic fever with high mortality rates in humans and nonhuman primates. The sequence of events that leads to release of filovirus particles from cells is poorly understood. Two contrasting mechanisms have been proposed, one proceeding via a "submarine-like" budding with the helical nucleocapsid emerging parallel to the plasma membrane, and the other via perpendicular "rocket-like" protrusion. Here we have infected cells with Marburg virus under BSL-4 containment conditions, and reconstructed the sequence of steps in the budding process in three dimensions using electron tomography of plastic-embedded cells. We find that highly infectious filamentous particles are released at early stages in infection. Budding proceeds via lateral association of intracellular nucleocapsid along its whole length with the plasma membrane, followed by rapid envelopment initiated at one end of the nucleocapsid, leading to a protruding intermediate. Scission results in local membrane instability at the rear of the virus. After prolonged infection, increased vesiculation of the plasma membrane correlates with changes in shape and infectivity of released viruses. Our observations demonstrate a cellular determinant of virus shape. They reconcile the contrasting models of filovirus budding and allow us to describe the sequence of events taking place during budding and release of Marburg virus. We propose that this represents a general sequence of events also followed by other filamentous and rod-shaped viruses.

  12. Dormência em sementes de arroz vermelho Dormancy in seeds of red rice

    Directory of Open Access Journals (Sweden)

    Carla Andréa Delatorre

    1999-09-01

    Full Text Available O arroz vermelho é considerado a principal planta daninha na maioria das lavouras de arroz, pois, além dos prejuízos causados pela competição, sua similaridade com o arroz cultivado dificulta seu controle. A dormência e a viabilidade de suas sementes no solo permitem a continuidade dos biotipos na lavoura e facilitam a disseminação para áreas próximas. A duração e a intensidade da dormência variam com o biotipo e com as condições ambientais vigentes durante o desenvolvimento da semente. A maior parte dos ecotipos apresenta dois tipos de dormência, uma devido às estruturas envoltórias e outra devido ao embrião. O período necessário para a superação da dormência é dependente das condições (temperatura e umidade a que a semente é exposta após a maturação. Várias substâncias têm sido eficientes na quebra da dormência, em especial, ácidos e citocininas. Outros reguladores tiveram apenas efeito parcial. Ressalta-se que todas as substâncias testadas não atuaram sobre as estruturas envoltórias. O mecanismo pelo qual ocorre a manutenção/alívio da dormência permanece desconhecido.Red rice is considered the major weed in rice areas. The similarity between red rice and cultivated rice difficults the red rice control. Seed dormancy and viability in the soil allow the maintanence of the biotype in the area and facilite the dissemination in surrounded areas. Dormancy duration and intensity depend on biotype and environmental conditions during seed development. In general, biotypes have two types of dormancy: one from surrounding structures and the other one from embryo. The dormancy relief can occur on different times. It depends on environmental conditions (temperature and humidity in afterripening. Some substances have shown good results on breaking dormancy, in special, acids and cytokinins, however, other hormones have shown only a partial effect. These substances have not affected the surrounding structures. The

  13. Activation of anaphase-promoting complex by p53 induces a state of dormancy in cancer cells against chemotherapeutic stress

    Science.gov (United States)

    Dai, Yafei; Wang, Lujuan; Tang, Jingqun; Cao, Pengfei; Luo, Zhaohui; Sun, Jun; Kiflu, Abraha; Sai, Buqing; Zhang, Meili; Wang, Fan; Li, Guiyuan; Xiang, Juanjuan

    2016-01-01

    Cancer dormancy is a stage in tumor progression in which residual disease remains occult and asymptomatic for a prolonged period. Cancer cell dormancy is the main cause of cancer recurrence and failure of therapy. However, cancer dormancy is poorly characterized and the mechanisms of how cancer cells develop dormancy and relapse remain elusive. In this study, 5- fluorouracil (5-FU) was used to induce cancer cell dormancy. We found that cancer cells escape the cytotoxicity of 5-FU by becoming “dormant”. After exposure to 5-FU, residual non-small cell lung cancer (NSCLC) cells underwent epithelial-mesenchymal transition (EMT), followed by mesenchymal-epithelial transition (MET). These EMT-transformed NSCLC cells were in the state of cell quiescence where cells were not dividing and were arrested in the cell cycle in G0-G1. The dormant cells underwent an EMT showed characteristics of cancer stem cells. P53 is strongly accumulated in response to 5-FU-induced dormant cells through the activation of ubiquitin ligase anaphase-promoting complex (APC/C) and TGF-β/Smad signaling. In contrast to the EMT-transformed cells, MET-transformed cells showed an increased ability to proliferate, suggesting that dormant EMT cells were reactivated in the MET process. During the EMT-MET process, DNA repair including nonhomologous end joining (NHEJ) and homologous recombination (HR) is critical to dormant cell reactivation. Our findings provide a mechanism to unravel cancer cell dormancy and reactivation of the cancer cell population. PMID:27009858

  14. Repellence of the red bud borer Resseliella oculiperda from grafted apple trees by impregnation of rubber budding strips with essential oils.

    Science.gov (United States)

    van Tol, Rob W H M; Swarts, Henk J; van der Linden, Anton; Visser, J H

    2007-05-01

    The red bud borer Resseliella oculiperda (Rübs.) is a pest insect of apple trees when rootstocks are grafted with scion buds by 'shield budding'. The female midges are attracted to the wounds of the grafted buds where they lay their eggs. The larvae feed on the cambium and destroy the buds completely or partially, leading to bad union of the buds with the rootstocks. Budding strips are used very often by growers to bind scion buds to rootstocks. These strips cannot prevent midges from reaching the damaged tissue. Chemical treatments applied to the grafts and other types of strip do not provide better protection against the pest and may cause other risks for growers. In orchard experiments in 2000 and 2001, the authors evaluated the repellent action provided by three essential oils and five compounds of plant origin against the midges by impregnating budding strips with them. The essential oils of lavender, Lavandula angustifolia (P. Mill.), and alpha-terpineol decreased the infestation of buds by more than 95 and 80% respectively. The other potential repellents tested [the essential oil of Juniperus virginiana (L.), citronellal, the essential oil of Cinnamomum camphora (L.) J. Presl, R-carvone, linalool and R-fenchone] decreased infestation by 67, 66, 51, 45, 37 and 25% respectively. The formulation and commercial development of budding strips impregnated with lavender oil is discussed.

  15. The Mechanism of Budding of Retroviruses from Cell Membranes

    Directory of Open Access Journals (Sweden)

    Andrew Pincetic

    2009-01-01

    Full Text Available Retroviruses have evolved a mechanism for the release of particles from the cell membrane that appropriates cellular protein complexes, referred to as ESCRT-I, -II, -III, normally involved in the biogenesis of multivesicular bodies. Three different classes of late assembly (L domains encoded in Gag, with core sequences of PPXY, PTAP, and YPXL, recruit different components of the ESCRT machinery to form a budding complex for virus release. Here, we highlight recent progress in identifying the role of different ESCRT complexes in facilitating budding, ubiquitination, and membrane targeting of avian sarcoma and leukosis virus (ASLV and human immunodeficiency virus, type 1 (HIV-1. These findings show that retroviruses may adopt parallel budding pathways by recruiting different host factors from common cellular machinery for particle release.

  16. Budding yeast colony growth study based on circular granular cell

    Science.gov (United States)

    Aprianti, Devi; Khotimah, S. N.; Viridi, S.

    2016-08-01

    Yeast colony growth can be modelled by using circular granular cells, which can grow and produce buds. The bud growth angle can be set to regulate cell budding pattern. Cohesion force, contact force and Stokes force were adopted to accommodate the behaviour and interactions among cells. Simulation steps are divided into two steps, the explicit step is due to cell growing and implicit step for the cell rearrangement. Only in explicit step that time change was performed. In this study, we examine the influence of cell diameter growth time and reproduction time combination toward the growth of cell number and colony formation. We find a commutative relation between the cell diameter growth time and reproduction time to the specific growth rate. The greater value of the multiplication of the parameters, the smaller specific growth rate is obtained. It also shows a linear correlation between the specific growth rate and colony diameter growth rate.

  17. Adventitious bud regeneration from the stigma of Sinapis alba L.

    Directory of Open Access Journals (Sweden)

    Elżbieta Zenkteler

    2012-12-01

    Full Text Available Stigmas isolated from flower buds of 'Nakielska' variety of Sinapis alba were used to develop a micropropagation method suitable for breeding of new cultivars. The origin of adventitious bud regeneration was studied on MS medium, under stimulation by bezylaminopurine (BAP in combination with 2,4-D - dichlorophenoxyacetic acid (2,4-D. Histological analysis showed the structure of Sinapis stigma (composed from four types of tissue: papillae, transmitting tissue, parenchyma and vascular bundles and revealed that numerous meristematic centers developed from parenchyma cells in close vicinity of vascular bundles. Buds very quickly appeared on the surface of initial explants and later formed multiplantlets that were easily rooted in the soil.

  18. The budding yeast Dbf2 protein kinase localises to the centrosome and moves to the bud neck in late mitosis.

    Science.gov (United States)

    Frenz, L M; Lee, S E; Fesquet, D; Johnston, L H

    2000-10-01

    Dbf2 is a multifunctional protein kinase in Saccharomyces cerevisiae that functions in transcription, the stress response and as part of a network of genes in exit from mitosis. By analogy with fission yeast it seemed likely that these mitotic exit genes would be involved in cytokinesis. As a preliminary investigation of this we have used Dbf2 tagged with GFP to examine intracellular localisation of the protein in living cells. Dbf2 is found on the centrosomes/spindle pole bodies (SPBs) and also at the bud neck where it forms a double ring. The localisation of Dbf2 is cell cycle regulated. It is on the SPBs for much of the cell cycle and migrates from there to the bud neck in late mitosis, consistent with a role in cytokinesis. Dbf2 partly co-localises with septins at the bud neck. A temperature-sensitive mutant of dbf2 also blocks progression of cytokinesis at 37 degrees C. Following cytokinesis some Dbf2 moves into the nascent bud. Localisation to the bud neck depends upon the septins and also the mitotic exit network proteins Mob1, Cdc5, Cdc14 and Cdc15. The above data are consistent with Dbf2 acting downstream in a pathway controlling cytokinesis.

  19. EFEITO DO FRIO NA BROTAÇÃO DE GEMAS DE PEREIRA (Pyrus communis L. cv. Carrick, EM PELOTAS, RS EFFECT OF CHILLING ON THE BUD BREAKING OF PEAR CV. CARRICK, IN PELOTAS, RS

    Directory of Open Access Journals (Sweden)

    FLÁVIO GILBERTO HERTER

    2001-08-01

    Full Text Available Objetivou-se, no presente trabalho, identificar a profundidade de dormência e a velocidade de brotação em gemas de pereira, submetidas a diferentes períodos de frio à temperatura de 4ºC ±1. O experimento foi conduzido na Embrapa-Clima Temperado, em Pelotas, em 1999. Em 1º de junho, foram coletados 50 ramos, na cultivar Carrick, com aproximadamente 30 cm de comprimento. Após, foram divididos em 5 lotes de 10 ramos, sendo 4 mantidos a 4ºC± 1, e um em condições ambiente, constituindo, assim, 5 tratamentos: 0 (Testemunha; 272; 544; 816 e 1088 horas de frio (HF. No final de cada tratamento, os ramos foram divididos em pequenas estacas, contendo apenas uma única gema, sendo, após, armazenados em câmara climática a 25ºC ± 1. Avaliou-se a brotação, considerando-se o estádio de ponta verde. A partir destes dados, calculou-se o tempo médio de brotação (TMB, bem como a percentagem de gemas brotadas, em cada um dos tratamentos. Utilizou-se o índice de velocidade de brotação (IVB, para determinar a eficiência da temperatura na brotação das gemas. A profundidade de dormência, das gemas terminais, diminuiu à medida que se aumentou o período de frio. As gemas axilares não foram influenciadas pelo tempo de exposição ao frio. Com base nos dados do IVB e dos coeficientes angulares, as gemas terminais da cv. Carrick necessitam de 800 horas de frio para completar a brotação, nas condições que foram conduzidos os experimentos.The objective for this work was to identify the dormancy depth and the bud-sprouting rate of pear trees kept at chilling conditions (4ºC±1 for different periods. The experiment was carried out using buds of twigs of the previous growth season from a pear orchard of the Embrapa Clima Temperado Research Center. The twigs were collected on June 1, 1999. The treatments were five period of chilling: 0 (control; 272; 544; 816; or 1088 hours at 4ºC±1. At the end of each treatment, the twigs were cut into

  20. Interface Region Imaging Spectrograph (IRIS) entrance aperture design

    Science.gov (United States)

    Cheimets, P.; Park, S.; Bergner, H.; Chou, C.; Gates, R.; Honsa, M.; Podgorski, W.; Yanari, C.

    2014-07-01

    The Interface Region Imaging Spectrograph (IRIS) is a complementary follow-on to Solar Dynamics Observatory Atmospheric Imaging Assembly (SDO-AIA) and funded as a member of the NASA SMEX program. This paper presents the thermal design of the IRIS telescope front end, with a focus on the IRIS door and entrance aperture assembly. The challenge of the IRIS entrance aperture, including the door design, was to manage the solar flux, both before and after the door was opened. This is especially a problem with instruments that are permanently pointed directly at the sun. Though there is an array of effective flux-rejecting coatings, they are expensive, hard to apply, harder to measure, delicate, prone to unpredictable performance decay with exposure, and very often a source of contamination. This paper presents a thermal control and protection method based on robust, inexpensive coatings and materials, combined to produce high thermal and structural isolation. The end result is a first line of thermal protection whose performance is easy to predict and well isolated from the instrument it is protecting.

  1. Entrance C - New Automatic Number Plate Recognition System

    CERN Multimedia

    2013-01-01

    Entrance C (Satigny) is now equipped with a latest-generation Automatic Number Plate Recognition (ANPR) system and a fast-action road gate.   During the month of August, Entrance C will be continuously open from 7.00 a.m. to 7.00 p.m. (working days only). The security guards will open the gate as usual from 7.00 a.m. to 9.00 a.m. and from 5.00 p.m. to 7.00 p.m. For the rest of the working day (9.00 a.m. to 5.00 p.m.) the gate will operate automatically. Please observe the following points:       Stop at the STOP sign on the ground     Position yourself next to the card reader for optimal recognition     Motorcyclists must use their CERN card     Cyclists may not activate the gate and should use the bicycle turnstile     Keep a safe distance from the vehicle in front of you   If access is denied, please check that your vehicle regist...

  2. Evaluation of entrance surface air kerma in pediatric chest radiography

    Science.gov (United States)

    Porto, L.; Lunelli, N.; Paschuk, S.; Oliveira, A.; Ferreira, J. L.; Schelin, H.; Miguel, C.; Denyak, V.; Kmiecik, C.; Tilly, J.; Khoury, H.

    2014-11-01

    The objective of this study was to evaluate the entrance surface air kerma in pediatric chest radiography. An evaluation of 301 radiographical examinations in anterior-posterior (AP) and posterior-anterior (PA) (166 examinations) and lateral (LAT) (135 examinations) projections was performed. The analyses were performed on patients grouped by age; the groups included ages 0-1 y, 1-5 y, 5-10 y, and 10-15 y. The entrance surface air kerma was determined with DoseCal software (Radiological Protection Center of Saint George's Hospital, London) and thermoluminescent dosimeters. Two different exposure techniques were compared. The doses received by patients who had undergone LAT examinations were 40% higher, on average, those in AP/PA examinations because of the difference in tube voltage. A large high-dose “tail” was observed for children up to 5 y old. An increase in tube potential and corresponding decrease in current lead to a significant dose reduction. The difference between the average dose values for different age ranges was not practically observed, implying that the exposure techniques are still not optimal. Exposure doses received using the higher tube voltage and lower current-time product correspond to the international diagnostic reference levels.

  3. Laminar flow in the entrance region of elliptical ducts

    Science.gov (United States)

    Bhatti, M. S.

    1983-06-01

    A closed-form analytical solution is developed to hitherto unsolved problem of steady laminar flow of a Newtonian fluid in the entrance region of elliptical ducts. The analysis is based on the Karman-Pohlhausen integral method and entails solution of the integrated forms of the mass and the momentum balance equations. According to this analysis, the hydrodynamic entrance length based on 99 percent approach to the fully developed flow is equal to 0.5132 lambda/(l + lambda-squared) where lambda is the aspect ratio. Also, the fully developed incremental pressure defect is found to be 7/6 which is independent of the aspect ratio. In the limit when the flow becomes fully developed, the solution converges to the known exact asymptotic solution. Available, wide-ranging velocity measurements for a circular tube agree with the analytical predictions within 7 percent. Also, available pressure drop measurements near the inlet of a circular tube agree with the analytical predictions within 2 percent.

  4. Seed dormancy release in Arabidopsis Cvi by dry after-ripening, low temperature, nitrate and light shows common quantitative patterns of gene expression directed by environmentally specific sensing.

    Science.gov (United States)

    Finch-Savage, William E; Cadman, Cassandra S C; Toorop, Peter E; Lynn, James R; Hilhorst, Henk W M

    2007-07-01

    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 Island accession seeds exposed to dry after-ripening (AR), or low temperature, nitrate and light when imbibed. Germination studies showed that the sensitivity of imbibed seeds to low temperature, nitrate and light was dependent upon the length of time spent AR following harvest. Seeds had an absolute requirement for light to complete dormancy release in all conditions, but this effect required an exposure to a prior dormancy relieving environment. Principal component analyses of the expression patterns observed grouped physiological states in a way that related to the depth of seed dormancy, rather than the type of environmental exposure. Furthermore, opposite changes in transcript abundance of genes in sets associated with dormancy, or dormancy relief through AR, were also related to the depth of dormancy and common to different environments. Besides these common quantitative changes, environment-specific gene expression patterns during dormancy relief are also described. For example, higher transcript abundance for genes linked to the process of nitrate accumulation, and nitrate reduction was associated with dormancy relief. The quantity of GA3ox1 transcripts increased during dormancy relief in all conditions, in particular when dormancy relief was completed by exposure to light. This contrasts with transcripts linked to abscisic acid (ABA) synthesis, which declined. The results are consistent with a role for the ABA/gibberellic acid balance in integrating dormancy-relieving environmental signals.

  5. Breaking seed dormancy in Cupressus atlantica Gaussen, an endemic and threatened coniferous tree in Morocco

    Institute of Scientific and Technical Information of China (English)

    Sfairi Youssef; Ouahmane Lahcen; Abbad Abdelaziz

    2012-01-01

    Cupressus atlantica Gaussen (Cupressaceae) is an endemic and endangered coniferous tree geographically restricted to the N'Fis valley in South-Western Morocco.Like many forest species,C atlantica exhibits dormancy which delays and reduces germination.To improve seed germination,different pre-treatments were conducted on C atlantica seeds after storage for different periods (one,two and five years)including:scarification with sandy paper; soaking seeds in hot distilled water at 60℃ and 80℃ for 15 min and soaking seeds for 48 h in a gibberellic acid (GA3) at 1,000 and 2,000 mg·L-1.Results showed that scarification with sandy paper increased the germination rate of Atlas cypress by up to 67%,indicating that the species possess essentially an exogenous dormancy (physical dormancy) due to the hard seed coat (hardseededness).Exogenous application of gibberellic acid (GA3) at 1,000 mg·L-1 was also effective in breaking seed dormancy and germination induction.These two treatments induced faster speed germination expressed by low number of days to first germination (8-10 days) and low values of mean germination times (MGT).However,germination rate,under any treatment,is greatly dependent on the year of seed collection.Seeds collected in year 2004 gave the highest value,suggesting that even after five years of storage,the germination capacity of C.atlantica seeds could remain high.This observation is very interesting in the ex-situ conservation of such endemic and endangered species where the production of seeds is irregular over the years.

  6. Association studies of dormancy and cooking quality traits in direct-seeded indica rice

    Indian Academy of Sciences (India)

    Sunayana Rathi; K. Pathak; R. N. S. Yadav; B. Kumar; R. N. Sarma

    2014-04-01

    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. Linkage disequilibrium between linked markers decreased with distance. Marker-trait associations were investigated using the unified mixed-model approach, considering both population structure (Q) and kinship (K). Genome-wide scanning, detected a total of seven significant marker-trait associations $(P \\lt 0.01)$, with the $R^2$ values ranging from 12.0 to 18.0%. The significant marker associations were for grain dormancy (RM27 on chromosome 2), -amylase activity (RM27 and RM234 on chromosomes 2 and 7, respectively), germination (RM27 and RM106 on chromosome 2), amylose (RM282 on chromosome 3) and grain length elongation ratio (RM142 on chromosome 4). The present study revealed the association of marker RM27 with traits like dormancy, α-amylase activity and germination. Simple correlation analysis of these traits revealed that these traits were positively correlated with each other and this marker may be useful for simultaneous improvement of these traits. The study indicates the presence of novel QTLs for a few traits under consideration. The study reveals association of traits like dormancy, -amylase activity, germination, amylose content, grain length elongation ratio with SSR markers indicating the feasibility of undertaking association analysis in conjunction with germplasm characterization.

  7. Release of sunflower seed dormancy by cyanide: cross-talk with ethylene signalling pathway.

    Science.gov (United States)

    Oracz, Krystyna; El-Maarouf-Bouteau, Hayat; Bogatek, Renata; Corbineau, Françoise; Bailly, Christophe

    2008-01-01

    Freshly harvested sunflower (Helianthus annuus L.) seeds are considered to be dormant because they fail to germinate at relatively low temperatures (10 degrees C). This dormancy results mainly from an embryo dormancy and disappears during dry storage. Although endogenous ethylene is known to be involved in sunflower seed alleviation of dormancy, little attention had been paid to the possible role of cyanide, which is produced by the conversion of 1-aminocyclopropane 1-carboxylic acid to ethylene, in this process. The aims of this work were to investigate whether exogenous cyanide could improve the germination of dormant sunflower seeds and to elucidate its putative mechanisms of action. Naked dormant seeds became able to germinate at 10 degrees C when they were incubated in the presence of 1 mM gaseous cyanide. Other respiratory inhibitors showed that this effect did not result from an activation of the pentose phosphate pathway or the cyanide-insensitive pathway. Cyanide stimulated germination of dormant seeds in the presence of inhibitors of ethylene biosynthesis, but its improving effect required functional ethylene receptors. It did not significantly affect ethylene production and the expression of genes involved in ethylene biosynthesis or in the first steps of ethylene signalling pathway. However, the expression of the transcription factor Ethylene Response Factor 1 (ERF1) was markedly stimulated in the presence of gaseous cyanide. It is proposed that the mode of action of cyanide in sunflower seed dormancy alleviation does not involve ethylene production and that ERF1 is a common component of the ethylene and cyanide signalling pathways.

  8. Proteome analysis of Norway maple (Acer platanoides L. seeds dormancy breaking and germination: influence of abscisic and gibberellic acids

    Directory of Open Access Journals (Sweden)

    Pawłowski Tomasz A

    2009-05-01

    Full Text Available Abstract Background Seed dormancy is controlled by the physiological or structural properties of a seed and the external conditions. It is induced as part of the genetic program of seed development and maturation. Seeds with deep physiological embryo dormancy can be stimulated to germinate by a variety of treatments including cold stratification. Hormonal imbalance between germination inhibitors (e.g. abscisic acid and growth promoters (e.g. gibberellins is the main cause of seed dormancy breaking. Differences in the status of hormones would affect expression of genes required for germination. Proteomics offers the opportunity to examine simultaneous changes and to classify temporal patterns of protein accumulation occurring during seed dormancy breaking and germination. Analysis of the functions of the identified proteins and the related metabolic pathways, in conjunction with the plant hormones implicated in seed dormancy breaking, would expand our knowledge about this process. Results A proteomic approach was used to analyse the mechanism of dormancy breaking in Norway maple seeds caused by cold stratification, and the participation of the abscisic (ABA and gibberellic (GA acids. Forty-four proteins showing significant changes were identified by mass spectrometry. Of these, eight spots were identified as water-responsive, 18 spots were ABA- and nine GA-responsive and nine spots were regulated by both hormones. The classification of proteins showed that most of the proteins associated with dormancy breaking in water were involved in protein destination. Most of the ABA- and GA-responsive proteins were involved in protein destination and energy metabolism. Conclusion In this study, ABA was found to mostly down-regulate proteins whereas GA up-regulated proteins abundance. Most of the changes were observed at the end of stratification in the germinated seeds. This is the most active period of dormancy breaking when seeds pass from the quiescent

  9. 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.

  10. Secreted Protein Acidic and Rich in Cysteine (SPARC) Mediates Metastatic Dormancy of Prostate Cancer in Bone.

    Science.gov (United States)

    Sharma, Sambad; Xing, Fei; Liu, Yin; Wu, Kerui; Said, Neveen; Pochampally, Radhika; Shiozawa, Yusuke; Lin, Hui-Kuan; Balaji, K C; Watabe, Kounosuke

    2016-09-09

    Prostate cancer is known to frequently recur in bone; however, how dormant cells switch its phenotype leading to recurrent tumor remains poorly understood. We have isolated two syngeneic cell lines (indolent and aggressive) through in vivo selection by implanting PC3mm stem-like cells into tibial bones. We found that indolent cells retained the dormant phenotype, whereas aggressive cells grew rapidly in bone in vivo, and the growth rates of both cells in culture were similar, suggesting a role of the tumor microenvironment in the regulation of dormancy and recurrence. Indolent cells were found to secrete a high level of secreted protein acidic and rich in cysteine (SPARC), which significantly stimulated the expression of BMP7 in bone marrow stromal cells. The secreted BMP7 then kept cancer cells in a dormant state by inducing senescence, reducing "stemness," and activating dormancy-associated p38 MAPK signaling and p21 expression in cancer cells. Importantly, we found that SPARC was epigenetically silenced in aggressive cells by promoter methylation, but 5-azacytidine treatment reactivated the expression. Furthermore, high SPARC promoter methylation negatively correlated with disease-free survival of prostate cancer patients. We also found that the COX2 inhibitor NS398 down-regulated DNMTs and increased expression of SPARC, which led to tumor growth suppression in bone in vivo These findings suggest that SPARC plays a key role in maintaining the dormancy of prostate cancer cells in the bone microenvironment.

  11. Downregulation of CXCR4 in Metastasized Breast Cancer Cells and Implication in Their Dormancy.

    Directory of Open Access Journals (Sweden)

    Kentaro Nobutani

    Full Text Available Our understanding of the mechanism of cancer dormancy is emerging, but the underlying mechanisms are not fully understood. Here we analyzed mouse xenograft tumors derived from human breast cancer tissue and the human breast cancer cell line MDA-MB-231 to identify the molecules associated with cancer dormancy. In immunohistological examination using the proliferation marker Ki-67, the tumors included both proliferating and dormant cancer cells, but the number of dormant cells was remarkably increased when they metastasized to the lung. In the gene expression analysis of the orthotopic cancer cells by a single-cell multiplex real-time quantitative reverse transcription PCR followed by flow cytometric analysis, restrained cellular proliferation was associated with downregulation of the chemokine receptor CXCR4. In the immunohistological and flow cytometric analyses, the expression level of CXCR4 in the metastasized cancer cells was decreased compared with that in the cancer cells in orthotopic tumors, although the expression level of the CXCR4 ligand CXCL12 was not reduced in the lung. In addition, the proliferation of the metastasized cancer cells was further decreased by the CXCR4 antagonist administration. In the ex vivo culture of the metastasized cancer cells, the expression level of CXCR4 was increased, and in the xenotransplantation of ex vivo cultured cancer cells, the expression level of CXCR4 was again decreased in the metastasized cancer cells in the lung. These findings indicate that CXCR4 is downregulated in metastasized breast cancer cells and implicated in their dormancy.

  12. Induction of 9-cis-epoxycarotenoid dioxygenase in Arabidopsis thaliana seeds enhances seed dormancy.

    Science.gov (United States)

    Martínez-Andújar, Cristina; Ordiz, M Isabel; Huang, Zhonglian; Nonogaki, Mariko; Beachy, Roger N; Nonogaki, Hiroyuki

    2011-10-11

    Full understanding of mechanisms that control seed dormancy and germination remains elusive. Whereas it has been proposed that translational control plays a predominant role in germination, other studies suggest the importance of specific gene expression patterns in imbibed seeds. Transgenic plants were developed to permit conditional expression of a gene encoding 9-cis-epoxycarotenoid dioxygenase 6 (NCED6), a rate-limiting enzyme in abscisic acid (ABA) biosynthesis, using the ecdysone receptor-based plant gene switch system and the ligand methoxyfenozide. Induction of NCED6 during imbibition increased ABA levels more than 20-fold and was sufficient to prevent seed germination. Germination suppression was prevented by fluridone, an inhibitor of ABA biosynthesis. In another study, induction of the NCED6 gene in transgenic seeds of nondormant mutants tt3 and tt4 reestablished seed dormancy. Furthermore, inducing expression of NCED6 during seed development suppressed vivipary, precocious germination of developing seeds. These results indicate that expression of a hormone metabolism gene in seeds can be a sole determinant of dormancy. This study opens the possibility of developing a robust technology to suppress or promote seed germination through engineering pathways of hormone metabolism.

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

    Directory of Open Access Journals (Sweden)

    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.

  14. RESEARCH OF SOPHORA JAPONICA L. FLOWER BUDS VOLATILE COMPOUNDS WITH GAS-CHROMATOGRAPHY/MASS- SPECTROMETRY METHOD

    Directory of Open Access Journals (Sweden)

    Cholak I.S.

    2013-10-01

    Full Text Available This work represents the results of the research ofessential oil contained in Sophora japonica L. flowerbuds volatile compounds collected during the nextstages of their development: green flower buds, formedflower buds and the beginning of flower buds opening.Essential oil assay content in Sophora japonica L.flower buds was determined with hydrodistillationmethod. Content of essential oil in the raw material isless than 0,1%. Qualitative composition and assaycontent of Sophora japonica L. flower buds essential oilconstituents were determined with chromato-massspectrometry method. In consequence of the research 80constituents were identified in Sophora japonica L.flower buds out of which 61 substances are during thegreen flower buds and beginning of flower budsopening stages, 66 substances are during formed flowerbuds stage. Substances are represented by aliphatic andcyclic terpenoids, their alcohols and ketones. Mostvolatile substances were extracted on the stage offormed buds.

  15. Wax ester synthesis is required for Mycobacterium tuberculosis to enter in vitro dormancy.

    Directory of Open Access Journals (Sweden)

    Tatiana D Sirakova

    Full Text Available Mycobacterium tuberculosis (Mtb is known to produce wax esters (WE when subjected to stress. However, nothing is known about the enzymes involved in biosynthesis of WE and their role in mycobacterial dormancy. We report that two putative Mtb fatty acyl-CoA reductase genes (fcr expressed in E. coli display catalytic reduction of fatty acyl-CoA to fatty aldehyde and fatty alcohol. Both enzymes (FCR1/Rv3391 and FCR2/Rv1543 showed a requirement for NADPH as the reductant, a preference for oleoyl-CoA over saturated fatty acyl-CoA and were inhibited by thiol-directed reagents. We generated Mtb gene-knockout mutants for each reductase. Metabolic incorporation of( 14C-oleate into fatty alcohols and WE was severely diminished in the mutants under dormancy-inducing stress conditions that are thought to be encountered by the pathogen in the host. The fatty acyl-CoA reductase activity in cell lysates of the mutants under nitric oxide stress was significantly reduced when compared with the wild type. Complementation restored the lost activity completely in the Δfcr1 mutant and partially in the Δfcr2 mutant. WE synthesis was inhibited in both Δfcr mutants. The Δfcr mutants exhibited faster growth rates, an increased uptake of (14C-glycerol suggesting increased permeability of the cell wall, increased metabolic activity levels and impaired phenotypic antibiotic tolerance under dormancy-inducing combined multiple stress conditions. Complementation of the mutants did not restore the development of antibiotic tolerance to wild-type levels. Transcript analysis of Δfcr mutants showed upregulation of genes involved in energy generation and transcription, indicating the inability of the mutants to become dormant. Our results indicate that the fcr1 and fcr2 gene products are involved in WE synthesis under in vitro dormancy-inducing conditions and that WE play a critical role in reaching a dormant state. Drugs targeted against the Mtb reductases may inhibit its

  16. Quantitative resistance to peanut bud necrosis tospovirus in groudnut.

    NARCIS (Netherlands)

    Buiel, A.A.M.

    1996-01-01

    Quantitative resistance to peanut bud necrosis virus (PBNV) is expressed as a reduced disease incidence (percentage of infected plants) in the groundnut crop. An increased plant density reduced this incidence, but the number of infected plants per unit area increased, maintaining high levels of PBNV

  17. A New Compound from the Bud of Chrysanthemum indicum L.

    Institute of Scientific and Technical Information of China (English)

    2005-01-01

    A new bicyclic spiroketone was isolated from the bud of Chrysanthemum indicum L.The chemical structure was elucidated as (1R, 9S, 10S)-10-hydroxyl-8 (2', 4'-diynehexylidene)-9-isovaleryloxy-2, 7-dioxaspiro [5, 4] decane based on the X-ray crystallography.

  18. Regulation of homologous recombination at telomeres in budding yeast

    DEFF Research Database (Denmark)

    Eckert-Boulet, Nadine; Lisby, Michael

    2010-01-01

    Homologous recombination is suppressed at normal length telomere sequences. In contrast, telomere recombination is allowed when telomeres erode in the absence of telomerase activity or as a consequence of nucleolytic degradation or incomplete replication. Here, we review the mechanisms...... that contribute to regulating mitotic homologous recombination at telomeres and the role of these mechanisms in signalling short telomeres in the budding yeast Saccharomyces cerevisiae....

  19. Axillary Bud Proliferation Approach for Plant Biodiversity Conservation and Restoration

    Directory of Open Access Journals (Sweden)

    F. Ngezahayo

    2014-01-01

    Full Text Available Due to mainly human population pressure and activities, global biodiversity is getting reduced and particularly plant biodiversity is becoming at high risk of extinction. Consequently, many efforts have been deployed to develop conservation methods. Because it does not involve cell dedifferentiation of differentiated cells but rather the development and growth of new shoots from preexisting meristems, the axillary bud proliferation approach is the method offering least risk of genetic instability. Indeed, meristems are more resistant to genetic changes than disorganized tissues. The present review explored through the scientific literature the axillary bud proliferation approach and the possible somaclonal variation that could arise from it. Almost genetic stability or low level of genetic variation is often reported. On the contrary, in a few cases studied to date, DNA methylation alterations often appeared in the progenies, showing epigenetic variations in the regenerated plants from axillary bud culture. Fortunately, epigenetic changes are often temporary and plants may revert to the normal phenotype. Thus, in the absence of genetic variations and the existence of reverting epigenetic changes over time, axillary bud culture can be adopted as an alternative nonconventional way of conserving and restoring of plant biodiversity.

  20. Entrance, exit, and reentrance of one shot with a shotgun

    DEFF Research Database (Denmark)

    Gulmann, C; Hougen, H P

    1999-01-01

    The case being reported is one of a homicidal shotgun fatality with an unusual wound pattern. A 34-year-old man was shot at close range with a 12-gauge shotgun armed with No. 5 birdshot ammunition. The shot entered the left axillary region, exited through the left infraclavicular region, and ther......The case being reported is one of a homicidal shotgun fatality with an unusual wound pattern. A 34-year-old man was shot at close range with a 12-gauge shotgun armed with No. 5 birdshot ammunition. The shot entered the left axillary region, exited through the left infraclavicular region......, and thereafter penetrated the left side of the neck, causing tearing of the left common carotid artery and the right internal carotid artery. The entrance wound in the axilla was larger than the other wounds, and before autopsy it was believed that the shotgun had been fired twice, causing one wound in the neck...

  1. Induction of ectopic taste buds by SHH reveals the competency and plasticity of adult lingual epithelium.

    Science.gov (United States)

    Castillo, David; Seidel, Kerstin; Salcedo, Ernesto; Ahn, Christina; de Sauvage, Frederic J; Klein, Ophir D; Barlow, Linda A

    2014-08-01

    Taste buds are assemblies of elongated epithelial cells, which are innervated by gustatory nerves that transmit taste information to the brain stem. Taste cells are continuously renewed throughout life via proliferation of epithelial progenitors, but the molecular regulation of this process remains unknown. During embryogenesis, sonic hedgehog (SHH) negatively regulates taste bud patterning, such that inhibition of SHH causes the formation of more and larger taste bud primordia, including in regions of the tongue normally devoid of taste buds. Here, using a Cre-lox system to drive constitutive expression of SHH, we identify the effects of SHH on the lingual epithelium of adult mice. We show that misexpression of SHH transforms lingual epithelial cell fate, such that daughter cells of lingual epithelial progenitors form cell type-replete, onion-shaped taste buds, rather than non-taste, pseudostratified epithelium. These SHH-induced ectopic taste buds are found in regions of the adult tongue previously thought incapable of generating taste organs. The ectopic buds are composed of all taste cell types, including support cells and detectors of sweet, bitter, umami, salt and sour, and recapitulate the molecular differentiation process of endogenous taste buds. In contrast to the well-established nerve dependence of endogenous taste buds, however, ectopic taste buds form independently of both gustatory and somatosensory innervation. As innervation is required for SHH expression by endogenous taste buds, our data suggest that SHH can replace the need for innervation to drive the entire program of taste bud differentiation.

  2. File list: ALL.Pan.05.AllAg.Pancreatic_bud [Chip-atlas[Archive

    Lifescience Database Archive (English)

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  10. The Arabidopsis aleurone layer responds to nitric oxide, gibberellin, and abscisic acid and is sufficient and necessary for seed dormancy.

    Science.gov (United States)

    Bethke, Paul C; Libourel, Igor G L; Aoyama, Natsuyo; Chung, Yong-Yoon; Still, David W; Jones, Russell L

    2007-03-01

    Seed dormancy is a common phase of the plant life cycle, and several parts of the seed can contribute to dormancy. Whole seeds, seeds lacking the testa, embryos, and isolated aleurone layers of Arabidopsis (Arabidopsis thaliana) were used in experiments designed to identify components of the Arabidopsis seed that contribute to seed dormancy and to learn more about how dormancy and germination are regulated in this species. The aleurone layer was found to be the primary determinant of seed dormancy. Embryos from dormant seeds, however, had a lesser growth potential than those from nondormant seeds. Arabidopsis aleurone cells were examined by light and electron microscopy, and cell ultrastructure was similar to that of cereal aleurone cells. Arabidopsis aleurone cells responded to nitric oxide (NO), gibberellin (GA), and abscisic acid, with NO being upstream of GA in a signaling pathway that leads to vacuolation of protein storage vacuoles and abscisic acid inhibiting vacuolation. Molecular changes that occurred in embryos and aleurone layers prior to germination were measured, and these data show that both the aleurone layer and the embryo expressed the NO-associated gene AtNOS1, but only the embryo expressed genes for the GA biosynthetic enzyme GA3 oxidase.

  11. 46 CFR 111.83-5 - Bottom entrance and protected enclosures.

    Science.gov (United States)

    2010-10-01

    ... ELECTRIC SYSTEMS-GENERAL REQUIREMENTS Shore Connection Boxes § 111.83-5 Bottom entrance and protected enclosures. Each shore connection box must have a bottom entrance for the shore connection cable. The box must provide protection to the shore connection when the connection is in use....

  12. University and the Entrance Examinations in a Greek Provincial Town: A Bottom-Up Perspective.

    Science.gov (United States)

    Benincasa, Luciana

    1998-01-01

    Focuses on the cultural meaning of university education and of participation in the extremely competitive entrance examinations to university, as viewed from a Greek provincial town. Notes that despite high graduate unemployment, university education and sitting for entrance examinations have important social status implications. (DSK)

  13. The Arabidopsis thaliana aleurone layer responds to nitric oxide, gibberellin, and abscisic acid and is sufficient and necessary for seed dormancy

    Science.gov (United States)

    Seed dormancy is a common phase of the plant life cycle and several parts of the seed can contribute to dormancy. Whole seeds, seeds lacking the testa, embryos, and isolated aleurone layers of Arabidopsis thaliana were used in experiments designed to identify components of the arabidopsis seed that ...

  14. Membrane-elasticity model of Coatless vesicle budding induced by ESCRT complexes.

    Directory of Open Access Journals (Sweden)

    Bartosz Różycki

    Full Text Available The formation of vesicles is essential for many biological processes, in particular for the trafficking of membrane proteins within cells. The Endosomal Sorting Complex Required for Transport (ESCRT directs membrane budding away from the cytosol. Unlike other vesicle formation pathways, the ESCRT-mediated budding occurs without a protein coat. Here, we propose a minimal model of ESCRT-induced vesicle budding. Our model is based on recent experimental observations from direct fluorescence microscopy imaging that show ESCRT proteins colocalized only in the neck region of membrane buds. The model, cast in the framework of membrane elasticity theory, reproduces the experimentally observed vesicle morphologies with physically meaningful parameters. In this parameter range, the minimum energy configurations of the membrane are coatless buds with ESCRTs localized in the bud neck, consistent with experiment. The minimum energy configurations agree with those seen in the fluorescence images, with respect to both bud shapes and ESCRT protein localization. On the basis of our model, we identify distinct mechanistic pathways for the ESCRT-mediated budding process. The bud size is determined by membrane material parameters, explaining the narrow yet different bud size distributions in vitro and in vivo. Our membrane elasticity model thus sheds light on the energetics and possible mechanisms of ESCRT-induced membrane budding.

  15. Tumor budding is an independent adverse prognostic factor in pancreatic ductal adenocarcinoma.

    Science.gov (United States)

    O'Connor, Kate; Li-Chang, Hector H; Kalloger, Steven E; Peixoto, Renata D; Webber, Douglas L; Owen, David A; Driman, David K; Kirsch, Richard; Serra, Stefano; Scudamore, Charles H; Renouf, Daniel J; Schaeffer, David F

    2015-04-01

    Tumor budding is a well-established adverse prognostic factor in colorectal cancer. However, the significance and diagnostic reproducibility of budding in pancreatic carcinoma requires further study. We aimed to assess the prognostic significance of tumor budding in pancreatic ductal adenocarcinoma, determine its relationship with other clinicopathologic features, and assess interobserver variability in its diagnosis. Tumor budding was assessed in 192 archival cases of pancreatic ductal adenocarcinoma using hematoxylin and eosin (H&E) sections; tumor buds were defined as single cells or nonglandular clusters composed of <5 cells. The presence of budding was determined through assessment of all tumor-containing slides, and associations with clinicopathologic features and outcomes were analyzed. Six gastrointestinal pathologists participated in an interobserver variability study of 120 images of consecutive tumor slides stained with H&E and cytokeratin. Budding was present in 168 of 192 cases and was associated with decreased overall survival (P=0.001). On multivariable analysis, tumor budding was prognostically significantly independent of stage, grade, tumor size, nodal status, lymphovascular invasion, and perineural invasion. There was substantial agreement among pathologists in assessing the presence of tumor budding using both H&E (K=0.63) and cytokeratin (K=0.63) stains. The presence of tumor budding is an independent adverse prognostic factor in pancreatic ductal carcinoma. The assessment of budding with H&E is reliable and could be used to better risk stratify patients with pancreatic ductal adenocarcinoma.

  16. Florigen is involved in axillary bud development at multiple stages in Arabidopsis.

    Science.gov (United States)

    Niwa, Masaki; Endo, Motomu; Araki, Takashi

    2013-11-01

    The wide variety of plant architectures is largely based on diverse and flexible modes of axillary shoot development. In Arabidopsis, floral transition (flowering) stimulates axillary bud development. The mechanism that links flowering and axillary bud development is, however, largely unknown. We recently showed that FLOWERING LOCUS T (FT) protein, which acts as florigen, promotes the phase transition of axillary meristems, whereas BRANCHED1 (BRC1) antagonizes the florigen action in axillary buds. Here, we present evidences for another possible role of florigen in axillary bud development. Ectopic overexpression of FT or another florigen gene TWIN SISTER OF FT (TSF) with LEAFY (LFY) induces ectopic buds at cotyledonary axils, confirming the previous proposal that these genes are involved in formation of axillary buds. Taken together with our previous report that florigen promotes axillary shoot elongation, we propose that florigen regulates axillary bud development at multiple stages to coordinate it with flowering in Arabidopsis.

  17. Induction of secondary dormancy by hypoxia in barley grains and its hormonal regulation.

    Science.gov (United States)

    Hoang, Hai Ha; Bailly, Christophe; Corbineau, Françoise; Leymarie, Juliette

    2013-04-01

    In barley, primary dormant grains did not germinate at 30 °C in air and at 15 °C in an atmosphere containing less than 10% O2, while they germinated easily at 15 °C in air. O2 tension in embryos measured with microsensors was 15.8% at 15 °C but only 0.3% at 30 °C. Incubation of grains at 30 °C is known to induce secondary dormancy in barley, and it was shown here that secondary dormancy was also induced by a 3 d treatment in O2 tensions lower than 10% at 15 °C. After such treatments, the grains lost their ability to germinate subsequently at 15 °C in air. During seed treatment in 5% O2, embryo abscisic acid (ABA) content decreased more slowly than in air and was not altered after transfer into air. Hypoxia did not alter the expression of ABA metabolism genes after 1 d, and induction of HvNCED2 occurred only after 3 d in hypoxia. Embryo sensitivity to ABA was similar in both primary and hypoxia-induced secondary dormant grains. Gibberellic acid (GA) metabolism genes were highly regulated and regulated earlier by the hypoxia treatment, with major changes in HvGA2ox3, HvGA3ox2 and HvGA20ox1 expression after 1 d, resulting in reduced GA signalling. Although a high temperature has an indirect effect on O2 availability, the data showed that it did not affect expression of prolyl-4-hydroxylases and that induction of secondary dormancy by hypoxia at 15 °C or by high temperature in air involved separate signalling pathways. Induction by hypoxia at 15 °C appears to be more regulated by GA and less by ABA than the induction by high temperature.

  18. Pre-sowing treatment for breaking dormancy in Acer velutinum Boiss.seed lots

    Institute of Scientific and Technical Information of China (English)

    Mostafa Farhadi; Mulualem Tigabu; Alireza Ghasemi Arian; Mehdi Sharifani; Abolfazl Daneshvar; Per Christer Oden

    2013-01-01

    Acer velutinum Boiss is a valuable tree species native to Iran,and its seeds possess physiological dormancy that hampers seedling production in the nursery for large-scale reforestation efforts.The aim of this study was to determine the optimal dormancy breaking treatments for A.velutinum seeds.We conducted a factorial experiment involving six seed lots collected along an elevation gradient from 300 to 1800 m at 300 m interval and four cold-moist stratification periods (0,4,8 and 16 weeks) at 4℃ and 70% relative humidity.The result shows that the germination of cold-moist stratified seeds was significantly (p < 0.0001)higher than the control for all seed lots.The highest germination capacity was recorded after 16 weeks of cold-moist stratification for all seed lots (68%-88% depending on the seed lot) except those collected from mid altitude sites (600 and 900 m) that germinated equally well (≥ 75%) after 4-and 8-week of clod-moist stratification compared to the other seed lots.The mean germination time was significantly shorter (12 to 19 days,depending on the seed lot) for seeds stratified for 16 weeks than for untreated seeds.It can be concluded that:(1) cold-moist stratification for 16 weeks is the best pre-sowing treatment for breaking dormancy in A.velutinum seeds; and (2) seeds should be collected from mid altitude sites (600 and 900 m) to get more than 80% germination within 15 days,and these seed lots even required shorter cold-moist stratification period (eight weeks) than other seed lots.

  19. Representing Microbial Dormancy in Soil Decomposition Models Improves Model Performance and Reveals Key Ecosystem Controls on Microbial Activity

    Science.gov (United States)

    He, Y.; Yang, J.; Zhuang, Q.; Wang, G.; Liu, Y.

    2014-12-01

    Climate feedbacks from soils can result from environmental change and subsequent responses of plant and microbial communities and nutrient cycling. Explicit consideration of microbial life history traits and strategy may be necessary to predict climate feedbacks due to microbial physiology and community changes and their associated effect on carbon cycling. In this study, we developed an explicit microbial-enzyme decomposition model and examined model performance with and without representation of dormancy at six temperate forest sites with observed soil efflux ranged from 4 to 10 years across different forest types. We then extrapolated the model to all temperate forests in the Northern Hemisphere (25-50°N) to investigate spatial controls on microbial and soil C dynamics. Both models captured the observed soil heterotrophic respiration (RH), yet no-dormancy model consistently exhibited large seasonal amplitude and overestimation in microbial biomass. Spatially, the total RH from temperate forests based on dormancy model amounts to 6.88PgC/yr, and 7.99PgC/yr based on no-dormancy model. However, no-dormancy model notably overestimated the ratio of microbial biomass to SOC. Spatial correlation analysis revealed key controls of soil C:N ratio on the active proportion of microbial biomass, whereas local dormancy is primarily controlled by soil moisture and temperature, indicating scale-dependent environmental and biotic controls on microbial and SOC dynamics. These developments should provide essential support to modeling future soil carbon dynamics and enhance the avenue for collaboration between empirical soil experiment and modeling in the sense that more microbial physiological measurements are needed to better constrain and evaluate the models.

  20. Budding Transition of Asymmetric Two-component Lipid Domains

    CERN Document Server

    Wolff, Jean; Andelman, David

    2016-01-01

    We propose a model that accounts for the budding transition of asymmetric two-component lipid domains, where the two monolayers (leaflets) have different average compositions controlled by independent chemical potentials. Assuming a coupling between the local curvature and local lipid composition in each of the leaflets, we discuss the morphology and thermodynamic behavior of asymmetric lipid domains. The membrane free-energy contains three contributions: the bending energy, the line tension, and a Landau free-energy for a lateral phase separation. Within a mean-field treatment, we obtain various phase diagrams containing fully budded, dimpled, and flat states as a function of the two leaflet compositions. The global phase behavior is analyzed, and depending on system parameters, the phase diagrams include one-phase, two-phase and three-phase regions. In particular, we predict various phase coexistence regions between different morphologies of domains, which may be observed in multi-component membranes or ves...

  1. How to halve ploidy: lessons from budding yeast meiosis.

    Science.gov (United States)

    Kerr, Gary William; Sarkar, Sourav; Arumugam, Prakash

    2012-09-01

    Maintenance of ploidy in sexually reproducing organisms requires a specialized form of cell division called meiosis that generates genetically diverse haploid gametes from diploid germ cells. Meiotic cells halve their ploidy by undergoing two rounds of nuclear division (meiosis I and II) after a single round of DNA replication. Research in Saccharomyces cerevisiae (budding yeast) has shown that four major deviations from the mitotic cell cycle during meiosis are essential for halving ploidy. The deviations are (1) formation of a link between homologous chromosomes by crossover, (2) monopolar attachment of sister kinetochores during meiosis I, (3) protection of centromeric cohesion during meiosis I, and (4) suppression of DNA replication following exit from meiosis I. In this review we present the current understanding of the above four processes in budding yeast and examine the possible conservation of molecular mechanisms from yeast to humans.

  2. Tumor budding is a strong and reproducible prognostic marker in T3N0 colorectal cancer.

    LENUS (Irish Health Repository)

    Wang, Lai Mun

    2012-02-01

    BACKGROUND: Tumor budding along the advancing front of colorectal adenocarcinoma is an early event in the metastatic process. A reproducible, prognostic budding scoring system based on outcomes in early stage colorectal cancer has not been established. DESIGN: One hundred twenty-eight T3N0M0 colorectal carcinoma patients with known outcome were identified. Tumor budding was defined as isolated tumor cells or clusters of <5 cells at the invasive tumor front. Tumor bud counts were generated in 5 regions at 200x by 2 pathologists (conventional bud count method). The median bud count per case was used to divide cases into low (median=0) and high budding (median > or =1) groups. Forty cases were reevaluated to assess reproducibility using the conventional and a novel rapid bud count method. RESULTS: Fifty-seven (45%) carcinomas had high and 71 (55%) had low budding scores. High budding was associated with an infiltrative growth pattern (P<0.0001) and lymphovascular invasion (P=0.005). Five-year cancer-specific survival was significantly poorer in high compared with low budding groups: 63% versus 91%, respectively, P<0.0001. Multivariate analysis demonstrated tumor budding to be independently prognostic (hazard ratio=4.76, P<0.001). Interobserver agreement was at least equivalent comparing the conventional to the rapid bud count methods: 87.5% agreement (kappa=0.75) versus 92.5% agreement (kappa=0.85), respectively. CONCLUSIONS: Tumor budding is a strong, reproducible, and independent prognostic marker of outcome that is easily assessed on hematoxylin and eosin slides. This may be useful for identifying the subset of T3N0M0 patients at high risk of recurrence who may benefit from adjuvant therapy.

  3. 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

  4. Endogenous peripheral neuromodulators of the mammalian taste bud.

    Science.gov (United States)

    Dando, Robin

    2010-10-01

    The sensitivity of the mammalian taste system displays a degree of plasticity based on short-term nutritional requirements. Deficiency in a particular substance may lead to a perceived increase in palatability of this substance, providing an additional drive to redress this nutritional imbalance through modification of intake. This alteration occurs not only in the brain but also, before any higher level processing has occurred, in the taste buds themselves. A brief review of recent advances is offered.

  5. Spiking Neural P Systems with Neuron Division and Budding

    OpenAIRE

    Pan, Linqiang; Paun, Gheorghe; Pérez Jiménez, Mario de Jesús

    2009-01-01

    In order to enhance the e±ciency of spiking neural P systems, we introduce the features of neuron division and neuron budding, which are processes inspired by neural stem cell division. As expected (as it is the case for P systems with active membranes), in this way we get the possibility to solve computationally hard problems in polynomial time. We illustrate this possibility with SAT problem.

  6. Entrance surface dose in cerebral interventional radiology procedures

    Energy Technology Data Exchange (ETDEWEB)

    Barrera-Rico, M.; Lopez-Rendon, X.; Rivera-Ordonez, C. E.; Gamboa-deBuen, I. [Instituto de Ciencias Nucleares, Universidad Nacional Autonoma de Mexico, 04510 DF (Mexico); Instituto Nacional de Neurologia y Neurocirugia Manuel Velasco Suarez, 14269 DF (Mexico); Instituto de Ciencias Nucleares, Universidad Nacional Autonoma de Mexico, 04510 DF (Mexico)

    2012-10-23

    At the Instituto Nacional de Neurologia y Neurocirugia (INNN) diagnostic as well as therapeutic procedures of interventional radiology are carried out. Since the procedures can last from some minutes to several hours, the absorbed dose for the patient could increase dangerously. An investigation had begun in order to determine the entrance surface dose (ESD) using 25 thermoluminiscent dosimeters TLD-100 and 8 strips of 15 Multiplication-Sign 1 cm{sup 2} of Gafchromic XR-QA2 film bound in a holder of 15 Multiplication-Sign 15 cm{sup 2} in the posteroanterior (PA) and lateral (LAT) positions during all the procedure. The results show that maximum ESD could be from 0.9 to 2.9 Gy for the PA position and between 1.6 and 2.5 Gy for the lateral position. The average ESD was between 0.7 and 1.3 Gy for the PA position, and from 0.44 to 1.1 Gy for the lateral position in a therapeutic procedure.

  7. Arenavirus budding: a common pathway with mechanistic differences.

    Science.gov (United States)

    Wolff, Svenja; Ebihara, Hideki; Groseth, Allison

    2013-01-31

    The Arenaviridae is a diverse and growing family of viruses that includes several agents responsible for important human diseases. Despite the importance of this family for public health, particularly in Africa and South America, much of its biology remains poorly understood. However, in recent years significant progress has been made in this regard, particularly relating to the formation and release of new enveloped virions, which is an essential step in the viral lifecycle. While this process is mediated chiefly by the viral matrix protein Z, recent evidence suggests that for some viruses the nucleoprotein (NP) is also required to enhance the budding process. Here we highlight and compare the distinct budding mechanisms of different arenaviruses, concentrating on the role of the matrix protein Z, its known late domain sequences, and the involvement of cellular endosomal sorting complex required for transport (ESCRT) pathway components. Finally we address the recently described roles for the nucleoprotein NP in budding and ribonucleoprotein complex (RNP) incorporation, as well as discussing possible mechanisms related to its involvement.

  8. Arenavirus Budding: A Common Pathway with Mechanistic Differences

    Directory of Open Access Journals (Sweden)

    Svenja Wolff

    2013-01-01

    Full Text Available The Arenaviridae is a diverse and growing family of viruses that includes several agents responsible for important human diseases. Despite the importance of this family for public health, particularly in Africa and South America, much of its biology remains poorly understood. However, in recent years significant progress has been made in this regard, particularly relating to the formation and release of new enveloped virions, which is an essential step in the viral lifecycle. While this process is mediated chiefly by the viral matrix protein Z, recent evidence suggests that for some viruses the nucleoprotein (NP is also required to enhance the budding process. Here we highlight and compare the distinct budding mechanisms of different arenaviruses, concentrating on the role of the matrix protein Z, its known late domain sequences, and the involvement of cellular endosomal sorting complex required for transport (ESCRT pathway components. Finally we address the recently described roles for the nucleoprotein NP in budding and ribonucleoprotein complex (RNP incorporation, as well as discussing possible mechanisms related to its involvement.

  9. An effect of entrance length on development of velocity profile in channel of millimeter dimensions

    Science.gov (United States)

    Jasikova, D.; Kotek, M.; Kopecky, V.

    2016-06-01

    Here we used modified PIV technique completed with long distance microscope probe for experimental investigation of the flow velocity profile in a rectangular duct. We came from the analytical and numerical prediction of the entrance length for fully developed velocity profile. The results of measurement completed knowledge about the flow stability and velocity profile shape in the channel of 0.00375 hydraulic diameters. There was marked a range of entrance length constant for the transient flow area. The presents of the fluctuating velocities in the transition flow is explained with POD snapshot and modes projection. The minimal entrance length for the laminar, transition, and turbulent flow is set.

  10. Similarity of Heat Transfer on Heat Source Elements in the Entrance Region in Electronic Equipment

    Institute of Scientific and Technical Information of China (English)

    Jane Z. Jiang; Sui Lin

    2001-01-01

    A similarity equation for heat transfer on heat source elements situated in the entrance region in electronic equipment is developed based on the experimental data obtained by Sparrow et al.[4]. The characteristic of the similarity equation is that the ratio of the heat transfer coefficient at the entrance region to that at the fully developed region is independent of the Reynolds number. It depends only on the row number of the elements situated in the entrance region. An example of the usefulness of the similarity equation is presented that determines the heat transfer on heat source elements in a power unit that contains only a small number of the heat source elements.

  11. Differentiation of Apical Bud Cells in a Newly Developed Apical Bud Transplantation Model Using GFP Transgenic Mice as Donor

    Science.gov (United States)

    Sakagami, Ryuji; Yoshinaga, Yasunori; Okamura, Kazuhiko

    2016-01-01

    Rodent mandibular incisors have a unique anatomical structure that allows teeth to grow throughout the lifetime of the rodent. This report presents a novel transplantation technique for studying the apical bud differentiation of rodent mandibular incisors. Incisal apical end tissue with green fluorescent protein from transgenic mouse was transplanted to wild type mice, and the development of the transplanted cells were immunohistologically observed for 12 weeks after the transplantation. Results indicate that the green fluorescent apical end tissue replaced the original tissue, and cells from the apical bud differentiated and extended toward the incisal edge direction. The immunostaining with podoplanin also showed that the characteristics of the green fluorescent tissue were identical to those of the original. The green fluorescent cells were only found in the labial side of the incisor up to 4 weeks. After 12 weeks, however, they were also found in the lingual side. Here the green fluorescent cementocyte-like cells were only present in the cementum close to the dentin surface. This study suggests that some of the cells that form the cellular cementum come from the apical tissue including the apical bud in rodent incisors. PMID:26978064

  12. Differentiation of Apical Bud Cells in a Newly Developed Apical Bud Transplantation Model Using GFP Transgenic Mice as Donor.

    Directory of Open Access Journals (Sweden)

    Naoki Maruo

    Full Text Available Rodent mandibular incisors have a unique anatomical structure that allows teeth to grow throughout the lifetime of the rodent. This report presents a novel transplantation technique for studying the apical bud differentiation of rodent mandibular incisors. Incisal apical end tissue with green fluorescent protein from transgenic mouse was transplanted to wild type mice, and the development of the transplanted cells were immunohistologically observed for 12 weeks after the transplantation. Results indicate that the green fluorescent apical end tissue replaced the original tissue, and cells from the apical bud differentiated and extended toward the incisal edge direction. The immunostaining with podoplanin also showed that the characteristics of the green fluorescent tissue were identical to those of the original. The green fluorescent cells were only found in the labial side of the incisor up to 4 weeks. After 12 weeks, however, they were also found in the lingual side. Here the green fluorescent cementocyte-like cells were only present in the cementum close to the dentin surface. This study suggests that some of the cells that form the cellular cementum come from the apical tissue including the apical bud in rodent incisors.

  13. Genome-wide analysis of gene expression in primate taste buds reveals links to diverse processes.

    Directory of Open Access Journals (Sweden)

    Peter Hevezi

    Full Text Available Efforts to unravel the mechanisms underlying taste sensation (gustation have largely focused on rodents. Here we present the first comprehensive characterization of gene expression in primate taste buds. Our findings reveal unique new insights into the biology of taste buds. We generated a taste bud gene expression database using laser capture microdissection (LCM procured fungiform (FG and circumvallate (CV taste buds from primates. We also used LCM to collect the top and bottom portions of CV taste buds. Affymetrix genome wide arrays were used to analyze gene expression in all samples. Known taste receptors are preferentially expressed in the top portion of taste buds. Genes associated with the cell cycle and stem cells are preferentially expressed in the bottom portion of taste buds, suggesting that precursor cells are located there. Several chemokines including CXCL14 and CXCL8 are among the highest expressed genes in taste buds, indicating that immune system related processes are active in taste buds. Several genes expressed specifically in endocrine glands including growth hormone releasing hormone and its receptor are also strongly expressed in taste buds, suggesting a link between metabolism and taste. Cell type-specific expression of transcription factors and signaling molecules involved in cell fate, including KIT, reveals the taste bud as an active site of cell regeneration, differentiation, and development. IKBKAP, a gene mutated in familial dysautonomia, a disease that results in loss of taste buds, is expressed in taste cells that communicate with afferent nerve fibers via synaptic transmission. This database highlights the power of LCM coupled with transcriptional profiling to dissect the molecular composition of normal tissues, represents the most comprehensive molecular analysis of primate taste buds to date, and provides a foundation for further studies in diverse aspects of taste biology.

  14. Changes of Phenolic Compounds Content and Activity of Enzymes Related to Phenolic Compounds in Fritillaria thunbergii Miq.Bulbs Stored at Different Cold Temperatures for Breaking Dormancy%浙贝母鳞茎酚类物质含量及相关酶活性与休眠解除的关系

    Institute of Scientific and Technical Information of China (English)

    彭昕; 金文韬; 凌庆枝; 何军邀

    2012-01-01

    [目的]探讨浙贝母鳞茎中酚类物质及相关酶活性与休眠解除的关系.[方法]将浙贝母鳞茎分别在4和10C条件下保湿贮藏至75 d,贮藏过程中定期取样测定鳞茎各部位酚类物质含量、苯丙氨酸解氨酶(PAL)活性和多酚氧化酶(PPO)活性,同时比较了发芽鳞茎与休眠鳞茎中酚类物质含量和PAL与PPO活性的差异.[结果]低温解除休眠过程中,鳞茎及芽内酚类物质含量均呈降低趋势;10℃处理30 ~45 d和4℃处理45~60 d是酚类物质减少、解除休眠的关键时期;浙贝母各部位酚类物质含量与其PPO活性均呈显著负相关;顶芽中酚类物质含量与PAL活性呈显著正相关;鳞片中酚类物质含量与PAL活性没有明显的相关性.[结论]酚类物质与浙贝母鳞茎休眠有一定相关性,酚类物质含量下降是低温处理解除浙贝母鳞茎休眠的生理机制之一.%[ Objective ] To analyze changes of phenolic compounds content and activity of enzymes related to phenolic compounds in Fritillaria thunbergii Miq. bulbs stored at different cold temperatures for breaking dormancy. [ Method] Bulbs of F. thunbergii were stored in moist sawdust up to 75 d at 4 or 10 ℃. The samples were taken periodically, and were used to determine phenolic compounds content, PAL activity, PPO activity in different parts of bulb. Differences in phenolic compounds content, PAL activity and PPO activity between dormant and dormancy-broken bulbs were analyzed. [ Result ] The results showed that a downward trend of phenolic compounds content in bulb was observed during the breaking of dormancy; 10 ℃ for 30 -45 d and 4 ℃ for 45 -60 d were the crucial period of dormancy release and the phenolic compounds decrease; phenolic compounds content and PPO activity were negatively correlated; phenolic compounds content and PAL activity in buds were significantly positive correlation; phenolic compounds content and PAL activity in bulbs had no significant

  15. Historical climates explain contrasting dormancy-breaking requirements in North American, Asian, and European woody species

    Science.gov (United States)

    Zohner, Constantin M.; Benito, Blas M.; Fridley, Jason D.; Svenning, Jens-Christian; Renner, Susanne S.

    2016-04-01

    Leaf-out times in temperate woody species are determined by winter chilling and spring warming, with day length playing a minor role. The species-specific relative importance of these phenological cues determines the sensitivity of leaf unfolding to climate warming in the globe's temperate forests. Using experimental and monitoring data on leaf-out cues in 495 woody species [about 1/3rd each from Asia, Europe, and North America (NA)], we show that NA species have higher winter chilling and spring warming requirements than do European and Asian species of similar genetic stock. The continent effect remained significant when controlling for the modern climates that species are adapted to, suggesting that contrasting historic climate conditions led to the differentiation of leaf-out strategies among NA, European, and Asian plants. The NA flora experienced more and longer periods of climatic instability and harshness (esp. since the Pliocene) than did southern Europe and East Asia, which may explain why NA species have higher dormancy requirements and leaf-out later than Asian species, which are characterized by a more shallow dormancy. That species from Asia require significantly less chilling than their NA relatives suggests contrasting responses of NA and Asian temperate forests to continued climate warming. Earlier leaf-out in NA trees and shrubs will be constrained by unmet chilling requirements as winters get warmer, whereas Asian woody species generally lack such temperature limitations.

  16. 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.

  17. Melatonin modulates glucose homeostasis during winter dormancy in a vespertilionid bat, Scotophilus heathi.

    Science.gov (United States)

    Srivastava, Raj Kamal; Krishna, Amitabh

    2010-03-01

    The role for melatonin in glucose homeostasis and insulin resistance is not very clear and has recently been an active area of investigation. The present study investigated the role of melatonin in seasonal accumulation of adipose tissue in Scotophilus heathi, with particular reference to its role in glucose homeostasis and development of insulin resistance. The circulating melatonin levels correlated positively (pinsulin resistance condition which improves after winter when most of the fat has been utilized as a metabolic fuel. The high circulating melatonin levels during the period of maximum body fat at the beginning of winter prepare the bats for winter dormancy by modulating the glucose homeostasis through affecting blood glucose levels, muscle and liver glycogen stores, insulin receptor and glucose transporter 4 (GLUT 4) expression. This is also confirmed by in vivo study in which melatonin injection improves the glucose tolerance, increases muscle insulin receptor and GLUT 4 expression, and enhances glucose clearance from the blood. The results of present study further showed that the effect of melatonin injection on the blood glucose levels is determined by the metabolic state of the bats and may protect from decrease in blood glucose level during extreme starvation, however, melatonin when injected during fed state increases glucose clearance from the blood. In summary, the present study suggested that melatonin interferes with the glucose homeostasis through modulating intracellular glucose transport and may protect bats from hypoglycemia during winter dormancy.

  18. 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.

  19. Overcoming seed dormancy of mooseer (Allium hirtifolium) through cold stratification, gibberellic acid, and acid scarification

    Institute of Scientific and Technical Information of China (English)

    Farshad Dashti; Hojat Ghahremani-Majd; Mahmood Esna-Ashari

    2012-01-01

    Abstract:Mooseer (Allium hirtifolium Boiss.) is bulbous perennial herb widely used in pharmaceutical and food industry in Iran.We studied germination of mooseer seeds in two separate experiments.In the first experiment,we evaluated four treatments:sulfuric acid scarification,sandpaper scarification,cold stratification,and gibberellic acid (GA3)application.In the second experiment,we evaluated combinations of these treatments.All treatments in the first experiment had no effect on seed germination,suggesting that mooseer seeds have physical and physiological dormancy.In the second experiment,the highest germination percentage (86.6%) was observed after five minutes scarification with sulfuric acid (75% v/v),followed by 60 days of cold stratification.Duration of sulfuric acid scarification (5,10,and 20 min) did not affect germination rates,but increasing duration of cold stratification (from 15to 60 days),increased germination from 28.3% to 86.6%.Our study showed that mooseer seeds have both physical and physiological dormancy.

  20. Evaluation of several methods for breaking dormancy of bitter vetch seeds (Vicia ervilia L.

    Directory of Open Access Journals (Sweden)

    Rouhi Hossein Reza

    2015-12-01

    Full Text Available This study analysed the effects of different treatments on breaking dormancy and germination of bitter vetch (Vicia ervilia L. freshly harvested seeds for seeding immediately. Partial scarified seeds (30 seconds with sandpaper were subjected to different treatments including: GA3 (250, 500 and 750 ppm, KNO3 (0.1, 0.2 and 0.3% w/v, cold stratification (2, 4 and 6 days, sulfuric acid (25, 50 and 75 seconds, hot water (90°C; for 2.5 and 5 minutes, hydropriming via seed soaking in distilled water (4 and 8 hours and mechanical scarification. Among the mentioned treatments, cold stratification for 6 days had a best effect on germination related parameters final germination percentage, mean germination time and vigour indexthan the other periods. In contrast to scarification with acid and hot water, mechanical scarification improved germination parameters but this effect was lower than the cold stratification. The results suggest that bitter vetch seed has both physical and physiological dormancy.

  1. Transcriptomic analysis of the exit from dormancy of Aspergillus fumigatus conidia

    Directory of Open Access Journals (Sweden)

    Coppée Jean-Yves

    2008-09-01

    Full Text Available Abstract Background Establishment of aspergillosis is depending upon the exit from dormancy and germination of the conidia of Aspergillus fumigatus in the lung. To gain an understanding of the molecular mechanisms underlying the early steps of conidial germination, we undertook a transcriptomic analysis using macroarrays constructed with PCR fragments from > 3,000 genes (around one third of the annotated A. fumigatus genome. Results Major results of this analysis are the following: (i conidia stored pre-packaged mRNAs transcripts (27% of genes have transcripts in the resting conidia; (ii incubation at 37°C in a nutritive medium induced up- and down-regulation of genes: 19% of the total number of genes deposited on the array were up-regulated whereas 22% of the genes with pre-packaged mRNA in the resting conidia were down-regulated; (iii most modifications were seen during the first 30 min of germination whereas very little modification of gene expression occurred during the following hour; (iv one-year old conidia and one-week old conidia behaved similarly at transcriptional level. Conclusion Transcriptomic data indicate that the exit from dormancy is associated with a shift from a fermentative metabolism to a respiratory metabolism as well as a trend toward immediate protein synthesis.

  2. 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.

  3. Current variability at the Pacific entrance of the Indonesian Throughflow

    Science.gov (United States)

    Kashino, Yuji; Watanabe, Hidetoshi; Herunadi, Bambang; Aoyama, Michio; Hartoyo, Djoko

    1999-05-01

    Current variability at the Pacific entrance of the Indonesian Throughflow is investigated using direct current and hydrographic measurements. Two moorings with three current meters (depths of 350, 550, and 1050 m) and one conductivity-temperature-depth profiler (260 m) were deployed at 4°1'N, 127°31'E and 3°11'N, 128°27'E between Talaud Islands and Morotai Island (Indonesia) from February 1994 to June 1995. Data from four hydrographic surveys conducted mainly between Mindanao and New Guinea from 1994 to 1996 are also used. The onset of a strong northwestward flow was observed at the southern mooring during boreal winter. In contrast, a southwestward flow containing salty South Pacific water was observed there during boreal summer. This current pattern change matched monsoon change around the mooring sites, suggesting that this variability is a seasonal signal in this region. This current change may occur because of the meridional shift of the Halmahera Eddy associated with an enlargement/diminishment of the Mindanao Dome. Our observation result during summer (the southwestward flow with the South Pacific water at the southern mooring) suggests that the Maluku Sea is one of the eastern routes of the Indonesian Throughflow. The current data also revealed that intraseasonal variability occurs in 50-day oscillations. Because the coherence between wind variability in the tropics with a period of 40-50 days (Madden-Julian Oscillation) and current variability with this period are >0.4, it is possible that the 50-day oscillation in the ocean current is induced by wind variability associated with the Madden-Julian Oscillation. The ocean eddy activity with an intrinsic period in this region may also be related to this 50-day oscillation.

  4. Conteúdo de carboidratos em gemas e ramos de macieira durante o outono e inverno em região de baixa ocorrência de frio Carbohydrate content in buds and stems of apple trees during autumn and winter in a region of low chill occurence

    Directory of Open Access Journals (Sweden)

    Ruy Inacio Neiva de Carvalho

    2004-08-01

    /23 and were treated or not with 1,440 hours of chill (4 to 7° C. The carbohydrates were analysed in buds and stem tissues close to the buds. The soluble carbohydrates (SC were evaluated by the phenol-sulfuric acid method and the final determination was made by spectrophotometry (490 nm absorbance. The non-soluble carbohydrates (NC were estimated by the mass of vegetal tissues non-soluble in alcohol and soluble in alcaline medium, after freeze drying. The total carbohydrate (SC + NC content represented 13.8 to 20.2 g.100g-1 of dry matter of buds and 9.9 to 15.3 g.100g-1 of dry matter of stems. The buds presented a higher level of SC in the initial dormancy period and a higher level of NC in the more intense dormancy period. The NC accumulation in buds were anticipated by the early chill treatment and the chill treatment during endodormancy promoted the SC accumulation. The SC content in stems increased along the dormancy development while the NC content remained constant.

  5. Dormancy, germination and emergence of weed seeds, with emphasis on the influence of light : results of a literature survey

    NARCIS (Netherlands)

    Riemens, M.M.; Scheepens, P.C.; Weide, van der R.Y.

    2004-01-01

    This note reports the results of an inventory study about the influence of the external factors temperature, light, nitrate, gaseous environment of seeds and moisture on the dormancy, germination and emergence of weed seeds. The inventory was made as a guideline for research aiming at the developmen

  6. Altitudinal and climatic associations of seed dormancy and flowering traits evidence adaptation of annual life cycle timing in Arabidopsis thaliana

    NARCIS (Netherlands)

    Souza Vidigal, de Deborah; Correia Silva Santana Marques, Alexandre; Willems, Leo A.J.; Buijs, Gonda; Méndez-Vigo, Belén; Hilhorst, Henk W.M.; Bentsink, Leónie; Picó, F.X.; Alonso-Blanco, Carlos

    2016-01-01

    The temporal control or timing of the life cycle of annual plants is presumed to provide adaptive strategies to escape harsh environments for survival and reproduction. This is mainly determined by the timing of germination, which is controlled by the level of seed dormancy, and of flowering init

  7. 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 an important c

  8. Safety Evaluation of Highway Tunnel-Entrance Illuminance Transition Based on Eye-Pupil Changes

    Directory of Open Access Journals (Sweden)

    Zhigang Du

    2014-10-01

    Full Text Available Utilizing the EMR-8B eye-tracker system, the pupil changes of eight drivers were monitored when they drove through 26 typical highway tunnels. Based on the test results, the driver’s pupil areas and pupil illuminance were found to be in a power function relationship at tunnel entrances. Furthermore, a quantitative relationship between the pupil area and its critical velocity was established, and the ratio of pupil area’s velocity in relation to its critical velocity was used to evaluate the lighting transitions and to establish the ideal curve of pupil illuminance at tunnel entrances. The results demonstrated that the relationship between the pupil illuminance of the tunnel entrance and the driver’s pupil areas conforms to the Stevens law found in experimental psychology; severe pupil illuminance transition within the range of 10 metres of the existing highway tunnel entrances, which results in great visual load, is in urgent need of improvement.

  9. A numerical solution for the entrance region of non-newtonian flow in annuli

    Directory of Open Access Journals (Sweden)

    Maia M.C.A.

    2003-01-01

    Full Text Available Continuity and momentum equations applied to the entrance region of an axial, incompressible, isothermal, laminar and steady flow of a power-law fluid in a concentric annulus, were solved by a finite difference implicit method. The Newtonian case was solved used for validation of the method and then compared to reported results. For the non-Newtonian case a pseudoplastic power-law model was assumed and the equations were transformed to obtain a pseudo-Newtonian system which enabled its solution using the same technique as that used for the Newtonian case. Comparison of the results for entrance length and pressure drop with those available in the literature showed a qualitative similarity, but significant quantitative differences. This can be attributed to the differences in entrance geometries and the definition of asymptotic entrance length.

  10. Should College Entrance Exam Results Be Made Public,or Kept Private?

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    The college entrance examination, usually called gaokao in China, is considered the most important test for middle school graduates. It’s the test that makes or breaks the futures of students as the outcome determines who

  11. Alleviating the Entrance to Serious Games by Exploring the Use of Commonly Available Tools

    NARCIS (Netherlands)

    Van Rosmalen, Peter; Klemke, Roland; Westera, Wim

    2011-01-01

    Van Rosmalen, P., Klemke, R., & Westera, W. (2011, 20-21 October). Alleviating the Entrance to Serious Games by Exploring the Use of Commonly Available Tools. Presentation at 5th European Conference on Games Based Learning, Athens, Greece.

  12. Reconstituting ring-rafts in bud-mimicking topography of model membranes

    Science.gov (United States)

    Ryu, Yong-Sang; Lee, In-Ho; Suh, Jeng-Hun; Park, Seung Chul; Oh, Soojung; Jordan, Luke R.; Wittenberg, Nathan J.; Oh, Sang-Hyun; Jeon, Noo Li; Lee, Byoungho; Parikh, Atul N.; Lee, Sin-Doo

    2014-07-01

    During vesicular trafficking and release of enveloped viruses, the budding and fission processes dynamically remodel the donor cell membrane in a protein- or a lipid-mediated manner. In all cases, in addition to the generation or relief of the curvature stress, the buds recruit specific lipids and proteins from the donor membrane through restricted diffusion for the development of a ring-type raft domain of closed topology. Here, by reconstituting the bud topography in a model membrane, we demonstrate the preferential localization of cholesterol- and sphingomyelin-enriched microdomains in the collar band of the bud-neck interfaced with the donor membrane. The geometrical approach to the recapitulation of the dynamic membrane reorganization, resulting from the local radii of curvatures from nanometre-to-micrometre scales, offers important clues for understanding the active roles of the bud topography in the sorting and migration machinery of key signalling proteins involved in membrane budding.

  13. Membrane tension is a key determinant of bud morphology in clathrin-mediated endocytosis

    CERN Document Server

    Hassinger, Julian E; Drubin, David G; Rangamani, Padmini

    2016-01-01

    In clathrin-mediated endocytosis (CME), clathrin and various adaptor proteins coat a patch of the plasma membrane, which is reshaped to form a budded vesicle. Experimental studies have demonstrated that elevated membrane tension can inhibit bud formation by a clathrin coat. In this study, we investigate the impact of membrane tension on the mechanics of membrane budding by simulating clathrin coats that either grow in area or progressively induce greater curvature. At low membrane tension, progressively increasing the area of a curvature-generating coat causes the membrane to smoothly evolve from a flat to budded morphology, whereas the membrane remains essentially flat at high membrane tensions. Interestingly, at physiologically relevant, intermediate membrane tensions, the shape evolution of the membrane undergoes a snapthrough instability in which increasing coat area causes the membrane to "snap" from an open, U-shaped bud to a closed, $\\Omega$-shaped bud. This instability is accompanied by a large energy...

  14. Endodormência de gemas de pessegueiro e ameixeira em região de baixa ocorrência de frio Endodormancy of peach and plum tree buds in a region of low chill occurrence

    Directory of Open Access Journals (Sweden)

    Ruy Inacio Neiva de Carvalho

    2010-09-01

    Full Text Available O objetivo desta pesquisa foi determinar a endodormência de gemas de pessegueiro cv. Chimarrita e ameixeira cv. Poli Rosa em uma região de baixa ocorrência de frio. Os ramos foram coletados em um pomar situado no município de Fazenda Rio Grande, Paraná, no período de abril a agosto dos anos de 2007 e 2008. Na última coleta, um grupo adicional de ramos foi coletado e mantido em refrigerador à temperatura de 4 a 7°C, por 672 horas. A avaliação da endodormência foi realizada por meio do teste biológico de estacas de nós isolados, que foram mantidas em condições controladas de temperatura (25°C e fotoperíodo (16 h. Foi realizada a quantificação das horas de frio (HF e das unidades de frio (UF ocorridas na região. As duas espécies foram avaliadas separadamente, como dois experimentos distintos. O delineamento experimental adotado foi o completamente casualizado, com nove tratamentos para o pessegueiro e 11 tratamentos para a ameixeira, ambos com quatro repetições. Os dois anos foram analisados individualmente. A endodormência mais intensa das gemas de pessegueiro cv. Chimarrita ocorreu no mês de maio, nos dois anos avaliados. A endodormência mais intensa de gemas de ameixeira cv. Poli Rosa ocorreu no mês de maio em 2007 e se estendeu até o mês de junho em 2008.The objective of this research was to evaluate the dormancy dynamic of peach tree 'Chimarrita' and plum tree 'Poli Rosa' buds in a region of low chill occurrence. The stems were collected in an orchard in Fazenda Rio Grande, State of Parana, Brazil, from April to August of 2007 and 2008. In the last date, an additional group of stems was collected and maintained in a refrigerator (4 to 7°C by 672 hours. The evaluation of dormancy was observed by the biological test of single node cuttings under controlled conditions of temperature (25°C and photoperiod (16 h. The quantification of chilling hours (CH and the chilling units (CU occurred in the region were performed

  15. On the border. Value and function of museum’s entrance hall and its symbolic meaning

    Directory of Open Access Journals (Sweden)

    Lucia Tarantino

    2013-11-01

    Full Text Available The text aims to analyze the museum entrance halls, mainly from the point of view of the growing phenomenon of mass tourism. The entrance space is examined not only for its functional characters but also for its symbolic power in structuring or changing the historical and cultural identity of the entire museum’s building. Both in new projects and in restoration of ancient museum buildings, in fact, contemporary architects seems to be increasingly attracted by this design aspect.

  16. High endemism at cave entrances: a case study of spiders of the genus Uthina

    Science.gov (United States)

    Yao, Zhiyuan; Dong, Tingting; Zheng, Guo; Fu, Jinzhong; Li, Shuqiang

    2016-01-01

    Endemism, which is typically high on islands and in caves, has rarely been studied in the cave entrance ecotone. We investigated the endemism of the spider genus Uthina at cave entrances. Totally 212 spiders were sampled from 46 localities, from Seychelles across Southeast Asia to Fiji. They mostly occur at cave entrances but occasionally appear at various epigean environments. Phylogenetic analysis of DNA sequence data from COI and 28S genes suggested that Uthina was grouped into 13 well-supported clades. We used three methods, the Bayesian Poisson Tree Processes (bPTP) model, the Bayesian Phylogenetics and Phylogeography (BPP) method, and the general mixed Yule coalescent (GMYC) model, to investigate species boundaries. Both bPTP and BPP identified the 13 clades as 13 separate species, while GMYC identified 19 species. Furthermore, our results revealed high endemism at cave entrances. Of the 13 provisional species, twelve (one known and eleven new) are endemic to one or a cluster of caves, and all of them occurred only at cave entrances except for one population of one species. The only widely distributed species, U. luzonica, mostly occurred in epigean environments while three populations were found at cave entrances. Additionally, eleven new species of the genus are described. PMID:27775081

  17. Analysis of the embryo proteome of sycamore (Acer pseudoplatanus L.) seeds reveals a distinct class of proteins regulating dormancy release.

    Science.gov (United States)

    Pawłowski, Tomasz Andrzej; Staszak, Aleksandra Maria

    2016-05-20

    Acer pseudoplatanus seeds are characterized by a deep physiological embryo dormancy that requires a few weeks of cold stratification in order to promote germination. Understanding the function of proteins and their related metabolic pathways, in conjunction with the plant hormones implicated in the breaking of seed dormancy, would expand our knowledge pertaining to this process. In this study, a proteomic approach was used to analyze the changes occurring in seeds in response to cold stratification, which leads to dormancy release. In addition, the involvement of abscisic (ABA) and gibberellic acids (GA) was also examined. Fifty-three proteins showing significant changes were identified by mass spectrometry. An effect of ABA on protein variation was observed at the beginning of stratification, while the influence of GA on protein abundance was observed during the middle phase of stratification. The majority of proteins associated with dormancy breaking in the presence of only water, and also ABA or GA, were classified as being involved in metabolism and genetic information processing. For metabolic-related proteins, the effect of ABA on protein abundance was stimulatory for half of the proteins and inhibitory for half of the proteins. On the other hand, the effect on genetic information processing related proteins was stimulatory. GA was found to upregulate both metabolic-related and genetic information processing-related proteins. While seed dormancy breaking depends on proteins involved in a variety of processes, proteins associated with methionine metabolism (adenosine kinase, methionine synthase) and glycine-rich RNA binding proteins appear to be of particular importance.

  18. 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.

  19. Dynamics of phytohormone and DNA methylation patterns changes during dormancy induction in strawberry (Fragaria × ananassa Duch.).

    Science.gov (United States)

    Zhang, Li; Wang, Yi; Zhang, Xinzhong; Zhang, Min; Han, Deguo; Qiu, Changpeng; Han, Zhenhai

    2012-01-01

    Changes in endogenous phytohormone levels, DNA methylation patterns, and expression levels of related genes during induction of dormancy in two strawberry cultivars, Darselect and All Star, were studied under controlled environmental conditions. At 12°C, regardless of day length, potted, runner-derived plants of both cultivars gradually exhibited morphological traits typical of dormancy after treatment for 8 weeks. These morphological changes were accompanied by a synchronous significant decline in indole-3-acetic acid (IAA) level and increases in abscisic acid (ABA) content and global genomic DNA methylation in young leaves. Exposed at 15°C and a short-day photoperiod, the changes in morphology, phytohormone levels and DNA methylation of both cultivars were similar to those observed at 12°C. Slight but non-significant changes in IAA and ABA levels and genomic DNA methylation occurred in young leaves at both 15°C with long days and 18°C with short days. These results indicated that temperature alone was sufficient to induce strawberry to enter the typical dormant phase, and day length had no impact at 12°C. The higher temperature permissible for dormancy induction in strawberry was 15°C, but at this temperature dormancy induction was modified by day length. The expression patterns of FaPIN1, FaNCED1, FaDRM and FaROS1 were coincident with the changes in phytohormone levels and DNA methylation. Although the two tested cultivars have different temporal responses with the different degree of cold tolerance and depth of dormancy, both the endogenous phytohormone and DNA methylation were changed when induced by external environmental factors.

  20. Changes in oxidative patterns during dormancy break by warm and cold stratification in seeds of an edible fruit tree.

    Science.gov (United States)

    Shalimu, Dilinuer; Sun, Jia; Baskin, Carol C; Baskin, Jerry M; Sun, Liwei; Liu, Yujun

    2016-01-01

    The transition from seed dormancy to germination is triggered by environmental factors, and in pomegranate (Punica granatum) seeds higher germination percentages are achieved by warm + cold stratification rather than by cold stratification alone. Our objective was to define the pattern of internal oxidative changes in pomegranate seeds as dormancy was being broken by warm + cold stratification and by cold stratification alone. Embryos isolated from seeds after 1-42 days of warm stratification, after 56 days of warm stratification + 7, 28 or 56 days of cold stratification, and after 1-84 days of cold stratification alone, were used in biochemical tests. Hydrogen peroxide (H2O2), nitric oxide (NO), proline, lipid peroxidation, protein carbonylation, and activities of the scavenging enzymes superoxide dismutase (SOD), hydrogen peroxide enzyme and peroxidase in the embryos were assessed by colorimetric methods. Our results indicated that warm + cold stratification had a stronger dormancy-breaking effect than cold stratification (85% versus 50% germination), which may be attributed to a higher yield of H2O2, NO, lipid peroxidation and protein carbonylation in warm + cold stratification. Furthermore, warm + cold stratification-induced H2O2 change led to greater changes (elevation followed by attenuation) in activities of the scavenging enzymes than that induced by cold stratification alone. These results indicated that restriction of the level of reactive oxygen species change within a positive and safe range by such enzymes promoted seed germination. In addition, a relatively strong elevation of proline during warm + cold stratification also contributed to dormancy breakage and subsequent germination. In conclusion, the strong dormancy alleviating effect of warm + cold stratification on pomegranate seeds may be attributed to the corresponding active oxidative change via H2O2, NO, proline, malondialdehyde, protein carbonylation and

  1. Metabolite changes in conifer buds and needles during forced bud break in Norway spruce (Picea abies and European silver fir (Abies alba

    Directory of Open Access Journals (Sweden)

    Priyanka eDhuli

    2014-12-01

    Full Text Available Environmental changes such as early spring and warm spells induce bud burst and photosynthetic processes in cold-acclimated coniferous trees and consequently, cellular metabolism in overwintering needles and buds. The purpose of the study was to examine metabolism in conifers under forced deacclimation (artificially induced spring by exposing shoots of Picea abies (boreal species and Abies alba (temperate species to a greenhouse environment (22°C, 16/8 h D/N cycle over a nine week period. Each week, we scored bud opening and collected samples for GC/MS–based metabolite profiling. We detected a total of 169 assigned metabolites and 80 identified metabolites, comprising compounds such as mono- and disaccharides, Krebs cycle acids, amino acids, polyols, phenolics and phosphorylated structures. Untargeted multivariate statistical analysis based on PCA and cluster analysis segregated samples by species, tissue type, and stage of tissue deacclimations. Similar patterns of metabolic regulation in both species were observed in buds (amino acids, Krebs cycle acids and needles (hexoses, pentoses, and Krebs cycle acids. Based on correlation of bud opening score with compound levels, distinct metabolites could be associated with bud and shoot development, including amino acids, sugars and acids with known osmolyte function, and secondary metabolites. This study has shed light on how elevated temperature affects metabolism in buds and needles of conifer species during the deacclimation phase, and contributes to the discussion about how phenological characters in conifers may respond to future global warming.

  2. [Iridoid glycosides from buds of Jasminum officinale L. var. grandiflorum].

    Science.gov (United States)

    Zhao, Gui-qin; Yin, Zhi-feng; Liu, Yu-cui; Li, Hong-bo

    2011-10-01

    The study on the buds of Jasminum officinale L. var. grandiflorum was carried out to look for anti-HBV constituents. The isolation and purification were performed by HPLC and chromatography on silica gel, polyamide and Sephadex LH-20 column. The structures were elucidated on the basis of physicochemical properties and spectral analysis. Six iridoid glycosides were identified as jasgranoside B (1), 6-O-methy-catalpol (2), deacetyl asperulosidic acid (3), aucubin (4), 8-dehydroxy shanzhiside (5), and loganin (6). Jasgranoside B (1) is a new compound. Compounds 2-6 were isolated from Jasminum officinale L. var. grandiflorum for the first time.

  3. γ-Lactam alkaloids from the flower buds of daylily.

    Science.gov (United States)

    Matsumoto, Takahiro; Nakamura, Seikou; Nakashima, Souichi; Ohta, Tomoe; Yano, Mamiko; Tsujihata, Junichiro; Tsukioka, Junko; Ogawa, Keiko; Fukaya, Masashi; Yoshikawa, Masayuki; Matsuda, Hisashi

    2016-07-01

    Four new alkaloids, hemerocallisamines IV-VII, were isolated from the methanol extract of flower buds of daylily. The chemical structures of the new compounds were elucidated on the basis of chemical and physicochemical evidence. The absolute stereochemistry of the hemerocallisamines IV-VI was elucidated by the application of the modified Mosher's method, HPLC analysis, and optical rotation. In the present study, the isolated alkaloids significantly inhibited the aggregation of Aβ42 in vitro. This is the first report about bioactive alkaloids with a γ-lactam ring from daylily. In addition, isolated nucleosides showed accelerative effects on neurite outgrowth under the non-fasting condition.

  4. UXO Detection and Characterization using new Berkeley UXO Discriminator (BUD)

    Science.gov (United States)

    Gasperikova, E.; Morrison, H. F.; Smith, J. T.; Becker, A.

    2006-05-01

    An optimally designed active electromagnetic system (AEM), Berkeley UXO Discriminator, BUD, has been developed for detection and characterization of UXO in the 20 mm to 150 mm size range. The system incorporates three orthogonal transmitters, and eight pairs of differenced receivers. The transmitter-receiver assembly together with the acquisition box, as well as the battery power and GPS receiver, is mounted on a small cart to assure system mobility. BUD not only detects the object itself but also quantitatively determines its size, shape, orientation, and metal content (ferrous or non-ferrous, mixed metals). Moreover, the principal polarizabilities and size of a metallic target can be determined from a single position of the BUD platform. The search for UXO is a two-step process. The object must first be detected and its location determined then the parameters of the object must be defined. A satisfactory classification scheme is one that determines the principal dipole polarizabilities of a target. While UXO objects have a single major polarizability (principal moment) coincident with the long axis of the object and two equal transverse polarizabilities, the scrap metal has all three principal moments entirely different. This description of the inherent polarizabilities of a target is a major advance in discriminating UXO from irregular scrap metal. Our results clearly show that BUD can resolve the intrinsic polarizabilities of a target and that there are very clear distinctions between symmetric intact UXO and irregular scrap metal. Target properties are determined by an inversion algorithm, which at any given time inverts the response to yield the location (x, y, z) of the target, its attitude and its principal polarizabilities (yielding an apparent aspect ratio). Signal-to-noise estimates (or measurements) are interpreted in this inversion to yield error estimates on the location, attitude and polarizabilities. This inversion at a succession of times provides

  5. The Entrance of Pyroclastic Flows into the Sea

    Science.gov (United States)

    Freundt, A.

    2001-12-01

    Explosive volcanoes, especially in subduction-zone and ocean-island settings, can generate pyroclastic flows that enter the sea. Geologic constraints on the interaction mechanisms and hazards are poor since resulting deposits hardly survive coastal erosion. The entrance of hot pyroclastic flows into water has been observed experimentally by letting shooting granular flows of ignimbrite ash heated to up to 420oC run down a chute into a water-filled tank. Flows of relatively cool ash, less than 150oC, impulsively displace some near-shore water generating a tsunami wave and then separate into a fine-ash over-water surge formed near shore and the main, coarser and denser material penetrating the water surface to form a turbulent mixing zone which advances downstream as long as the granular flow is maintained. Pumice floats to the surface, lithics and coarse ash fall out onto the floor, but ash remaining in suspension forms a turbidity current flowing down the tank. At temperatures above 250oC, almost all ash is initially transported along the water surface, rather than immediately penetrating it. Transport over water is facilitated by steam explosions derived from mixing of some of the ash with water across the surface. Ash fountains throw dry ash forward before it contacts the water, triggering the next steam explosion farther away from shore where fountains collapse onto the water surface. Each time ash and heat are consumed by mixing; the distance to where explosions extend thus depends on initial mass flux and temperature. Most fine ash forms an ash-cloud surge travelling over water, loosing sediment plumes that unite on the tank floor to form a turbidity current. Tsunami waves generated by coastal impact appear to be additionally driven by surface-water displacement by massive ash-input from ash fountains. Grain size distribution is also critical in determining interaction processes. Moderately well sorted medium ash generates strong steam explosions and becomes

  6. β-Catenin signaling regulates temporally discrete phases of anterior taste bud development

    Science.gov (United States)

    Thirumangalathu, Shoba; Barlow, Linda A.

    2015-01-01

    The sense of taste is mediated by multicellular taste buds located within taste papillae on the tongue. In mice, individual taste buds reside in fungiform papillae, which develop at mid-gestation as epithelial placodes in the anterior tongue. Taste placodes comprise taste bud precursor cells, which express the secreted factor sonic hedgehog (Shh) and give rise to taste bud cells that differentiate around birth. We showed previously that epithelial activation of β-catenin is the primary inductive signal for taste placode formation, followed by taste papilla morphogenesis and taste bud differentiation, but the degree to which these later elements were direct or indirect consequences of β-catenin signaling was not explored. Here, we define discrete spatiotemporal functions of β-catenin in fungiform taste bud development. Specifically, we show that early epithelial activation of β-catenin, before taste placodes form, diverts lingual epithelial cells from a taste bud fate. By contrast, β-catenin activation a day later within Shh+ placodes, expands taste bud precursors directly, but enlarges papillae indirectly. Further, placodal activation of β-catenin drives precocious differentiation of Type I glial-like taste cells, but not other taste cell types. Later activation of β-catenin within Shh+ precursors during papilla morphogenesis also expands taste bud precursors and accelerates Type I cell differentiation, but papilla size is no longer enhanced. Finally, although Shh regulates taste placode patterning, we find that it is dispensable for the accelerated Type I cell differentiation induced by β-catenin. PMID:26525674

  7. Quick detection of Dryocosmus kuriphilus Yasumatsu (Hymenoptera: Cynipidae) in chestnut dormant buds by nested PCR.

    Science.gov (United States)

    Sartor, C; Marinoni, D Torello; Quacchia, A; Botta, R

    2012-06-01

    Dryocosmus kuriphilus Yasumatsu (Hymenoptera: Cynipidae) develops in chestnut buds that remain asymptomatic from oviposition (June-July) until budburst; it is, thus, easily spread by plant material used in propagation. Therefore, it is particularly interesting to identify infested plant batches before their movement. Unfortunately, a non-destructive method for checking buds has not yet been developed, and the only technique available is the screening of a bud sample. The visual investigation is long and requires highly skilled and trained staff. The purpose of this work was to set up an effective and fast method able to identify the presence of first instar larvae of D. kuriphilus in a large number of chestnut buds by PCR. Four primer pairs were designed on nuclear and mitochondrial sequences of a set of seven gall wasp taxa and tested on five different cynipid's DNA. Nested diagnostic PCR was carried out on DNA extracted from samples of 2 g buds simulating four levels of infestation (larvae were added to uninfested buds); 320 bp amplicon of 28S sequence was chosen as a marker to detect one larva out of 2 g buds. The method showed a potential efficiency of 5000 to 15,000 buds per week, depending on bud size.

  8. Qualitative and quantitative differences between taste buds of the rat and mouse

    Directory of Open Access Journals (Sweden)

    Ma Huazhi

    2007-01-01

    Full Text Available Abstract Background Numerous electrophysiological, ultrastructural, and immunocytochemical studies on rodent taste buds have been carried out on rat taste buds. In recent years, however, the mouse has become the species of choice for molecular and other studies on sensory transduction in taste buds. Do rat and mouse taste buds have the same cell types, sensory transduction markers and synaptic proteins? In the present study we have used antisera directed against PLCβ2, α-gustducin, serotonin (5-HT, PGP 9.5 and synaptobrevin-2 to determine the percentages of taste cells expressing these markers in taste buds in both rodent species. We also determined the numbers of taste cells in the taste buds as well as taste bud volume. Results There are significant differences (p 3 is smaller than a rat taste bud (64,200 μm3. The numerical density of taste cells in mouse circumvallate taste buds (2.1 cells/1000 μm3 is significantly higher than that in the rat (1.2 cells/1000 μm3. Conclusion These results suggest that rats and mice differ significantly in the percentages of taste cells expressing signaling molecules. We speculate that these observed dissimilarities may reflect differences in their gustatory processing.

  9. Engineering geologic conditions at the sinkhole entrance to Logan Cave, Benton County, Arkansas

    Science.gov (United States)

    Schulz, William H.; McKenna, Jonathan P.

    2004-01-01

    Logan Cave, located in Benton County, Arkansas, is inhabited by several endangered and threatened species. The cave and surrounding area was designated a National Wildlife Refuge under the control of the U.S. Fish and Wildlife Service (USFWS) in 1989. Cave researchers access the cave through a steep-sided sinkhole entrance, which also is one of the two access points used by endangered bats. There is evidence of instability of one of the entrance slopes that has raised concerns that the entrance could close if slope failure was to occur. At the request of USFWS, we performed an engineering geologic investigation of the sinkhole to evaluate stability of this slope, which is comprised of soil, and other mechanisms of sediment transport into the cave entrance. The investigation included engineering geologic mapping, sampling and laboratory testing of subsurface geologic materials, and slope-stability analysis. We found that the sinkhole slope that extends into the entrance of the cave is comprised of sandy and gravelly soil to the depths explored (6.4 meters). This soil likely was deposited as alluvium within a previous, larger sinkhole. Based on properties of the alluvium, geometry of the slope, and results of finite-element slope-stability analyses, we conclude that the slope is marginally stable. Future failures of the slope probably would be relatively thin and small, thus several would be required to completely close the cave entrance. However, sediment is accumulating within the cave entrance due to foot traffic of those accessing the cave, surface-water erosion and transport, and shallow slope failures from the other sinkhole slopes. We conclude that the entrance will be closed by sediment in the future, similar to another entrance that we identified that completely closed in the past. Several measures could be taken to reduce the potential for closure of the cave entrance, including periodic sediment removal, installation of materials that reduce erosion by

  10. Micropropagation of Hedychium coronarium J. Koenig through rhizome bud.

    Science.gov (United States)

    Mohanty, Pritam; Behera, Shashikanta; Swain, Swasti S; Barik, Durga P; Naik, Soumendra K

    2013-10-01

    An optimized protocol was developed for in vitro plant regeneration of a medicinally important herb Hedychium coronarium J. Koenig using sprouted buds of rhizomes. The rhizomes with sprouted bud were inoculated on Murashige and Skoog (Physiol Plant 15:473-497, 1962) medium (MS) supplemented with either N(6)-benzyladenine (BA) alone (1.0-4.0 mg L(-1)) or in combination with 0.5 mg L(-1) naphthalene acetic acid (NAA). Of these combinations, MS supplemented with a combination of 2.0 mg L(-1) BA and 0.5 mg L(-1) NAA was most effective. In this medium, best shoots (3.6) and roots (4.0) regeneration was observed simultaneously with an average shoot and root length of 4.7 cm and 4.2 cm respectively. Regeneration of shoots and roots in the same medium at the same time (One step shoot and root regeneration) reduced the time for production of in vitro plantlets and eliminates the media cost of rooting. Cent-percent (100 %) success in plant establishment was observed in both gradual acclimatization process as well as when plants were directly transferred to outdoor in clay pots containing a mixture of garden soil and sand (2:1) without any sequential acclimatization stage.

  11. A computational clonal analysis of the developing mouse limb bud.

    Directory of Open Access Journals (Sweden)

    Luciano Marcon

    Full Text Available A comprehensive spatio-temporal description of the tissue movements underlying organogenesis would be an extremely useful resource to developmental biology. Clonal analysis and fate mappings are popular experiments to study tissue movement during morphogenesis. Such experiments allow cell populations to be labeled at an early stage of development and to follow their spatial evolution over time. However, disentangling the cumulative effects of the multiple events responsible for the expansion of the labeled cell population is not always straightforward. To overcome this problem, we develop a novel computational method that combines accurate quantification of 2D limb bud morphologies and growth modeling to analyze mouse clonal data of early limb development. Firstly, we explore various tissue movements that match experimental limb bud shape changes. Secondly, by comparing computational clones with newly generated mouse clonal data we are able to choose and characterize the tissue movement map that better matches experimental data. Our computational analysis produces for the first time a two dimensional model of limb growth based on experimental data that can be used to better characterize limb tissue movement in space and time. The model shows that the distribution and shapes of clones can be described as a combination of anisotropic growth with isotropic cell mixing, without the need for lineage compartmentalization along the AP and PD axis. Lastly, we show that this comprehensive description can be used to reassess spatio-temporal gene regulations taking tissue movement into account and to investigate PD patterning hypothesis.

  12. Green Synthesis of Novel Jasmine Bud-Shaped Copper Nanoparticles

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    Malathi Sampath

    2014-01-01

    Full Text Available Novel jasmine bud-shaped copper nanoparticles were synthesized by a green chemical reduction method using polyvinylpyrrolidone (PVP as a capping agent, L-ascorbic acid (AA as a reducing agent as well as antioxidant agent, isonicotinic acid hydrazide (INH as a reducing agent, and water as a solvent at 60–70°C (pH-7 in the presence of air. The UV-Vis absorption maximum obtained is 573 nm. The crystal lattice (fcc structure of Cu Nps was confirmed by X-ray diffraction (XRD. The novel jasmine bud shape was visualized in a transmission electron microscope (TEM. The height of single copper nanobud was 6.41 nm as measured by atomic force microscope (AFM. The average particle size 6.95 nm is obtained by XRD results. Antibacterial activity of the Cu nanobuds was evaluated by testing against Gram-negative (Escherichia coli and Gram-positive (Staphylococcus aureus bacteria.

  13. Study on the causes of Sapium sebiferum seed dormancy and the methods for dormancy breaking%乌桕种子休眠原因及解除方法研究

    Institute of Scientific and Technical Information of China (English)

    李淑娴; 刘菁菁; 田树霞; 尹佟明

    2011-01-01

    对乌桕种子的休眠原因进行了研究,发现乌桕种皮具有较好的透水性,所以种皮透水性不是造成乌桕种子休眠的主要原因.通过乌桕种子的离体胚发芽实验,证实乌柏种子的胚在离体条件下没有休眠现象;而乌桕种子的种皮及胚乳浸提物对种子发芽有显著抑制作用,所以乌桕种子的种皮及胚乳存在发芽内源抑制物,这可能是造成乌桕种子休眠的主要原因.另外,利用浓硫酸处理不能解除乌桕种子的休眠,直接低温层积也不能彻底打破乌桕种子的休眠;激素处理可有效解除内源抑制物造成的种子休眠,且通过比对实验发现,先用500或1 000 mg/L赤霉素处理,再层积100 d能有效打破乌桕种子的休眠.%In this paper, systematic study was conducted to explore the causes of seed dormancy in the Chinese tal-lowtree {Sapium sebiferum ( Linn. ) Roxb. ). Other than the early reports, coats of the tallowtree seeds were found to have good water permeability, which suggested that seed coats were not the main cause that inhibited the seed germination. Meanwhile, germination test indicated that in-vitro embryo of tallowtree seeds didn't undergo dormancy. However, extracting solutions of the seed coat and endosperm could suppress seed germination significantly, which implied the existence of endogenesis germination inhibitory substances in the corresponding seed parts. Based on these findings, we proposed that inhibitory substances could be the main reasons that caused tallowtree seeds dormancy. Ttie tests of breaking tallowtree seed dormancy showed that: dormancy of tallow tree seeds could not be broken by both treatment with concentrated H2SO4 and the cold stratification method. However, by testing with different gibberellic acid solutions, dormancy could be overcome by soaking the seeds in 500 or 1 000 mg/L GA3 followed by 100 (GA3) days stratification.

  14. The role of lipases in the removal of dormancy in apple seeds.

    Science.gov (United States)

    Zarska-Maciejewska, B; St Lewak

    1976-01-01

    It was found that the temperature optimum for apple (Malus domestica Borb.) seed acid lipase is the same as that for seed after-ripening process. The activity of the enzyme occurs between the 40th and 70th days of stratification, whereas the activity of alkaline lipase very low at that time appears about 20 days later. The changes of both enzyme activities were also studied during dark and light culture of embryos isolated from seeds after different times of stratification. Only the alkaline enzyme activity is under the control of light. It was concluded that essentially the same process, i.e. the hydrolysis of reserve fats is catalysed by two different enzymes: acid lipase acting during the cold-mediated breaking of embryo dormancy and alkaline lipase acting during the germination of dormant embryos, thus being under light control.

  15. Nanoscale measurement of trace element distributions in Spartina alterniflora root tissue during dormancy

    Science.gov (United States)

    Feng, Huan; Qian, Yu; Cochran, J. Kirk; Zhu, Qingzhi; Hu, Wen; Yan, Hanfei; Li, Li; Huang, Xiaojing; Chu, Yong S.; Liu, Houjun; Yoo, Shinjae; Liu, Chang-Jun

    2017-01-01

    This paper reports a nanometer-scale investigation of trace element (As, Ca, Cr, Cu, Fe, Mn, Ni, S and Zn) distributions in the root system Spartina alterniflora during dormancy. The sample was collected on a salt marsh island in Jamaica Bay, New York, in April 2015 and the root was cross-sectioned with 10 μm resolution. Synchrotron X-ray nanofluorescence was applied to map the trace element distributions in selected areas of the root epidermis and endodermis. The sampling resolution was 60 nm to increase the measurement accuracy and reduce the uncertainty. The results indicate that the elemental concentrations in the epidermis, outer endodermis and inner endodermis are significantly (p Pearson correlation analysis on the average concentrations of each element in the selected areas shows that most of the elements are significantly (p correlated, which suggests that these elements may share the same transport pathways.

  16. 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.

  17. Phytoplankton growth after a century of dormancy illuminates past resilience to catastrophic darkness.

    Science.gov (United States)

    Ribeiro, Sofia; Berge, Terje; Lundholm, Nina; Andersen, Thorbjørn J; Abrantes, Fátima; Ellegaard, Marianne

    2011-01-01

    Photosynthesis evolved in the oceans more than 3 billion years ago and has persisted throughout all major extinction events in Earth's history. The most recent of such events is linked to an abrupt collapse of primary production due to darkness following the Chicxulub asteroid impact 65.5 million years ago. Coastal phytoplankton groups (particularly dinoflagellates and diatoms) appear to have been resilient to this biotic crisis, but the reason for their high survival rates is still unknown. Here we show that the growth performance of dinoflagellate cells germinated from resting stages is unaffected by up to a century of dormancy. Our results clearly indicate that phytoplankton resting stages can endure periods of darkness far exceeding those estimated for the Cretaceous-Paleogene extinction and may effectively aid the rapid resurgence of primary production in coastal areas after events of prolonged photosynthesis shut-down.

  18. A fate map of the murine pancreas buds reveals a multipotent ventral foregut organ progenitor.

    Directory of Open Access Journals (Sweden)

    Jesse R Angelo

    Full Text Available The definitive endoderm is the embryonic germ layer that gives rise to the budding endodermal organs including the thyroid, lung, liver and pancreas as well as the remainder of the gut tube. DiI fate mapping and whole embryo culture were used to determine the endodermal origin of the 9.5 days post coitum (dpc dorsal and ventral pancreas buds. Our results demonstrate that the progenitors of each bud occupy distinct endodermal territories. Dorsal bud progenitors are located in the medial endoderm overlying somites 2-4 between the 2 and 11 somite stage (SS. The endoderm forming the ventral pancreas bud is found in 2 distinct regions. One territory originates from the left and right lateral endoderm caudal to the anterior intestinal portal by the 6 SS and the second domain is derived from the ventral midline of the endoderm lip (VMEL. Unlike the laterally located ventral foregut progenitors, the VMEL population harbors a multipotent progenitor that contributes to the thyroid bud, the rostral cap of the liver bud, ventral midline of the liver bud and the midline of the ventral pancreas bud in a temporally restricted manner. This data suggests that the midline of the 9.5 dpc thyroid, liver and ventral pancreas buds originates from the same progenitor population, demonstrating a developmental link between all three ventral foregut buds. Taken together, these data define the location of the dorsal and ventral pancreas progenitors in the prespecified endodermal sheet and should lead to insights into the inductive events required for pancreas specification.

  19. BudBurst Buddies: Introducing Young Citizen Scientists to Plants and Environmental Change

    Science.gov (United States)

    Ward, D.; Gardiner, L. S.; Henderson, S.

    2011-12-01

    As part of Project BudBurst, the BudBurst Buddies recently moved to the National Ecological Network (NEON) as part of its Education and Public Engagement efforts. The BudBurst Buddies (www.budburstbuddies.org) were created to engage elementary school age children in the science of observing plants and the timing of phenological (life cycle) events. BudBurst Buddies is a part of the Project BudBurst national citizen science initiative (www.budburst.org), which allows individuals to engage in the scientific process, contributing to a better understanding of climate change while increasing public awareness of phenology and the impacts of climate change on plants. As a first step towards engaging the next generation of citizen scientists, BudBurst Buddies provides the opportunity for children to gain experience with scientific research and increases awareness of how plants change throughout the year. Hundreds of young students have participated in the inaugural year of BudBurst Buddies. Children can participate in BudBurst Buddies on their own, with their families, or in formal or informal education settings. The program was recently highlighted by education staff at the New York Hall of Science and numerous classrooms have been implementing this resource as part of their curriculum. Each child who participates creates a journal about a plant of his or her choosing, makes observations of the plant over the growing season and submits findings online, earning an official BudBurst Buddies certificate. An online storybook for kids tells how two children, Lily and Sage, observed plants in their neighborhood and became BudBurst Buddies. This presentation will provide an overview of the BudBurst Buddies resources including a new implementation guide and will also share feedback from the first year of implementation.

  20. GATA6 is a crucial regulator of Shh in the limb bud.

    Directory of Open Access Journals (Sweden)

    Elena Kozhemyakina

    2014-01-01

    Full Text Available In the limb bud, patterning along the anterior-posterior (A-P axis is controlled by Sonic Hedgehog (Shh, a signaling molecule secreted by the "Zone of Polarizing Activity", an organizer tissue located in the posterior margin of the limb bud. We have found that the transcription factors GATA4 and GATA6, which are key regulators of cell identity, are expressed in an anterior to posterior gradient in the early limb bud, raising the possibility that GATA transcription factors may play an additional role in patterning this tissue. While both GATA4 and GATA6 are expressed in an A-P gradient in the forelimb buds, the hindlimb buds principally express GATA6 in an A-P gradient. Thus, to specifically examine the role of GATA6 in limb patterning we generated Prx1-Cre; GATA6(fl/fl mice, which conditionally delete GATA6 from their developing limb buds. We found that these animals display ectopic expression of both Shh and its transcriptional targets specifically in the anterior mesenchyme of the hindlimb buds. Loss of GATA6 in the developing limbs results in the formation of preaxial polydactyly in the hindlimbs. Conversely, forced expression of GATA6 throughout the limb bud represses expression of Shh and results in hypomorphic limbs. We have found that GATA6 can bind to chromatin (isolated from limb buds encoding either Shh or Gli1 regulatory elements that drive expression of these genes in this tissue, and demonstrated that GATA6 works synergistically with FOG co-factors to repress expression of luciferase reporters driven by these sequences. Most significantly, we have found that conditional loss of Shh in limb buds lacking GATA6 prevents development of hindlimb polydactyly in these compound mutant embryos, indicating that GATA6 expression in the anterior region of the limb bud blocks hindlimb polydactyly by repressing ectopic expression of Shh.

  1. GATA6 is a crucial regulator of Shh in the limb bud.

    Science.gov (United States)

    Kozhemyakina, Elena; Ionescu, Andreia; Lassar, Andrew B

    2014-01-01

    In the limb bud, patterning along the anterior-posterior (A-P) axis is controlled by Sonic Hedgehog (Shh), a signaling molecule secreted by the "Zone of Polarizing Activity", an organizer tissue located in the posterior margin of the limb bud. We have found that the transcription factors GATA4 and GATA6, which are key regulators of cell identity, are expressed in an anterior to posterior gradient in the early limb bud, raising the possibility that GATA transcription factors may play an additional role in patterning this tissue. While both GATA4 and GATA6 are expressed in an A-P gradient in the forelimb buds, the hindlimb buds principally express GATA6 in an A-P gradient. Thus, to specifically examine the role of GATA6 in limb patterning we generated Prx1-Cre; GATA6(fl/fl) mice, which conditionally delete GATA6 from their developing limb buds. We found that these animals display ectopic expression of both Shh and its transcriptional targets specifically in the anterior mesenchyme of the hindlimb buds. Loss of GATA6 in the developing limbs results in the formation of preaxial polydactyly in the hindlimbs. Conversely, forced expression of GATA6 throughout the limb bud represses expression of Shh and results in hypomorphic limbs. We have found that GATA6 can bind to chromatin (isolated from limb buds) encoding either Shh or Gli1 regulatory elements that drive expression of these genes in this tissue, and demonstrated that GATA6 works synergistically with FOG co-factors to repress expression of luciferase reporters driven by these sequences. Most significantly, we have found that conditional loss of Shh in limb buds lacking GATA6 prevents development of hindlimb polydactyly in these compound mutant embryos, indicating that GATA6 expression in the anterior region of the limb bud blocks hindlimb polydactyly by repressing ectopic expression of Shh.

  2. Potential for evolutionary change in the seasonal timing of germination in sea beet (Beta vulgaris ssp. maritima) mediated by seed dormancy.

    Science.gov (United States)

    Wagmann, Kristen; Hautekèete, Nina-Coralie; Piquot, Yves; Van Dijk, Henk

    2010-07-01

    In sea beet (Beta vulgaris ssp. maritima), germination occurs in autumn or spring and is mediated by dormancy which can be released by cold or dry periods. Environmental change such as current climate change may require evolutionary response in seasonal timing. Here, we explore the potential for such evolutionary change. Seed dormancy was studied in a composite population based on seeds from all over the species range in France together with several generations of reciprocal crosses. We found high, repeatable variability for dormancy rate among individuals under greenhouse conditions and confirmed its relevance for germination phenology in the field. Our data fitted best with an exclusively maternal determination of the dormancy phenotype. Narrow-sense heritability, h(2) approximately 0.5 in the composite population and approximately 0.4 in the original local populations, was such that rapid evolutionary change in the relative proportions of autumn and spring germination may be possible.

  3. Effects of nonuniform Mach-number entrance on scramjet nozzle flowfield and performance

    Science.gov (United States)

    Zhang, Pu; Xu, Jinglei; Quan, Zhibin; Mo, Jianwei

    2016-12-01

    Considering the non-uniformities of nozzle entrance influenced by the upstream, the effects of nonuniform Mach-number coupled with shock and expansion-wave on the flowfield and performances of single expansion ramp nozzle (SERN) are numerically studied using Reynolds-Averaged Navier-Stokes equations. The adopted Reynolds-averaged Navier-Stokes methodology is validated by comparing the numerical results with the cold experimental data, and the average method used in this paper is discussed. Uniform and nonuniform facility nozzles are designed to generate different Mach-number profile for the inlet of SERN, which is direct-connected with different facility nozzle, and the whole flowfield is simulated. Because of the coupling of shock and expansion-wave, flow direction of nonuniform SERN entrance is distorted. Compared with Mach contour of uniform case, the line is more curved for coupling shock-wave entrance (SWE) case, and flatter for the coupling expansion-wave entrance (EWE) case. Wall pressure distribution of SWE case appears rising region, whereas decreases like stairs of EWE case. The numerical results reveal that the coupled shock and expansion-wave play significant roles on nozzle performances. Compared with the SERN performances of uniform entrance case at the same work conditions, the thrust of nonuniform entrance cases reduces by 3-6%, pitch moment decreases by 2.5-7%. The negative lift presents an incremental trend with EWE while the situation is the opposite with SWE. These results confirm that considering the entrance flow parameter nonuniformities of a scramjet nozzle coupled with shock or expansion-wave from the upstream is necessary.

  4. Quebra de dormência de pereira 'Hosui' com uso de óleo mineral em dois tipos de condução Dormancy broken of 'Hosui' pear trees with mineral oil in two training systems

    Directory of Open Access Journals (Sweden)

    Odirlei Raimundo de Oliveira

    2008-06-01

    , need to have their dormancy broken by artificial means. In order to minimize such problem, an experiment was conducted in a 4-year-old 'Hosui' pear (Pyrus pyrifolia with 4.0 x 4.0m tree spacing orchard, at the Canguiri Station, in Pinhais-PR (latitude 25º25'S, longitude 49º08' and altitude of 920m, pertaining to the Federal University of Parana, in which accumulation of 141 chilling hours under 7.2ºC was reached during the 2005 winter. Treatments were applied when plants were at the A1 phenological stage (bud swelling, using a completely randomized factorial design with 4 replications in a 2x4x7 factorial scheme in which two types of tree training, vase or central leader, three mineral oil concentrations, 4, 6 or 8%, and a control applied from August to November 2005, and seven weekly performed evaluations based on the number of buds at pre-budding stage as well as broken and dead buds in four previously selected horizontally inclined 1-year-old stems per tree were tested. Obtained results showed that application of mineral oil at 4, 6 and 8% anticipated bud break compared to the control and enhanced bud break percentage in both training systems, being the concentrations of 6% and 8% more effective in anticipating bud break than 4%. The percentage of bud break at the 84th day after mineral oil application did not differ between the two training systems, i.e. vase and central leader.

  5. An actin-binding protein, CAP, is expressed in a subset of rat taste bud cells.

    Science.gov (United States)

    Ishimaru, Y; Yasuoka, A; Asano-Miyoshi, M; Abe, K; Emori, Y

    2001-02-12

    Single cell cDNA libraries were constructed from taste bud cells of rat circumvallate papillae. Using three steps of screening, including differential hybridization, sequence analyses and in situ hybridization, a clone encoding a rat homolog of yeast adenylyl cyclase-associated protein (CAP) was identified to be highly expressed in a subset of taste bud cells.

  6. Alternaria alternata, causal agent of dead (dormant) flower bud disease of pear

    NARCIS (Netherlands)

    Wenneker, M.; Tjou-Tam-Sin, L.T.; Bruggen, van A.S.; Vink, P.

    2006-01-01

    Dead (dormant) flower buds of pear are an important phenomenon in pear production in the Netherlands. Vigourous or unbalanced tree growth and Pseudomonas syringae pv. syringae are mentioned as likely causes of dead flower buds. Several tree growth control treatments including ethephon, Regalis (Proh

  7. Key stages in mammary gland development: the mammary end bud as a motile organ.

    Science.gov (United States)

    Hinck, Lindsay; Silberstein, Gary B

    2005-01-01

    In the rodent, epithelial end buds define the tips of elongating mammary ducts. These highly motile structures undergo repeated dichotomous branching as they aggressively advance through fatty stroma and, turning to avoid other ducts, they finally cease growth leaving behind the open, tree-like framework on which secretory alveoli develop during pregnancy. This review identifies the motility of end buds as a unique developmental marker that represents the successful integration of systemic and local mammotrophic influences, and covers relevant advances in ductal growth regulation, extracellular matrix (ECM) remodeling, and cell adhesion in the inner end bud. An unexpected growth-promoting synergy between insulin-like growth factor-1 and progesterone, in which ducts elongate without forming new end buds, is described as well as evidence strongly supporting self-inhibition of ductal elongation by end-bud-secreted transforming growth factor-beta acting on stromal targets. The influence of the matrix metalloproteinase ECM-remodeling enzymes, notably matrix metalloproteinase-2, on end bud growth is discussed in the broader context of enzymes that regulate the polysaccharide-rich glycosaminoglycan elements of the ECM. Finally, a critical, motility-enabling role for the cellular architecture of the end bud is identified and the contribution of cadherins, the netrin/neogenin system, and ErbB2 to the structure and motility of end buds is discussed.

  8. Proteomic study of 'Moncada' mandarin buds from on- versus off-crop trees.

    Science.gov (United States)

    Muñoz-Fambuena, Natalia; Mesejo, Carlos; Reig, Carmina; Agustí, Manuel; Tárraga, Susana; Lisón, Purificación; Iglesias, Domingo J; Primo-Millo, Eduardo; González-Mas, M Carmen

    2013-12-01

    A proteomic analysis of buds from mandarin trees with contrasting fruit load (on- and off-crop trees) was carried out during the onset of low-temperature induction. The aim of the study was to find out more about the molecular mechanism relating to alternate bearing in Citrus and its relationship with flowering. The 'Moncada' variety (Clementine 'Oroval'x'Kara' mandarin), displaying remarkable behaviour in alternate production, was used in this study. From 2D DIGE gel, 192 spots were isolated: 97 showed increased expression in the off-crop buds as compared to the on-crop buds, while 95 exhibited enhanced expression in the on-crop buds versus the off-crop buds. These spots were identified by MALDI-MS or LC-MS-MS. The largest groups of proteins up-expressed in the off-crop buds were the proteins involved in carbohydrate and amino acid metabolism, and the proteins expressed in response to stimuli such as reactive oxygen species. The largest groups of proteins up-expressed in the on-crop buds were related to primary metabolism, oxidative stress and defence responses. Depending on their function, some of these proteins can stimulate the flowering, such as fructose-bisphosphate aldolase or leucine-rich repeat transmembrane protein kinase, while others can inhibit it, such as cytochrome c oxidase subunit II. Twenty-two other proteins with unknown functions were up-expressed in the on- or off-crop buds.

  9. Have NEC Coat, Will Travel: Structural Basis of Membrane Budding During Nuclear Egress in Herpesviruses.

    Science.gov (United States)

    Bigalke, J M; Heldwein, E E

    2017-01-01

    Herpesviruses are unusual among enveloped viruses because they bud twice yet acquire a single envelope. Furthermore, unlike other DNA viruses that replicate in the nucleus, herpesviruses do not exit it by passing through the nuclear pores or by rupturing the nuclear envelope. Instead, herpesviruses have a complex mechanism of nuclear escape whereby nascent capsids bud at the inner nuclear membrane to form perinuclear virions that subsequently fuse with the outer nuclear membrane, releasing capsids into the cytosol. This makes them some of the very few known viruses that bud into the nuclear envelope. The envelope acquired during nuclear budding does not end up in the mature viral particle but instead allows the capsid to translocate from the nucleus into the cytosol. The viral nuclear egress complex (NEC) is a critical player in the nuclear egress, yet its function and mechanism have remained enigmatic. Recent studies have demonstrated that the NEC buds membranes without the help of other proteins by forming a honeycomb coat, which established the NEC as the first virally encoded budding machine that operates at the nuclear, as opposed to cytoplasmic, membrane. This review discusses our current understanding of the NEC budding mechanism, with the emphasis on studies that illuminated the structure of the NEC coat and its role in capsid budding during herpesvirus nuclear escape.

  10. 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.

  11. Budding yeast dma proteins control septin dynamics and the spindle position checkpoint by promoting the recruitment of the Elm1 kinase to the bud neck.

    Directory of Open Access Journals (Sweden)

    Laura Merlini

    Full Text Available The first step towards cytokinesis in budding yeast is the assembly of a septin ring at the future site of bud emergence. Integrity of this ring is crucial for cytokinesis, proper spindle positioning, and the spindle position checkpoint (SPOC. This checkpoint delays mitotic exit and cytokinesis as long as the anaphase spindle does not properly align with the division axis. SPOC signalling requires the Kin4 protein kinase and the Kin4-regulating Elm1 kinase, which also controls septin dynamics. Here, we show that the two redundant ubiquitin-ligases Dma1 and Dma2 control septin dynamics and the SPOC by promoting the efficient recruitment of Elm1 to the bud neck. Indeed, dma1 dma2 mutant cells show reduced levels of Elm1 at the bud neck and Elm1-dependent activation of Kin4. Artificial recruitment of Elm1 to the bud neck of the same cells is sufficient to re-establish a normal septin ring, proper spindle positioning, and a proficient SPOC response in dma1 dma2 cells. Altogether, our data indicate that septin dynamics and SPOC function are intimately linked and support the idea that integrity of the bud neck is crucial for SPOC signalling.

  12. Budding yeast dma proteins control septin dynamics and the spindle position checkpoint by promoting the recruitment of the Elm1 kinase to the bud neck.

    Science.gov (United States)

    Merlini, Laura; Fraschini, Roberta; Boettcher, Barbara; Barral, Yves; Lucchini, Giovanna; Piatti, Simonetta

    2012-01-01

    The first step towards cytokinesis in budding yeast is the assembly of a septin ring at the future site of bud emergence. Integrity of this ring is crucial for cytokinesis, proper spindle positioning, and the spindle position checkpoint (SPOC). This checkpoint delays mitotic exit and cytokinesis as long as the anaphase spindle does not properly align with the division axis. SPOC signalling requires the Kin4 protein kinase and the Kin4-regulating Elm1 kinase, which also controls septin dynamics. Here, we show that the two redundant ubiquitin-ligases Dma1 and Dma2 control septin dynamics and the SPOC by promoting the efficient recruitment of Elm1 to the bud neck. Indeed, dma1 dma2 mutant cells show reduced levels of Elm1 at the bud neck and Elm1-dependent activation of Kin4. Artificial recruitment of Elm1 to the bud neck of the same cells is sufficient to re-establish a normal septin ring, proper spindle positioning, and a proficient SPOC response in dma1 dma2 cells. Altogether, our data indicate that septin dynamics and SPOC function are intimately linked and support the idea that integrity of the bud neck is crucial for SPOC signalling.

  13. Squeezing at entrance of proton transport pathway in proton-translocating pyrophosphatase upon substrate binding.

    Science.gov (United States)

    Huang, Yun-Tzu; Liu, Tseng-Huang; Lin, Shih-Ming; Chen, Yen-Wei; Pan, Yih-Jiuan; Lee, Ching-Hung; Sun, Yuh-Ju; Tseng, Fan-Gang; Pan, Rong-Long

    2013-07-05

    Homodimeric proton-translocating pyrophosphatase (H(+)-PPase; EC 3.6.1.1) is indispensable for many organisms in maintaining organellar pH homeostasis. This unique proton pump couples the hydrolysis of PPi to proton translocation across the membrane. H(+)-PPase consists of 14-16 relatively hydrophobic transmembrane domains presumably for proton translocation and hydrophilic loops primarily embedding a catalytic site. Several highly conserved polar residues located at or near the entrance of the transport pathway in H(+)-PPase are essential for proton pumping activity. In this investigation single molecule FRET was employed to dissect the action at the pathway entrance in homodimeric Clostridium tetani H(+)-PPase upon ligand binding. The presence of the substrate analog, imidodiphosphate mediated two sites at the pathway entrance moving toward each other. Moreover, single molecule FRET analyses after the mutation at the first proton-carrying residue (Arg-169) demonstrated that conformational changes at the entrance are conceivably essential for the initial step of H(+)-PPase proton translocation. A working model is accordingly proposed to illustrate the squeeze at the entrance of the transport pathway in H(+)-PPase upon substrate binding.

  14. Lgr5 Identifies Progenitor Cells Capable of Taste Bud Regeneration after Injury.

    Directory of Open Access Journals (Sweden)

    Norifumi Takeda

    Full Text Available Taste buds are composed of a variety of taste receptor cell types that develop from tongue epithelium and are regularly replenished under normal homeostatic conditions as well as after injury. The characteristics of cells that give rise to regenerating taste buds are poorly understood. Recent studies have suggested that Lgr5 (leucine-rich repeat-containing G-protein coupled receptor 5 identifies taste bud stem cells that contribute to homeostatic regeneration in adult circumvallate and foliate taste papillae, which are located in the posterior region of the tongue. Taste papillae in the adult anterior region of the tongue do not express Lgr5. Here, we confirm and extend these studies by demonstrating that Lgr5 cells give rise to both anterior and posterior taste buds during development, and are capable of regenerating posterior taste buds after injury induced by glossopharyngeal nerve transection.

  15. Cell kinetic study on the relation between irradiation hypogeusia and taste buds in rats

    Energy Technology Data Exchange (ETDEWEB)

    Kubota, Hideharu; Furumoto, Keiichi [Nippon Dental Univ., Tokyo (Japan)

    1998-12-01

    The present study was designed to elucidate the mechanism of hypogeusia caused by irradiation. X-ray treatment at 10 Gy or 20 Gy was given to the maxillofacial region including the tongue in rats, and the involvement of taste bud for hypogeusia was investigated. In addition, cytological kinetics were immunohistologically studied using bromodeoxyuridine in the taste bud and in the lingual mucosal epithelium. The following results were obtained: In the 10 Gy group, the number of taste bud become less after the exposure, but no hypogeusia was observed during the experimental period. In the 20 Gy group, any labeled taste bud was not observed on the 7th day, and all taste buds disappeared by the 10th day. In the lingual mucosal epithelium, the number of basal cells decreased to the minimum, and the body weight and total water intake decreased coincidently in the 20 Gy group, which were few in the 10 Gy group. (author)

  16. The ureteric bud epithelium: morphogenesis and roles in metanephric kidney patterning.

    Science.gov (United States)

    Nagalakshmi, Vidya K; Yu, Jing

    2015-03-01

    The mammalian metanephric kidney is composed of two epithelial components, the collecting duct system and the nephron epithelium, that differentiate from two different tissues -the ureteric bud epithelium and the nephron progenitors, respectively-of intermediate mesoderm origin. The collecting duct system is generated through reiterative ureteric bud branching morphogenesis, whereas the nephron epithelium is formed in a process termed nephrogenesis, which is initiated with the mesenchymal-epithelial transition of the nephron progenitors. Ureteric bud branching morphogenesis is regulated by nephron progenitors, and in return, the ureteric bud epithelium regulates nephrogenesis. The metanephric kidney is physiologically divided along the corticomedullary axis into subcompartments that are enriched with specific segments of these two epithelial structures. Here, we provide an overview of the major molecular and cellular processes underlying the morphogenesis and patterning of the ureteric bud epithelium and its roles in the cortico-medullary patterning of the metanephric kidney.

  17. Study on Causes of Dormancy and Methods for Breaking Dormancy of Cephalotaxus sinensis (Rehd. & Wils.)Li Seeds%粗榧种子休眠原因及其解除方法研究

    Institute of Scientific and Technical Information of China (English)

    司倩倩; 臧德奎; 傅剑波; 刘济祥

    2016-01-01

    The causes of seed dormancy of Cephalotaxus sinensis (Rehd.&Wils.)Li were investigated through detecting seed viability,water permeability of seed coat and bioactivity of extracts from different parts of seeds.And the cold stratification was used to break dormancy.The results showed that the seed viability was 90% with greater germination potential.There were germination inhibitors in seed coat and endosperm (including embryo),and the inhibiton of endosperm (including embryo)was stronger than that of seed coat. The mechanical restraint and the existence of germination inhibitors were the causes for seed dormancy.Cold stratification was an effective way to break seed dormancy of Cephalotaxus sinensis.%通过测定种子活力、种皮透水性、不同部位浸提液的生物活性,研究了粗榧种子休眠原因,并采用低温层积打破休眠。结果表明:粗榧种子生活力为90%,具备较大的发芽潜力;粗榧种皮及胚乳(含胚)中均含有萌发抑制物质,且胚乳(含胚)抑制强度大于种皮;机械束缚和萌发抑制物的存在是造成种子休眠的原因,采用低温层积处理可以打破种子休眠。

  18. BudBurst Buddies: A New Tool for Engaging the Youngest Citizen Scientists

    Science.gov (United States)

    Gardiner, L. S.; Henderson, S.; Ward, D.

    2010-12-01

    BudBurst Buddies (www.budburstbuddies.org) introduces elementary school age children to the science of observing plants and the timing of phenological (life cycle) events. BudBurst Buddies is a new part of the Project BudBurst national citizen science initiative (www.budburst.org), which allows individuals to engage in the scientific process, contributing to a better understanding of climate change while increasing public awareness of phenology and the impacts of climate change on plants. As a first step towards engaging the next generation of citizen scientists, BudBurst Buddies provides the opportunity for children to gain experience with scientific research and increases awareness of how plants change throughout the year. Children can participate in BudBurst Buddies on their own, with their families, or in formal or informal education settings. Each child who participates creates a journal about a plant of his or her choosing, makes observations of the plant over the growing season and submits findings online, earning an official BudBurst Buddies certificate. An online storybook for kids tells how two children, Lily and Sage, observed plants in their neighborhood and became BudBurst Buddies. This presentation will provide an overview of the BudBurst Buddies newly developed resources. BudBurst Buddies is a part of Project BudBurst, a national citizen science program coordinated by the National Ecological Observatory Network (NEON) and the Chicago Botanic Garden. Funding for this resource was provided by NEON, NSF, NASA, and the National Geographic Education Foundation.

  19. Breaking-bud pollination: a new pollination process in partially opened flowers by small bees.

    Science.gov (United States)

    Yamaji, Futa; Ohsawa, Takeshi A

    2015-09-01

    Plant-pollinator interactions have usually been researched in flowers that have fully opened. However, some pollinators can visit flowers before full opening and contribute to fruit and seed sets. In this paper, we researched the pollination biology of flowers just starting to open in four field experiments. We observed the insect visitors to Lycoris sanguinea var. sanguinea for 3 years at five sites. These observations revealed that only small bees, Lasioglossum japonicum, often entered through tiny spaces between the tepals of 'breaking buds' (i.e. partially opened flowers) and collected pollen. We hypothesized that they can pollinate this species at the breaking-bud stage, when the stigma is located near the anthers. To measure the pollination effect of small bees at the breaking-bud stage, we bagged several breaking buds after small bees had visited them and examined whether these buds were pollinated. In bagging experiments, 30% of the breaking buds set fruit and seeds. Fruit-set ratios of the breaking buds did not differ significantly from those of the fully opened flowers, which had been visited by several insect species. We also counted the pollen grain numbers on the body of L. japonicum and on the anthers of randomly-selected and manipulated flowers. These experiments revealed that all of the captured bees had some pollen of target plants and that L. japonicum collected most of the pollen grains at the breaking-bud stage. Our results showed that the new pollination process, breaking-bud pollination, happened in breaking buds by L. japonicum, although there is no evidence to reveal that this is the most effective pollination method for L. sanguinea var. sanguinea. In principle, this new pollination process can occur in other flowering plants and our results are a major contribution to studies of plant-pollinator interactions.

  20. The Terminal End Bud: the Little Engine that Could.

    Science.gov (United States)

    Paine, Ingrid S; Lewis, Michael T

    2017-02-06

    The mammary gland is one of the most regenerative organs in the body, with the majority of development occurring postnatally and in the adult mammal. Formation of the ductal tree is orchestrated by a specialized structure called the terminal end bud (TEB). The TEB is responsible for the production of mature cell types leading to the elongation of the subtending duct. The TEB is also the regulatory control point for basement membrane deposition, branching, angiogenesis, and pattern formation. While the hormonal control of TEB growth is well characterized, the local regulatory factors are less well understood. Recent studies of pubertal outgrowth and ductal elongation have yielded surprising details in regards to ongoing processes in the TEB. Here we summarize the current understanding of TEB biology, discuss areas of future study, and discuss the use of the TEB as a model for the study of breast cancer.

  1. Guillaume Budé, l’humaniste et le prince

    Directory of Open Access Journals (Sweden)

    Sylvie Le Clech-Charton

    2009-09-01

    Full Text Available Grande figure de la Renaissance des lettres et des arts en France, tout à la fois écrivain, traducteur, ambassadeur, créateur du dépôt légal et fondateur du Collège de France, maître de la librairie du roi à Fontainebleau, Guillaume Budé (1468-1540 est essentiellement connu pour le rôle de conseiller politique et culturel qu’il joua auprès de François Ier, dont il fut le secrétaire. Il a été surtout étudié du point de vue de sa production littéraire savante, mais non sous l’angle de son mili...

  2. Dynamical Analysis of Protein Regulatory Network in Budding Yeast Nucleus

    Institute of Scientific and Technical Information of China (English)

    LI Fang-Ting; JIA Xun

    2006-01-01

    @@ Recent progresses in the protein regulatory network of budding yeast Saccharomyces cerevisiae have provided a global picture of its protein network for further dynamical research. We simplify and modularize the protein regulatory networks in yeast nucleus, and study the dynamical properties of the core 37-node network by a Boolean network model, especially the evolution steps and final fixed points. Our simulation results show that the number of fixed points N(k) for a given size of the attraction basin k obeys a power-law distribution N(k)∝k-2.024. The yeast network is more similar to a scale-free network than a random network in the above dynamical properties.

  3. Effects of different treatments on seed germination and breaking seed dormancy of Prosopis koelziana and Prosopis Juliflora

    Institute of Scientific and Technical Information of China (English)

    Salman Zare; Ali Tavili; Mohammad Javad Darini

    2011-01-01

    For improving seed germination of Prosopis koelziana and Prosopis juliflora, different treatments of seeds were conducted, including scarification with sulfuric acid 98% for l0 and 15 min, sandy paper,hot water for 5 and 10 min, potasium nitrate 0.1%, gibberellic acid at 250 mg.L-1 and 500 mg.L-1 and combinational treatment of scarification with gibberellic acid of 250 mg.L-1 and 500 mg.L-1. The results show that scarifications with sandy paper and sulfuric acids 98% were the most effective treatments on breaking seed dormancy and seed germination induction. Scarification with sulfuric acid 98% for 15 min was the best treatment. According to the positive effect of scarification and lack of reaction of seeds against KNO3 and gibberellic acid, the kind of seed dormancy was determined as exogenous.

  4. 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......-dormant frogs and cocoon-less dormant frogs. Treadmill (0.054 ms-1) exercising frogs consumed nearly seven times more oxygen than resting individuals (8.45 and 1.25 mmol O2 kg-1h-1, respectively). During a six-month dormancy period Pyxicephalus lost an average of 13.7% of its body mass, while plasma osmotic...... oxygen affinity, the affinity of 'stripped' (cofactor-free) Pyxicephalus Hb shows low sensitivity to this effector. Hb-oxygen affinity is moreover insensitive to Cl- ions (that depress O2 affinity of most vertebrate haemoglobins) but oxygen affinity is strongly increased by urea and metHb formation...

  5. The formation of premuscle masses during chick wing bud development.

    Science.gov (United States)

    Schramm, C; Solursh, M

    1990-01-01

    The skeletal musculature of chick limb buds is derived from somitic cells that migrate into the somatopleure of the future limb regions. These cells become organized into the earliest muscle primordia, the dorsal and ventral premuscle masses, prior to myogenic differentiation. Therefore, skeletal-muscle specific markers cannot be used to observe myogenic cells during the process of premuscle mass formation. In this study, an alternative marking method was used to determine the specific stages during which this process occurs. Quail somite strips were fluorescently labeled and implanted into chick hosts. Paraffin sections of the resulting chimeric wing buds were stained with the monoclonal antibody QH1 in order to identify graft-derived endothelium. Non-endothelial graft-derived cells present in the wing mesenchyme were assumed to be myogenic. At Hamburger and Hamilton stage 20, myogenic cells were distributed throughout the central region of the limb, including the future dorsal and ventral premuscle mass regions and the prechondrogenic core region. By stage 21, the myogenic cells were present at greater density in dorsal and ventral regions than in the core. By stage 23, nearly all myogenic cells were located in the dorsal and ventral premuscle masses. Therefore, the two premuscle masses become established by stage 21 and premuscle mass formation is not complete until stage 23 or later. Premuscle mass formation occurs concurrently with early chondrogenic events, as observed with the marker peanut agglutinin. To facilitate the investigation of possible underlying mechanisms of premuscle mass formation, the micromass culture system was evaluated, to determine whether or not it can serve as an accurate in vitro model system. The initially randomly distributed myogenic cells were observed to segregate from prechondrogenic regions prior to myogenic differentiation. This is similar to myogenic patterning in vivo.

  6. Characterization of dependencies between growth and division in budding yeast.

    Science.gov (United States)

    Mayhew, Michael B; Iversen, Edwin S; Hartemink, Alexander J

    2017-02-01

    Cell growth and division are processes vital to the proliferation and development of life. Coordination between these two processes has been recognized for decades in a variety of organisms. In the budding yeast Saccharomyces cerevisiae, this coordination or 'size control' appears as an inverse correlation between cell size and the rate of cell-cycle progression, routinely observed in G1 prior to cell division commitment. Beyond this point, cells are presumed to complete S/G2/M at similar rates and in a size-independent manner. As such, studies of dependence between growth and division have focused on G1 Moreover, in unicellular organisms, coordination between growth and division has commonly been analysed within the cycle of a single cell without accounting for correlations in growth and division characteristics between cycles of related cells. In a comprehensive analysis of three published time-lapse microscopy datasets, we analyse both intra- and inter-cycle dependencies between growth and division, revisiting assumptions about the coordination between these two processes. Interestingly, we find evidence (i) that S/G2/M durations are systematically longer in daughters than in mothers, (ii) of dependencies between S/G2/M and size at budding that echo the classical G1 dependencies, and (iii) in contrast with recent bacterial studies, of negative dependencies between size at birth and size accumulated during the cell cycle. In addition, we develop a novel hierarchical model to uncover inter-cycle dependencies, and we find evidence for such dependencies in cells growing in sugar-poor environments. Our analysis highlights the need for experimentalists and modellers to account for new sources of cell-to-cell variation in growth and division, and our model provides a formal statistical framework for the continued study of dependencies between biological processes.

  7. Entrance channel effect with stable and radioactive beams using dynamical cluster decay model

    Energy Technology Data Exchange (ETDEWEB)

    Kumar, Raj, E-mail: rajkumarfzr@gmail.com [Dipartimento di Fisica “Galileo Galilei” and INFN, University of Padova, Padova-35131 (Italy); Jain, Deepika [School of Physics and Material Science, Thapar University, Patiala-147004 (India)

    2014-09-15

    The decay of hot and rotating {sup 172}Yb*, formed in two entrance channels {sup 124}Sn + {sup 48}Ca and {sup 132}Sn + {sup 40}Ca, is studied using the dynamical cluster-decay model. The effect of entrance channel, deformations (up to β{sub 2}), barrier modification and fusion enhancement are addressed. The decay pattern of compound system, formed in different channels at comparable energy around the barrier, shows change in magnitude with structure remains almost same. There is an increase in the fusion probability with decrease in barrier modification, which leads to fusion enhancement at low energies. The higher ℓ values are contributing for {sup 132}Sn + {sup 40}Ca channel at lower energies as compare to {sup 124}Sn + {sup 48}Ca. It is inferred that with the use of stable and radioactive beam, forming same compound nucleus, the entrance channel dependence changes with the excitation energy.

  8. Effects of Magnetic Particles Entrance Arrange-ments on Mixing Efficiency of a Magnetic Bead Micromixer

    Institute of Scientific and Technical Information of China (English)

    Reza Kamali∗; Seyed Alireza Shekoohi; Alireza Binesh

    2014-01-01

    In this study, a computer code is developed to numerically investigate a magnetic bead micromixer under different conditions. The micromixer consists of a microchannel and numerous micro magnetic particles which enter the micromixer by fluid flows and are actuated by an alternating magnetic field normal to the main flow. An important feature of micromixer which is not considered before by researchers is the particle entrance arrangement into the micromixer. This parameter could effectively affect the micromixer efficiency. There are two general micro magnetic particle entrance arrangements in magnetic bead micromixers: determined position entrance and random position entrance. In the case of determined position entrances, micro magnetic particles enter the micromixer at specific positions of entrance cross section. However, in a random position entrance, particles enter the microchannel with no order. In this study mixing efficiencies of identical magnetic bead micromixers which only differ in particle entrance arrangement are numerically investigated and compared. The results reported in this paper illustrate that the prepared computer code can be one of the most powerful and beneficial tools for the magnetic bead micromixer performance analysis. In addition, the results show that some features of the magnetic bead micromixer are strongly affected by the entrance arrangement of the particles.

  9. DELAY OF GERMINATION1 (DOG1) regulates both seed dormancy and flowering time through microRNA pathways

    Science.gov (United States)

    Huo, Heqiang; Wei, Shouhui; Bradford, Kent J.

    2016-01-01

    Seed germination and flowering, two critical developmental transitions in plant life cycles, are coordinately regulated by genetic and environmental factors to match plant establishment and reproduction to seasonal cues. The DELAY OF GERMINATION1 (DOG1) gene is involved in regulating seed dormancy in response to temperature and has also been associated genetically with pleiotropic flowering phenotypes across diverse Arabidopsis thaliana accessions and locations. Here we show that DOG1 can regulate seed dormancy and flowering times in lettuce (Lactuca sativa, Ls) and Arabidopsis through an influence on levels of microRNAs (miRNAs) miR156 and miR172. In lettuce, suppression of LsDOG1 expression enabled seed germination at high temperature and promoted early flowering in association with reduced miR156 and increased miR172 levels. In Arabidopsis, higher miR156 levels resulting from overexpression of the MIR156 gene enhanced seed dormancy and delayed flowering. These phenotypic effects, as well as conversion of MIR156 transcripts to miR156, were compromised in DOG1 loss-of-function mutant plants, especially in seeds. Overexpression of MIR172 reduced seed dormancy and promoted early flowering in Arabidopsis, and the effect on flowering required functional DOG1. Transcript levels of several genes associated with miRNA processing were consistently lower in dry seeds of Arabidopsis and lettuce when DOG1 was mutated or its expression was reduced; in contrast, transcript levels of these genes were elevated in a DOG1 gain-of-function mutant. Our results reveal a previously unknown linkage between two critical developmental phase transitions in the plant life cycle through a DOG1–miR156–miR172 interaction. PMID:27035986

  10. 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

  11. DELAY OF GERMINATION1 (DOG1) regulates both seed dormancy and flowering time through microRNA pathways.

    Science.gov (United States)

    Huo, Heqiang; Wei, Shouhui; Bradford, Kent J

    2016-04-12

    Seed germination and flowering, two critical developmental transitions in plant life cycles, are coordinately regulated by genetic and environmental factors to match plant establishment and reproduction to seasonal cues. The DELAY OF GERMINATION1 (DOG1) gene is involved in regulating seed dormancy in response to temperature and has also been associated genetically with pleiotropic flowering phenotypes across diverse Arabidopsis thaliana accessions and locations. Here we show that DOG1 can regulate seed dormancy and flowering times in lettuce (Lactuca sativa, Ls) and Arabidopsis through an influence on levels of microRNAs (miRNAs) miR156 and miR172. In lettuce, suppression of LsDOG1 expression enabled seed germination at high temperature and promoted early flowering in association with reduced miR156 and increased miR172 levels. In Arabidopsis, higher miR156 levels resulting from overexpression of the MIR156 gene enhanced seed dormancy and delayed flowering. These phenotypic effects, as well as conversion of MIR156 transcripts to miR156, were compromised in DOG1 loss-of-function mutant plants, especially in seeds. Overexpression of MIR172 reduced seed dormancy and promoted early flowering in Arabidopsis, and the effect on flowering required functional DOG1 Transcript levels of several genes associated with miRNA processing were consistently lower in dry seeds of Arabidopsis and lettuce when DOG1 was mutated or its expression was reduced; in contrast, transcript levels of these genes were elevated in a DOG1 gain-of-function mutant. Our results reveal a previously unknown linkage between two critical developmental phase transitions in the plant life cycle through a DOG1-miR156-miR172 interaction.

  12. Cloning and characterization of a novel Gladiolus hybridus AFP family gene (GhAFP-like) related to corm dormancy.

    Science.gov (United States)

    Wu, Jian; Seng, Shanshan; Carianopol, Carina; Sui, Juanjuan; Yang, Qiuyan; Zhang, Fengqin; Jiang, Huiru; He, Junna; Yi, Mingfang

    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.

  13. Dormancy alleviation by NO or HCN leading to decline of protein carbonylation levels in apple (Malus domestica Borkh.) embryos.

    Science.gov (United States)

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

    2014-08-15

    Deep dormancy of apple (Malus domestica Borkh.) embryos can be overcome by short-term pre-treatment with nitric oxide (NO) or hydrogen cyanide (HCN). Dormancy alleviation of embryos modulated by NO or HCN and the first step of germination depend on temporary increased production of reactive oxygen species (ROS). Direct oxidative attack on some amino acid residues or secondary reactions via reactive carbohydrates and lipids can lead to the formation of protein carbonyl derivatives. Protein carbonylation is a widely accepted covalent and irreversible modification resulting in inhibition or alteration of enzyme/protein activities. It also increases the susceptibility of proteins to proteolytic degradation. The aim of this work was to investigate protein carbonylation in germinating apple embryos, the dormancy of which was removed by pre-treatment with NO or HCN donors. It was performed using a quantitative spectrophotometric method, while patterns of carbonylated protein in embryo axes were analyzed by immunochemical techniques. The highest concentration of protein carbonyl groups was observed in dormant embryos. It declined in germinating embryos pre-treated with NO or HCN, suggesting elevated degradation of modified proteins during seedling formation. A decrease in the concentration of carbonylated proteins was accompanied by modification in proteolytic activity in germinating apple embryos. A strict correlation between the level of protein carbonyl groups and cotyledon growth and greening was detected. Moreover, direct in vitro carbonylation of BSA treated with NO or HCN donors was analyzed, showing action of both signaling molecules as protein oxidation agents.

  14. 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.

  15. Mycobacterium tuberculosis DosR regulon gene Rv0079 encodes a putative, 'dormancy associated translation inhibitor (DATIN'.

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    Ashutosh Kumar

    Full Text Available Mycobacterium tuberculosis is a major human pathogen that has evolved survival mechanisms to persist in an immune-competent host under a dormant condition. The regulation of M. tuberculosis metabolism during latent infection is not clearly known. The dormancy survival regulon (DosR regulon is chiefly responsible for encoding dormancy related functions of M. tuberculosis. We describe functional characterization of an important gene of DosR regulon, Rv0079, which appears to be involved in the regulation of translation through the interaction of its product with bacterial ribosomal subunits. The protein encoded by Rv0079, possibly, has an inhibitory role with respect to protein synthesis, as revealed by our experiments. We performed computational modelling and docking simulation studies involving the protein encoded by Rv0079 followed by in vitro translation and growth curve analysis experiments, involving recombinant E. coli and Bacille Calmette Guérin (BCG strains that overexpressed Rv0079. Our observations concerning the interaction of the protein with the ribosomes are supportive of its role in regulation/inhibition of translation. We propose that the protein encoded by locus Rv0079 is a 'dormancy associated translation inhibitor' or DATIN.

  16. An A20/AN1-zinc-finger domain containing protein gene in tea is differentially expressed during winter dormancy and in response to abiotic stress and plant growth regulators

    Directory of Open Access Journals (Sweden)

    Asosii Paul

    2015-03-01

    Full Text Available The present manuscript describes cloning and expression characterization of A20/AN1-zinc-finger domain containing protein (CsZfp gene in an evergreen tree tea [Camellia sinensis (L. O. Kuntze] in response to winter dormancy (WD, abiotic stresses (polyethylene glycol, hydrogen peroxide, and sodium chloride and plant growth regulators [abscisic acid (ABA, and gibberellic acid (GA3]. CsZfp encoded a putative protein of 173 amino acids with a calculated molecular weight of 18.44 kDa, an isoelectric point (pI of 6.50 and grand average of hydropathicity (GRAVY value of −0.334. The gene did not have an intron, and belonged to a multi-gene family. During the period of active growth (PAG, CsZfp showed maximum expression in root and fruit as compared to leaf, floral bud and stem. Interaction studies between temperature and plant growth regulators on the expression of CsZfp showed that ABA upregulated CsZfp expression at growth temperature (GT; 25 °C but had no effect at low temperature (LT; 4 °C. In response to GA3, upregulation was observed at LT but not at GT. Further, the expression was not modulated by LT either in the tissue harvested during PAG or during WD. It was interesting to record that the expression of CsZfp was upregulated by hydrogen peroxide and sodium chloride, whereas it was non-responsive to polyethylene glycol. The possible role of CsZfp in playing key but differential roles in tea to various abiotic stresses is discussed.

  17. Variations of metabolites and proteome in Lonicera japonica Thunb. buds and flowers under UV radiation.

    Science.gov (United States)

    Zhu, Wei; Zheng, Wen; Hu, Xingjiang; Xu, Xiaobao; Zhang, Lin; Tian, Jingkui

    2017-04-01

    Lonicera japonica Thunb., also known as Jin Yin Hua and Japanese honeysuckle, is used as a herbal medicine in Asian countries. Its flowers have been used in folk medicine in the clinic and in making food or healthy beverages for over 1500years in China. To investigate the molecular processes involved in L. japonica development from buds to flowers exposed to UV radiation, a comparative proteomics analysis was performed. Fifty-four proteins were identified as differentially expressed, including 42 that had increased expression and 12 that had decreased expression. The levels of the proteins related to glycolysis, TCA/organic acid transformation, major carbohydrate metabolism, oxidative pentose phosphate, stress, secondary metabolism, hormone, and mitochondrial electron transport were increased during flower opening process after exposure to UV radiation. Six metabolites in L. japonica buds and flowers were identified and relatively quantified using LC-MS/MS. The antioxidant activity was performed using a 1,1-diphenyl-2-picrylhydrazyl assay, which revealed that L. japonica buds had more activity than the UV irradiated flowers. This suggests that UV-B radiation induces production of endogenous ethylene in L. japonica buds, thus facilitating blossoming of the buds and activating the antioxidant system. Additionally, the higher metabolite contents and antioxidant properties of L. japonica buds indicate that the L. japonica bud stage may be a more optimal time to harvest than the flower stage when using for medicinal properties.

  18. Automated quantification of budding Saccharomyces cerevisiae using a novel image cytometry method.

    Science.gov (United States)

    Laverty, Daniel J; Kury, Alexandria L; Kuksin, Dmitry; Pirani, Alnoor; Flanagan, Kevin; Chan, Leo Li-Ying

    2013-06-01

    The measurements of concentration, viability, and budding percentages of Saccharomyces cerevisiae are performed on a routine basis in the brewing and biofuel industries. Generation of these parameters is of great importance in a manufacturing setting, where they can aid in the estimation of product quality, quantity, and fermentation time of the manufacturing process. Specifically, budding percentages can be used to estimate the reproduction rate of yeast populations, which directly correlates with metabolism of polysaccharides and bioethanol production, and can be monitored to maximize production of bioethanol during fermentation. The traditional method involves manual counting using a hemacytometer, but this is time-consuming and prone to human error. In this study, we developed a novel automated method for the quantification of yeast budding percentages using Cellometer image cytometry. The automated method utilizes a dual-fluorescent nucleic acid dye to specifically stain live cells for imaging analysis of unique morphological characteristics of budding yeast. In addition, cell cycle analysis is performed as an alternative method for budding analysis. We were able to show comparable yeast budding percentages between manual and automated counting, as well as cell cycle analysis. The automated image cytometry method is used to analyze and characterize corn mash samples directly from fermenters during standard fermentation. Since concentration, viability, and budding percentages can be obtained simultaneously, the automated method can be integrated into the fermentation quality assurance protocol, which may improve the quality and efficiency of beer and bioethanol production processes.

  19. Prognostic significance of tumor budding and single cell invasion in gastric adenocarcinoma

    Science.gov (United States)

    Che, Keying; Zhao, Yang; Qu, Xiao; Pang, Zhaofei; Ni, Yang; Zhang, Tiehong; Du, Jiajun; Shen, Hongchang

    2017-01-01

    Purpose Gastric carcinoma (GC) is a highly aggressive cancer and one of the leading causes of cancer-related deaths worldwide. Histopathological evaluation pertaining to invasiveness is likely to provide additional information in relation to patient outcome. In this study, we aimed to evaluate the prognostic significance of tumor budding and single cell invasion in gastric adenocarcinoma. Materials and methods Hematoxylin and eosin-stained slides generated from 296 gastric adenocarcinoma patients with full clinical and pathological and follow-up information were systematically reviewed. The patients were grouped on the basis of tumor budding, single cell invasion, large cell invasion, mitotic count, and fibrosis. The association between histopathological parameters, different classification systems, and overall survival (OS) was statistically analyzed. Results Among the 296 cases that were analyzed, high-grade tumor budding was observed in 49.0% (145) of them. Single cell invasion and large cell invasion were observed in 62.8% (186) and 16.9% (50) of the cases, respectively. Following univariate analysis, patients with high-grade tumor budding had shorter OS than those with low-grade tumor budding (hazard ratio [HR]: 2.260, Ptumor budding and single cell invasion were observed to be independent risk factors for gastric adenocarcinoma (PTumor budding and single cell invasion in gastric adenocarcinoma are associated with an unfavorable prognosis.

  20. Sugars are under light control during bud burst in Rosa sp.

    Science.gov (United States)

    Girault, Tiffanie; Abidi, Farouk; Sigogne, Monique; Pelleschi-Travier, Sandrine; Boumaza, Rachid; Sakr, Soulaiman; Leduc, Nathalie

    2010-08-01

    Bud burst in certain species is conditioned by the luminous environment. With roses, the requirement for light is absolute, and darkness totally inhibits bud burst. Few studies have looked into understanding the action of light on the physiological bud burst processes. Here, we show the impact of light on certain components of glucidic metabolism during bud burst. Measurements were taken on decapitated plants of Rosa hybrida L. 'Radrazz' exposed either to darkness, white, blue or R light. Results show that a mobilization of bud and the carrying stem sucrose reserves only takes place in light and accompanies the bud burst. Furthermore, the activity of the RhVI vacuolar acid invertase which contributes to the breakdown of sucrose in the buds, as well as the transcription of the RhVI gene, is reduced in darkness, although it is strongly stimulated by light. The same analysis concerning the RhNAD-SDH gene, coding an NAD-dependent sorbitol dehydrogenase, shows, on the contrary, a strong induction of its transcription in darkness that could reflect the use of survival mechanisms in this condition.

  1. [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

  2. Roles of gibberellins and abscisic acid in dormancy and germination of red bayberry (Myrica rubra) seeds.

    Science.gov (United States)

    Chen, Shun-Ying; Kuo, Shing-Rong; Chien, Ching-Te

    2008-09-01

    Intact seeds from freshly harvested fruits of Myrica rubra (Sieb et Zucc.) were dormant and required 8 weeks of warm stratification followed by 12 weeks of cold stratification for germination. Exogenous application of gibberellic acid (GA(3)) to intact fresh seeds was effective in breaking dormancy, with > 70% of seeds germinating when treated with 5.2 mM GA(3) and incubated at a day/night temperature of 30/20 degrees C for 20 weeks. Removing the hard endocarp or endocarp plus seed coat of fresh seeds promoted germination, and addition of GA(3) to the embryo accelerated germination. The gibberellins GA(1) and GA(4) were more effective than GA(3) in promoting germination of seeds with the endocarp removed. Endogenous contents of GA(1), GA(3), GA(4), GA(7) and GA(20) were quantified by gas chromatography-mass spectrometry-selected ion monitoring in the endocarps, seed coats and embryos of fresh seeds treated with 5.2 mM GA(3). The content of GA(3) decreased in the endocarp during incubation, whereas GA(1) contents increased in the endocarp and seed coat. A high GA(1) content was detected in the endocarps and embryos of newly germinated seeds. We speculate that GA(3) was converted to GA(1) during incubation and that GA(1) is involved in seed germination. Endogenous abscisic acid (ABA) contents were measured in fresh seeds and in warm and cold stratified seeds. The ABA content in fresh seeds was distributed in the order endocarp > seed coat > embryo, with the content in the endocarp being about 132-fold higher than in the seed coat and embryo. Total ABA content of seeds subjected to warm or cold stratification, or both, was 8.7- to 14.0-fold lower than that of fresh seeds. Low contents of endogenous GA(1), GA(3), GA(7) and GA(20), but elevated contents of GA(4), were found in the seed coats and endocarps of warm plus cold stratified seeds and in the seed coats and embryos of newly germinated seeds. These observations, coupled with the finding that GA stimulated

  3. 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.

  4. Contribution of Underlying Connective Tissue Cells to Taste Buds in Mouse Tongue and Soft Palate.

    Science.gov (United States)

    Boggs, Kristin; Venkatesan, Nandakumar; Mederacke, Ingmar; Komatsu, Yoshihiro; Stice, Steve; Schwabe, Robert F; Mistretta, Charlotte M; Mishina, Yuji; Liu, Hong-Xiang

    2016-01-01

    Taste buds, the sensory organs for taste, have been described as arising solely from the surrounding epithelium, which is in distinction from other sensory receptors that are known to originate from neural precursors, i.e., neural ectoderm that includes neural crest (NC). Our previous study suggested a potential contribution of NC derived cells to early immature fungiform taste buds in late embryonic (E18.5) and young postnatal (P1-10) mice. In the present study we demonstrated the contribution of the underlying connective tissue (CT) to mature taste buds in mouse tongue and soft palate. Three independent mouse models were used for fate mapping of NC and NC derived connective tissue cells: (1) P0-Cre/R26-tdTomato (RFP) to label NC, NC derived Schwann cells and derivatives; (2) Dermo1-Cre/RFP to label mesenchymal cells and derivatives; and (3) Vimentin-CreER/mGFP to label Vimentin-expressing CT cells and derivatives upon tamoxifen treatment. Both P0-Cre/RFP and Dermo1-Cre/RFP labeled cells were abundant in mature taste buds in lingual taste papillae and soft palate, but not in the surrounding epithelial cells. Concurrently, labeled cells were extensively distributed in the underlying CT. RFP signals were seen in the majority of taste buds and all three types (I, II, III) of differentiated taste bud cells, with the neuronal-like type III cells labeled at a greater proportion. Further, Vimentin-CreER labeled cells were found in the taste buds of 3-month-old mice whereas Vimentin immunoreactivity was only seen in the CT. Taken together, our data demonstrate a previously unrecognized origin of taste bud cells from the underlying CT, a conceptually new finding in our knowledge of taste bud cell derivation, i.e., from both the surrounding epithelium and the underlying CT that is primarily derived from NC.

  5. Contribution of Underlying Connective Tissue Cells to Taste Buds in Mouse Tongue and Soft Palate.

    Directory of Open Access Journals (Sweden)

    Kristin Boggs

    Full Text Available Taste buds, the sensory organs for taste, have been described as arising solely from the surrounding epithelium, which is in distinction from other sensory receptors that are known to originate from neural precursors, i.e., neural ectoderm that includes neural crest (NC. Our previous study suggested a potential contribution of NC derived cells to early immature fungiform taste buds in late embryonic (E18.5 and young postnatal (P1-10 mice. In the present study we demonstrated the contribution of the underlying connective tissue (CT to mature taste buds in mouse tongue and soft palate. Three independent mouse models were used for fate mapping of NC and NC derived connective tissue cells: (1 P0-Cre/R26-tdTomato (RFP to label NC, NC derived Schwann cells and derivatives; (2 Dermo1-Cre/RFP to label mesenchymal cells and derivatives; and (3 Vimentin-CreER/mGFP to label Vimentin-expressing CT cells and derivatives upon tamoxifen treatment. Both P0-Cre/RFP and Dermo1-Cre/RFP labeled cells were abundant in mature taste buds in lingual taste papillae and soft palate, but not in the surrounding epithelial cells. Concurrently, labeled cells were extensively distributed in the underlying CT. RFP signals were seen in the majority of taste buds and all three types (I, II, III of differentiated taste bud cells, with the neuronal-like type III cells labeled at a greater proportion. Further, Vimentin-CreER labeled cells were found in the taste buds of 3-month-old mice whereas Vimentin immunoreactivity was only seen in the CT. Taken together, our data demonstrate a previously unrecognized origin of taste bud cells from the underlying CT, a conceptually new finding in our knowledge of taste bud cell derivation, i.e., from both the surrounding epithelium and the underlying CT that is primarily derived from NC.

  6. Limb patterning genes and heterochronic development of the emu wing bud

    Directory of Open Access Journals (Sweden)

    Craig A. Smith

    2016-12-01

    Full Text Available Abstract Background The forelimb of the flightless emu is a vestigial structure, with greatly reduced wing elements and digit loss. To explore the molecular and cellular mechanisms associated with the evolution of vestigial wings and loss of flight in the emu, key limb patterning genes were examined in developing embryos. Methods Limb development was compared in emu versus chicken embryos. Immunostaining for cell proliferation markers was used to analyze growth of the emu forelimb and hindlimb buds. Expression patterns of limb patterning genes were studied, using whole-mount in situ hybridization (for mRNA localization and RNA-seq (for mRNA expression levels. Results The forelimb of the emu embryo showed heterochronic development compared to that in the chicken, with the forelimb bud being retarded in its development. Early outgrowth of the emu forelimb bud is characterized by a lower level of cell proliferation compared the hindlimb bud, as assessed by PH3 immunostaining. In contrast, there were no obvious differences in apoptosis in forelimb versus hindlimb buds (cleaved caspase 3 staining. Most key patterning genes were expressed in emu forelimb buds similarly to that observed in the chicken, but with smaller expression domains. However, expression of Sonic Hedgehog (Shh mRNA, which is central to anterior–posterior axis development, was delayed in the emu forelimb bud relative to other patterning genes. Regulators of Shh expression, Gli3 and HoxD13, also showed altered expression levels in the emu forelimb bud. Conclusions These data reveal heterochronic but otherwise normal expression of most patterning genes in the emu vestigial forelimb. Delayed Shh expression may be related to the small and vestigial structure of the emu forelimb bud. However, the genetic mechanism driving retarded emu wing development is likely to rest within the forelimb field of the lateral plate mesoderm, predating the expression of patterning genes.

  7. 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

  8. ABI4 regulates primary seed dormancy by regulating the biogenesis of abscisic acid and gibberellins in arabidopsis.

    Science.gov (United States)

    Shu, Kai; Zhang, Huawei; Wang, Shengfu; Chen, Mingluan; Wu, Yaorong; Tang, Sanyuan; Liu, Chunyan; Feng, Yuqi; Cao, Xiaofeng; Xie, Qi

    2013-06-01

    Seed dormancy is an important economic trait for agricultural production. Abscisic acid (ABA) and Gibberellins (GA) are the primary factors that regulate the transition from dormancy to germination, and they regulate this process antagonistically. The detailed regulatory mechanism involving crosstalk between ABA and GA, which underlies seed dormancy, requires further elucidation. Here, we report that ABI4 positively regulates primary seed dormancy, while negatively regulating cotyledon greening, by mediating the biogenesis of ABA and GA. Seeds of the Arabidopsis abi4 mutant that were subjected to short-term storage (one or two weeks) germinated significantly more quickly than Wild-Type (WT), and abi4 cotyledons greened markedly more quickly than WT, while the rates of germination and greening were comparable when the seeds were subjected to longer-term storage (six months). The ABA content of dry abi4 seeds was remarkably lower than that of WT, but the amounts were comparable after stratification. Consistently, the GA level of abi4 seeds was increased compared to WT. Further analysis showed that abi4 was resistant to treatment with paclobutrazol (PAC), a GA biosynthesis inhibitor, during germination, while OE-ABI4 was sensitive to PAC, and exogenous GA rescued the delayed germination phenotype of OE-ABI4. Analysis by qRT-PCR showed that the expression of genes involved in ABA and GA metabolism in dry and germinating seeds corresponded to hormonal measurements. Moreover, chromatin immunoprecipitation qPCR (ChIP-qPCR) and transient expression analysis showed that ABI4 repressed CYP707A1 and CYP707A2 expression by directly binding to those promoters, and the ABI4 binding elements are essential for this repression. Accordingly, further genetic analysis showed that abi4 recovered the delayed germination phenotype of cyp707a1 and cyp707a2 and further, rescued the non-germinating phenotype of ga1-t. Taken together, this study suggests that ABI4 is a key factor that

  9. Phenotypic plasticity, QTL mapping and genomic characterization of bud set in black poplar

    Directory of Open Access Journals (Sweden)

    Fabbrini Francesco

    2012-04-01

    Full Text Available Abstract Background The genetic control of important adaptive traits, such as bud set, is still poorly understood in most forest trees species. Poplar is an ideal model tree to study bud set because of its indeterminate shoot growth. Thus, a full-sib family derived from an intraspecific cross of P. nigra with 162 clonally replicated progeny was used to assess the phenotypic plasticity and genetic variation of bud set in two sites of contrasting environmental conditions. Results Six crucial phenological stages of bud set were scored. Night length appeared to be the most important signal triggering the onset of growth cessation. Nevertheless, the effect of other environmental factors, such as temperature, increased during the process. Moreover, a considerable role of genotype × environment (G × E interaction was found in all phenological stages with the lowest temperature appearing to influence the sensitivity of the most plastic genotypes. Descriptors of growth cessation and bud onset explained the largest part of phenotypic variation of the entire process. Quantitative trait loci (QTL for these traits were detected. For the four selected traits (the onset of growth cessation (date2.5, the transition from shoot to bud (date1.5, the duration of bud formation (subproc1 and bud maturation (subproc2 eight and sixteen QTL were mapped on the maternal and paternal map, respectively. The identified QTL, each one characterized by small or modest effect, highlighted the complex nature of traits involved in bud set process. Comparison between map location of QTL and P. trichocarpa genome sequence allowed the identification of 13 gene models, 67 bud set-related expressional and six functional candidate genes (CGs. These CGs are functionally related to relevant biological processes, environmental sensing, signaling, and cell growth and development. Some strong QTL had no obvious CGs, and hold great promise to identify unknown genes that affect bud set

  10. Investigating the Association between Turkish Freshman's Multiple Intelligence Profiles and University Entrance Exam Performance

    Science.gov (United States)

    Atas, Sait; Erisen, Yavuz

    2016-01-01

    Even though curriculum designers in Turkey considered Gardner's multiple intelligence theory as one of the most important theories during the curricula reform in 2005, the university entrance examination system is still on the basis of the two intelligence areas only, mathematical-logical and linguistics intelligence. The aim of this study was to…

  11. Gender Bias and Caste Exclusion in Engineering Admission: Inferences from the Engineering Entrance Examination in Kerala

    Science.gov (United States)

    Rajasenan, D.

    2014-01-01

    The major problem of the engineering entrance examination is the exclusion of certain sections of the society in social, economic, regional and gender dimensions. This has seldom been taken for analysis towards policy correction. To lessen this problem a minor policy shift was prepared in the year 2011 with a 50-50 proportion in academic marks and…

  12. Sleep Patterns and Academic Performance during Preparation for College Entrance Exam in Chinese Adolescents

    Science.gov (United States)

    Wang, Guanghai; Ren, Fen; Liu, Zhijun; Xu, Guangxing; Jiang, Fan; Skora, Elizabeth; Lewin, Daniel S.

    2016-01-01

    Background: Deficient sleep is linked to detrimental outcomes in health and school performance for adolescents. This study characterized sleep patterns in Chinese adolescents preparing for the College Entrance Exam (CEE) and evaluated the association between sleep patterns, self-rated academic performance, and the CEE scores. Methods: A sample of…

  13. Yersinia ruckeri infection of rainbow trout: entrance portals and spread in the host

    DEFF Research Database (Denmark)

    Deshmukh, S.; Khimmakthong, U.; Chettri, J. K.;

    2013-01-01

    The portal of entrance of either formalin inactivated or live Yersinia ruckeri organism in rainbow trout fish was studied by applying immunohistochemistry and in-situ hybridization. The sequential study involved a specific monoclonal antibody and a specific oligonucleotide probe binding to Yersinia...

  14. 33 CFR 334.390 - Atlantic Ocean south of entrance to Chesapeake Bay; firing range.

    Science.gov (United States)

    2010-07-01

    ... to Chesapeake Bay; firing range. 334.390 Section 334.390 Navigation and Navigable Waters CORPS OF....390 Atlantic Ocean south of entrance to Chesapeake Bay; firing range. (a) The danger zone. A section... four (4) nautical miles. (3) Firing on the ranges will be suspended as long as any vessel is within...

  15. Search for entrance-channel dependence in the population of superdeformed bands in {sup 191}Hg

    Energy Technology Data Exchange (ETDEWEB)

    Soramel, F.; Khoo, T.L.; Janssens, R.V.F. [and others

    1995-08-01

    The population intensity of some SD bands in the mass 150 region were observed to depend on the mass symmetry of the entrance channel in the fusion reaction. The authors raised the possibility that the population of SD bands had a memory of the entrance channel. To check this interesting possibility, we made measurements of the population intensities of superdeformed (SD) bands in the {sup 160}Gd({sup 36}S,5n){sup 191}Hg and {sup 130}Te({sup 64}Ni,3n){sup 191}Hg reactions. To ensure that any observed effect was not due to a simple angular momentum difference in the entrance channels, we also measured the average entry points and spin distributions of normal and SD states in {sup 191}Hg in the two reactions. The entry points and spin distributions for {sup 191}Hg are the same and, indeed, so are the SD intensities in the two reactions. Hence, no entrance-channel effect is observed in the population of the SD band in {sup 191}Hg, in contrast with data for SD bands in the mass 150 regions. We suggest that the effect observed previously in the mass 150 region is due to an angular momentum effect. A letter reporting our results was submitted for publication.

  16. The Entrance and Exit Effects in Small Electrochemical Filter-Press Reactors Used in the Laboratory

    Science.gov (United States)

    Frias-Ferrer, Angel; Gonzalez-Garcia, Jose; Saez, Veronica; Exposito, Eduardo; Sanchez-Sanchez, Carlos M.; Mantiel, Vicente; Walsh, Frank C.; Aldaz, Antonio; Walsh, Frank C.

    2005-01-01

    A laboratory experiment designed to examine the entrance and exit effects in small electrochemical filter-press reactors used in the laboratory is presented. The single compartment of the filter-press reactor is filled with different turbulence promoters to study their influence as compared to the empty configuration.

  17. Toward Implementing Computer-Assisted Foreign Language Assessment in the Official Spanish University Entrance Examination

    Science.gov (United States)

    Sanz, Ana Gimeno; Pavón, Ana Sevilla

    2015-01-01

    In 2008 the Spanish Government announced the inclusion of an oral section in the foreign language exam of the National University Entrance Examination during the year 2012 (Royal Decree 1892/2008, of 14 November 2008, Ministerio de Educación, Gobierno de España, 2008). Still awaiting the implementation of these changes, and in an attempt to offer…

  18. Entrance Exam Admission Policies on Ethnic Minorities and Equal Educational Rights for Minorities in China

    Science.gov (United States)

    Weiwei, Lang

    2010-01-01

    In 1977, the Chinese government reinstated the national unified college entrance exam enrollment system. As a part of this system, the government also implemented preferential policies on the enrollment of minorities that authorized the increase or decrease of exam scores and enrollment cutoff points; the policies were therefore seen as…

  19. Family Background and Students' Achievement on a University Entrance Exam in Brazil

    Science.gov (United States)

    Guimaraes, Juliana; Sampaio, Breno

    2013-01-01

    This paper examines the determinants of students' performance on the entrance test at Universidade Federal de Pernambuco, Brazil. Particular attention is paid to the importance of family background variables, such as parents' education and family income, on students' performance and how they relate to the probability of attending public schools…

  20. Spanish Pre-University Students' Use of English: CEA Results from the University Entrance Examination

    Science.gov (United States)

    Diez-Bedmar, Maria Belen

    2011-01-01

    In this paper an updated overview of the main errors that Spanish students make when writing the English exam in the University Entrance Examination is provided. To do so, a Computer-aided Error Analysis (CEA) (Dagneaux, Denness & Granger, 1998) was conducted on a representative sample of the students who took the exam in June 2008 in Jaen,…

  1. Entrance Qualifications Affect the Performance of Nutrition Students at University: A Pilot Study

    Science.gov (United States)

    Owusu-Apenten, Richard; Xu, Wen Li

    2012-01-01

    This study assessed the effect of admissions qualifications on the subsequent academic performances of BSc nutrition students at a UK university. Entrance qualifications for three groups (Grp01, Grp02, Grp03) reading for a BSc(Hons) degree in, Dietetics, Food & Nutrition or Human Nutrition (n = 105) were determined from their UCAS (Universities…

  2. Effect of University Entrance Exam on Gifted High School Students’ Motivation Scrutinized: An Iranian Perspective

    Directory of Open Access Journals (Sweden)

    Ali Kazemi

    2014-09-01

    Full Text Available Passing University Entrance Exams (UEE successfully has long been a major concern for Iranian high school students. High Schools for the Gifted admit highly intelligent and hardworking students, who reportedly form a remarkable proportion of students admitted in best universities of Iran, through hard entrance exams. This study aimed to investigate attitudes of students educating in High Schools for the Gifted towards learning English, their dominant motivation type (instrumental or integrative, and the likely effect Iranian University Entrance Exam has on their motivation.  For the purpose of this investigation, 166 male and female participants educating in the four grades of high school were selected through Stratified Random Sampling Method from both boys’ and girls’ High Schools for the Gifted. A 26-item questioner previously developed by the researchers, investigating the participants’ attitudes towards English learning, their dominant motivation type, and the likely effect of Iranian UEE on their motivation was administered to them. Descriptive statistics and the analysis of variance were used to analyze the data, and the results revealed that all participants educating in the four grades of high school showed positive attitudes towards English learning, and that 1st and 2nd grade subjects were both instrumentally and integratively motivated, whereas 3rd and 4th graders were instrumentally motivated. The degree of subjects’ concern about the Iranian UEE significantly affected their motivational orientations and prioritization.Keywords: Motivation, Interest, Instrumental, Integrative, University Entrance Exam, Gifted Students

  3. Correlation among High School Senior Students' Test Anxiety, Academic Performance and Points of University Entrance Exam

    Science.gov (United States)

    Karatas, Hakan; Alci, Bulent; Aydin, Hasan

    2013-01-01

    Test anxiety seems like a benign problem to some people, but it can be potentially serious when it leads to high levels of distress and academic failure. The aim of this study is to define the correlation among high school senior students' test anxiety, academic performance (GPA) and points of university entrance exam (UEE). The study group of…

  4. Predicting Success Using HESI A2 Entrance Tests in an Associate Degree Nursing Program

    Science.gov (United States)

    Bodman, Susan

    2012-01-01

    A challenge presented to nurse educators is retention of nursing students. This has led nursing faculty to review admission requirements and question how well entrance tests predict success in Associate Degree Nursing Programs. The purpose of this study was to investigate the relationship between the HESI Admission Assessment Exam (HESI A2) and…

  5. Learning beyond graduation: exploring newly qualified specialists' entrance into daily practice from a learning perspective.

    Science.gov (United States)

    Cuyvers, Katrien; Donche, Vincent; Van den Bossche, Piet

    2016-05-01

    The entrance of newly qualified medical specialists into daily practice is considered to be a stressful period in which curriculum support is absent. Although engaging in both personal and professional learning and development activities is recognized fundamental for lifelong professional competence, research on medical professionals' entrance into practice is scarce. This research aims to contribute to the framework of medical professionals' informal learning and outlines the results of an exploratory study on the nature of learning in daily practice beyond postgraduate training. Eleven newly qualified physicians from different specialized backgrounds participated in a phenomenographic study, using a critical incident method and a grounded theory approach. Results demonstrated that learning in the workplace is, to a large extent, informal and associated with a variety of learning experiences. Analysis shows that experiences related to diagnostics and treatments are important sources for learning. Furthermore, incidents related to communication, changing roles, policy and organization offer learning opportunities, and therefore categorized as learning experiences. A broad range of learning activities are identified in dealing with these learning experiences. More specifically, actively engaging in actions and interactions, especially with colleagues of the same specialty, are the most mentioned. Observing others, consulting written sources, and recognizing uncertainties, are also referred to as learning activities. In the study, interaction, solely or combined with other learning activities, are deemed as very important by specialists in the initial entrance into practice. These insights can be used to develop workplace structures to support the entrance into practice following postgraduate training.

  6. Historical Analysis of the Policy on the College Entrance System in South Korea

    Science.gov (United States)

    Choi, Hee Jun; Park, Ji-Hye

    2013-01-01

    The national college admission system has quite frequently been altered in South Korea since Korea was liberated from Japanese colonial rule in 1945. Nonetheless, there are still many ways in which the national college entrance system can be improved. This article initially analysed and synthesized the issues associated with the Korean college…

  7. Personal Well-Being of Gifted Students Following Participation in an Early College-Entrance Program

    Science.gov (United States)

    Boazman, Janette; Sayler, Michael

    2011-01-01

    In this study, life satisfaction and its correlates were explored through analysis of the experiences and psychological traits of highly gifted students who were accelerated into an early college-entrance program. Happiness, fulfillment in life, assuredness, and good dispositions are constructs that point toward positive character development and…

  8. Alleviating the Entrance to Serious Games by Exploring the Use of Commonly Available Tools

    NARCIS (Netherlands)

    Van Rosmalen, Peter; Klemke, Roland; Westera, Wim

    2011-01-01

    Van Rosmalen, P., Klemke, R., & Westera, W. (2011). Alleviating the Entrance to Serious Games by Exploring the Use of Commonly Available Tools. In D. Gouscos, & M. Meimaris (Eds.), Proceedings of the 5th European Conference on Games Based Learning (pp. 613-619), Athens, Greece. 20-21 October 2011.

  9. Voltage-gated sodium channels in taste bud cells

    Directory of Open Access Journals (Sweden)

    Williams Mark E

    2009-03-01

    Full Text Available Abstract Background Taste bud cells transmit information regarding the contents of food from taste receptors embedded in apical microvilli to gustatory nerve fibers innervating basolateral membranes. In particular, taste cells depolarize, activate voltage-gated sodium channels, and fire action potentials in response to tastants. Initial cell depolarization is attributable to sodium influx through TRPM5 in sweet, bitter, and umami cells and an undetermined cation influx through an ion channel in sour cells expressing PKD2L1, a candidate sour taste receptor. The molecular identity of the voltage-gated sodium channels that sense depolarizing signals and subsequently initiate action potentials coding taste information to gustatory nerve fibers is unknown. Results We describe the molecular and histological expression profiles of cation channels involved in electrical signal transmission from apical to basolateral membrane domains. TRPM5 was positioned immediately beneath tight junctions to receive calcium signals originating from sweet, bitter, and umami receptor activation, while PKD2L1 was positioned at the taste pore. Using mouse taste bud and lingual epithelial cells collected by laser capture microdissection, SCN2A, SCN3A, and SCN9A voltage-gated sodium channel transcripts were expressed in taste tissue. SCN2A, SCN3A, and SCN9A were expressed beneath tight junctions in subsets of taste cells. SCN3A and SCN9A were expressed in TRPM5 cells, while SCN2A was expressed in TRPM5 and PKD2L1 cells. HCN4, a gene previously implicated in sour taste, was expressed in PKD2L1 cells and localized to cell processes beneath the taste pore. Conclusion SCN2A, SCN3A and SCN9A voltage-gated sodium channels are positioned to sense initial depolarizing signals stemming from taste receptor activation and initiate taste cell action potentials. SCN2A, SCN3A and SCN9A gene products likely account for the tetrodotoxin-sensitive sodium currents in taste receptor cells.

  10. The MLA Survey of Postsecondary Entrance and Degree Requirements for Languages Other Than English, 2009-10

    Science.gov (United States)

    Lusin, Natalia

    2012-01-01

    Since 1953, the MLA has conducted a survey of entrance and degree requirements for languages other than English. The surveys reveal trends over time and show how colleges and universities in the United States have added, dropped, or changed their requirements. Entrance and degree requirements are one measure of the value that an institution…

  11. Variações do conteúdo de carboidratos em gemas e ramos de dois anos de macieira em região de baixa ocorrência de frio Variations of carbohydrate content in two year old buds and stems of apple trees in a region of low chill occurence

    Directory of Open Access Journals (Sweden)

    Ruy Inacio Neiva de Carvalho

    2005-12-01

    spectrophotometry (490 nm absorbency. The non-soluble carbohydrates (NC were estimated by the mass of vegetal tissues insoluble in alcohol and soluble in alcaline medium, after freeze drying. Significant variations of carbohydrate content were observed in the two year old buds and stems during the dormancy. The increase of dormancy intensity in autumn is associated with the reduction of SC content in buds. The treatment with 1,440 hours of chill modify the variations of SC content in stems and NC content in buds.

  12. 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.

  13. Influence of dormancy on microbial competition under intermittent substrate supply: insights from model simulations.

    Science.gov (United States)

    Stolpovsky, Konstantin; Fetzer, Ingo; Van Cappellen, Philippe; Thullner, Martin

    2016-06-01

    Most natural environments are characterized by frequent changes of their abiotic conditions. Microorganisms can respond to such changes by switching their physiological state between activity and dormancy allowing them to endure periods of unfavorable abiotic conditions. As a consequence, the competitiveness of microbial species is not simply determined by their growth performance under favorable conditions but also by their ability and readiness to respond to periods of unfavorable environmental conditions. The present study investigates the relevance of factors controlling the abundance and activity of individual bacterial species competing for an intermittently supplied substrate. For this purpose, numerical experiments were performed addressing the response of microbial systems to regularly applied feeding pulses. Simulation results show that community dynamics may exhibit a non-trivial link to the frequency of the external constraints and that for a certain combination of these environmental conditions coexistence of species is possible. The ecological implication of our results is that even non-dominant, neglected species can have a strong influence on realized species composition of dominant key species, due to their invisible presence enable the coexistence between important key species and by this affecting provided function of the system.

  14. Pleiotropy in the wild: the dormancy gene DOG1 exerts cascading control on life cycles.

    Science.gov (United States)

    Chiang, George C K; Barua, Deepak; Dittmar, Emily; Kramer, Elena M; de Casas, Rafael Rubio; Donohue, Kathleen

    2013-03-01

    In the wild, organismal life cycles occur within seasonal cycles, so shifts in the timing of developmental transitions can alter the seasonal environment experienced subsequently. Effects of genes that control the timing of prior developmental events can therefore be magnified in the wild because they determine seasonal conditions experienced by subsequent life stages, which can influence subsequent phenotypic expression. We examined such environmentally induced pleiotropy of developmental-timing genes in a field experiment with Arabidopsis thaliana. When studied in the field under natural seasonal variation, an A. thaliana seed-dormancy gene, Delay Of Germination 1 (DOG1), was found to influence not only germination, but also flowering time, overall life history, and fitness. Flowering time of the previous generation, in turn, imposed maternal effects that altered germination, the effects of DOG1 alleles, and the direction of natural selection on these alleles. Thus under natural conditions, germination genes act as flowering genes and potentially vice versa. These results illustrate how seasonal environmental variation can alter pleiotropic effects of developmental-timing genes, such that effects of genes that regulate prior life stages ramify to influence subsequent life stages. In this case, one gene acting at the seed stage impacted the entire life cycle.

  15. The effect of fire on the dormancy break of three annual legume seeds

    Directory of Open Access Journals (Sweden)

    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.

  16. Exceptional preservation of tiny embryos documents seed dormancy in early angiosperms.

    Science.gov (United States)

    Friis, Else Marie; Crane, Peter R; Pedersen, Kaj Raunsgaard; Stampanoni, Marco; Marone, Federica

    2015-12-24

    The rapid diversification of angiosperms through the Early Cretaceous period, between about 130-100 million years ago, initiated fundamental changes in the composition of terrestrial vegetation and is increasingly well understood on the basis of a wealth of palaeobotanical discoveries over the past four decades and their integration with improved knowledge of living angiosperms. Prevailing hypotheses, based on evidence both from living and from fossil plants, emphasize that the earliest angiosperms were plants of small stature with rapid life cycles that exploited disturbed habitats in open, or perhaps understorey, conditions. However, direct palaeontogical data relevant to understanding the seed biology and germination ecology of Early Cretaceous angiosperms are sparse. Here we report the discovery of embryos and their associated nutrient storage tissues in exceptionally well-preserved angiosperm seeds from the Early Cretaceous. Synchrotron radiation X-ray tomographic microscopy of the fossil embryos from many taxa reveals that all were tiny at the time of dispersal. These results support hypotheses based on extant plants that tiny embryos and seed dormancy are basic for angiosperms as a whole. The minute size of the fossil embryos, and the modest nutrient storage tissues dictated by the overall small seed size, is also consistent with the interpretation that many early angiosperms were opportunistic, early successional colonizers of disturbance-prone habitats.

  17. Paradoxical dependencies of tumor dormancy and progression on basic cell kinetics.

    Science.gov (United States)

    Enderling, Heiko; Anderson, Alexander R A; Chaplain, Mark A J; Beheshti, Afshin; Hlatky, Lynn; Hahnfeldt, Philip

    2009-11-15

    Even after a tumor is established, it can early on enter a state of dormancy marked by balanced cell proliferation and cell death. Disturbances to this equilibrium may affect cancer risk, as they may cause the eventual lifetime clinical presentation of a tumor that might otherwise have remained asymptomatic. Previously, we showed that cell death, proliferation, and migration can play a role in shifting this dynamic, making the understanding of their combined influence on tumor development essential. We developed an individual cell-based computer model of the interaction of cancer stem cells and their nonstem progeny to study early tumor dynamics. Simulations of tumor growth show that three basic components of tumor growth--cell proliferation, migration, and death--combine in unexpected ways to control tumor progression and, thus, clinical cancer risk. We show that increased proliferation capacity in nonstem tumor cells and limited cell migration overall lead to space constraints that inhibit proliferation and tumor growth. By contrast, increasing the rate of cell death produces the expected tumor size reduction in the short term, but results ultimately in paradoxical accelerated long-term growth owing to the liberation of cancer stem cells and formation of self-metastases.

  18. Comparative Analysis of Water Quality between the Runoff Entrance and Middle of Recycling Irrigation Reservoirs

    Directory of Open Access Journals (Sweden)

    Haibo Zhang

    2015-07-01

    Full Text Available Recycling irrigation reservoirs (RIRs are an emerging aquatic ecosystem of critical importance, for conserving and protecting increasingly scarce water resources. Here, we compare water quality between runoff entrance and middle of four RIRs in nurseries in Virginia (VA and Maryland (MD. Surface water temperature (T and oxidation-reduction potential (ORP were lower in the middle than at the entrance, while the trend was opposite for dissolved oxygen (DO, pH and chlorophyll a (Chla. The magnitude of these differences between the entrance and middle decreased with increasing depth. These differences were magnified by water stratification from April to October. Minimum differences were observed for electrical conductivity (EC, total dissolved solids (TDS and turbidity (TUR. Cluster analyses were performed on water quality difference data to evaluate whether the differences vary with respect to reservoirs. Two clusters were formed with one consisting primarily of VA reservoirs, and the other consisting mostly of MD reservoirs in both years. Water quality in the middle and at the entrance of RIRs was expected to vary greatly because of runoff inflow. The two-point water quality differences observed here, although statistically significant, are not large enough to cause significant impact on crop health and productivity for most water quality parameters except pH. Additional analysis of outlet data shows that the range and magnitude of water quality difference between the middle and the outlet are comparable to those between the middle and entrance of RIRs. These results indicate that monitoring at a single point is sufficient to obtain reliable water quality estimates for most water quality parameters in RIRs except pH. This is important when considering the cost of labor and equipment necessary for documenting water quality in agricultural production systems. However, additional pH measurements are still necessary to make practical water quality

  19. Timing robustness in the budding and fission yeast cell cycles.

    KAUST Repository

    Mangla, Karan

    2010-02-01

    Robustness of biological models has emerged as an important principle in systems biology. Many past analyses of Boolean models update all pending changes in signals simultaneously (i.e., synchronously), making it impossible to consider robustness to variations in timing that result from noise and different environmental conditions. We checked previously published mathematical models of the cell cycles of budding and fission yeast for robustness to timing variations by constructing Boolean models and analyzing them using model-checking software for the property of speed independence. Surprisingly, the models are nearly, but not totally, speed-independent. In some cases, examination of timing problems discovered in the analysis exposes apparent inaccuracies in the model. Biologically justified revisions to the model eliminate the timing problems. Furthermore, in silico random mutations in the regulatory interactions of a speed-independent Boolean model are shown to be unlikely to preserve speed independence, even in models that are otherwise functional, providing evidence for selection pressure to maintain timing robustness. Multiple cell cycle models exhibit strong robustness to timing variation, apparently due to evolutionary pressure. Thus, timing robustness can be a basis for generating testable hypotheses and can focus attention on aspects of a model that may need refinement.

  20. Tanshinones extend chronological lifespan in budding yeast Saccharomyces cerevisiae.

    Science.gov (United States)

    Wu, Ziyun; Song, Lixia; Liu, Shao Quan; Huang, Dejian

    2014-10-01

    Natural products with anti-aging property have drawn great attention recently but examples of such compounds are exceedingly scarce. By applying a high-throughput assay based on yeast chronological lifespan measurement, we screened the anti-aging activity of 144 botanical materials and found that dried roots of Salvia miltiorrhiza Bunge have significant anti-aging activity. Tanshinones isolated from the plant including cryptotanshione, tanshinone I, and tanshinone IIa, are the active components. Among them, cryptotanshinone can greatly extend the budding yeast Saccharomyces cerevisiae chronological lifespan (up to 2.5 times) in a dose- and the-time-of-addition-dependent manner at nanomolar concentrations without disruption of cell growth. We demonstrate that cryptotanshinone prolong chronological lifespan via a nutrient-dependent regime, especially essential amino acid sensing, and three conserved protein kinases Tor1, Sch9, and Gcn2 are required for cryptotanshinone-induced lifespan extension. In addition, cryptotanshinone significantly increases the lifespan of SOD2-deleted mutants. Altogether, those data suggest that cryptotanshinone might be involved in the regulation of, Tor1, Sch9, Gcn2, and Sod2, these highly conserved longevity proteins modulated by nutrients from yeast to humans.

  1. Asymmetric nucleosomes flank promoters in the budding yeast genome.

    Science.gov (United States)

    Ramachandran, Srinivas; Zentner, Gabriel E; Henikoff, Steven

    2015-03-01

    Nucleosomes in active chromatin are dynamic, but whether they have distinct structural conformations is unknown. To identify nucleosomes with alternative structures genome-wide, we used H4S47C-anchored cleavage mapping, which revealed that 5% of budding yeast (Saccharomyces cerevisiae) nucleosome positions have asymmetric histone-DNA interactions. These asymmetric interactions are enriched at nucleosome positions that flank promoters. Micrococcal nuclease (MNase) sequence-based profiles of asymmetric nucleosome positions revealed a corresponding asymmetry in MNase protection near the dyad axis, suggesting that the loss of DNA contacts around H4S47 is accompanied by protection of the DNA from MNase. Chromatin immunoprecipitation mapping of selected nucleosome remodelers indicated that asymmetric nucleosomes are bound by the RSC chromatin remodeling complex, which is required for maintaining nucleosomes at asymmetric positions. These results imply that the asymmetric nucleosome-RSC complex is a metastable intermediate representing partial unwrapping and protection of nucleosomal DNA on one side of the dyad axis during chromatin remodeling.

  2. Initiation of Begonia erythrophylla L. vitroculture from axillary buds

    Directory of Open Access Journals (Sweden)

    Julieta - Emilia ROMOCEA

    2010-11-01

    Full Text Available In our aim was to establish a short-term in vitro culture of Begonia erythrophylla L., different culture media compositions were tested: complex variants added with growth regulators and simplified modified media with Heller microelements and MS macroelements. Adventitious shoots elongating over 13 mm in length were efficiently obtained from axillary bud segments of the strain of begonia Begonia erythrophylla L. on MS basic mineral medium culture containing different concentration of growth regulators, in order to identify optimal culture conditions, which would facilitate the achievement of a vitroculture, allowing the in vitro culture of this studied species. On complex regeneration variant V1 – mineral basic medium culture MB - MS supplemented with 1 mg/l BA, the rooting process was absent, but according to this carried out research, plantlets were obtained by rooting the elongated shoots on Murashige-Skoog (1962 basic mineral media containing 1 mg/l IBA, respectively a basic mineral medium culture without growth regulators, producing a much better organogenesis, where the phenomenon was greater in rooting process.

  3. Neural crest contribution to lingual mesenchyme, epithelium and developing taste papillae and taste buds

    OpenAIRE

    Liu, Hong-Xiang; Komatsu, Yoshihiro; Mishina, Yuji; Mistretta, Charlotte M.

    2012-01-01

    The epithelium of mammalian tongue hosts most of the taste buds that transduce gustatory stimuli into neural signals. In the field of taste biology, taste bud cells have been described as arising from “local epithelium”, in distinction from many other receptor organs that are derived from neurogenic ectoderm including neural crest (NC). In fact, contribution of NC to both epithelium and mesenchyme in the developing tongue is not fully understood. In the present study we used two independent, ...

  4. Functional expression of ionotropic purinergic receptors on mouse taste bud cells

    OpenAIRE

    2007-01-01

    Neurotransmitter receptors on taste bud cells (TBCs) and taste nerve fibres are likely to contribute to taste transduction by mediating the interaction among TBCs and that between TBCs and taste nerve fibres. We investigated the functional expression of P2 receptor subtypes on TBCs of mouse fungiform papillae. Electrophysiological studies showed that 100 [mu m ATP applied to their basolateral membranes either depolarized or hyperpolarized a few cells per taste bud. Ca2+ imaging showed that si...

  5. The diversity of fungi colonizing necrotic inflorescence buds of rhododendron (Rhododendron L.)

    OpenAIRE

    Małgorzata Żołna; Barbara Kierpiec-Baran; Maria Kowalik

    2013-01-01

    The infection of rhododendron (Rhododendron L.) inflorescence buds caused by pathogenic fungi induces its browning, withering, and dieback. The identification of fungi causing the infection of rhododendron inflorescence buds can be a reason for creating new improved cultivars with genetically determined resistance to pathogens. The investigations were carried out in 2010–2011 on the collection of ornamental plants of the Faculty of Horticulture, University of Agriculture in Kraków. The materi...

  6. Florigen is involved in axillary bud development at multiple stages in Arabidopsis

    OpenAIRE

    Niwa, Masaki; Endo, Motomu; Araki, Takashi

    2013-01-01

    The wide variety of plant architectures is largely based on diverse and flexible modes of axillary shoot development. In Arabidopsis, floral transition (flowering) stimulates axillary bud development. The mechanism that links flowering and axillary bud development is, however, largely unknown. We recently showed that FLOWERING LOCUS T (FT) protein, which acts as florigen, promotes the phase transition of axillary meristems, whereas BRANCHED1 (BRC1) antagonizes the florigen action in axillary ...

  7. Taste Bud Labeling in Whole Tongue Epithelial Sheet in Adult Mice.

    Science.gov (United States)

    Venkatesan, Nandakumar; Boggs, Kristin; Liu, Hong-Xiang

    2016-04-01

    Molecular labeling in whole-mount tissues provides an efficient way to obtain general information about the formation, maintenance, degeneration, and regeneration of many organs and tissues. However, labeling of lingual taste buds in whole tongue tissues in adult mice has been problematic because of the strong permeability barrier of the tongue epithelium. In this study, we present a simple method for labeling taste buds in the intact tongue epithelial sheet of an adult mouse. Following intralingual protease injection and incubation, immediate fixation of the tongue on mandible in 4% paraformaldehyde enabled the in situ shape of the tongue epithelium to be well maintained after peeling. The peeled epithelium was accessible to taste bud labeling with a pan-taste cell marker, keratin 8, and a type II taste cell marker, α-gustducin, in all three types of taste papillae, that is, fungiform, foliate, and circumvallate. Overnight incubation of tongue epithelial sheets with primary and secondary antibodies was sufficient for intense labeling of taste buds with both fluorescent and DAB visualizations. Labeled individual taste buds were easy to identify and quantify. This protocol provides an efficient way for phenotypic analyses of taste buds, especially regarding distribution pattern and number.

  8. Expression and function of myc during asexual reproduction of the budding ascidian Polyandrocarpa misakiensis.

    Science.gov (United States)

    Fujiwara, Shigeki; Isozaki, Takaomi; Mori, Kyoko; Kawamura, Kazuo

    2011-12-01

    The budding ascidian Polyandrocarpa misakiensis proliferates asexually by budding. The atrial epithelium is a multipotent but differentiated tissue, which transdifferentiates into various tissues and organs after the bud separates from the parental body. We isolated cDNA clones homologous to the myc proto-oncogene from P. misakiensis. The cDNA, named Pm-myc, encoded a polypeptide of 639 amino acid residues, containing Myc-specific functional motifs, Myc box I and Myc box II, and the basic helix-loop-helix domain. Expression of Pm-myc was observed in the atrial epithelium in the organ-forming region of the developing bud, where the epithelial cells dedifferentiate and re-enter the cell cycle. The expression was also observed in fibroblast-like cells, which are known to participate in the organogenesis together with the epithelial cells. Unexpectedly, the atrial epithelium expressed Pm-myc more than one day before the dedifferentiation. The organogenesis was disturbed by Pm-myc-specific double-stranded RNA. In situ hybridization revealed that Pm-myc-positive fibroblast-like cells disappeared around the organ primordium of the dsRNA-treated bud. The results suggest that the mesenchymal-epithelial transition of fibroblast-like cells is important for the organogenesis in this budding ascidian species.

  9. Programmed cell death during terminal bud senescence in a sympodial branching tree,Eucommia ulmoides

    Institute of Scientific and Technical Information of China (English)

    XU Wenjie; Kalima-N'Koma MWANGE; CUI Keming

    2004-01-01

    Eucommia ulmoides Oliv. is a typical sympodial branching tree. The apical bud of the branch ages and dies every year, replaced by the nearby axillary bud in the second year. Structural assays and a series of biochemical analyses were performed to analyze the senescence mechanism in the apical bud. It was revealed that most cells of the apical bud underwent the programmed cell death (PCD) during the senescence: the chromosomes were congregated and the nuclear contents were condensed, as shown by 4′,6-diamidino-2-phenylindole (DAPI) fluorescence. DNA fragmentation was detected during senescence using the terminal deoxynucleotidyl transferase (TdT)-mediated dUTP nick end in situ labeling (TUNEL) method, coincident with the appearance of a DNA ladder. Moreover, a 20 kD DNase related to fragmentation was found. PCD was initiated first in the young leaves, leaf primordia and peripheral zone cells, then in the central mother cells and initial layer cells in the apical meristem. The terminal buds remain in vegetative growth during senescence, in contrast to buds of many annual plants.

  10. Association of Dermatological Conditions of External Ear with the Use of Cotton Buds

    Directory of Open Access Journals (Sweden)

    Salahuddin Ahmed

    2014-09-01

    Full Text Available Background: The habit of cleaning the external auditory canal with cotton buds is a common practice of the masses. It has strong association with neurodermatitis and contact dermatitis of the external ear. It is also associated with acute otitis externa, rupture of tympanic membrane causing bleeding and temporary hearing loss in some cases. In many cases the injury will heal but damage to minuscule bones deep inside the ear can cause permanent deafness. Objective: The objective of this study was to determine the association of dermatological condition of external ear with the use of cotton buds. Materials and Methods: This case control study was done from January to October 2012 in the Ear Nose Throat Department of Pakistan Level III Hospital, Darfur, Sudan. Sixty seven patients with dermatological diseases of external ear were cases and 83 subjects without dermatological diseases of external ear were selected as controls. Results: Among 67 cases, 58 were cotton bud users and among 83 controls only 29 were cotton bud users. Different types of dermatological diseases were neurodermatitis (34.32%, otitis externa (28.36%, contact dermatitis (26.87% and wax impaction (8.95%. Ninety three percent of cotton bud users were ignorant of harmful effects of this bad habit. Conclusion: There is a strong association of dermatological diseases of external ear with the use of cotton bud which should be discouraged by fortifying the warning by manufacturers and health education at various educational levels.

  11. Glutamate may be an efferent transmitter that elicits inhibition in mouse taste buds.

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    Yijen A Huang

    Full Text Available Recent studies suggest that l-glutamate may be an efferent transmitter released from axons innervating taste buds. In this report, we determined the types of ionotropic synaptic glutamate receptors present on taste cells and that underlie this postulated efferent transmission. We also studied what effect glutamate exerts on taste bud function. We isolated mouse taste buds and taste cells, conducted functional imaging using Fura 2, and used cellular biosensors to monitor taste-evoked transmitter release. The findings show that a large fraction of Presynaptic (Type III taste bud cells (∼50% respond to 100 µM glutamate, NMDA, or kainic acid (KA with an increase in intracellular Ca(2+. In contrast, Receptor (Type II taste cells rarely (4% responded to 100 µM glutamate. At this concentration and with these compounds, these agonists activate glutamatergic synaptic receptors, not glutamate taste (umami receptors. Moreover, applying glutamate, NMDA, or KA caused taste buds to secrete 5-HT, a Presynaptic taste cell transmitter, but not ATP, a Receptor cell transmitter. Indeed, glutamate-evoked 5-HT release inhibited taste-evoked ATP secretion. The findings are consistent with a role for glutamate in taste buds as an inhibitory efferent transmitter that acts via ionotropic synaptic glutamate receptors.

  12. DORMANCY BREAKING OF OIL PALM SEED TENERA VARIETY BY SOAKING FOR A CERTAIN LENGTH OF TIME IN THE SULFURIC ACID SOLUTION

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    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.

  13. Consequences of Repeated Defoliation on Belowground Bud Banks of Carex brevicuspis (Cyperaceae) in the Dongting Lake Wetlands, China.

    Science.gov (United States)

    Chen, Xin-Sheng; Deng, Zheng-Miao; Xie, Yong-Hong; Li, Feng; Hou, Zhi-Yong; Wu, Chao

    2016-01-01

    Despite the predominant role of bud banks in the regeneration of clonal macrophyte populations, few studies have examined the way in which clonal macrophytes adjust the demographic features of bud banks to regulate population dynamics in response to defoliation in wetlands. We investigated the density and composition of bud banks under repeated defoliation in the wetland sedge Carex brevicuspis C. B. Clarke in the Dongting Lake wetlands, China. The density and biomass of rhizome buds and shoots did not decrease significantly in response to repeated defoliation over two consecutive years. The composition of bud banks, which consisted of long and short rhizome buds, also did not change significantly in response to repeated defoliation. Nevertheless, the ramet height and the shoot, root, and rhizome mass of C. brevicuspis declined significantly under repeated defoliation. Our findings suggest that bud banks are a conservative reproductive strategy that enables C. brevicuspis to tolerate a certain amount of defoliation. The maintenance of large bud banks after repeated defoliation may enable C. brevicuspis populations to regenerate and persist in disturbed habitats. However, bud bank density of C. brevicuspis might decline in the long term because the amount of carbon stored in rhizome buds and plants is reduced by frequent defoliation.

  14. Effect of Seed Position on Parental Plant on Proportion of Seeds Produced with Nondeep and Intermediate Physiological Dormancy.

    Science.gov (United States)

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

    2017-01-01

    The position in which seeds develop on the parental plant can have an effect on dormancy-break and germination. We tested the hypothesis that the proportion of seeds with intermediate physiological dormancy (PD) produced in the proximal position on a raceme of Isatis violascens plants is higher than that produced in the distal position, and further that this difference is related to temperature during seed development. Plants were watered at 3-day intervals, and silicles and seeds from the proximal (early) and distal (late) positions of racemes on the same plants were collected separately and tested for germination. After 0 and 6 months dry storage at room temperature (afterripening), silicles and seeds were cold stratified for 0-16 weeks and tested for germination. Mean daily maximum and minimum temperatures during development/maturation of the two groups of seeds did not differ. A higher proportion of seeds with the intermediate level than with the nondeep level of PD was produced by silicles in the proximal position than by those in the distal position, while the proportion of seeds with nondeep PD was higher in the distal than in the proximal position of the raceme. The differences were not due only to seed mass. Since temperature and soil moisture conditions were the same during development of the seeds in the raceme, differences in proportion of seeds with intermediate and nondeep PD are attributed to position on parental plant. The ecological consequence of this phenomenon is that it ensures diversity in dormancy-breaking and germination characteristics within a seed cohort, a probable bet-hedging strategy. This is the first demonstration of position effects on level of PD in the offspring.

  15. Genotyping of endosperms to determine seed dormancy genes regulating germination through embryonic, endospermic, or maternal tissues in rice.

    Science.gov (United States)

    Gu, Xing-You; Zhang, Jinfeng; Ye, Heng; Zhang, Lihua; Feng, Jiuhuan

    2015-02-01

    Seed dormancy is imposed by one or more of the embryo, endosperm, and maternal tissues that belong to two generations and represent two ploidy levels. Many quantitative trait loci (QTL) have been identified for seed dormancy as measured by gross effects on reduced germination rate or delayed germination in crop or model plants. This research developed an endosperm genotype-based genetic approach to determine specific tissues through which a mapped QTL regulates germination using rice as a model. This approach involves testing germination velocity for partially after-ripened seeds harvested from single plants heterozygous for a tested QTL and genotyping endosperms from individual germinated and nongerminated seeds with a codominant DNA marker located on the QTL peak region. Information collected about the QTL includes genotypic frequencies in germinated and/or nongerminated subpopulations; allelic frequency distributions during a germination period; endosperm or embryo genotypic differences in germination velocity; and genotypic frequencies for gametes involved in the double fertilization to form the sampled seeds. Using this approach, the seed dormancy loci SD12, SD1-2, and SD7-1 were determined to regulate germination through the embryo, endosperm, and maternal tissues, respectively; SD12 and SD1-2 acted additively on germination velocity in the offspring tissues; and SD12 also was associated with the preferential fertilization of male gametes in rice. This new genetic approach can be used to characterize mapped genes/QTL for tissue-specific functions in endospermic seeds and for marker-assisted selection of QTL alleles before or immediately after germination in crop breeding.

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

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    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.

  17. Integrated analysis of seed proteome and mRNA oxidation reveals distinct post-transcriptional features regulating dormancy in wheat (Triticum aestivum L.).

    Science.gov (United States)

    Gao, Feng; Rampitsch, Christof; Chitnis, Vijaya R; Humphreys, Gavin D; Jordan, Mark C; Ayele, Belay T

    2013-10-01

    Wheat seeds can be released from a dormant state by after-ripening; however, the underlying molecular mechanisms are still mostly unknown. We previously identified transcriptional programmes involved in the regulation of after-ripening-mediated seed dormancy decay in wheat (Triticum aestivum L.). Here, we show that seed dormancy maintenance and its release by dry after-ripening in wheat is associated with oxidative modification of distinct seed-stored mRNAs that mainly correspond to oxidative phosphorylation, ribosome biogenesis, nutrient reservoir and α-amylase inhibitor activities, suggesting the significance of post-transcriptional repression of these biological processes in regulating seed dormancy. We further show that after-ripening induced seed dormancy release in wheat is mediated by differential expression of specific proteins in both dry and hydrated states, including those involved in proteolysis, cellular signalling, translation and energy metabolism. Among the genes corresponding to these proteins, the expression of those encoding α-amylase/trypsin inhibitor and starch synthase appears to be regulated by mRNA oxidation. Co-expression analysis of the probesets differentially expressed and oxidized during dry after-ripening along with those corresponding to proteins differentially regulated between dormant and after-ripened seeds produced three co-expressed gene clusters containing more candidate genes potentially involved in the regulation of seed dormancy in wheat. Two of the three clusters are enriched with elements that are either abscisic acid (ABA) responsive or recognized by ABA-regulated transcription factors, indicating the association between wheat seed dormancy and ABA sensitivity.

  18. 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.

  19. An efficient method in breaking of dormancy from Bunium persicum(Boiss)Fedtsch seeds:a valuable herb of middle East and Central Asia

    Institute of Scientific and Technical Information of China (English)

    Yousef; Emamipoor; Mahmood; Maziah

    2014-01-01

    Objective:To develop a protocol lor breaking of seed dormancy and increasing the seed germination rate of Bunium persicum.Methods:The seeds were treated with 3.1.6.3.12.5.25.50 and 100 μmol/L of benzyl aminopurine.gibberellic acid(GA,),thidiazuron(TDZ) and forchlorlenuron.Then,seeds were transferred to two different temperature conditions including room temperature(25 ℃) and chilling temperature(2-5℃).Results:The treatment of moist seeds with chilling temperature(2—5℃) broke seed dormancy and showed maximum germination,which was 54.7%after 60 d treatment.Also,the treatment of dn 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 moistroom condition,there was evidence ol higher and lower seed germination rate:GA,(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 moistchilling condition revealed higher rale of breaking of seed dormancy when 6.3 μmol/L TDZ was combined with 100 μmol/L GA,.showing 93.7%genninatiou rate.Conclusions: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.

  20. An efficient method in breaking of dormancy from Bunium persicum (Boiss) Fedtsch seeds:a valuable herb of Middle East and Central Asia

    Institute of Scientific and Technical Information of China (English)

    Yousef Emamipoor; Mahmood Maziah

    2014-01-01

    Objective: To develop a protocol for breaking of seed dormancy and increasing the seed germination rate of Bunium persicum. Methods: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). Results: 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. Conclusions: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.

  1. Origin of irreversibility of cell cycle start in budding yeast.

    Directory of Open Access Journals (Sweden)

    Gilles Charvin

    2010-01-01

    Full Text Available Budding yeast cells irreversibly commit to a new division cycle at a regulatory transition called Start. This essential decision-making step involves the activation of the SBF/MBF transcription factors. SBF/MBF promote expression of the G1 cyclins encoded by CLN1 and CLN2. Cln1,2 can activate their own expression by inactivating the Whi5 repressor of SBF/MBF. The resulting transcriptional positive feedback provides an appealing, but as yet unproven, candidate for generating irreversibility of Start. Here, we investigate the logic of the Start regulatory module by quantitative single-cell time-lapse microscopy, using strains in which expression of key regulators is efficiently controlled by changes of inducers in a microfluidic chamber. We show that Start activation is ultrasensitive to G1 cyclin. In the absence of CLN1,2-dependent positive feedback, we observe that Start transit is reversible, due to reactivation of the Whi5 transcriptional repressor. Introduction of the positive feedback loop makes Whi5 inactivation and Start activation irreversible, which therefore guarantees unidirectional entry into S phase. A simple mathematical model to describe G1 cyclin turn on at Start, entirely constrained by empirically measured parameters, shows that the experimentally measured ultrasensitivity and transcriptional positive feedback are necessary and sufficient dynamical characteristics to make the Start transition a bistable and irreversible switch. Our study thus demonstrates that Start irreversibility is a property that arises from the architecture of the system (Whi5/SBF/Cln2 loop, rather than the consequence of the regulation of a single component (e.g., irreversible protein degradation.

  2. Origin of irreversibility of cell cycle start in budding yeast.

    Science.gov (United States)

    Charvin, Gilles; Oikonomou, Catherine; Siggia, Eric D; Cross, Frederick R

    2010-01-19

    Budding yeast cells irreversibly commit to a new division cycle at a regulatory transition called Start. This essential decision-making step involves the activation of the SBF/MBF transcription factors. SBF/MBF promote expression of the G1 cyclins encoded by CLN1 and CLN2. Cln1,2 can activate their own expression by inactivating the Whi5 repressor of SBF/MBF. The resulting transcriptional positive feedback provides an appealing, but as yet unproven, candidate for generating irreversibility of Start. Here, we investigate the logic of the Start regulatory module by quantitative single-cell time-lapse microscopy, using strains in which expression of key regulators is efficiently controlled by changes of inducers in a microfluidic chamber. We show that Start activation is ultrasensitive to G1 cyclin. In the absence of CLN1,2-dependent positive feedback, we observe that Start transit is reversible, due to reactivation of the Whi5 transcriptional repressor. Introduction of the positive feedback loop makes Whi5 inactivation and Start activation irreversible, which therefore guarantees unidirectional entry into S phase. A simple mathematical model to describe G1 cyclin turn on at Start, entirely constrained by empirically measured parameters, shows that the experimentally measured ultrasensitivity and transcriptional positive feedback are necessary and sufficient dynamical characteristics to make the Start transition a bistable and irreversible switch. Our study thus demonstrates that Start irreversibility is a property that arises from the architecture of the system (Whi5/SBF/Cln2 loop), rather than the consequence of the regulation of a single component (e.g., irreversible protein degradation).

  3. Atividade de enzimas relacionadas com a mobilização de carboidratos durante a dormência da nogueira (Juglans Regia Walnut enzyme activity related with carbohydrate mobilization during dormancy period

    Directory of Open Access Journals (Sweden)

    Idemir Citadin

    2009-06-01

    Full Text Available A brotação da nogueira é dependente da mobilização de carboidratos do lenho para as gemas localizadas na porção superior dos ramos. O objetivo do trabalho foi contribuir para o entendimento do mecanismo de brotação acrótona da nogueira, em clima temperado, através da mensuração da atividade da ±-amilase (EC 3.2.1.1 e sacarose fosfato sintase (SPS - EC 2.4.1.14 relacionadas com a mobilização de carboidratos, durante o período de dormência. Para cada coleta, foram amostrados cinco ramos do ano, durante os meses de setembro a março. Em abril, próximo à retomada do crescimento ativo, foram feitas três amostragens. As partes apical, subapical e da base dos ramos foram separadas em casca, lenho (xilema e gemas. O tempo médio de brotação (TMB em condições controladas (25ºC, a umidade ponderal e a atividade das enzimas acima relacionadas foram determinadas. Os resultados obtidos reforçam a teoria de que o gradiente de brotação na nogueira se desenvolve durante a ecodormência e apresenta uma relação de dependência com a atividade da á-amilase; não está evidente a relação da atividade da SPS com a evolução do crescimento das gemas, durante a ecodormência.Juglans regia L. sprout depends on the carbohydrate mobilization from the parenchyma cells into the buds located in the upper portion of the twigs. The objective of this work was to contribute to the walnut tree sprout acrotony mechanism, in temperate climate, through the activity of alpha-amylase (EC 3.2.1.1, and Sucrose Phosphate Synthase (SPS - EC 2.4.1.14 mensuration, related to carbohydrate mobilization, during the dormancy period. From September to March, five one-year-old twigs were monthly sampled around. In April, close to budbreak, three samples were accomplished. The twigs were divided in apical, sub-apical, and base, and separated in bark, buds and wood (xylem. The average time of bud break in controlled conditions (25ºC, water content, and activity

  4. Cancer Dormancy: A Regulatory Role for Endogenous Immunity in Establishing and Maintaining the Tumor Dormant State

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    Constantin N. Baxevanis

    2015-07-01

    Full Text Available The significant contribution of host immunity in early tumorigenesis has been recently recognized as a result of our better understanding of the molecular pathways regulating tumor cell biology and tumor-lymphocyte interactions. Emerging evidence suggests that disseminated dormant tumor cells derived from primary tumors before or after immune surveillance, are responsible for subsequent metastases. Recent trends from the field of onco-immunology suggest that efficiently stimulating endogenous anticancer immunity is a prerequisite for the successful outcome of conventional cancer therapies. Harnessing the immune system to achieve clinical efficacy is realistic in the context of conventional therapies resulting in immunogenic cell death and/or immunostimulatory side effects. Targeted therapies designed to target oncogenic pathways in tumor cells can also positively regulate the endogenous immune response and tumor microenvironment. Identification of T cell inhibitory signals has prompted the development of immune checkpoint inhibitors, which specifically hinder immune effector inhibition, reinvigorating and potentially expanding the preexisting anticancer immune response. This anticancer immunity can be amplified in the setting of immunotherapies, mostly in the form of vaccines, which boost naturally occurring T cell clones specifically recognizing tumor antigens. Thus, a promising anticancer therapy will aim to activate patients’ naturally occurring anticancer immunity either to eliminate residual tumor cells or to prolong dormancy in disseminated tumor cells. Such an endogenous anticancer immunity plays a significant role for controlling the balance between dormant tumor cells and tumor escape, and restraining metastases. In this review, we mean to suggest that anticancer therapies aiming to stimulate the endogenous antitumor responses provide the concept of the therapeutic management of cancer.

  5. Effects of different temperatures and hormone treatments on breaking dormancy in potato tubers

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    Tavakoli Khadige

    2014-01-01

    Full Text Available Mini propagation is a new method to produce potato. A factorial experiment based on completely randomized block design with three replications was conducted to investigate the effect of two temperature levels (18 and 25°C and six hormone treatments (H1: 0% of ethanol + 0 mg/l of gibberellic acid, H2: 0% of ethanol + 10 mg/l of gibberellic acid, H3: 0.5% of ethanol + 0 mg/l of gibberellic acid, H4: 0.5% of ethanol + 10 mg/l of gibberellic acid, H5: 0.5% of ethanol + 20 mg/l of gibberellic acid, H6: 0.5% of ethanol + 30 mg/l of gibberellic acid on mini tubers of two varieties of potato (Agria and Santé. The longest sprouts were about 14.13 mm long and they were produced by Santé variety at 18°C and H1 hormone level. Sprouting percentage was higher in Santé (75.69% than in Agria (59.72%. The highest average percentage of sprouted tubers (95% was achieved at the temperature of 18°C and with H4 hormone treatment. Santé had the shortest dormancy duration by using H1 hormone level at 18°C. Applying H6 hormone level at 18°C produced more sprouts per tuber in Santé. Santé was better than Agria with or without hormone treatment in respect of all measured traits. Higher GA concentration accelerates tuber sprouting in both varieties.

  6. Matrix Stiffness Modulates Proliferation, Chemotherapeutic Response and Dormancy in Hepatocellular Carcinoma Cells

    Science.gov (United States)

    Schrader, Jörg; Gordon-Walker, Timothy T; Aucott, Rebecca L; van Deemter, Mariëlle; Quaas, Alexander; Walsh, Shaun; Benten, Daniel; Forbes, Stuart J; Wells, Rebecca G; Iredale, John P

    2010-01-01

    There is increasing evidence that the physical environment is a critical mediator of tumor behavior. Hepatocellular carcinoma (HCC) develops within an altered biomechanical environment and increasing matrix stiffness is a strong predictor of HCC development. The aim of this study was to establish whether changes in matrix stiffness, which are characteristic of inflammation and fibrosis, regulate HCC cell proliferation and chemotherapeutic response. Using an in vitro system of “mechanically-tunable” matrix-coated polyacrylamide gels, matrix stiffness was modeled across a pathophysiologically-relevant range, corresponding to values encountered in normal and fibrotic livers. Results Increasing matrix stiffness was found to promote HCC cell proliferation. The proliferative index (assessed by Ki67 staining) of Huh7 and HepG2 cells was 2.7-fold and 12.2-fold higher, respectively, when the cells were cultured on stiff (12kPa) versus soft (1kPa) supports. This was associated with stiffness-dependent regulation of basal and HGF-stimulated mitogenic signaling through extracellular regulated kinase (ERK), protein kinase B (PKB/Akt) and signal transducer and activator of transcription 3 (STAT3). β1-integrin and focal adhesion kinase (FAK) were found to modulate stiffness-dependent HCC cell proliferation. Following treatment with cisplatin, we observed reduced apoptosis in HCC cells cultured on a stiff versus soft (physiological) supports. Interestingly, however, surviving cells from soft supports had significantly higher clonogenic capacity than surviving cells from a stiff microenvironment. This was associated with enhanced expression of cancer stem cell markers, including CD44, CD133, c-kit, CXCR4, octamer-4 (OCT4) and NANOG. Conclusion Increasing matrix stiffness promotes proliferation and chemotherapeutic resistance, whereas a soft environment induces reversible cellular dormancy and stem cell characteristics in HCC. This has implications for both the treatment of

  7. Dormancy and the Influence of photoperiod and temperature on sexual maturity in Nicrophorus nepalensis (Coleoptera: Silphidae)

    Institute of Scientific and Technical Information of China (English)

    Wenbe Hwang; Shiuh-Feng Shiao

    2011-01-01

    Carrion beetles (Nicrophorus spp.) use small vertebrate carcasses for food and reproduction. Their ecology and behaviors are highly affected by the availability of carcasses and the surrounding environmental conditions. Our results revealed that in subtropical Fushan, northern Taiwan, N. nepalensis was mainly active in spring (February to May), and could also be found in autumn (October and November); but there was no capture record in summer (June to September) and winter (December and January). A laboratory temperature tolerance study indicated that N. nepalensis adults become inactive at temperatures above 26°C, and had the highest mortality when the temperature was raised from 27℃ to 28℃. Furthermore, N. nepalensis became sexually mature at 20℃, depending on the photoperiod: the longer the day, the lower the percentage of sexually mature 2-week-old females after emergence. In another experiment, N. nepalensis virgins were paired under three possible conditions at Fushan. At 15℃ and 20℃, if carcasses were presented to the pairs within 3 days after emergence, all laid eggs in the second week after emergence. If carcasses were presented 1 week after emergence, most began to reproduce at 20℃ with 12.5 h of daylight. However, at 15℃ with 11 h of daylight, the carrion beetles hibernated first, and reproduced in the ninth week after emergence. At 25℃ with 14 h of daylight, carrion beetles did not bury the mouse carcasses, the females did not lay eggs, and the adult lifespan was only one-third of that at 20℃. This study revealed that both photoperiod and temperature influence the time needed to reach the sexual maturity of N. nepalensis; and also implied that the narrow temperature tolerance range and dormancy behavior of carrion beetles are highly regulated by those environmental factors.

  8. 5'-end sequences of budding yeast full-length cDNA clones and quality scores - Budding yeast cDNA sequencing project | LSDB Archive [Life Science Database Archive metadata

    Lifescience Database Archive (English)

    Full Text Available Budding yeast cDNA sequencing project 5'-end sequences of budding yeast full-length cDNA clones and quality ...scores Data detail Data name 5'-end sequences of budding yeast full-length cDNA clones and quality scores De...from the budding yeast full-length cDNA library by the vector-capping method, the sequence quality score gen...s accession only. Sequence 5'-end sequence data of budding yeast full-length cDNA clones. FASTA format. Quality Phred's quality... Update History of This Database Site Policy | Contact Us 5'-end sequences of budding yeast full-length cDNA clones and quality

  9. Estimation of suspended sediment flux from acoustic Doppler current profiling along the Jinhae Bay entrance

    Institute of Scientific and Technical Information of China (English)

    WANG Yaping; CHU Yong Shik; LEE Hee Jun; HAN Choong Keun; OH Byung Chul

    2005-01-01

    A Nortek acoustic Doppler current profiler (NDP) was installed on a moving vessel to survey the entrance to the Jinhae Bay on August 22~23, 2001. The current velocity and acoustic backscattering signal were collected along two cross-sections; water samples were also collected during the measurement. The acoustic signals were normalized to compensate for the loss incurred by acoustic beam spreading in the seawater. The in situ calibration shows that a significant relationship is present between suspended sediment concentrations (SSC) and normalized acoustic signals. Two acoustic parameters have been determined to construct an acoustic-concentration model.Using this derived model, the SSC patterns along the surveyed cross-sections were obtained by the conversion of acoustic data. Using the current velocity and SSC data, the flux of suspended sediment was estimated. It indicates that the sediment transport into the bay through the entrance has an order of magnitude of 100 t per tidal cycle.

  10. Exploring social patterns of participation in university-entrance level mathematics in England

    OpenAIRE

    Noyes, Andrew

    2009-01-01

    In recent years in England there has been considerable attention given to a range of apparent crises in mathematics education, one of which has been the long term decline of participation in university-entrance level (Advanced or A) mathematics. Given the negative impact upon mathematics participation of Curriculum 2000, together with the government’s emphasis on Science Technology Engineering and Mathematics (STEM) subjects, the political intent to increase participation in Advanced level m...

  11. Modeling of bud break of Scots pine in northern Finland in 1908–2014

    Directory of Open Access Journals (Sweden)

    Hannu eSalminen

    2015-03-01

    Full Text Available Bud break and height-growth of Scots pine (Pinus sylvestris L. in the northern boreal zone in Lapland, Finland, was followed through the entire growing seasons in 2001–2003 and 2008–2010 in sapling stands representing two different locations in northern Finland about 250 kilometers apart along latitudinal transect. The field measurements continued at the southern site also through 2011–2013. Air temperature was recorded hourly at the sites. A simple optimization algorithm (GA was used to adjust parameters of the models predicting the timing of bud break of Scots pine in order to minimize the difference between observed and predicted dates. The models giving the best performance and century-long daily temperatures were used to reconstruct bud-break time series. The temperature observations were recorded during 1908–2014 in Sodankylä that locates in-between the sapling stands in north–south direction and during 1877–2014 in Karasjok that is in Norway about 145 kilometers north-west from the northernmost stand of this study.On average buds began to extend on the beginning of May in the southernmost stand and in mid-May in the northernmost stands, and the variation between years was in the range of three weeks. Simple day-length-triggered (fixed date model predicted most accurately the date of bud break; RMSE was 2 and 4 days in the northern and southern site, respectively. The reconstructed bud-break series indicate that based on temperature observations from Sodankylä, growth onset of Scots pine clearly has advanced since 1960s but was as currently early in the 1920s and 1950s. Temperature record from Karasjok indicated similar variation but there was a weak linear trend advancing bud break by about 3–4 days during a 100 years period.

  12. Neural crest contribution to lingual mesenchyme, epithelium and developing taste papillae and taste buds.

    Science.gov (United States)

    Liu, Hong-Xiang; Komatsu, Yoshihiro; Mishina, Yuji; Mistretta, Charlotte M

    2012-08-15

    The epithelium of mammalian tongue hosts most of the taste buds that transduce gustatory stimuli into neural signals. In the field of taste biology, taste bud cells have been described as arising from "local epithelium", in distinction from many other receptor organs that are derived from neurogenic ectoderm including neural crest (NC). In fact, contribution of NC to both epithelium and mesenchyme in the developing tongue is not fully understood. In the present study we used two independent, well-characterized mouse lines, Wnt1-Cre and P0-Cre that express Cre recombinase in a NC-specific manner, in combination with two Cre reporter mouse lines, R26R and ZEG, and demonstrate a contribution of NC-derived cells to both tongue mesenchyme and epithelium including taste papillae and taste buds. In tongue mesenchyme, distribution of NC-derived cells is in close association with taste papillae. In tongue epithelium, labeled cells are observed in an initial scattered distribution and progress to a clustered pattern between papillae, and within papillae and early taste buds. This provides evidence for a contribution of NC to lingual epithelium. Together with previous reports for the origin of taste bud cells from local epithelium in postnatal mouse, we propose that NC cells migrate into and reside in the epithelium of the tongue primordium at an early embryonic stage, acquire epithelial cell phenotypes, and undergo cell proliferation and differentiation that is involved in the development of taste papillae and taste buds. Our findings lead to a new concept about derivation of taste bud cells that include a NC origin.

  13. The Entrance Effect on Gases Flow Characteristics in Micro-tube

    Institute of Scientific and Technical Information of China (English)

    Chengwen Li; Li Jia; Tiantian Zhang

    2009-01-01

    Entrance region may have important effect on gases flow characteristics in micro-channels. It's concluded in the available papers that the entrance effect causes significant difference. An experimental system of single-phase gas flow characteristics in microchannels was set up. Flow characteristics of nitrogen in PEEK polymer micro-tube (hydraulic diameter is 5531am) was studied experimentally. According to the data of nitrogen flow in the mi-cro-tube with the length ranging from 0.1m tol.524m, it is shown that the friction constant becomes higher when the tube becomes shorter. By using pipe cutting methods, it's confirmed that entrance effect is one of the key fac-tors that cause friction constant higher than conventional theory. It's found that friction constant of fully devel-oped flow is lower than the value predicted by conventional theory in turbulent region. The result indicates that the flow transition occurs at Reynolds number ranging from 1600-2000. The phenomenon of obvious early transi-tion is not found.

  14. SIMULATION OF THE PROCESS OF FLOW SEPARATION AT THE ENTRANCE OF SQUARE ASPIRATING PORT

    Directory of Open Access Journals (Sweden)

    Olga A. Averkova

    2014-01-01

    Full Text Available We consider the flow at the inlet to the suction square hole with sharp edges, which is located in an infinite space. The purpose of this study is to construct a mathematical model of flow separation at the entrance to square suction canal with sharp edges, located in infinite space, by using square vortex frameworks. As a part of ideology of the method of discrete vortices in the non-stationary quasi-axisymmetric formulation, we constructed the mathematical model of separated flow at the inlet to the square aspirating pipe and its software-algorithmic implementation. We have determined the velocity field at the entrance to suction channel and a line of flow separation. Determine the velocity field in typical cross-sections of the suction channel, dimensions of the efficient absorption, compression ratio of the jet. Were received analytical formulas for calculating separation surfaces current. Profiling the entrance opening of the suction hole detected on the outlines separation surface will improve the acoustic and aerodynamic properties of the exhaust systems. The obtained results can be useful for designing of local exhaust ventilation of reduced energy consumption.

  15. Study on Characters of Hard Seeds of Amphicarpaea edgeworthii Benth. (Leguminosae)and Methods for Breaking Dormancy%Study on Characters of Hard Seeds of Amphicarpaea edgeworthii Benth. (Leguminosae)and Methods for Breaking Dormancy

    Institute of Scientific and Technical Information of China (English)

    Lifeng ZHANG; Xingwen WU; Yuehui SHE

    2012-01-01

    [Objective] This study aimed to understand the characters of hard seeds of Amphicarpaea edgeworthii Benth. (Leguminosae) and explore the methods for break- ing dormancy. [Method] For both aerial and subterranean seeds of A. edgeworthii, the morphological characteristics were observed and the appropriate temperature for germination was explored. For aerial seeds of A. edgeworthii, the characters of hard seeds were studied, and concentrated sulfuric acid treatment, hot water soak treat- ment and mechanical damage treatment were compared to explore the methods for breaking seed dormancy. [Result] The aerial seeds were oblate and averaged 3.38 mm in length, 3.02 mm in width, 1.88 mm in thickness, 15.32 g in thousand grain weight, with a hard seed rate after of up to 98% natural maturation. The subter- ranean seeds were approximately oblate with a maximum diameter of 15 mm and a hundred grain weight of (50.08-58.26 g); among all the treatments for breaking hardseededness, cutting seed coat treatment and concentrated sulfuric acid treatment for 20 minutes were the most effective methods, whereas hot water soak treatment was the least effective method; constant temperature between 20 and 30 ℃ was optimum for the germination of aerial seeds, and alternative temperature of 30/20 ℃ was most appropriate for the germination of subterranean seeds. [Conclusion] Cutting seed coat treatment and concentrated sulfuric acid treatment for 20 minutes were the most effective methods to break the hardseededness of A. edgeworthii.

  16. Reactivation from latency displays HIV particle budding at plasma membrane, accompanying CD44 upregulation and recruitment

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    Sano Kouichi

    2009-07-01

    Full Text Available Abstract Background It has been accepted that HIV buds from the cell surface in T lymphocytes, whereas in macrophages it buds into intracellular endosomes. Recent studies, on the other hand, suggest that HIV preferentially buds from the cell surface even in monocytic cells. However, most studies are based on observations in acutely infected cells and little is known about HIV budding concomitant with reactivation from latency. Such studies would provide a better understanding of a reservoir for HIV. Results We observed HIV budding in latently infected T lymphocytic and monocytic cell lines following TNF-α stimulation and examined the upregulation of host factors that may be involved in particle production. Electron microscopy analysis revealed that reactivation of latently infected J1.1 cells (latently infected Jurkat cells with HIV-1 and U1 cells (latently infected U937 cells with HIV-1 displayed HIV particle budding predominantly at the plasma membrane, a morphology that is similar to particle budding in acutely infected Jurkat and U937 cells. When mRNA expression levels were quantified by qRT-PCR, we found that particle production from reactivated J1.1 and U1 cells was accompanied by CD44 upregulation. This upregulation was similarly observed when Jurkat and U937 cells were acutely infected with HIV-1 but not when just stimulated with TNF-α, suggesting that CD44 upregulation was linked with HIV production but not with cell stimulation. The molecules in endocytic pathways such as CD63 and HRS were also upregulated when U1 cells were reactivated and U937 cells were acutely infected with HIV-1. Confocal microscopy revealed that these upregulated host molecules were recruited to and accumulated at the sites where mature particles were formed at the plasma membrane. Conclusion Our study indicates that HIV particles are budded at the plasma membrane upon reactivation from latency, a morphology that is similar to particle budding in acute

  17. Preliminary proteomics analysis of the total proteins of flower bud induction of apple trees

    Institute of Scientific and Technical Information of China (English)

    Shangyin CAO; Qiuming ZHANG; Zhiyong ZHU; Junying GUO; Yuling CHEN; Huabai XUE

    2008-01-01

    Apple is one of the most important fruit trees in the world. Nevertheless, mainly due to its long juvenile period, its breeding work constantly falls far behind other crops. So the aim of this study is to reveal the mechanism of apple flower bud differentiation, shorten the juvenile period and accelerate its breeding process. Proteomics technology (including two-dimensional gel electrophor-esis (2-DE), biomass spectrometry and bioinformatics) was applied to work on the specific protein of flower bud and leaf bud after the brachyblasts of 'Fuji' stopped growth for 3-9 weeks. The results showed that the mor-phodifferentiation of flower bud did not begin until the seventh week after the brachyblast stopped growth. Furthermore, compared with the leaf bud, flower bud had significant changes in the expression of 283 protein spots in quality and quantity on 2-DE maps. Among the 283 protein spots, four protein spots (16.4, 30.2, 40.3 and 65.1 kD) were characteristic of the flower bud in the archae-stage (initial inflorescence appeared) at the begin-ning of flower-bud differentiation, three (39.3, 60.2 and 66.3 kD) in the post-stage (Lateral-flower appears) and one (77.1 kD) in the sepal stage on 2-DE maps. Analysis by peptide mass fingerprinting and matrix-assisted laser desorption ionization time of flight mass spectrometry also identified and forecasted functionally by blasting dif-ferent databases. In the four specific proteins, it was found that spots No. 256 (16.4 kD) and 298 (30.2 kD) were unknown proteins, spot Nos. 327 (40.3 kD) was identified as the synthesis enzyme protein and spot No. 367 (40.3 kD) was identified as a RNA-binding protein involved in transcription. When flower bud started to dif-ferentiate morphologically, we detected four specific pro-teins which were 16.4, 30.2, 40.3 and 65.1 kD. Three specific proteins 39.3, 60.2 and 66.3 kD were observed at side flower-appearing stage. When calyx began to emerge, there was one specific protein: 77.1 kD. The

  18. Multiple Shh signaling centers participate in fungiform papilla and taste bud formation and maintenance.

    Science.gov (United States)

    Liu, Hong Xiang; Ermilov, Alexandre; Grachtchouk, Marina; Li, Libo; Gumucio, Deborah L; Dlugosz, Andrzej A; Mistretta, Charalotte M

    2013-10-01

    The adult fungiform taste papilla is a complex of specialized cell types residing in the stratified squamous tongue epithelium. This unique sensory organ includes taste buds, papilla epithelium and lateral walls that extend into underlying connective tissue to surround a core of lamina propria cells. Fungiform papillae must contain long-lived, sustaining or stem cells and short-lived, maintaining or transit amplifying cells that support the papilla and specialized taste buds. Shh signaling has established roles in supporting fungiform induction, development and patterning. However, for a full understanding of how Shh transduced signals act in tongue, papilla and taste bud formation and maintenance, it is necessary to know where and when the Shh ligand and pathway components are positioned. We used immunostaining, in situ hybridization and mouse reporter strains for Shh, Ptch1, Gli1 and Gli2-expression and proliferation markers to identify cells that participate in hedgehog signaling. Whereas there is a progressive restriction in location of Shh ligand-expressing cells, from placode and apical papilla cells to taste bud cells only, a surrounding population of Ptch1 and Gli1 responding cells is maintained in signaling centers throughout papilla and taste bud development and differentiation. The Shh signaling targets are in regions of active cell proliferation. Using genetic-inducible lineage tracing for Gli1-expression, we found that Shh-responding cells contribute not only to maintenance of filiform and fungiform papillae, but also to taste buds. A requirement for normal Shh signaling in fungiform papilla, taste bud and filiform papilla maintenance was shown by Gli2 constitutive activation. We identified proliferation niches where Shh signaling is active and suggest that epithelial and mesenchymal compartments harbor potential stem and/or progenitor cell zones. In all, we report a set of hedgehog signaling centers that regulate development and maintenance of taste

  19. H2O2 mediates the regulation of ABA catabolism and GA biosynthesis in Arabidopsis seed dormancy and germination.

    Science.gov (United States)

    Liu, Yinggao; Ye, Nenghui; Liu, Rui; Chen, Moxian; Zhang, Jianhua

    2010-06-01

    H(2)O(2) is known as a signal molecule in plant cells, but its role in the regulation of aqbscisic acid (ABA) and gibberellic acid (GA) metabolism and hormonal balance is not yet clear. In this study it was found that H(2)O(2) affected the regulation of ABA catabolism and GA biosynthesis during seed imbibition and thus exerted control over seed dormancy and germination. As seen by quantitative RT-PCR (QRT-PCR), H(2)O(2) up-regulated ABA catabolism genes (e.g. CYP707A genes), resulting in a decreased ABA content during imbibition. This action required the participation of nitric oxide (NO), another signal molecule. At the same time, H(2)O(2) also up-regulated GA biosynthesis, as shown by QRT-PCR. When an ABA catabolism mutant, cyp707a2, and an overexpressing plant, CYP707A2-OE, were tested, ABA content was negatively correlated with GA biosynthesis. Exogenously applied GA was able to over-ride the inhibition of germination at low concentrations of ABA, but had no obvious effect when ABA concentrations were high. It is concluded that H(2)O(2) mediates the up-regulation of ABA catabolism, probably through an NO signal, and also promotes GA biosynthesis. High concentrations of ABA inhibit GA biosynthesis but a balance of these two hormones can jointly control the dormancy and germination of Arabidopsis seeds.

  20. The beneficial effect of small toxic molecules on dormancy alleviation and germination of apple embryos is due to NO formation.

    Science.gov (United States)

    Gniazdowska, Agnieszka; Krasuska, Urszula; Debska, Karolina; Andryka, Paulina; Bogatek, Renata

    2010-09-01

    Deep dormancy of apple (Malus domestica Borkh.) seeds is terminated by a 3-month-long cold stratification. It is expressed by rapid germination of seeds and undisturbed growth of seedlings. However, stimulation of germination of isolated apple embryos is also observed after applying inhibitors of cytochrome c oxidase: nitric oxide (NO) or hydrogen cyanide (HCN) during the first 3-6 h of imbibition of dormant embryos. The aim of this work was to compare the effect of yet another toxic gaseous molecule carbon monoxide (CO) with the effects of HCN and NO on germination of apple embryos and growth and development of young seedlings. We demonstrated that stimulation of germination after short-term pre-treatment with HCN, NO or CO was accompanied by enhanced NO emission from the embryo axes during their elongation. Moreover, similarly high NO production from non-dormant embryos, after cold stratification, was detected. Therefore, we propose that NO may act as signaling molecule in apple embryo dormancy break.

  1. Pressure drop measurements in the transition region for a circular tube with a square-edged entrance

    Science.gov (United States)

    Ghajar, Afshin J.; Augustine, Jody R.

    1990-06-01

    Pressure drop measurements were made in a horizontal circular straight tube with a square-edged entrance under isothermal flow conditions. The experiments covered a Reynolds number range from 512 to 14,970. A total of thirty-three sets of experimental data for the twenty pressure tap locations along the 20 ft length of the test section were gathered. For the square-edged entrance the range of Reynolds number for which transition flow exists was determined to be between 2070 to 2840. A correlation for prediction of fully developed skin friction coefficient in this region is recommended. In the entrance region the length required for the friction factor to become fully developed in both the laminar and turbulent regions was found to be inversely proportional to the Reynolds number, with the turbulent data showing a stronger dependency. A correlation for prediction of entrance length in the turbulent region is offered.

  2. Tumor Budding, uPA, and PAI-1 in Colorectal Cancer: Update of a Prospective Study.

    Science.gov (United States)

    Märkl, Bruno; Hardt, Jochen; Franz, Simon; Schaller, Tina; Schenkirsch, Gerhard; Kriening, Bernadette; Hoffmann, Reinhard; Rüth, Stefan

    2017-01-01

    Aims. The prognostic role of the proteases uPA and PAI-1, as well as tumor budding, in colon cancer, has been investigated previously. Methods. We provide 6-year follow-up data and results of the validation set. The initial test set and validation set consisted of 55 colon cancers and 68 colorectal cancers, respectively. Tissue samples were analyzed for uPA and PAI-1 using a commercially available Enzyme-Linked Immunosorbent Assay (ELISA). Tumor budding was analyzed on cytokeratin-stained slides. Survival analyses were performed using cut-offs that were determined previously. Results. uPA was not prognostic for outcome. PAI-1 showed a trend towards reduced cancer specific survival in PAI-1 high-grade cases (68 versus 83 months; P = 0.091). The combination of high-grade PAI-1 and tumor budding was associated with significantly reduced cancer specific survival (60 versus 83 months; P = 0.021). After pooling the data from both sets, multivariate analyses revealed that the factors pN-stage, V-stage, and a combination of tumor budding and PAI-1 were independently prognostic for the association with distant metastases. Conclusions. A synergistic adverse effect of PAI-1 and tumor budding in uni- and multivariable analyses was found. PAI-1 could serve as a target for anticancer therapy.

  3. ALG-2 attenuates COPII budding in vitro and stabilizes the Sec23/Sec31A complex.

    Directory of Open Access Journals (Sweden)

    Jonas M la Cour

    Full Text Available Coated vesicles mediate the traffic of secretory and membrane cargo proteins from the endoplasmic reticulum (ER to the Golgi apparatus. The coat protein complex (COPII involved in vesicle budding is constituted by a GTPase, Sar1, the inner coat components of Sec23/Sec24 and the components of the outer coat Sec13/Sec31A. The Ca(2+-binding protein ALG-2 was recently identified as a Sec31A binding partner and a possible link to Ca(2+ regulation of COPII vesicle budding. Here we show that ALG-2/Ca(2+ is capable of attenuating vesicle budding in vitro through interaction with an ALG-2 binding domain in the proline rich region of Sec31A. Binding of ALG-2 to Sec31A and inhibition of COPII vesicle budding is furthermore dependent on an intact Ca(2+-binding site at EF-hand 1 of ALG-2. ALG-2 increased recruitment of COPII proteins Sec23/24 and Sec13/31A to artificial liposomes and was capable of mediating binding of Sec13/31A to Sec23. These results introduce a regulatory role for ALG-2/Ca(2+ in COPII tethering and vesicle budding.

  4. A2BR adenosine receptor modulates sweet taste in circumvallate taste buds.

    Directory of Open Access Journals (Sweden)

    Shinji Kataoka

    Full Text Available In response to taste stimulation, taste buds release ATP, which activates ionotropic ATP receptors (P2X2/P2X3 on taste nerves as well as metabotropic (P2Y purinergic receptors on taste bud cells. The action of the extracellular ATP is terminated by ectonucleotidases, ultimately generating adenosine, which itself can activate one or more G-protein coupled adenosine receptors: A1, A2A, A2B, and A3. Here we investigated the expression of adenosine receptors in mouse taste buds at both the nucleotide and protein expression levels. Of the adenosine receptors, only A2B receptor (A2BR is expressed specifically in taste epithelia. Further, A2BR is expressed abundantly only in a subset of taste bud cells of posterior (circumvallate, foliate, but not anterior (fungiform, palate taste fields in mice. Analysis of double-labeled tissue indicates that A2BR occurs on Type II taste bud cells that also express Gα14, which is present only in sweet-sensitive taste cells of the foliate and circumvallate papillae. Glossopharyngeal nerve recordings from A2BR knockout mice show significantly reduced responses to both sucrose and synthetic sweeteners, but normal responses to tastants representing other qualities. Thus, our study identified a novel regulator of sweet taste, the A2BR, which functions to potentiate sweet responses in posterior lingual taste fields.

  5. Yap1, transcription regulator in the Hippo signaling pathway, is required for Xenopus limb bud regeneration.

    Science.gov (United States)

    Hayashi, Shinichi; Tamura, Koji; Yokoyama, Hitoshi

    2014-04-01

    The Hippo signaling pathway is conserved from insects to mammals and is important for multiple processes, including cell proliferation, apoptosis and tissue homeostasis. Hippo signaling is also crucial for regeneration, including intercalary regeneration, of the whole body in the flatworm and of the leg in the cricket. However, its role in vertebrate epimorphic regeneration is unknown. Therefore, to identify principles of regeneration that are conserved among bilaterians, we investigated the role of Hippo signaling in the limb bud regeneration of an anuran amphibian, Xenopus laevis. We found that a transcription factor, Yap1, an important downstream effector of Hippo signaling, is upregulated in the regenerating limb bud. To evaluate Yap1׳s function in limb bud regeneration, we made transgenic animals that expressed a dominant-negative form of Yap under a heat-shock promoter. Overexpression of a dominant-negative form of Yap in tadpoles reduced cell proliferation, induced ectopic apoptosis, perturbed the expression domains of limb-patterning genes including hoxa13, hoxa11, and shh in the regenerating limb bud. Transient expression of a dominant-negative Yap in transgenic tadpoles also caused limb bud regeneration defects, and reduced intercalary regeneration. These results indicate that Yap1 has a crucial role in controlling the limb regenerative capacity in Xenopus, and suggest that the involvement of Hippo signaling in regeneration is conserved between vertebrates and invertebrates. This finding provides molecular evidence that common principles underlie regeneration across phyla, and may contribute to the development of new therapies in regenerative medicine.

  6. The diversity of fungi colonizing necrotic inflorescence buds of rhododendron (Rhododendron L.

    Directory of Open Access Journals (Sweden)

    Małgorzata Żołna

    2013-07-01

    Full Text Available The infection of rhododendron (Rhododendron L. inflorescence buds caused by pathogenic fungi induces its browning, withering, and dieback. The identification of fungi causing the infection of rhododendron inflorescence buds can be a reason for creating new improved cultivars with genetically determined resistance to pathogens. The investigations were carried out in 2010–2011 on the collection of ornamental plants of the Faculty of Horticulture, University of Agriculture in Kraków. The material comprised infected inflorescence buds collected from nine newly bred taxa and one botanical species of rhododendron. 596 colonies of fungi belonging to 31 species were isolated from infected rhododendron inflorescence buds. The dominant species were: Pestalotiopsis sydowiana, Truncatella truncata, Alternaria alternata, Phialophora asteris, and Trichoderma viride, which constituted almost 74% of the isolated fungi population. Boeremia exigua var. exigua, Epicoccum nigrum, Fusarium poae, Mammaria echinobotryoides, Paraphoma chrysanthemicola, Phialophora cyclaminis, Phoma eupyrena, Talaromyces wortmannii, Umbelopsis isabellina, and other fungi were isolated in a lower number. The results of mycological analysis confirm the diversity of species colonizing necrotic inflorescence buds of rhododendron. .

  7. Arenavirus budding resulting from viral-protein-associated cell membrane curvature.

    Science.gov (United States)

    Schley, David; Whittaker, Robert J; Neuman, Benjamin W

    2013-09-06

    Viral replication occurs within cells, with release (and onward infection) primarily achieved through two alternative mechanisms: lysis, in which virions emerge as the infected cell dies and bursts open; or budding, in which virions emerge gradually from a still living cell by appropriating a small part of the cell membrane. Virus budding is a poorly understood process that challenges current models of vesicle formation. Here, a plausible mechanism for arenavirus budding is presented, building on recent evidence that viral proteins embed in the inner lipid layer of the cell membrane. Experimental results confirm that viral protein is associated with increased membrane curvature, whereas a mathematical model is used to show that localized increases in curvature alone are sufficient to generate viral buds. The magnitude of the protein-induced curvature is calculated from the size of the amphipathic region hypothetically removed from the inner membrane as a result of translation, with a change in membrane stiffness estimated from observed differences in virion deformation as a result of protein depletion. Numerical results are based on experimental data and estimates for three arenaviruses, but the mechanisms described are more broadly applicable. The hypothesized mechanism is shown to be sufficient to generate spontaneous budding that matches well both qualitatively and quantitatively with experimental observations.

  8. Study of budding yeast colony formation and its characterizations by using circular granular cell

    Science.gov (United States)

    Aprianti, D.; Haryanto, F.; Purqon, A.; Khotimah, S. N.; Viridi, S.

    2016-03-01

    Budding yeast can exhibit colony formation in solid substrate. The colony of pathogenic budding yeast can colonize various surfaces of the human body and medical devices. Furthermore, it can form biofilm that resists drug effective therapy. The formation of the colony is affected by the interaction between cells and with its growth media. The cell budding pattern holds an important role in colony expansion. To study this colony growth, the molecular dynamic method was chosen to simulate the interaction between budding yeast cells. Every cell was modelled by circular granular cells, which can grow and produce buds. Cohesion force, contact force, and Stokes force govern this model to mimic the interaction between cells and with the growth substrate. Characterization was determined by the maximum (L max) and minimum (L min) distances between two cells within the colony and whether two lines that connect the two cells in the maximum and minimum distances intersect each other. Therefore, it can be recognized the colony shape in circular, oval, and irregular shapes. Simulation resulted that colony formation are mostly in oval shape with little branch. It also shows that greater cohesion strength obtains more compact colony formation.

  9. Relation Between Endodormancy Induction and Changes in Two Main Electron Transport Pathways of Nectarine Buds

    Institute of Scientific and Technical Information of China (English)

    YU Qin; GAO Dong-sheng; XU Xiao-ming; LI Jin; XU Chen-shan

    2008-01-01

    Operation regulations of two main electron transport pathways in nectarine (Prunus persica var. nectariana cv. Shuguang) buds during endodormancy induction were studied to understand possible roles which two main electron transport pathways played in the buds of deciduous fruit trees during endodormancy induction. Respiratory inhibitors (KCN and SHAM) were used to investigate total respiration rate (Vt), the development and operation of the alternative pathway and partitioning of electrons between the cytochrome and alternative pathways in nectarine buds during endodormancy induction. Results indicated that changes of V, in flower and leaf buds showed single and double hump-shaped curves, respectively. In endodormancy induction, the capacity (V^,,) and activity (pValt) of the alternative pathway rapidly increased, but changes of them had different patterns during the entire measuration. At the same time, changes of engagements of the alternative (pValt/Vt) and cytochrome pathway (p'Vcy/Vt) were opposite, and p'Vcyt/Vt was always further higher than pValt/Vt during the entire measuration. All these results indicated that the development and operation of the alternative pathway played important roles in endodormancy induction, but the cytochrome pathway was the main pathway for mitochondrial electron transport in buds during endodormancy induction.

  10. The United States Military Entrance Processing Command (USMEPCOM) Uses Six Sigma Process to Develop and Improve Data Quality

    Science.gov (United States)

    2007-06-01

    mecpom.army.mil Original title on 712 A/B: The United States Military Entrance Processing Command (USMEPCOM) uses Six Sigma process to develop and...Entrance Processing Command (USMEPCOM) uses Six Sigma Process to Develop and Improve Data Quality 5a. CONTRACT NUMBER 5b. GRANT NUMBER 5c. PROGRAM...Processing Command (USMEPCOM) uses Six Sigma Process to Develop and Improve Data Quality 3 • USMEPCOM Overview/History • Purpose • Define: What is Important

  11. An efficient method in breaking of dormancy from B unium persicum (Boiss Fedtsch seeds: a valuable herb of Middle East and Central Asia

    Directory of Open Access Journals (Sweden)

    Yousef Emamipoor

    2014-08-01

    Conclusions: 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.

  12. 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 Isl

  13. Eukar yotic cell encystation and cancer cell dormancy:is a greater devil veiled in the details of a lesser evil?

    Institute of Scientific and Technical Information of China (English)

    Abdul Mannan Baig; Naveed Ahmed Khan; Farhat Abbas

    2015-01-01

    Cancer cell dormancy is the main cause of cancer recurrence and failure of therapy as dormant cells evade not only the anticancer drugs but also the host immune system. hTese dormant cells veil themselves from detection by imaging and/or using biomarkers, which imposes an additional problem in targeting such cells. A similar form of hibernation process known as encystation is studied in detail for pathogenic unicellular eukaryotic microorganisms. By examination using microarray gene expression proifles, immunocytochemistry tools, and siRNAs during the process of encystation, understanding the covert features of cancer cell dormancy as proposed could be possible. hTis knowledge can be extended to dormant cancer cells to uncover the mechanisms that underlie this ghost, yet dangerous state of human cancers. We propose a strategy to induce dormancy and exit this state by application of knowledge gained from the encystation induction and retrieval processes in pathogenic eukaryotic microorganisms. Given that early detection and characterization of dormant malignant tumor cells is important as a general strategy to monitor and prevent the development of overt metastatic disease, this homology may enable the design of therapies that could either awake the dormant cell from dormancy to make it available for therapies or prolong such a phase to make cancer appear as a chronic disease.

  14. Induction of dormancy in Arabidopsis summer annuals requires parallel regulation of DOG1 and hormone metabolism by low temperature and CBF transcription factors.

    Science.gov (United States)

    Kendall, Sarah L; Hellwege, Anja; Marriot, Poppy; Whalley, Celina; Graham, Ian A; Penfield, Steven

    2011-07-01

    Summer annuals overwinter as seeds in the soil seed bank. This is facilitated by a cold-induced increase in dormancy during seed maturation followed by a switch to a state during seed imbibition in which cold instead promotes germination. Here, we show that the seed maturation transcriptome in Arabidopsis thaliana is highly temperature sensitive and reveal that low temperature during seed maturation induces several genes associated with dormancy, including DELAY OF GERMINATION1 (DOG1), and influences gibberellin and abscisic acid levels in mature seeds. Mutants lacking DOG1, or with altered gibberellin or abscisic acid synthesis or signaling, in turn show reduced ability to enter the deeply dormant states in response to low seed maturation temperatures. In addition, we find that DOG1 promotes gibberellin catabolism during maturation. We show that C-REPEAT BINDING FACTORS (CBFs) are necessary for regulation of dormancy and of GA2OX6 and DOG1 expression caused by low temperatures. However, the temperature sensitivity of CBF transcription is markedly reduced in seeds and is absent in imbibed seeds. Our data demonstrate that inhibition of CBF expression is likely a critical feature allowing cold to promote rather than inhibit germination and support a model in which CBFs act in parallel to a low-temperature signaling pathway in the regulation of dormancy.

  15. Induction of Dormancy in Arabidopsis Summer Annuals Requires Parallel Regulation of DOG1 and Hormone Metabolism by Low Temperature and CBF Transcription Factors[W][OA

    Science.gov (United States)

    Kendall, Sarah L.; Hellwege, Anja; Marriot, Poppy; Whalley, Celina; Graham, Ian A.; Penfield, Steven

    2011-01-01

    Summer annuals overwinter as seeds in the soil seed bank. This is facilitated by a cold-induced increase in dormancy during seed maturation followed by a switch to a state during seed imbibition in which cold instead promotes germination. Here, we show that the seed maturation transcriptome in Arabidopsis thaliana is highly temperature sensitive and reveal that low temperature during seed maturation induces several genes associated with dormancy, including DELAY OF GERMINATION1 (DOG1), and influences gibberellin and abscisic acid levels in mature seeds. Mutants lacking DOG1, or with altered gibberellin or abscisic acid synthesis or signaling, in turn show reduced ability to enter the deeply dormant states in response to low seed maturation temperatures. In addition, we find that DOG1 promotes gibberellin catabolism during maturation. We show that C-REPEAT BINDING FACTORS (CBFs) are necessary for regulation of dormancy and of GA2OX6 and DOG1 expression caused by low temperatures. However, the temperature sensitivity of CBF transcription is markedly reduced in seeds and is absent in imbibed seeds. Our data demonstrate that inhibition of CBF expression is likely a critical feature allowing cold to promote rather than inhibit germination and support a model in which CBFs act in parallel to a low-temperature signaling pathway in the regulation of dormancy. PMID:21803937

  16. Molecular and genealogical analysis of grain dormancy in Japanese wheat varieties, with specific focus on MOTHER OF FT AND TFL1 on chromosome 3A.

    Science.gov (United States)

    Chono, Makiko; Matsunaka, Hitoshi; Seki, Masako; Fujita, Masaya; Kiribuchi-Otobe, Chikako; Oda, Shunsuke; Kojima, Hisayo; Nakamura, Shingo

    2015-03-01

    In the wheat (Triticum aestivum L.) cultivar 'Zenkoujikomugi', a single nucleotide polymorphism (SNP) in the promoter of MOTHER OF FT AND TFL1 on chromosome 3A (MFT-3A) causes an increase in the level of gene expression, resulting in strong grain dormancy. We used a DNA marker to detect the 'Zenkoujikomugi'-type (Zen-type) SNP and examined the genotype of MFT-3A in Japanese wheat varieties, and we found that 169 of 324 varieties carry the Zen-type SNP. In Japanese commercial varieties, the frequency of the Zen-type SNP was remarkably high in the southern part of Japan, but low in the northern part. To examine the relationship between MFT-3A genotype and grain dormancy, we performed a germination assay in three wheat-growing seasons. On average, the varieties carrying the Zen-type SNP showed stronger grain dormancy than the varieties carrying the non-Zen-type SNP. Among commercial cultivars, 'Iwainodaichi' (Kyushu), 'Junreikomugi' (Kinki-Chugoku-Shikoku), 'Kinuhime' (Kanto-Tokai), 'Nebarigoshi' (Tohoku-Hokuriku), and 'Kitamoe' (Hokkaido) showed the strongest grain dormancy in each geographical group, and all these varieties, except for 'Kitamoe', were found to carry the Zen-type SNP. In recent years, the number of varieties carrying the Zen-type SNP has increased in the Tohoku-Hokuriku region, but not in the Hokkaido region.

  17. Genetic mapping of major-effect seed dormancy quantitative trait loci on chromosome 2B using recombinant substitution lines in tetraploid wheat

    Science.gov (United States)

    Durum wheat cultivars can benefit from having some level of seed dormancy to help reduce seed damage and lower grain quality caused by pre-harvest sprouting (PHS) occurring during wet harvesting conditions. Previously a single chromosome substitution line carrying chromosome 2B of wild emmer in the...

  18. Multiple shoot-bud formation and plantlet regeneration on Castanea sativa Mill. seeds in culture.

    Science.gov (United States)

    Rodríguez, R

    1982-06-01

    Primordial initiation and development of shoot-buds has been accomplished by using shoots derived from chestnut (Castanea sativa Mill) seedlings cultured with added 6-benzylaminopurine (BAP). Germination of chestnut seeds in the presence of BAP (4 - 40 μM) stimulated varying numbers of shoot-buds in those areas of the main axis that were favorably altered. When excised single shoots from these treated seeds were subcultured on a fresh medium containing BAP (4 - 40 μM) continual shoot production was observed. Bud growth and shoot elongation were stimulated by transferring cultures to a reduced concentration of BAP (2 μM) plus indole-3-butyric acid (IBA 0.4 μM). Plant regeneration occurred in the presence of IBA (0.8 μM) after a preconditioning treatment in which naphthaleneacetic acid (NAA 50 μM) and kinetin (k 2 μM) were applied to the tissue culture shoots for 7 days in light.

  19. Progress and renewal in gustation: new insights into taste bud development.

    Science.gov (United States)

    Barlow, Linda A

    2015-11-01

    The sense of taste, or gustation, is mediated by taste buds, which are housed in specialized taste papillae found in a stereotyped pattern on the surface of the tongue. Each bud, regardless of its location, is a collection of ∼100 cells that belong to at least five different functional classes, which transduce sweet, bitter, salt, sour and umami (the taste of glutamate) signals. Taste receptor cells harbor functional similarities to neurons but, like epithelial cells, are rapidly and continuously renewed throughout adult life. Here, I review recent advances in our understanding of how the pattern of taste buds is established in embryos and discuss the cellular and molecular mechanisms governing taste cell turnover. I also highlight how these findings aid our understanding of how and why many cancer therapies result in taste dysfunction.

  20. Multiple Enhancers Regulate Hoxd Genes and the Hotdog LncRNA during Cecum Budding

    Directory of Open Access Journals (Sweden)

    Saskia Delpretti

    2013-10-01

    Full Text Available Hox genes are required for the development of the intestinal cecum, a major organ of plant-eating species. We have analyzed the transcriptional regulation of Hoxd genes in cecal buds and show that they are controlled by a series of enhancers located in a gene desert flanking the HoxD cluster. The start site of two opposite long noncoding RNAs (lncRNAs, Hotdog and Twin of Hotdog, selectively contacts the expressed Hoxd genes in the framework of a topological domain, coinciding with robust transcription of these genes during cecum budding. Both lncRNAs are specifically transcribed in the cecum, albeit bearing no detectable function in trans. Hedgehogs have kept this regulatory potential despite the absence of the cecum, suggesting that these mechanisms are used in other developmental situations. In this context, we discuss the implementation of a common “budding toolkit” between the cecum and the limbs.

  1. Ferrite-Cored Solenoidal Induction Coil Sensor for BUD (MM-1667)

    Energy Technology Data Exchange (ETDEWEB)

    Morrison, F.; Becker, A.; Conti, U.; Gasperikova, E.

    2011-06-15

    We have designed and lab tested a new ferrite cored induction coil sensor for measuring the secondary fields from metallic UXO with the BUD system. The objective was to replace the 5-inch diameter air-cored coils in the BUD system with smaller sensors that would allow the placement of multiple sensors in the smaller package of the new BUD hand-held system. A ferrite-cored solenoidal coil of length L can easily be made to have sensitivity and noise level roughly the same as an air-cored coil of a diameter on the same order as L. A ferrite-cored solenoidal coil can easily have a feedback configuration to achieve critical damping. The feedback configuration leads to a very stable response. Feedback ferrite-cored solenoidal coils show very little interaction as long as they are separated by one half their length.

  2. Stämföringar av Bud Powell : En studie om Bud Powells sätt att stämföra

    OpenAIRE

    Sjöstrand, Samuel

    2014-01-01

    Syftet med examensarbetet är att erbjuda pianister en möjlighet att lära sig att använda Bud Powells sätt att stämföra ackord. Frågorna som kommer att diskuteras är: 1.Vad är bebop? 2. Vem var Bud Powell? 3. Hur stämförde Powell ackord? För att besvara dessa forskningsfrågor baserar jag min metod på litteraturstudier och transkriptioner av inspelningar. Detta görs utifrån en hermeneutisk metod. I arbetet diskuteras Powells sätt att stämföra ackord ur ett pedagogiskt perspektiv och användning ...

  3. Pulmonary metastatic microangiopathy of colon cancer presenting as a "tree in bud" pattern.

    Science.gov (United States)

    Bosmans, S; Weynand, B; Coche, E

    2008-01-01

    The authors report an unusual case of a "tree in bud" pattern of vascular origin caused by colon cancer metastases. A 60-year-old man presented for routine follow-up of a colon tumour resected surgically 15 years previously. Clinical examination, laboratory tests, including carcino-embryonic antigen and inflammatory parameters, and chest radiograph were normal. Multislice CT of the lungs revealed the presence of several "tree in bud" opacities. The connection to the pulmonary arteries was well depicted by reformatted maximal intensity projection images. Biopsy of some of the nodules was characterized by mucinous material and neoplastic cells within the small vessels, consistent with metastases from the known colon adenocarcinoma.

  4. Project BudBurst - Meeting the Needs of Climate Change Educators and Scientists

    Science.gov (United States)

    Henderson, S.

    2015-12-01

    It is challenging for many to get a sense of what climate change means as long periods of time are involved - like decades - which can be difficult to grasp. However, there are a number of citizen science based projects, including NEON's Project BudBurst, that provide the opportunity for both learning about climate change and advancing scientific knowledge. In this presentation, we will share lessons learned from Project BudBurst. Project BudBurst is a national citizen science initiative designed to engage the public in observations of phenological (plant life cycle) events and to increase climate literacy. Project BudBurst is important from an educational perspective, but also because it enables scientists to broaden the geographic and temporal scale of their observations. The goals of Project BudBurst are to 1) increase awareness of phenology as an area of scientific study; 2) Increase awareness of the impacts of changing climates on plants at a continental-scale; and 3) increase science literacy by engaging participants in the scientific process. It was important to better understand if and how Project BudBurst is meeting its goals. Specifically, does participation by non-experts advance scientific knowledge? Does participation advance educational goals and outcomes? Is participation an effective approach to advance/enhance science education in both formal and informal settings? Critical examination of Project BudBurst supports advancement of scientific knowledge and realization of educational objectives. Citizen science collected observations and measurements are being used by scientists as evidenced by the increase of such data in scientific publication. In addition, we found that there is a significant increase in educators utilizing citizen science as part of their instruction. Part of this increase is due to the resources and professional development materials available to educators. Working with partners also demonstrated that the needs of both science and

  5. Download - Budding yeast cDNA sequencing project | LSDB Archive [Life Science Database Archive metadata

    Lifescience Database Archive (English)

    Full Text Available Budding yeast cDNA sequencing project Download First of all, please read the license of this database. Data ...names and data descriptions are about the downloadable data in this page. They might not correspond to the c...f the data. # Data name File Simple search and download 1 README README_e.html - 2 5'-end sequences of buddi...ng yeast full-length cDNA clones and quality scores yeast_seq_qual.zip (59.9MB) Simple search and download 3...Downlaod via FTP Joomla SEF URLs by Artio About This Database Database Description Download License Update H

  6. Efeito do extrato de alho na quebra de dormência de gemas de videiras e no controle in vitro do agente causal da antracnose (Elsinoe ampelina Shear Effect of garlic extract on bud break of grapevines and in vitro control of causal agent of antracnose (Elsinoe ampelina Shear

    Directory of Open Access Journals (Sweden)

    Renato Vasconcelos Botelho

    2009-03-01

    Full Text Available Considerando a redução ou eliminação do uso de substâncias sintéticas que preconizam os sistemas sustentáveis de produção de frutas, este trabalho teve como objetivo a busca de novas alternativas para a quebra de dormência e o controle de doenças em videiras. Estacas de videira contendo uma gema foram pulverizadas com os seguintes tratamentos: 1 testemunha; 2 OV (óleo vegetal 1%; 3 extrato de alho (EA 3%; 4 EA 3% + OV 1%. Posteriormente, as estacas foram mantidas em câmara de crescimento (25±2.5ºC por 56 dias. O único tratamento que estimulou a brotação das estacas de videira cv. Isabel Precoce foi o EA 3% + OV 1%, que atingiu 35% de brotação, diferindo estatisticamente dos tratamentos- testemunha (12,5%, OV 1% (17,5% e EA 3% (15,0%. Provavelmente, o estádio de endodormência profunda das gemas, após apenas 90 horas de frio ( Considering the reduction or elimination of synthetic compounds used in sustainable fruit production systems, this work aimed to search for new alternatives for bud break dormancy and diseases control in grapevines. Single-bud cuttings of grapevines were sprayed with the following treatments: 1 control, 2 1% SO (soybean oil, 3 3% GE (garlic extract, 4 3% GE + 1% SO. After that, the cuttings were kept in a growth chamber (25±2.5ºC for 56 days. The unique treatment that stimulated sprouting of grapevines cv. Isabel Precoce was 3% GE + 1% S, that reached 35% sprouting, differing statistically from the control (12.5%, 1% SO (17.5% and 3% GE (15.0%. Probably, the stage of deep endodormancy of buds, after only 90 chilling hours (< 7.0ºC, avoided better results of bud breaks treatments. Three experiments were carried out in vitro, with different garlic extract doses aiming to evaluate the control of the fungus Elsinoe ampelina. In all trials, there were quadratic effects on mycelial growth, without differences between garlic extract treatments, evidencing its fungicide effect, even for the lowest dose of 0

  7. Preliminary Tests of Nose- and Side- Entrance Blower Cooling Systems for Radial Engines, Special Report

    Science.gov (United States)

    Biermann, David; Valentine, E. Floyd

    1939-01-01

    Two cowling systems intended to reduce the drag and improve the low-speed cooling characteristics of conventional radial engine cowlings were tested in model form to determine the practicability of the methods. One cowling included a blower mounted on the rear face of a large propeller spinner which drew cooling air in through side entrance ducts located behind the equivalent engine orifice plate. The air was passed through the equivalent engine orifice plate from rear to front and out through a slot between the spinner and the engine plate. The blower produced substantially all the power necessary to circulate the cooling air in some cases, so the quantity of air flowing was independent of the air speed, Two types of blowers were used, a centrifugal type and one using airfoil blades which forced the air outward from the center of rotation. The other cowling was similar to the conventional N.A.C.A. cowling except for the addition of a large propeller spinner nose. The spinner was provided with a hole in the nose to admit cooling air and blower blades to increase the pressure for cooling at low speeds. The tests show that with both cowling types the basic drag of the nacelle was reduced substantially below that for the N.A.C.A. cowling by virtue of the better nose shape made possible by the spinner . The drag due to the side-entrance ducts was nearly zero when the openings were closed or when the blower was drawing in a certain quantity of air in proportion to the air speed. The drag increased, however, when air mas allowed to spill from the openings. The nose-entrance blower showed considerable promise as a cooling means although the blower tested was relatively inefficient, owing to the fact that the blower compartments evidently were expanded too rapidly under the conditions imposed. by the design.

  8. Empirical models for liquid metal heat transfer in the entrance region of tubes and rod bundles

    Science.gov (United States)

    Jaeger, Wadim

    2016-10-01

    Experiments focusing on liquid metals heat transfer in pipes and rod bundles with thermally and hydraulically developing flow are reviewed. Empirical heat transfer correlations are developed for engineering applications. In the developing regions the heat transfer is in-stationary. The heat transfer at the entrance is around 100 % higher due to the developing process including the lateral exchange of energy and momentum than for developed flow. Developing flow is not physically considered in the framework of system codes, which are used for thermal-hydraulic analysis of power and process plants with a multitude of components like pipes, tanks, valves and heat exchangers. Therefore, the application to liquid metal flows is limited to developed flow, which is independent of the distance from the flow entrance. The heat transfer enhancement in developing flows is important for the optimization of components like heat exchangers and helps to reduce unnecessary conservatism. In this work, empirical models are developed to account for developing flows in pipes and rod bundles. A literature review is performed to collect available experimental data for developing flow in liquid metal heat transfer. The evaluation shows that the length for pure thermally developing pipe flow is much larger (20-30 hydraulic diameters) than for combined thermally and hydraulically developing flow (10-15 hydraulic diameters). In rod bundles, fully combined developed flow is established after 30-40 hydraulic diameters downstream of the entrance. The derived empirical models for the heat transfer enhancement in the developing regions are implemented into a best estimate system code. The validation of these models by means of post-test analyses of 16 experiments shows that they are very well able to represent the heat transfer in developing regions.

  9. L1 Writing Experiences and L2 Writing Instruction : University Entrance Exams in Japan

    OpenAIRE

    Ross, Paul; Paul, ROSS

    2005-01-01

    This poper examines an L1 learning experience shared by many EFL students in Japan: writing an essay in Japanese on university entrance exams. The main purpose is to identify the features of the experience that L2 writing teachers need to address in their classrooms. The major issues that are investigated are 1) what kind of writing students are expected to do on the exams, 2) what the purpose of the essay question is, and 3) what kind of training students receive to improve their writing ski...

  10. Researches on evaluation of smooth entrance in cutting using electrical current. A case study

    Directory of Open Access Journals (Sweden)

    Diţu Valentin

    2017-01-01

    Full Text Available At metal drilling, at the beginning of the process, the cutting tool in the chisel edge zone, frictions and plastically deforms the material, and then enters in cutting. If the drill is entered smoothly in cutting with a special device, its life is increased. The paper presents how the electrical current at cutting is used for the evaluation of smooth entrance in cutting in comparison with classical cutting. These are demonstrated for 41MoC11 steel drilled with a set of 30 tools having 8 mm diameter.

  11. Researches on evaluation of smooth entrance in cutting using electrical current. A case study

    OpenAIRE

    Diţu Valentin; Oancea Gheorghe; Daicu Raluca

    2017-01-01

    At metal drilling, at the beginning of the process, the cutting tool in the chisel edge zone, frictions and plastically deforms the material, and then enters in cutting. If the drill is entered smoothly in cutting with a special device, its life is increased. The paper presents how the electrical current at cutting is used for the evaluation of smooth entrance in cutting in comparison with classical cutting. These are demonstrated for 41MoC11 steel drilled with a set of 30 tools having 8 mm d...

  12. Dormancy Breaking and Storage Behavior of Garcinia cowa Roxb. (Guttiferae) Seeds: Implications for Ecological Function and Germplasm Conservation

    Institute of Scientific and Technical Information of China (English)

    Yong LIU; Yu-Ping QIU; Ling ZHANG; Jin CHEN

    2005-01-01

    The dormancy breaking and storage behavior of Garcinia cowa Roxb. seeds were investigated.The seeds of G. cowa had 8-11 months dormancy in their natural habitat. Seeds were matured and dispersed at the end of the rainy season (mid-late August to late September) and were scatter-hoarded by rodents as food for winter after the seeds had fallen to the ground. Seedlings often emerged in the forest during the rainy season (May to August) the following year. Intact seeds of G. cowa failed to germinate after being sown at 30 ℃ for 120 d and the mean germination time (MGT) of seeds cultured in a shade (50% sunlight)nursery was 252 d. The most effective method of breaking dormancy was to remove the seed coat totally,which reduced the MGT to 13 d at 30 ℃. Germination was also promoted by partial removal of the seed coat (excising the hilum and exposing the radicle) and chemical scarification (immersion in 1% H2O2 for 1 d).Unscarified seeds take up water rapidly in the first 96 h, but water was absorbed by the outside seed coat,without penetrating through it. The moisture content (MC) of G. cowa seeds was high (50% in fresh weight)at shedding. The seeds could tolerate desiccation to some extent, until the MC reached approximately 40%;below that, the viability decreases rapidly and all seeds died at approximately 17% of MC. Seed viability decreased rapidly when seeds were chilled at 4 ℃; germination was 2% after storage for 1 week. Even stored at 10 ℃, seeds began to be damaged after 4 weeks. Seed storage for 1 yr revealed that in both dry (relative humidity (35 ± 5)%) and moist (wet sand) storage conditions, seed viability declined, but germination percentages for seeds stored under moist conditions are better than for seed stored under dry conditions.Because of their low tolerance to desiccation, marked chilling sensitivity and relatively short lifespan, G.cowa seeds should be classified into the tropical recalcitrant category. The ecological implications of dormant

  13. A unique approach to demonstrating that apical bud temperature specifically determines leaf initiation rate in the dicot Cucumis sativus

    NARCIS (Netherlands)

    Savvides, Andreas; Dieleman, Anja; Ieperen, van Wim; Marcelis, Leo F.M.

    2016-01-01

    Main conclusion: Leaf initiation rate is largely determined by the apical bud temperature even when apical bud temperature largely deviates from the temperature of other plant organs.We have long known that the rate of leaf initiation (LIR) is highly sensitive to temperature, but previous studies

  14. Epistatic natural allelic variation reveals a function of AGAMOUS-LIKE6 in axillary bud formation in Arabidopsis

    NARCIS (Netherlands)

    Huang, X.; Effgen, S.; Meyer, R.C.; Theres, K.; Koornneef, M.

    2012-01-01

    In the Arabidopsis Multiparent Recombinant Inbred Line mapping population, a limited number of plants were detected that lacked axillary buds in most of the axils of the cauline (stem) leaves, but formed such buds in almost all rosette axils. Genetic analysis showed that polymorphisms in at least th

  15. The Role of Leaves in Photocontrol of Flower Bud Abscission in Hibiscus rosa-sinensis L. 'Nairobi'

    NARCIS (Netherlands)

    Meeteren, van U.; Gelder, van A.

    2000-01-01

    When compared with exposure to darkness, exposing Hibiscus rosa-sinensis L. 'Nairobi' plants to red light (635 to 685 nm, 2.9 μmol?m-2?s-1) delayed flower bud abscission, while exposure to far-red light (705 to 755 nm, μmol?m-2?s-1) accelerated this process. Flower bud abscission in response to ligh

  16. Neurturin-GFRalpha2 signaling controls liver bud migration along the ductus venosus in the chick embryo.

    Science.gov (United States)

    Tatsumi, Norifumi; Miki, Rika; Katsu, Kenjiro; Yokouchi, Yuji

    2007-07-01

    During chick liver development, the liver bud arises from the foregut, invaginates into the septum transversum, and elongates along and envelops the ductus venosus. However, the mechanism of liver bud migration is only poorly understood. Here, we demonstrate that a GDNF family ligand involved in neuronal outgrowth and migration, neurturin (NRTN), and its receptor, GFRalpha2, are essential for liver bud migration. In the chick embryo, we found that GFRalpha2 was expressed in the liver bud and that NRTN was expressed in the endothelial cells of the ductus venosus. Inhibition of GFRalpha2 signaling suppressed liver bud elongation along the ductus venous without affecting cell proliferation and apoptosis. Moreover, ectopic expression of NRTN perturbed the directional migration along the ductus venosus, leading to splitting or ectopic branching of the liver. We showed that liver buds selectively migrated toward an NRTN-soaked bead in vitro. These data represent a new model for liver bud migration: NRTN secreted from endothelial cells functions as a chemoattractant to direct the migration of the GFRalpha2-expressing liver bud in early liver development.

  17. 枳椇种子休眠原因及解除方法%A study on the seed dormancy mechanism and ways of dormancy breaking in Hovenia acerba Lindl.

    Institute of Scientific and Technical Information of China (English)

    李英; 沈永宝

    2014-01-01

    从枳椇种子的种皮结构和透性、离体胚萌发等方面开展种子休眠原因的研究,同时采取低温层积、浓硫酸处理、机械处理等方法研究枳椇种子休眠解除技术。结果表明:枳椇种子种皮结构致密,透水性差是抑制种子萌发的主要原因,种子休眠类型为物理休眠( PY)。低温层积75 d枳椇种子的发芽率达到72%,层积90 d种子发芽率达到76%,且发芽速度更快;浓硫酸处理5~25 min,种子发芽率在76%~81%,各处理种子的发芽率没有差异,但浓硫酸处理30 min对种子明显产生伤害,发芽率仅为64%;切除部分种皮的种子在置床后4 d开始萌发,发芽速度与层积90 d的发芽速度一致,置床16 d后萌发结束,发芽率为80%;擦伤种子表面的种子置床后6 d开始萌发,发芽率为73%。%In this paper, we studied seed dormant reasons of Hovenia acerba Lindl. based on the observations on the structure and permeability of seed coat and the seed embryo growth. In order to find out an effective way to overcome seed dormancy, the seeds were treated by cold stratification at 3-5 ℃, acid scarification, and mechanical scarification. The results showed that the low seed coat permeability was the main reasons of seed dormancy, and which was a type of phys-ical dormancy ( PY) . 72% seeds germinated when exposure to cold stratification at 3-5℃ for 75 days, and 76% seeds germinated when exposure to cold stratification for 90 days and germinated more quickly. Soaking with sulfuric acid for 5 to 25 minutes promoted seed germination rate to 76%-81%. There were no obvious differences in germination rate among these ways of breaking the dormancy. However,there was a significant seed damage when exposure to acid scarification o-ver 30 minutes, because the seed germination rate was only 64%. The seed started to sprout at the 4th day after parts of seed coat were removed, the germination rate reached to

  18. Comparative GC analyses of ripe fruits, leaves and floral buds essential oils of Tunisian Myrtus communis L.

    Directory of Open Access Journals (Sweden)

    Ahmed Snoussi

    2014-07-01

    Full Text Available The chemical composition of essential oils obtained by hydrodistillation from Tunisian wild growing myrtle ripe fruits, leaves and floral buds was examined by GC and GC-MS. The yields of hydrodistilled oils obtained from different plant parts were: leaves 0.5%, floral buds 0.2% and ripe fruits 0.02%. Significant differences were found in the concentration of main constituents of the oils: α-pinene [48.9% (floral buds, 34.3% (fruits, 23.7% (leaves], 1,8-cineole [15.3% (floral buds, 26.6% (fruits, 61.0% (leaves]. The leaves oil contained less linalool than floral buds and ripe fruits oils. Tunisian myrtle is characterized by the absence of myrtenyl acetate.

  19. The yeast prefoldin-like URI-orthologue Bud27 associates with the RSC nucleosome remodeler and modulates transcription.

    Science.gov (United States)

    Mirón-García, María Carmen; Garrido-Godino, Ana Isabel; Martínez-Fernández, Verónica; Fernández-Pevida, Antonio; Cuevas-Bermúdez, Abel; Martín-Expósito, Manuel; Chávez, Sebastián; de la Cruz, Jesús; Navarro, Francisco

    2014-09-01

    Bud27, the yeast orthologue of human URI/RMP, is a member of the prefoldin-like family of ATP-independent molecular chaperones. It has recently been shown to mediate the assembly of the three RNA polymerases in an Rpb5-dependent manner. In this work, we present evidence of Bud27 modulating RNA pol II transcription elongation. We show that Bud27 associates with RNA pol II phosphorylated forms (CTD-Ser5P and CTD-Ser2P), and that its absence affects RNA pol II occupancy of transcribed genes. We also reveal that Bud27 associates in vivo with the Sth1 component of the chromatin remodeling complex RSC and mediates its association with RNA pol II. Our data suggest that Bud27, in addition of contributing to Rpb5 folding within the RNA polymerases, also participates in the correct assembly of other chromatin-associated protein complexes, such as RSC, thereby modulating their activity.

  20. Insights into horizontal acquisition patterns of dormancy and reactivation regulon genes in mycobacterial species using a partitioning-based framework

    Indian Academy of Sciences (India)

    VARUN MEHRA; TARINI SHANKAR GHOSH; SHARMILA S MANDE

    2016-09-01

    Horizontal Gene Transfer (HGT) events, initially thought to be rare in Mycobacterium tuberculosis, have recentlybeen shown to be involved in the acquisition of virulence operons in M. tuberculosis. We have developed a newpartitioning framework based HGT prediction algorithm, called Grid3M, and applied the same for the prediction ofHGTs in Mycobacteria. Validation and testing using simulated and real microbial genomes indicated better performanceof Grid3M as compared with other widely used HGT prediction methods. Specific analysis of the genesbelonging to dormancy/reactivation regulons across 14 mycobacterial genomes indicated that horizontal acquisition isspecifically restricted to important accessory proteins. The results also revealed Burkholderia species to be a probablesource of HGT genes belonging to these regulons. The current study provides a basis for similar analyses investigatingthe functional/evolutionary aspects of HGT genes in other pathogens. A database of Grid3M predicted HGTs incompletely sequenced genomes is available at https://metagenomics.atc.tcs.com/Grid3M/.