Evolutionary conservation of plant gibberellin signalling pathway components

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Reski Ralf

2007-11-01

Full Text Available Abstract Background: Gibberellins (GA are plant hormones that can regulate germination, elongation growth, and sex determination. They ubiquitously occur in seed plants. The discovery of gibberellin receptors, together with advances in understanding the function of key components of GA signalling in Arabidopsis and rice, reveal a fairly short GA signal transduction route. The pathway essentially consists of GID1 gibberellin receptors that interact with F-box proteins, which in turn regulate degradation of downstream DELLA proteins, suppressors of GA-controlled responses. Results: Arabidopsis sequences of the gibberellin signalling compounds were used to screen databases from a variety of plants, including protists, for homologues, providing indications for the degree of conservation of the pathway. The pathway as such appears completely absent in protists, the moss Physcomitrella patens shares only a limited homology with the Arabidopsis proteins, thus lacking essential characteristics of the classical GA signalling pathway, while the lycophyte Selaginella moellendorffii contains a possible ortholog for each component. The occurrence of classical GA responses can as yet not be linked with the presence of homologues of the signalling pathway. Alignments and display in neighbour joining trees of the GA signalling components confirm the close relationship of gymnosperms, monocotyledonous and dicotyledonous plants, as suggested from previous studies. Conclusion: Homologues of the GA-signalling pathway were mainly found in vascular plants. The GA signalling system may have its evolutionary molecular onset in Physcomitrella patens, where GAs at higher concentrations affect gravitropism and elongation growth.

DELAY OF GERMINATION 1 mediates a conserved coat-dormancy mechanism for the temperature- and gibberellin-dependent control of seed germination

Czech Academy of Sciences Publication Activity Database

Graeber, K.; Linkies, A.; Steinbrecher, T.; Tarkowská, Danuše; Turečková, Veronika; Ignatz, M.; Voegele, A.; Urbanová, Terezie; Strnad, Miroslav; Leubner-Metzger, Gerhard

2014-01-01

Roč. 111, č. 34 (2014), E3571-E3580 ISSN 0027-8424 R&D Projects: GA ČR GD522/08/H003; GA MŠk LK21306; GA MŠk(CZ) LO1204; GA ČR GA14-34792S Grant - others:GA MŠk(CZ) ED0007/01/01 Program:ED Institutional support: RVO:61389030 Keywords : dormancy gene DOG1 * gibberellin metabolism * germination temperature Subject RIV: EB - Genetics ; Molecular Biology Impact factor: 9.674, year: 2014

PHOTOPERIODIC HISTORY AFFECTS THE CRITICAL DAYLENGTH OF THE SHORT-DAY PLANT ACROSYMPHYTON-PURPURIFERUM (RHODOPHYTA)

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BREEMAN, AM

The crustose tetrasporophyte of the red alga Acrosymphyton purpuriferum is a qualitative short-day plant in the formation of its tetrasporangia. The critical daylength for the response was determined in plants precultured in various long-day regimes [20:4, 18:6, 16:8 and 14:10 (L:D, h)]. There was a

Opposing effects of external gibberellin and Daminozide on Stevia growth and metabolites.

Science.gov (United States)

Karimi, Mojtaba; Hashemi, Javad; Ahmadi, Ali; Abbasi, Alireza; Pompeiano, Antonio; Tavarini, Silvia; Guglielminetti, Lorenzo; Angelini, Luciana G

2015-01-01

Steviol glycosides (SVglys) and gibberellins are originated from the shared biosynthesis pathway in Stevia (Stevia rebaudiana Bertoni). In this research, two experiments were conducted to study the opposing effects of external gibberellin (GA3) and Daminozide (a gibberellin inhibitor) on Stevia growth and metabolites. Results showed that GA3 significantly increased the stem length and stem dry weight in Stevia. Total soluble sugar content increased while the SVglys biosynthesis was decreased by external GA3 applying in Stevia leaves. In another experiment, the stem length was reduced by Daminozide spraying on Stevia shoots. The Daminozide did not affect the total SVglys content, while in 30 ppm concentration, significantly increased the soluble sugar production in Stevia leaves. Although the gibberellins biosynthesis pathway has previously invigorated in Stevia leaf, the Stevia response to external gibberellins implying on high precision regulation of gibberellins biosynthesis in Stevia and announces that Stevia is able to kept endogenous gibberellins in a low quantity away from SVglys production. Moreover, the assumption that the internal gibberellins were destroyed by Daminozide, lack of Daminozide effects on SVglys production suggests that gibberellins biosynthesis could not act as a competitive factor for SVglys production in Stevia leaves.

The role of phytochrome A and gibberellins in growth under long and short day conditions: Studies in hybrid aspen

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Eriksson, M.E. [Swedish Univ. of Agricultural Sciences, Umeaa (Sweden). Dept. of Forest Genetics and Plant Physiology

2000-07-01

This thesis addresses questions concerning the regulation of growth and, specifically, the cessation of growth in response to short days in deciduous tree species. The model tree used in the studies was hybrid aspen (Populus tremula L. x P. tremuloides Michx.). We have exploited the possibility of transforming this species to modulate the level of expression of target genes using over-expression and antisense techniques. The target genes in the studies were the photoreceptor phytochrome A (phyA) and gibberellin 20-oxidase (GA 20-oxidase), the latter being a highly regulated enzyme involved in the biosynthesis of gibberellins (GAs). The photoreceptor phyA has been implicated in photoperiodic regulation of growth, while GAs may regulate the physiological response further downstream. The endogenous expression of these genes has been investigated in parallel with studies of various plants with ectopic and reduced levels of expression. The main focus has been on the early stages of induction of growth cessation and its physiological and molecular mechanisms. Studies of hybrid aspen plants with an increased or reduced expression of phyA, show this receptor to mediate the photoperiodic regulation of growth. Plants with ectopic expression could not stop growing despite drastically shortened photoperiods, while the antisense plants showed the reverse phenotype, with a higher sensitivity resulting in earlier cessation of growth. The role of GAs in growth inhibition was also addressed using plants with a reduction in GA levels. These plants showed early cessation of growth and dormancy, and thus an increased sensitivity toward daylength. Conversely, plants with increased rates of GA biosynthesis showed increased growth and stopped growing much later. Furthermore, increases in GA biosynthesis, resulting in high levels of GAs have a major impact on growth. Plants with high GA levels have increased elongation and diameter growth, due to higher rates of cell production in the

A novel class of gibberellin 2-oxidases control semidwarfism, tillering, and root development in rice.

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Lo, Shuen-Fang; Yang, Show-Ya; Chen, Ku-Ting; Hsing, Yue-Ie; Zeevaart, Jan A D; Chen, Liang-Jwu; Yu, Su-May

2008-10-01

Gibberellin 2-oxidases (GA2oxs) regulate plant growth by inactivating endogenous bioactive gibberellins (GAs). Two classes of GA2oxs inactivate GAs through 2beta-hydroxylation: a larger class of C(19) GA2oxs and a smaller class of C(20) GA2oxs. In this study, we show that members of the rice (Oryza sativa) GA2ox family are differentially regulated and act in concert or individually to control GA levels during flowering, tillering, and seed germination. Using mutant and transgenic analysis, C(20) GA2oxs were shown to play pleiotropic roles regulating rice growth and architecture. In particular, rice overexpressing these GA2oxs exhibited early and increased tillering and adventitious root growth. GA negatively regulated expression of two transcription factors, O. sativa homeobox 1 and TEOSINTE BRANCHED1, which control meristem initiation and axillary bud outgrowth, respectively, and that in turn inhibited tillering. One of three conserved motifs unique to the C(20) GA2oxs (motif III) was found to be important for activity of these GA2oxs. Moreover, C(20) GA2oxs were found to cause less severe GA-defective phenotypes than C(19) GA2oxs. Our studies demonstrate that improvements in plant architecture, such as semidwarfism, increased root systems and higher tiller numbers, could be induced by overexpression of wild-type or modified C(20) GA2oxs.

Springs-neaps cycles in daily total seabed light: Daylength-induced changes

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Roberts, E. M.; Bowers, D. G.; Davies, A. J.

2014-04-01

In shallow, tidal seas, daily total seabed light is determined largely by the interaction of the solar elevation cycle, the tidal cycle in water depth, and any temporal variability in turbidity. Since tidal range, times of low water, and often turbidity vary in regular ways over the springs-neaps cycle, daily total seabed light exhibits cycles of the same periodicity. Corresponding cycles are likely to be induced in the daily total primary production of benthic algae and plants, particularly those light-limited specimens occupying the lower reaches of a sub-tidal population. Consequently, this effect is an important control on the growth patterns, depth distribution and survival of, for example, macroalgal forests and seagrass meadows. Seasonal changes in daylength exert an important additional control on these cycles, as they alter the fraction of the tidal and turbidity cycles occurring within daylight hours. Bowers et al. (1997) modelled this phenomenon numerically and predicted that for a site with low water at about midday and midnight at neaps tides, 6 am and 6 pm at springs, daily total seabed light peaks at neaps in winter, but the ‘sense' of the cycle ‘switches' so that it peaks at springs in summer - the longer daylength permits the morning and evening low water springs to contribute substantially to the daily total. Observations for such a site in North Wales (UK), presented in this paper, show that no such ‘switch' occurs, and neaps tides host the largest daily totals throughout the year. The predicted ‘switch' is not observed because turbidity increases generally at spring tides, and specifically at low water springs, both of which were not accounted for in the model. Observations at a second site in Brittany (France), diametrically opposite in terms of the times of low water at neaps and at springs, indicate a peak at springs throughout the year. Analytical tools are developed to calculate the percentage of daily total sea surface irradiance

Effects of gibberellin mutations on in vitro shoot bud regeneration of ...

African Journals Online (AJOL)

hormone in regulating plant growth and development. It is interesting to know the effects of gibberellin and its signalling pathway on plant regeneration. In this report Arabidopsis thaliana landsberg (wild type), ga1-3 (gibberellin biosynthesis deficiency mutant), gai (gibberellin insensitive mutant), penta mutant (lacking GA1, ...

Karrikins delay soybean seed germination by mediating abscisic acid and gibberellin biogenesis under shaded conditions

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Meng, Yongjie; Chen, Feng; Shuai, Haiwei; Luo, Xiaofeng; Ding, Jun; Tang, Shengwen; Xu, Shuanshuan; Liu, Jianwei; Liu, Weiguo; Du, Junbo; Liu, Jiang; Yang, Feng; Sun, Xin; Yong, Taiwen; Wang, Xiaochun; Feng, Yuqi; Shu, Kai; Yang, Wenyu

2016-01-01

Karrikins (KAR) are a class of signal compounds, discovered in wildfire smoke, which affect seed germination. Currently, numerous studies have focused on the model plant Arabidopsis in the KAR research field, rather than on crops. Thus the regulatory mechanisms underlying KAR regulation of crop seed germination are largely unknown. Here, we report that KAR delayed soybean seed germination through enhancing abscisic acid (ABA) biosynthesis, while impairing gibberellin (GA) biogenesis. Interestingly, KAR only retarded soybean seed germination under shaded conditions, rather than under dark and white light conditions, which differs from in Arabidopsis. Phytohormone quantification showed that KAR enhanced ABA biogenesis while impairing GA biosynthesis during the seed imbibition process, and subsequently, the ratio of active GA4 to ABA was significantly reduced. Further qRT-PCR analysis showed that the transcription pattern of genes involved in ABA and GA metabolic pathways are consistent with the hormonal measurements. Finally, fluridone, an ABA biogenesis inhibitor, remarkably rescued the delayed-germination phenotype of KAR-treatment; and paclobutrazol, a GA biosynthesis inhibitor, inhibited soybean seed germination. Taken together, these evidences suggest that KAR inhibit soybean seed germination by mediating the ratio between GA and ABA biogenesis. PMID:26902640

Karrikins delay soybean seed germination by mediating abscisic acid and gibberellin biogenesis under shaded conditions.

Science.gov (United States)

Meng, Yongjie; Chen, Feng; Shuai, Haiwei; Luo, Xiaofeng; Ding, Jun; Tang, Shengwen; Xu, Shuanshuan; Liu, Jianwei; Liu, Weiguo; Du, Junbo; Liu, Jiang; Yang, Feng; Sun, Xin; Yong, Taiwen; Wang, Xiaochun; Feng, Yuqi; Shu, Kai; Yang, Wenyu

2016-02-23

Karrikins (KAR) are a class of signal compounds, discovered in wildfire smoke, which affect seed germination. Currently, numerous studies have focused on the model plant Arabidopsis in the KAR research field, rather than on crops. Thus the regulatory mechanisms underlying KAR regulation of crop seed germination are largely unknown. Here, we report that KAR delayed soybean seed germination through enhancing abscisic acid (ABA) biosynthesis, while impairing gibberellin (GA) biogenesis. Interestingly, KAR only retarded soybean seed germination under shaded conditions, rather than under dark and white light conditions, which differs from in Arabidopsis. Phytohormone quantification showed that KAR enhanced ABA biogenesis while impairing GA biosynthesis during the seed imbibition process, and subsequently, the ratio of active GA4 to ABA was significantly reduced. Further qRT-PCR analysis showed that the transcription pattern of genes involved in ABA and GA metabolic pathways are consistent with the hormonal measurements. Finally, fluridone, an ABA biogenesis inhibitor, remarkably rescued the delayed-germination phenotype of KAR-treatment; and paclobutrazol, a GA biosynthesis inhibitor, inhibited soybean seed germination. Taken together, these evidences suggest that KAR inhibit soybean seed germination by mediating the ratio between GA and ABA biogenesis.

Regulation of assimilate partitioning by daylength and spectral quality

Energy Technology Data Exchange (ETDEWEB)

Britz, S.J. [USDA-Climate Stress Lab., Beltsville, MD (United States)

1994-12-31

Photosynthesis is the process by which plants utilize light energy to assimilate and transform carbon dioxide into products that support growth and development. The preceding review provides an excellent summary of photosynthetic mechanisms and diurnal patterns of carbon metabolism with emphasis on the importance of gradual changes in photosynthetically-active radiation at dawn and dusk. In addition to these direct effects of irradiance, there are indirect effects of light period duration and spectral quality on carbohydrate metabolism and assimilate partitioning. Both daylength and spectral quality trigger developmental phenomena such as flowering (e.g., photoperiodism) and shade avoidance responses, but their effects on partitioning of photoassimilates in leaves are less well known. Moreover, the adaptive significance to the plants of such effects is sometimes not clear.

Rice ethylene-response AP2/ERF factor OsEATB restricts internode elongation by down-regulating a gibberellin biosynthetic gene.

Science.gov (United States)

Qi, Weiwei; Sun, Fan; Wang, Qianjie; Chen, Mingluan; Huang, Yunqing; Feng, Yu-Qi; Luo, Xiaojin; Yang, Jinshui

2011-09-01

Plant height is a decisive factor in plant architecture. Rice (Oryza sativa) plants have the potential for rapid internodal elongation, which determines plant height. A large body of physiological research has shown that ethylene and gibberellin are involved in this process. The APETALA2 (AP2)/Ethylene-Responsive Element Binding Factor (ERF) family of transcriptional factors is only present in the plant kingdom. This family has various developmental and physiological functions. A rice AP2/ERF gene, OsEATB (for ERF protein associated with tillering and panicle branching) was cloned from indica rice variety 9311. Bioinformatic analysis suggested that this ERF has a potential new function. Ectopic expression of OsEATB showed that the cross talk between ethylene and gibberellin, which is mediated by OsEATB, might underlie differences in rice internode elongation. Analyses of gene expression demonstrated that OsEATB restricts ethylene-induced enhancement of gibberellin responsiveness during the internode elongation process by down-regulating the gibberellin biosynthetic gene, ent-kaurene synthase A. Plant height is negatively correlated with tiller number, and higher yields are typically obtained from dwarf crops. OsEATB reduces rice plant height and panicle length at maturity, promoting the branching potential of both tillers and spikelets. These are useful traits for breeding high-yielding crops.

Karrikins delay soybean seed germination by mediating abscisic acid and gibberellin biogenesis under shaded conditions

OpenAIRE

Meng, Yongjie; Chen, Feng; Shuai, Haiwei; Luo, Xiaofeng; Ding, Jun; Tang, Shengwen; Xu, Shuanshuan; Liu, Jianwei; Liu, Weiguo; Du, Junbo; Liu, Jiang; Yang, Feng; Sun, Xin; Yong, Taiwen; Wang, Xiaochun

2016-01-01

Karrikins (KAR) are a class of signal compounds, discovered in wildfire smoke, which affect seed germination. Currently, numerous studies have focused on the model plant Arabidopsis in the KAR research field, rather than on crops. Thus the regulatory mechanisms underlying KAR regulation of crop seed germination are largely unknown. Here, we report that KAR delayed soybean seed germination through enhancing abscisic acid (ABA) biosynthesis, while impairing gibberellin (GA) biogenesis. Interest...

Gibberellin control of stamen development: a fertile field.

Science.gov (United States)

Plackett, Andrew R G; Thomas, Stephen G; Wilson, Zoe A; Hedden, Peter

2011-10-01

Stamen development is governed by a conserved genetic pathway, within which the role of hormones has been the subject of considerable recent research. Our understanding of the involvement of gibberellin (GA) signalling in this developmental process is further advanced than for the other phytohormones, and here we review recent experimental results in rice (Oryza sativa) and Arabidopsis (Arabidopsis thaliana) that have provided insight into the timing and mechanisms of GA regulation of stamen development, identifying the tapetum and developing pollen as major targets. GA signalling governs both tapetum secretory functions and entry into programmed cell death via the GAMYB class of transcription factor, the targets of which integrate with the established genetic framework for the regulation of tapetum function at multiple hierarchical levels. Copyright © 2011 Elsevier Ltd. All rights reserved.

Exogenous auxin represses soybean seed germination through decreasing the gibberellin/abscisic acid (GA/ABA) ratio

OpenAIRE

Shuai, Haiwei; Meng, Yongjie; Luo, Xiaofeng; Chen, Feng; Zhou, Wenguan; Dai, Yujia; Qi, Ying; Du, Junbo; Yang, Feng; Liu, Jiang; Yang, Wenyu; Shu, Kai

2017-01-01

Auxin is an important phytohormone which mediates diverse development processes in plants. Published research has demonstrated that auxin induces seed dormancy. However, the precise mechanisms underlying the effect of auxin on seed germination need further investigation, especially the relationship between auxins and both abscisic acid (ABA) and gibberellins (GAs), the latter two phytohormones being the key regulators of seed germination. Here we report that exogenous auxin treatment represse...

The Effect of Gibberellin on Plant Growth and Development

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1960-11-04

8217P? 1O cerh bi; ncv tnd the ntanber of berries In e-.c ch bunch. The &ver-r.j? c -vjeirht of-’a berry ::wes then derived for each bt/mchyaoD...gibberellin web strongly in evidence. In the " :* : control bunches/of the Mrran|P’variety the^er/age/weight : ,of .8. berry was 1.08 g,: fend

The differential gene expression of key enzyme in the gibberellin pathway in the potato (solanum tuberosum) mutant

International Nuclear Information System (INIS)

Shi, J.B.; Ye, G.J.; Yang, Y.Z.; Wang, F.; Zhou, Y; Wang, J.

2016-01-01

In the present study, the expression patterns of the key genes in the gibberellin synthesis pathway in the potato dwarf mutant M4P-9 were detected using quantitative real-time PCR. Using Actin as an internal control, CPS1, KS, KO, GA20ox1, and GA2ox1, genes for key gibberellin synthesis enzymes, were evaluated, along with a gibberellin receptor gene. The standard curves were obtained from dilutions of PCR product; the correlation coefficient for Actin was 0.995, and those for the target genes varied from 0.994 to 1.000. The expression patterns of gibberellin pathway genes in different growth stages and tissues were calculated according to the method of Pfaffl. These genes showed expression patterns that varied based on growth stage and tissue type. The higher expression levels of CPS1 and GA2ox1 in roots, the lower expression levels of GA20ox1 in roots during tuber formation stage; as well as the increased expression of GA20ox1 and GA2ox1 genes in stems during the tuber formation stage, likely play key roles in the plant height phenotype in M4P-9 mutant materials. This article provides a basis for researching the mechanism of gibberellin synthesis in potato. (author)

Rice Ethylene-Response AP2/ERF Factor OsEATB Restricts Internode Elongation by Down-Regulating a Gibberellin Biosynthetic Gene1[W][OA

Science.gov (United States)

Qi, Weiwei; Sun, Fan; Wang, Qianjie; Chen, Mingluan; Huang, Yunqing; Feng, Yu-Qi; Luo, Xiaojin; Yang, Jinshui

2011-01-01

Plant height is a decisive factor in plant architecture. Rice (Oryza sativa) plants have the potential for rapid internodal elongation, which determines plant height. A large body of physiological research has shown that ethylene and gibberellin are involved in this process. The APETALA2 (AP2)/Ethylene-Responsive Element Binding Factor (ERF) family of transcriptional factors is only present in the plant kingdom. This family has various developmental and physiological functions. A rice AP2/ERF gene, OsEATB (for ERF protein associated with tillering and panicle branching) was cloned from indica rice variety 9311. Bioinformatic analysis suggested that this ERF has a potential new function. Ectopic expression of OsEATB showed that the cross talk between ethylene and gibberellin, which is mediated by OsEATB, might underlie differences in rice internode elongation. Analyses of gene expression demonstrated that OsEATB restricts ethylene-induced enhancement of gibberellin responsiveness during the internode elongation process by down-regulating the gibberellin biosynthetic gene, ent-kaurene synthase A. Plant height is negatively correlated with tiller number, and higher yields are typically obtained from dwarf crops. OsEATB reduces rice plant height and panicle length at maturity, promoting the branching potential of both tillers and spikelets. These are useful traits for breeding high-yielding crops. PMID:21753115

Detection of endogenous gibberellins and their relationship to hypocotyl elongation in soybean seedlings

International Nuclear Information System (INIS)

Bensen, R.J.; Beall, F.D.; Mullet, J.E.; Morgan, P.W.

1990-01-01

Four gibberellins, GA 53 , GA 19 , GA 20 , and GA 1 , were detected by bioassay, chromatography in two HPLC systems, and combined gas chromatography-mass spectroscopy-selected ion monitoring (GC-MS-SIM) in etiolated soybean (Glycine max [L.] Merr.) hypocotyls. GC-MS-SIM employed [ 2 H 2 ]-labeled standards for each endogenous gibberellin detected, and quantities estimated from bioassays and GC-MS-SIM were similar. This result plus the tentative detection of GA 44 and GA 8 (standards not available) indicates that the early-C-13-hydroxylation pathway for gibberellin biosynthesis predominates in soybean hypocotyls. Other gibberellins were not detected. Growth rates decreased after transfer to low water potential (ψ w ) vermiculite and were completely arrested 24 hours after transfer. The GA 1 content in the elongating region of hypocotyls had declined to 38% of the 0 time value at 24 hours after transfer to low ψ w vermiculite, a level which was only 13% of the GA 1 content in control seedlings at the same time (24 hours posttransfer). Seedlings were growth responsive to exogenous GA 3 , and this GA 3 -promoted growth was inhibited by exogenous ABA. The data are consistent with the hypothesis that changes in GA 1 and ABA levels play a role in adjusting hypocotyl elongation rates. However, the changes observed are not of sufficient magnitude nor do they occur rapidly enough to suggest they are the primary regulators of elongation rate responses to rapidly changing plant water status

The mitochondrial phosphate transporters modulate plant responses to salt stress via affecting ATP and gibberellin metabolism in Arabidopsis thaliana.

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Wei Zhu

Full Text Available The mitochondrial phosphate transporter (MPT plays crucial roles in ATP production in plant cells. Three MPT genes have been identified in Arabidopsis thaliana. Here we report that the mRNA accumulations of AtMPTs were up-regulated by high salinity stress in A. thaliana seedlings. And the transgenic lines overexpressing AtMPTs displayed increased sensitivity to salt stress compared with the wild-type plants during seed germination and seedling establishment stages. ATP content and energy charge was higher in overexpressing plants than those in wild-type A. thaliana under salt stress. Accordingly, the salt-sensitive phenotype of overexpressing plants was recovered after the exogenous application of atractyloside due to the change of ATP content. Interestingly, Genevestigator survey and qRT-PCR analysis indicated a large number of genes, including those related to gibberellin synthesis could be regulated by the energy availability change under stress conditions in A. thaliana. Moreover, the exogenous application of uniconazole to overexpressing lines showed that gibberellin homeostasis was disturbed in the overexpressors. Our studies reveal a possible link between the ATP content mediated by AtMPTs and gibberellin metabolism in responses to high salinity stress in A. thaliana.

Helminthosporic acid functions as an agonist for gibberellin receptor

OpenAIRE

Miyazaki, Sho; Jiang, Kai; Kobayashi, Masatomo; Asami, Tadao; Nakajima, Masatoshi

2017-01-01

Helminthosporol was isolated from a fungus, Helminthosporium sativum, as a natural plant growth regulator in 1963. It showed gibberellin-like bioactivity that stimulated the growth of the second leaf sheath of rice. After studying the structure–activity relationship between the compound and some synthesized analogs, it was found that helminthosporic acid (H-acid) has higher gibberellin-like activity and chemical stability than helminthosporol. In this study, we showed that (1) H-acid displays...

Changes in endogenous gibberellin-like substances in onion bulbs (Allium cepa L. cv. Sochaczewska during storage

Directory of Open Access Journals (Sweden)

Elżbieta Kielak

2013-12-01

Full Text Available Onions cv. Sochaczewska were dried up under an umbrella roof till October 15th or till November 15th and thereafter stored in a cold room at 0-1°C until May 15th. During 4-year of experiment gibberellin activity was determined each month during storage. Three periods of high activity of gibberellins were found in most cases: in December, in February-March and in late spring. In general, onions dried longer (till November 15th, showed lower gibberellin activity than onions dried shorter. Gibberellin-like substances under investigation are localized in almost all Rf zones of chromatogram. Sprouting and rooting was related to gibberellin activity.

Analysis of Transcriptional Responses of the Inflorescence Meristems in Jatropha curcas Following Gibberellin Treatment

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Wen-Kai Hui

2018-02-01

Full Text Available Jatropha curcas L. seeds an oilseed plant with great potential for biodiesel production. However, low seed yield, which was limited by its lower female flowers, was a major drawback for its utilization. Our previous study found that the flower number and female-to-male ratio were increased by gibberellin treatment. Here, we compared the transcriptomic profiles of inflorescence meristem at different time points after gibberellic acid A3 (GA3 treatment. The present study showed that 951 differentially expressed genes were obtained in response to gibberellin treatment, compared with control samples. The 6-h time point was an important phase in the response to exogenous gibberellin. Furthermore, the plant endogenous gibberellin, auxin, ethylene, abscisic acid, and brassinolide-signaling transduction pathways were repressed, whereas the genes associated with cytokinin and jasmonic acid signaling were upregulated for 24-h time point following GA3 treatment. In addition, the floral meristem determinacy genes (JcLFY, JcSOC1 and floral organ identity genes (JcAP3, JcPI, JcSEP1-3 were significantly upregulated, but their negative regulator (JcSVP was downregulated after GA3 treatment. Moreover, the effects of phytohormone, which was induced by exogenous plant growth regulator, mainly acted on the female floral differentiation process. To the best of our knowledge, this data is the first comprehensive analysis of the underlying transcriptional response mechanism of floral differentiation following GA3 treatment in J. curcas, which helps in engineering high-yielding varieties of Jatropha.

Hormonal regulation of gluconeogenesis in cereal aleurone is strongly cultivar-dependent and gibberellin action involves SLENDER1 but not GAMYB.

Science.gov (United States)

Eastmond, Peter J; Jones, Russell L

2005-11-01

Storage oil is a major constituent in the cereal aleurone layer. The aim of this study was to investigate how gibberellin (GA) and abscisic acid (ABA) regulate conversion of oil to sugar in barley aleurone. The activity of the glyoxylate cycle enzyme isocitrate lyase (ICL) was surveyed in eight barley cultivars. Surprisingly, some cultivars do not require GA for the induction of ICL (e.g. Himalaya), whereas some do (e.g. Golden Promise). Furthermore, in Golden Promise, GA also stimulates triacylglycerol breakdown and enhances the net flux of carbon from acetate to sugar. In contrast, ABA strongly represses ICL activity and the flux of carbon from oil to sugar in both Golden Promise and Himalaya. Biolistics using a promoter reporter showed that GA and ABA regulate ICL at the level of transcription. Studies using barley and rice mutants and pharmacological agents show that GA-dependent induction of ICL activity is mediated by SLENDER1 and requires cGMP, but does not involve the transcription factor GAMYB. Gibberellin and ABA therefore act antagonistically to regulate gluconeogenesis in the aleurone layer as well as controlling the production and secretion of hydrolases into the starchy endosperm. We suggest that the variation between different barley cultivars might be a result of selective breeding to alter seed dormancy.

Cryptochrome and Phytochrome Cooperatively but Independently Reduce Active Gibberellin Content in Rice Seedlings under Light Irradiation

OpenAIRE

Hirose, Fumiaki; Inagaki, Noritoshi; Hanada, Atsushi; Yamaguchi, Shinjiro; Kamiya, Yuji; Miyao, Akio; Hirochika, Hirohiko; Takano, Makoto

2012-01-01

In contrast to a wealth of knowledge about the photoregulation of gibberellin metabolism in dicots, that in monocots remains largely unclear. In this study, we found that a blue light signal triggers reduction of active gibberellin content in rice seedlings with simultaneous repression of two gibberellin 20-oxidase genes (OsGA20ox2 and OsGA20ox4) and acute induction of four gibberellin 2-oxidase genes (OsGA2ox4–OsGA2ox7). For further examination of the regulation of these genes, we establishe...

Modifying action of gibberellin on the cytogenetic effect of radiation in Crepis capillaris L

International Nuclear Information System (INIS)

Avakyan, V.A.; Vardanyan, A.A.

1979-01-01

Radioprotactive properties of gibberellin were studied during treating the Crepic capillaris seeds before irradiation. The radioprotective effect observed did not depend on the interphase stage. Gibberellin was shown to unduce no chromosome mutations

A Study of Gibberellin Homeostasis and Cryptochrome-Mediated Blue Light Inhibition of Hypocotyl Elongation1[W][OA

Science.gov (United States)

Zhao, Xiaoying; Yu, Xuhong; Foo, Eloise; Symons, Gregory M.; Lopez, Javier; Bendehakkalu, Krishnaprasad T.; Xiang, Jing; Weller, James L.; Liu, Xuanming; Reid, James B.; Lin, Chentao

2007-01-01

Cryptochromes mediate blue light-dependent photomorphogenic responses, such as inhibition of hypocotyl elongation. To investigate the underlying mechanism, we analyzed a genetic suppressor, scc7-D (suppressors of cry1cry2), which suppressed the long-hypocotyl phenotype of the cry1cry2 (cryptochrome1/cryptochrome2) mutant in a light-dependent but wavelength-independent manner. scc7-D is a gain-of-expression allele of the GA2ox8 gene encoding a gibberellin (GA)-inactivating enzyme, GA 2-oxidase. Although scc7-D is hypersensitive to light, transgenic seedlings expressing GA2ox at a level higher than scc7-D showed a constitutive photomorphogenic phenotype, confirming a general role of GA2ox and GA in the suppression of hypocotyl elongation. Prompted by this result, we investigated blue light regulation of mRNA expression of the GA metabolic and catabolic genes. We demonstrated that cryptochromes are required for the blue light regulation of GA2ox1, GA20ox1, and GA3ox1 expression in transient induction, continuous illumination, and photoperiodic conditions. The kinetics of cryptochrome induction of GA2ox1 expression and cryptochrome suppression of GA20ox1 or GA3ox1 expression correlate with the cryptochrome-dependent transient reduction of GA4 in etiolated wild-type seedlings exposed to blue light. Therefore we propose that in deetiolating seedlings, cryptochromes mediate blue light regulation of GA catabolic/metabolic genes, which affect GA levels and hypocotyl elongation. Surprisingly, no significant change in the GA4 content was detected in the whole shoot samples of the wild-type or cry1cry2 seedlings grown in the dark or continuous blue light, suggesting that cryptochromes may also regulate GA responsiveness and/or trigger cell- or tissue-specific changes of the level of bioactive GAs. PMID:17644628

Gibberellin influence on the morphogenesis of the moss Bryum argenteum Hedw. in in vitro conditions

OpenAIRE

Sabovljević Aneta; Sabovljević Marko; Grubišić D.

2010-01-01

The moss Bryum argenteum Hedw. was treated with gibberellins as well as some inhibitors of gibberellin biosynthesis in order to investigate their influence on B. argenteum morphogenesis. Generally, gibberellins have not been chemically identified in bryophytes, while other groups of classical phytohormones (auxins, cytokinins, abscisic acid and ethylene) have been chemically identified in these plants. The in vitro culture of the moss Bryum argenteum was established from sterilized spores. Th...

APETALA 2-domain-containing transcription factors: focusing on abscisic acid and gibberellins antagonism.

Science.gov (United States)

Shu, Kai; Zhou, Wenguan; Yang, Wenyu

2018-02-01

The phytohormones abscisic acid (ABA) and gibberellin (GA) antagonistically mediate diverse plant developmental processes including seed dormancy and germination, root development, and flowering time control, and thus the optimal balance between ABA and GA is essential for plant growth and development. Although more than a half and one century have passed since the initial discoveries of ABA and GA, respectively, the precise mechanisms underlying ABA-GA antagonism still need further investigation. Emerging evidence indicates that two APETALA 2 (AP2)-domain-containing transcription factors (ATFs), ABI4 in Arabidopsis and OsAP2-39 in rice, play key roles in ABA and GA antagonism. These two transcription factors precisely regulate the transcription pattern of ABA and GA biosynthesis or inactivation genes, mediating ABA and GA levels. In this Viewpoint article, we try to shed light on the effects of ATFs on ABA-GA antagonism, and summarize the overlapping but distinct biological functions of these ATFs in the antagonism between ABA and GA. Finally, we strongly propose that further research is needed into the detailed roles of additional numerous ATFs in ABA and GA crosstalk, which will improve our understanding of the antagonism between these two phytohormones. © 2017 The Authors. New Phytologist © 2017 New Phytologist Trust.

[Effects of fluridone, gibberellin acid and germination temperature on dormancy-breaking for Epimedium wushanense].

Science.gov (United States)

Su, He; Wang, Yue; Yang, Yang; Dong, Xue-Hui

2016-07-01

We introduced Epimedium wushanense seed which has been stratified for 90 days at 10/20 ℃ as experimental materials, with which we studied the effects of fluridone, gibberellin acid and temperature on E. wushanense germination. The results were suggested as shown below. ①Temperature, fluridone and gibberellin acid can both solely or jointly affect germination energy, germination rate significantly. Among those factors, fluridone affect germination rate and germination energy the most, followed by gibberellin acid and temperature. The highest germination rate under 4 ℃ and 10/20 ℃ stratification are 79.3%, 72.0% respectively, which resulted from treatment of F10GA300 and F20GA200 respectively. The highest germination energy under 4 ℃ and 10/20 ℃ stratification are 52.7%, 52.0%, respectively, which both resulted from F20GA200. ②Compared with 4 ℃ germination, seed could not germinate at 10/20 ℃ germination. Nontheless, application of fluridone can lead E. wushanense seeds to germinating.③The effects of gibberellin acid and interaction between gibberellin acid and fluridone significantly affect seed rotten rate during germination. In addition, soaking is another remarkable factor which increased seed rotten rate. As a result, it is feasible to promote E. wushanense dormancy releasing with gibberellin acid and fluridone associating with a proper germination temperature. Further, it is necessary taking actions to avoid seed rotten rate for saving E. wushanense nurseries'cost. Copyright© by the Chinese Pharmaceutical Association.

Colonization by the endophyte Piriformospora indica leads to early flowering in Arabidopsis thaliana likely by triggering gibberellin biosynthesis

KAUST Repository

Kim, Dongjin; Abdelaziz, Mohamad E.; Ntui, Valentine Otang; Guo, Xiujie; Al-Babili, Salim

2017-01-01

Piriformospora indica is an endophytic fungus colonizing roots of a wide variety of plants. Previous studies showed that P. indica promotes early flowering and plant growth in the medicinal plant Coleus forskohlii. To determine the impact of P. indica on flowering time in Arabidopsis, we co-cultivated the plants with P. indica under long day condition. P. indica inoculated Arabidopsis plants displayed significant early flowering phenotype. qRT-PCR analysis of colonized plants revealed an up-regulation of flowering regulatory (FLOWERING LOCUS T, LEAFY, and APETALA1) and gibberellin biosynthetic (Gibberellin 20-Oxidase2, Gibberellin 3-Oxidase1 and Gibberellin requiring1) genes, while the flowering-repressing gene FLOWERING LOCUS C was down regulated. Quantification of gibberellins content showed that the colonization with P. indica caused an increase in GA4 content. Compared to wild-type plants, inoculation of the Arabidopsis ga5 mutant affected in gibberellin biosynthetic gene led to less pronounced changes in the expression of genes regulating flowering and to a lower increase in GA4 content. Taken together, our data indicate that P. indica promotes early flowering in Arabidopsis likely by increasing gibberellin content.

Colonization by the endophyte Piriformospora indica leads to early flowering in Arabidopsis thaliana likely by triggering gibberellin biosynthesis

KAUST Repository

Kim, Dongjin

2017-06-28

Piriformospora indica is an endophytic fungus colonizing roots of a wide variety of plants. Previous studies showed that P. indica promotes early flowering and plant growth in the medicinal plant Coleus forskohlii. To determine the impact of P. indica on flowering time in Arabidopsis, we co-cultivated the plants with P. indica under long day condition. P. indica inoculated Arabidopsis plants displayed significant early flowering phenotype. qRT-PCR analysis of colonized plants revealed an up-regulation of flowering regulatory (FLOWERING LOCUS T, LEAFY, and APETALA1) and gibberellin biosynthetic (Gibberellin 20-Oxidase2, Gibberellin 3-Oxidase1 and Gibberellin requiring1) genes, while the flowering-repressing gene FLOWERING LOCUS C was down regulated. Quantification of gibberellins content showed that the colonization with P. indica caused an increase in GA4 content. Compared to wild-type plants, inoculation of the Arabidopsis ga5 mutant affected in gibberellin biosynthetic gene led to less pronounced changes in the expression of genes regulating flowering and to a lower increase in GA4 content. Taken together, our data indicate that P. indica promotes early flowering in Arabidopsis likely by increasing gibberellin content.

Effect of cotyledons and epicotyl upon the activity of endogenous gibberellins in roots of flax (Linum usitatissimum L. seedlings

Directory of Open Access Journals (Sweden)

Krystyna M. Janas

2013-12-01

Full Text Available In 11-day-old flax seedlings, the level of endogenous gibberellins in roots decreased within 12 hours after the excision of cotyledons and the epicotyl; however, 24 to 48 hours after excision the gibberellin level increased again. The decrease in the gibberellin level within the first 12 hours after excision suggests a participation of the cotyledons and the epicotyl in the biosynthesis of endogenous gibberellins.

Light Regulation of Gibberellin Biosynthesis and Mode of Action.

Science.gov (United States)

García-Martinez, José Luis; Gil, Joan

2001-12-01

Some phenotypic effects produced in plants by light are very similar to those induced by hormones. In this review, the light-gibberellin (GA) interaction in germination, de-etiolation, stem growth, and tuber formation (process regulated by GAs) are discussed. Germination of lettuce and Arabidopsis seeds depends on red irradiation (R), which enhances the expression of GA 3-oxidase genes (GA3ox) and leads to an increase in active GA content. De-etiolation of pea seedling alters the expression of GA20ox and GA3ox genes and induces a rapid decrease of GA1 content. Stem growth of green plants is also affected by diverse light irradiation characteristics. Low light intensity increases stem elongation and active GA content in pea and Brassica. Photoperiod controls active GA levels in long-day rosette (spinach and Silene) and in woody plants (Salix and hybrid aspen) by regulating different steps of GA biosynthesis, mainly through transcript levels of GA20ox and GA3ox genes. Light modulation of stem elongation in light-grown plants is controlled by phytochrome, which modifies GA biosynthesis and catabolism (tobacco, potato, cowpea, Arabidopsis) and GA-response (pea, cucumber, Arabidopsis). In Arabidopsis and tobacco, ATH1 (a gene encoding an homeotic transcription factor) is a positive mediator of a phyB-specific signal transduction cascade controlling GA levels by regulating the expression of GA20ox and GA3ox. Tuber formation in potato is controlled by photoperiod (through phyB) and GAs. Inductive short-day conditions alter the diurnal rhythm of GA20ox transcript abundance, and increases the expression of a new protein (PHOR1) that plays a role in the photoperiod-GA interaction.

Hollow fiber-based liquid-liquid-liquid micro-extraction with osmosis: II. Application to quantification of endogenous gibberellins in rice plant.

Science.gov (United States)

Wu, Qian; Wu, Dapeng; Duan, Chunfeng; Shen, Zheng; Guan, Yafeng

2012-11-23

The phenomenon and benefits of osmosis in hollow fiber-based liquid-liquid-liquid micro-extraction (HF-LLLME) were theoretically discussed in part I of this study. In this work, HF-LLLME with osmosis was coupled with high performance liquid chromatography-triple quadrupole mass spectrometry (HPLC-triple quadrupole MS/MS) to analyze eight gibberellins (gibberellin A(1), gibberellin A(3), gibberellin A(4), gibberellin A(7), gibberellin A(8), gibberellin A(9), gibberellin A(19) and gibberellin A(20)) in rice plant samples. According to the theory of HF-LLLME with osmosis, single factor experiments, orthogonal design experiments and mass transfer simulation of extraction process were carried out to select the optimal conditions. Cyclohexanol - n-octanol (1:3, v/v) was selected as organic membrane. Donor phase of 12 mL was adjusted to pH 2 and 20% NaCl (w/v) was added. Acceptor phase with an initial volume of 20 μL was the solution of 0.12 mol L(-1) Na(2)CO(3)-NaHCO(3) buffer (pH 9). Temperature was chosen to be 30 °C and extraction time was selected to be 90 min. Under optimized conditions, this method provided good linearity (r, 0.99552-0.99991) and low limits of detection (0.0016-0.061 ng mL(-1)). Finally, this method was applied to the analysis of endogenous gibberellins from plant extract which was obtained with traditional solvent extraction of rice plant tissues, and the relative recoveries were from 62% to 166%. Copyright © 2012 Elsevier B.V. All rights reserved.

Rare sugar D-allose suppresses gibberellin signaling through hexokinase-dependent pathway in Oryza sativa L.

Science.gov (United States)

Fukumoto, Takeshi; Kano, Akihito; Ohtani, Kouhei; Yamasaki-Kokudo, Yumiko; Kim, Bong-Gyu; Hosotani, Kouji; Saito, Miu; Shirakawa, Chikage; Tajima, Shigeyuki; Izumori, Ken; Ohara, Toshiaki; Shigematsu, Yoshio; Tanaka, Keiji; Ishida, Yutaka; Nishizawa, Yoko; Tada, Yasuomi; Ichimura, Kazuya; Gomi, Kenji; Akimitsu, Kazuya

2011-12-01

One of the rare sugars, D-allose, which is the epimer of D-glucose at C3, has an inhibitory effect on rice growth, but the molecular mechanisms of the growth inhibition by D-allose were unknown. The growth inhibition caused by D-allose was prevented by treatment with hexokinase inhibitors, D-mannoheptulose and N-acetyl-D-glucosamine. Furthermore, the Arabidopsis glucose-insensitive2 (gin2) mutant, which is a loss-of-function mutant of the glucose sensor AtHXK1, showed a D-allose-insensitive phenotype. D-Allose strongly inhibited the gibberellin-dependent responses such as elongation of the second leaf sheath and induction of α-amylase in embryo-less half rice seeds. The growth of the slender rice1 (slr1) mutant, which exhibits a constitutive gibberellin-responsive phenotype, was also inhibited by D-allose, and the growth inhibition of the slr1 mutant by D-allose was also prevented by D-mannoheptulose treatment. The expressions of gibberellin-responsive genes were down-regulated by D-allose treatment, and the down-regulations of gibberellin-responsive genes were also prevented by D-mannoheptulose treatment. These findings reveal that D-allose inhibits the gibberellin-signaling through a hexokinase-dependent pathway.

Hormonal control of seed development in gibberellin- and ABA-deficient tomato (Lycopersicon esculentum Mill. cv. Moneymaker) mutants

NARCIS (Netherlands)

Castro, de R.D.; Hilhorst, H.W.M.

2006-01-01

Developing seeds of tomato gibberellin (GA)-deficient gib1 and abscisic acid (ABA)-deficient sitw mutants enabled us to analyze the role of GA in the regulation of embryo histo-differentiation, and the role of ABA in the regulation of maturation and quiescence. Our data show that DNA synthesis and

Evidence for the Translocation of Gibberellin A_3 and Gibberellin-Like Substances in Grafts between Normal, Dwarf_1 and Dwarf_5 Seedlings of Zea mays L.

OpenAIRE

M., Katsumi; D.E., Foard; B.O., Phinney; Biology Department, International Christian University; Department of Botany and Plant Pathology, Purdue University; Department of Biology, University of California

1983-01-01

Approach grafts were made between the cut surfaces of mesocotyls from normal and dwarf seedlings of Zea mays L. (maize). The dwarfs were the non-allelic single gene gibberellin mutants, dwarf_1 and dwarf_5. The graft combinations were normal-normal, normal-dwarf_1, normal-dwarf_5, dwarf_1-dwarf_1, dwarf_5-dwarf_5, and dwarf_1-dwarf_5. The grafts were used to demonstrate the movement of gibberellin-like substances across the union. GA_3, added to one member of the graft, resulted in leaf-sheat...

Gibberellin-induced changes in the populations of translatable mRNAs and accumulated polypeptides in dwarfs of maize and pea

International Nuclear Information System (INIS)

Chory, J.; Voytas, D.F.; Olszewski, N.E.; Ausubel, F.M.

1987-01-01

Two-dimensional gel electrophoresis was used to characterize the molecular mechanism of gibberellin-induced stem elongation in maize and pea. Dwarf mutants of maize and pea lack endogenous gibberellin (GA 1 ) but become phenotypically normal with exogenous applications of this hormone. Sections from either etiolated maize or green pea seedlings were incubated in the presence of [ 35 S] methionine for 3 hours with or without gibberellin. Labeled proteins from soluble and particulate fractions were analyzed by two-dimensional gel electrophoresis and specific changes in the patterns of protein synthesis were observed upon treatment with gibberellin. Polyadenylated mRNAs from etiolated or green maize shoots and green pea epicotyls treated or not with gibberellin (a 0.5 to 16 hour time course) were assayed by translation in a rabbit reticulocyte extract and separation of products by two-dimensional gel electrophoresis. Both increases and decreases in the levels of specific polypeptides were seen for pea and corn, and these changes were observed within 30 minutes of treatment with gibberellin. Together, these data indicate that gibberellin induces changes in the expression of a subset of gene products within elongating dwarfs. This may be due to changes in transcription rate, mRNA stability, or increased efficiency of translation of certain mRNAs

Gibberellin influence on the morphogenesis of the moss Bryum argenteum Hedw. in in vitro conditions

Directory of Open Access Journals (Sweden)

Sabovljević Aneta

2010-01-01

Full Text Available The moss Bryum argenteum Hedw. was treated with gibberellins as well as some inhibitors of gibberellin biosynthesis in order to investigate their influence on B. argenteum morphogenesis. Generally, gibberellins have not been chemically identified in bryophytes, while other groups of classical phytohormones (auxins, cytokinins, abscisic acid and ethylene have been chemically identified in these plants. The in vitro culture of the moss Bryum argenteum was established from sterilized spores. The apical shoots of untreated gametophytes grown in vitro were used to investigate the influence of different substances on secondary protonema and on the growth and multiplication of the gametophytes. B. argenteum reacts differently to the growth regulators applied. Both gibberellins applied in vitro (GA3 and GA7 have a positive effect on B. argenteum morphogenesis. Shoot multiplication was negatively affected by three tested growth retardants (ancymidol, BX-112 and chlorocholine chloride, while these substances did not have such strong effects on the moss protonema development.

Gibberellin biosynthesis in cell-free extracts from developing Cucurbita maxima embryos and the identification of new endogenous gibberellins.

Science.gov (United States)

Lange, T; Hedden, P; Graebe, J E

1993-03-01

Gibberellin (GA) biosynthetic pathways from GA12-aldehyde, GA12 and GA53 were investigated in cell-free systems from developing embryos of Cucurbita maxima L. Gibberellin A12-aldehyde and GA12 were converted to GA25, putative 12α-hydroxyGA25, GA13 and GA39 as main products. Minor products were GA4, GA34 and, when GA12 was the substrate, putative 12α-hydroxyGA12. The intermediates GA15 and GA24 accumulated at low protein concentrations. The influence of various factors on GA12 metabolism was examined. At low 2-oxoglutarate and ascorbate concentrations, or at acid pH, 3β-hydroxylated products predominated, whereas with increasing 2-oxoglutarate and ascorbate concentrations, or at neutral pH, the yield of 12α-hydroxylated GAs increased. Gibberellin A53 was metabolised mainly to the C20-GAs GA44, GA19, GA17, GA23 and GA28, with the C19-GAs GA20, GA1 and GA8 as minor products. Only C19-GAs were 2β-hydroxylated, which is a main characteristic of the embryo systems. In addition to GA13, GA25, GA39, GA43, GA49, GA58, GA74, 12α-hydroxyGA25 and GA39 3-isovalerate, which were known previously from embryos of C. maxima, GA1, GA4, GA17, GA28, GA37, GA38, GA48, GA85, 12α-hydroxyGA37 and putative 12α-hydroxyGA43 were identified as endogenous components by full-scan capillary gas chromatography-mass spectrometry and Kovats retention indices. Evidence for putative 2β-hydroxyGA28 and GA23 was also obtained but it was less conclusive because of contamination.

Silencing SlMED18, tomato Mediator subunit 18 gene, restricts internode elongation and leaf expansion.

Science.gov (United States)

Wang, Yunshu; Hu, Zongli; Zhang, Jianling; Yu, XiaoHui; Guo, Jun-E; Liang, Honglian; Liao, Changguang; Chen, Guoping

2018-02-19

Mediator complex, a conserved multi-protein, is necessary for controlling RNA polymerase II (Pol II) transcription in eukaryotes. Given little is known about them in tomato, a tomato Mediator subunit 18 gene was isolated and named SlMED18. To further explore the function of SlMED18, the transgenic tomato plants targeting SlMED18 by RNAi-mediated gene silencing were generated. The SlMED18-RNAi lines exhibited multiple developmental defects, including smaller size and slower growth rate of plant and significantly smaller compound leaves. The contents of endogenous bioactive GA 3 in SlMED18 silenced lines were slightly less than that in wild type. Furthermore, qRT-PCR analysis indicated that expression of gibberellins biosynthesis genes such as SlGACPS and SlGA20x2, auxin transport genes (PIN1, PIN4, LAX1 and LAX2) and several key regulators, KNOX1, KNOX2, PHAN and LANCEOLATE(LA), which involved in the leaf morphogenesis were significantly down-regulated in SlMED18-RNAi lines. These results illustrated that SlMED18 plays an essential role in regulating plant internode elongation and leaf expansion in tomato plants and it acts as a key positive regulator of gibberellins biosynthesis and signal transduction as well as auxin proper transport signalling. These findings are the basis for understanding the function of the individual Mediator subunits in tomato.

Carbohydrates and gibberellins relationship in potato tuberization

Czech Academy of Sciences Publication Activity Database

Ševčíková, H.; Mašková, P.; Tarkowská, Danuše; Mašek, T.; Lipavská, H.

2017-01-01

Roč. 214, JUL (2017), s. 53-63 ISSN 0176-1617 R&D Projects: GA ČR GA14-34792S Institutional support: RVO:61389030 Keywords : Carbohydrate distribution * Gibberellin * Photoautotrophic cultivation * Potato * Tuberization Subject RIV: CB - Analytical Chemistry, Separation OBOR OECD: Plant sciences, botany Impact factor: 3.121, year: 2016

Characterization of the molecular mechanism underlying gibberellin perception complex formation in rice.

Science.gov (United States)

Hirano, Ko; Asano, Kenji; Tsuji, Hiroyuki; Kawamura, Mayuko; Mori, Hitoshi; Kitano, Hidemi; Ueguchi-Tanaka, Miyako; Matsuoka, Makoto

2010-08-01

The DELLA protein SLENDER RICE1 (SLR1) is a repressor of gibberellin (GA) signaling in rice (Oryza sativa), and most of the GA-associated responses are induced upon SLR1 degradation. It is assumed that interaction between GIBBERELLIN INSENSITIVE DWARF1 (GID1) and the N-terminal DELLA/TVHYNP motif of SLR1 triggers F-box protein GID2-mediated SLR1 degradation. We identified a semidominant dwarf mutant, Slr1-d4, which contains a mutation in the region encoding the C-terminal GRAS domain of SLR1 (SLR1(G576V)). The GA-dependent degradation of SLR1(G576V) was reduced in Slr1-d4, and compared with SLR1, SLR1(G576V) showed reduced interaction with GID1 and almost none with GID2 when tested in yeast cells. Surface plasmon resonance of GID1-SLR1 and GID1-SLR1(G576V) interactions revealed that the GRAS domain of SLR1 functions to stabilize the GID1-SLR1 interaction by reducing its dissociation rate and that the G576V substitution in SLR1 diminishes this stability. These results suggest that the stable interaction of GID1-SLR1 through the GRAS domain is essential for the recognition of SLR1 by GID2. We propose that when the DELLA/TVHYNP motif of SLR1 binds with GID1, it enables the GRAS domain of SLR1 to interact with GID1 and that the stable GID1-SLR1 complex is efficiently recognized by GID2.

Comprehensive gene expression analysis of rice aleurone cells: probing the existence of an alternative gibberellin receptor.

Science.gov (United States)

Yano, Kenji; Aya, Koichiro; Hirano, Ko; Ordonio, Reynante Lacsamana; Ueguchi-Tanaka, Miyako; Matsuoka, Makoto

2015-02-01

Current gibberellin (GA) research indicates that GA must be perceived in plant nuclei by its cognate receptor, GIBBERELLIN INSENSITIVE DWARF1 (GID1). Recognition of GA by GID1 relieves the repression mediated by the DELLA protein, a model known as the GID1-DELLA GA perception system. There have been reports of potential GA-binding proteins in the plasma membrane that perceive GA and induce α-amylase expression in cereal aleurone cells, which is mechanistically different from the GID1-DELLA system. Therefore, we examined the expression of the rice (Oryza sativa) α-amylase genes in rice mutants impaired in the GA receptor (gid1) and the DELLA repressor (slender rice1; slr1) and confirmed their lack of response to GA in gid1 mutants and constitutive expression in slr1 mutants. We also examined the expression of GA-regulated genes by genome-wide microarray and quantitative reverse transcription-polymerase chain reaction analyses and confirmed that all GA-regulated genes are modulated by the GID1-DELLA system. Furthermore, we studied the regulatory network involved in GA signaling by using a set of mutants defective in genes involved in GA perception and gene expression, namely gid1, slr1, gid2 (a GA-related F-box protein mutant), and gamyb (a GA-related trans-acting factor mutant). Almost all GA up-regulated genes were regulated by the four named GA-signaling components. On the other hand, GA down-regulated genes showed different expression patterns with respect to GID2 and GAMYB (e.g. a considerable number of genes are not controlled by GAMYB or GID2 and GAMYB). Based on these observations, we present a comprehensive discussion of the intricate network of GA-regulated genes in rice aleurone cells. © 2015 American Society of Plant Biologists. All Rights Reserved.

Biosynthesis of 12α-and 13-hydroxylated gibberellins in a cell-free system from Cucurbita maxima endosperm and the identification of new endogenous gibberellins.

Science.gov (United States)

Lange, T; Hedden, P; Graebe, J E

1993-03-01

Gibberellin (GA) biosynthesis in cell-free systems from Cucurbita maxima L. endosperm was reinvestigated using incubation conditions different from those employed in previous work. The metabolism of GA12 yielded GA13, GA43 and 12α-hydroxyGA43 as major products, GA4, GA37, GA39, GA46 and four unidentified compounds as minor products. The intermediates GA15, GA24 and GA25 accumulated at low protein concentrations. The structure of the previously uncharacterised 12α-hydroxyGA43 was inferred from its mass spectrum and by its formation from both GA39 and GA43. Gibberellin A39 and 12α-hydroxyGA43 were formed by a soluble 12α-hydroxylase that had not been detected before. Gibberellin A12-aldehyde was metabolised to essentially the same products as GA12 but with less efficiency. A new 13-hydroxylation pathway was found. Gibberellin A53, formed from GA12 by a microsomal oxidase, was converted by soluble 2-oxoglutarate-dependent oxidases to GA1 GA23, GA28, GA44, and putative 2β-hydroxyGA28. Minor products were GA19, GA20, GA38 and three unidentified GAs. Microsomal 13-hydroxylation (the formation of GA53) was suppressed by the cofactors for 2-oxoglutarate-dependent enzymes. Reinvestigation of the endogenous GAs confirmed the significance of the new metabolic products. In addition to the endogenous GAs reported by Blechschmidt et al. (1984, Phytochemistry 23, 553-558), GA1, GA8, GA25, GA28, GA36, GA48 and 12α-hydroxyGA43 were identified by full-scan capillary gas chromatography-mass spectrometry and Kovats retention indices. Thus both the 12α-hydroxylation and the 13-hydroxylation pathways found in the cell-free system operate also in vivo, giving rise to 12α-hydroxyGA43 and GA1 (or GA8), respectively, as their end products. Evidence for endogenous GA20 and GA24 was also obtained but it was less conclusive due to interference.

Studies on the role of gibberellins in the regulation of spermatogenesis in Chara vulgaris L.

Directory of Open Access Journals (Sweden)

Maria Kwiatkowska

2014-01-01

Full Text Available Antheridia from isolated nodes of Chara vulgaris, developing in the presence of either AMO-1618 or GA3, were studied. AMO-1618 which lowers the level of endogenous gibberellins causes a significant, proportional to the concentration, reduction in: 1 the number of antheridial filaments formed in antheridia, 2 spermatid number within a filament, as a result of eliminating one mitotic division at the first stage of spermatogenesis. Exogenous GA3 at the concentration 10-5 M evokes opposite effect i.e. increase in the number of antheridial filaments and increase in the number of spermatids within filament. Total number of spermatids within an antheridium decreases under the influence of 10-4M AMO-1618 three times in comparison with the control, whereas it increases twice following 10-5M GA3 treatment. It has been suggested that the normal course of spermatogenesis requires precisely determined level of endogenous gibberellins.

Interaction of a gibberellin-induced factor with the upstream region of an alpha-amylase gene in rice aleurone tissue.

OpenAIRE

Ou-Lee, T M; Turgeon, R; Wu, R

1988-01-01

The interaction between the DNA sequences of an alpha-amylase (EC 3.2.1.1) gene and a tissue-specific factor induced in rice (Oryza sativa L.) aleurone tissue by gibberellin was studied. DNA mobility-shift during electrophoresis indicated that a 500-base-pair sequence (HS500) of a rice alpha-amylase genomic clone (OSamy-a) specifically interacted with a factor from gibberellin-induced rice aleurone tissue. The amount of complex formed between the HS500 DNA fragment and the gibberellin-induced...

Comprehensive Gene Expression Analysis of Rice Aleurone Cells: Probing the Existence of an Alternative Gibberellin Receptor1

Science.gov (United States)

Yano, Kenji; Aya, Koichiro; Hirano, Ko; Ordonio, Reynante Lacsamana; Ueguchi-Tanaka, Miyako; Matsuoka, Makoto

2015-01-01

Current gibberellin (GA) research indicates that GA must be perceived in plant nuclei by its cognate receptor, GIBBERELLIN INSENSITIVE DWARF1 (GID1). Recognition of GA by GID1 relieves the repression mediated by the DELLA protein, a model known as the GID1-DELLA GA perception system. There have been reports of potential GA-binding proteins in the plasma membrane that perceive GA and induce α-amylase expression in cereal aleurone cells, which is mechanistically different from the GID1-DELLA system. Therefore, we examined the expression of the rice (Oryza sativa) α-amylase genes in rice mutants impaired in the GA receptor (gid1) and the DELLA repressor (slender rice1; slr1) and confirmed their lack of response to GA in gid1 mutants and constitutive expression in slr1 mutants. We also examined the expression of GA-regulated genes by genome-wide microarray and quantitative reverse transcription-polymerase chain reaction analyses and confirmed that all GA-regulated genes are modulated by the GID1-DELLA system. Furthermore, we studied the regulatory network involved in GA signaling by using a set of mutants defective in genes involved in GA perception and gene expression, namely gid1, slr1, gid2 (a GA-related F-box protein mutant), and gamyb (a GA-related trans-acting factor mutant). Almost all GA up-regulated genes were regulated by the four named GA-signaling components. On the other hand, GA down-regulated genes showed different expression patterns with respect to GID2 and GAMYB (e.g. a considerable number of genes are not controlled by GAMYB or GID2 and GAMYB). Based on these observations, we present a comprehensive discussion of the intricate network of GA-regulated genes in rice aleurone cells. PMID:25511432

Plant growth enhancement and associated physiological responses are coregulated by ethylene and gibberellin in response to harpin protein Hpa1.

Science.gov (United States)

Li, Xiaojie; Han, Bing; Xu, Manyu; Han, Liping; Zhao, Yanying; Liu, Zhilan; Dong, Hansong; Zhang, Chunling

2014-04-01

The harpin protein Hpa1 produced by the bacterial blight pathogen of rice induces several growth-promoting responses in plants, activating the ethylene signaling pathway, increasing photosynthesis rates and EXPANSIN (EXP) gene expression levels, and thereby enhancing the vegetative growth. This study was attempted to analyze any mechanistic connections among the above and the role of gibberellin in these responses. Hpa1-induced growth enhancement was evaluated in Arabidopsis, tomato, and rice. And growth-promoting responses were determined mainly as an increase of chlorophyll a/b ratio, which indicates a potential elevation of photosynthesis rates, and enhancements of photosynthesis and EXP expression in the three plant species. In Arabidopsis, Hpa1-induced growth-promoting responses were partially compromised by a defect in ethylene perception or gibberellin biosynthesis. In tomato and rice, compromises of Hpa1-induced growth-promoting responses were caused by a pharmacological treatment with an ethylene perception inhibitor or a gibberellin biosynthesis inhibitor. In the three plant species, moreover, Hpa1-induced growth-promoting responses were significantly impaired, but not totally eliminated, by abolishing ethylene perception or gibberellin synthesis. However, simultaneous nullifications in both ethylene perception and gibberellin biosynthesis almost canceled the full effects of Hpa1 on plant growth, photosynthesis, and EXP2 expression. Theses results suggest that ethylene and gibberellin coregulate Hpa1-induced plant growth enhancement and associated physiological and molecular responses.

Characterization of the Molecular Mechanism Underlying Gibberellin Perception Complex Formation in Rice[C][W

Science.gov (United States)

Hirano, Ko; Asano, Kenji; Tsuji, Hiroyuki; Kawamura, Mayuko; Mori, Hitoshi; Kitano, Hidemi; Ueguchi-Tanaka, Miyako; Matsuoka, Makoto

2010-01-01

The DELLA protein SLENDER RICE1 (SLR1) is a repressor of gibberellin (GA) signaling in rice (Oryza sativa), and most of the GA-associated responses are induced upon SLR1 degradation. It is assumed that interaction between GIBBERELLIN INSENSITIVE DWARF1 (GID1) and the N-terminal DELLA/TVHYNP motif of SLR1 triggers F-box protein GID2-mediated SLR1 degradation. We identified a semidominant dwarf mutant, Slr1-d4, which contains a mutation in the region encoding the C-terminal GRAS domain of SLR1 (SLR1G576V). The GA-dependent degradation of SLR1G576V was reduced in Slr1-d4, and compared with SLR1, SLR1G576V showed reduced interaction with GID1 and almost none with GID2 when tested in yeast cells. Surface plasmon resonance of GID1-SLR1 and GID1-SLR1G576V interactions revealed that the GRAS domain of SLR1 functions to stabilize the GID1-SLR1 interaction by reducing its dissociation rate and that the G576V substitution in SLR1 diminishes this stability. These results suggest that the stable interaction of GID1-SLR1 through the GRAS domain is essential for the recognition of SLR1 by GID2. We propose that when the DELLA/TVHYNP motif of SLR1 binds with GID1, it enables the GRAS domain of SLR1 to interact with GID1 and that the stable GID1-SLR1 complex is efficiently recognized by GID2. PMID:20716699

Exposure to red light, temperature and exogenous gibberellins ...

African Journals Online (AJOL)

Red light, temperature and gibberellins are well known for their capacity to induce higher germination in dormant seeds of several plant species. In the current study, we investigated the effect of various temperature (10, 13, 16, 19, 22 and 25°C) and gibberellic acid (GA3) and GA4+7 concentrations (0.1, 1, 10, and 100 uM) ...

Arabidopsis miR171-Targeted Scarecrow-Like Proteins Bind to GT cis-Elements and Mediate Gibberellin-Regulated Chlorophyll Biosynthesis under Light Conditions

Science.gov (United States)

Ma, Zhaoxue; Hu, Xupeng; Cai, Wenjuan; Huang, Weihua; Zhou, Xin; Luo, Qian; Yang, Hongquan; Wang, Jiawei; Huang, Jirong

2014-01-01

An extraordinarily precise regulation of chlorophyll biosynthesis is essential for plant growth and development. However, our knowledge on the complex regulatory mechanisms of chlorophyll biosynthesis is very limited. Previous studies have demonstrated that miR171-targeted scarecrow-like proteins (SCL6/22/27) negatively regulate chlorophyll biosynthesis via an unknown mechanism. Here we showed that SCLs inhibit the expression of the key gene encoding protochlorophyllide oxidoreductase (POR) in light-grown plants, but have no significant effect on protochlorophyllide biosynthesis in etiolated seedlings. Histochemical analysis of β-glucuronidase (GUS) activity in transgenic plants expressing pSCL27::rSCL27-GUS revealed that SCL27-GUS accumulates at high levels and suppresses chlorophyll biosynthesis at the leaf basal proliferation region during leaf development. Transient gene expression assays showed that the promoter activity of PORC is indeed regulated by SCL27. Consistently, chromatin immunoprecipitation and quantitative PCR assays showed that SCL27 binds to the promoter region of PORC in vivo. An electrophoretic mobility shift assay revealed that SCL27 is directly interacted with G(A/G)(A/T)AA(A/T)GT cis-elements of the PORC promoter. Furthermore, genetic analysis showed that gibberellin (GA)-regulated chlorophyll biosynthesis is mediated, at least in part, by SCLs. We demonstrated that SCL27 interacts with DELLA proteins in vitro and in vivo by yeast-two-hybrid and coimmunoprecipitation analysis and found that their interaction reduces the binding activity of SCL27 to the PORC promoter. Additionally, we showed that SCL27 activates MIR171 gene expression, forming a feedback regulatory loop. Taken together, our data suggest that the miR171-SCL module is critical for mediating GA-DELLA signaling in the coordinate regulation of chlorophyll biosynthesis and leaf growth in light. PMID:25101599

A Gibberellin-Mediated DELLA-NAC Signaling Cascade Regulates Cellulose Synthesis in Rice.

Science.gov (United States)

Huang, Debao; Wang, Shaogan; Zhang, Baocai; Shang-Guan, Keke; Shi, Yanyun; Zhang, Dongmei; Liu, Xiangling; Wu, Kun; Xu, Zuopeng; Fu, Xiangdong; Zhou, Yihua

2015-06-01

Cellulose, which can be converted into numerous industrial products, has important impacts on the global economy. It has long been known that cellulose synthesis in plants is tightly regulated by various phytohormones. However, the underlying mechanism of cellulose synthesis regulation remains elusive. Here, we show that in rice (Oryza sativa), gibberellin (GA) signals promote cellulose synthesis by relieving the interaction between SLENDER RICE1 (SLR1), a DELLA repressor of GA signaling, and NACs, the top-layer transcription factors for secondary wall formation. Mutations in GA-related genes and physiological treatments altered the transcription of CELLULOSE SYNTHASE genes (CESAs) and the cellulose level. Multiple experiments demonstrated that transcription factors NAC29/31 and MYB61 are CESA regulators in rice; NAC29/31 directly regulates MYB61, which in turn activates CESA expression. This hierarchical regulation pathway is blocked by SLR1-NAC29/31 interactions. Based on the results of anatomical analysis and GA content examination in developing rice internodes, this signaling cascade was found to be modulated by varied endogenous GA levels and to be required for internode development. Genetic and gene expression analyses were further performed in Arabidopsis thaliana GA-related mutants. Altogether, our findings reveal a conserved mechanism by which GA regulates secondary wall cellulose synthesis in land plants and provide a strategy for manipulating cellulose production and plant growth. © 2015 American Society of Plant Biologists. All rights reserved.

Influence of gibberellin and daminozide on the expression of terpene synthases and on monoterpenes in common sage (Salvia officinalis).

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Schmiderer, Corinna; Grausgruber-Gröger, Sabine; Grassi, Paolo; Steinborn, Ralf; Novak, Johannes

2010-07-01

Common sage (Salvia officinalis L., Lamiaceae) is one of the most important medicinal and aromatic plants, with antioxidant, antimicrobial, spasmolytic, astringent, antihidrotic and specific sensorial properties. The essential oil of the plant, composed mainly of the monoterpenes 1,8-cineole, alpha-thujone, beta-thujone and camphor, is responsible for some of these effects. Gibberellins regulate diverse physiological processes in plants, such as seed germination, shoot elongation and cell division. In this study, we analyzed the effect of exogenously applied plant growth regulators, namely gibberellic acid (GA(3)) and daminozide, on leaf morphology and essential oil formation of two leaf stages during the period of leaf expansion. Essential oil content increased with increasing levels of gibberellins and decreased when gibberellin biosynthesis was blocked with daminozide. With increasing levels of gibberellins, 1,8-cineole and camphor contents increased. Daminozide blocked the accumulation of alpha- and beta-thujone. GA(3) at the highest level applied also led to a significant decrease of alpha- and beta-thujone. Monoterpene synthases are a class of enzymes responsible for the first step in monoterpene biosynthesis, competing for the same substrate geranylpyrophosphate. The levels of gene expression of the three most important monoterpene synthases in sage were investigated, 1,8-cineole synthase leading directly to 1,8-cineole, (+)-sabinene synthase responsible for the first step in the formation of alpha- and beta-thujone, and (+)-bornyl diphosphate synthase, the first step in camphor biosynthesis. The foliar application of GA(3) increased, while daminozide significantly decreased gene expression of the monoterpene synthases. The amounts of two of the end products, 1,8-cineole and camphor, were directly correlated with the levels of gene expression of the respective monoterpene synthases, indicating transcriptional control, while the formation of alpha- and beta

SHOEBOX Modulates Root Meristem Size in Rice through Dose-Dependent Effects of Gibberellins on Cell Elongation and Proliferation.

Science.gov (United States)

Li, Jintao; Zhao, Yu; Chu, Huangwei; Wang, Likai; Fu, Yanru; Liu, Ping; Upadhyaya, Narayana; Chen, Chunli; Mou, Tongmin; Feng, Yuqi; Kumar, Prakash; Xu, Jian

2015-08-01

Little is known about how the size of meristem cells is regulated and whether it participates in the control of meristem size in plants. Here, we report our findings on shoebox (shb), a mild gibberellin (GA) deficient rice mutant that has a short root meristem size. Quantitative analysis of cortical cell length and number indicates that shb has shorter, rather than fewer, cells in the root meristem until around the fifth day after sowing, from which the number of cortical cells is also reduced. These defects can be either corrected by exogenous application of bioactive GA or induced in wild-type roots by a dose-dependent inhibitory effect of paclobutrazol on GA biosynthesis, suggesting that GA deficiency is the primary cause of shb mutant phenotypes. SHB encodes an AP2/ERF transcription factor that directly activates transcription of the GA biosynthesis gene KS1. Thus, root meristem size in rice is modulated by SHB-mediated GA biosynthesis that regulates the elongation and proliferation of meristem cells in a developmental stage-specific manner.

SHOEBOX Modulates Root Meristem Size in Rice through Dose-Dependent Effects of Gibberellins on Cell Elongation and Proliferation.

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Jintao Li

2015-08-01

Full Text Available Little is known about how the size of meristem cells is regulated and whether it participates in the control of meristem size in plants. Here, we report our findings on shoebox (shb, a mild gibberellin (GA deficient rice mutant that has a short root meristem size. Quantitative analysis of cortical cell length and number indicates that shb has shorter, rather than fewer, cells in the root meristem until around the fifth day after sowing, from which the number of cortical cells is also reduced. These defects can be either corrected by exogenous application of bioactive GA or induced in wild-type roots by a dose-dependent inhibitory effect of paclobutrazol on GA biosynthesis, suggesting that GA deficiency is the primary cause of shb mutant phenotypes. SHB encodes an AP2/ERF transcription factor that directly activates transcription of the GA biosynthesis gene KS1. Thus, root meristem size in rice is modulated by SHB-mediated GA biosynthesis that regulates the elongation and proliferation of meristem cells in a developmental stage-specific manner.

The occurrence of gibberellin-binding protein(s) in pea

Energy Technology Data Exchange (ETDEWEB)

Liu, Z.H.

1988-01-01

In vitro gibberellin (GA) binding properties of a cytosol fraction from epicotyls of dwarf pea (Pisum sativum L. cv. Progress No. 9) and tall pea (Pisum sativum L. cv. Alaska) were investigated using ({sup 3}H)GA{sub 4} in a DEAE filter paper assay at 0-3 C. The binding obtained is saturable, reversible, and temperature labile in dwarf pea, and has a half-life of dissociation of 5-6 min. By varying the concentration of ({sup 3}H)GA{sub 4} in the incubation medium the Kd was estimated to be 120-140 nM in dwarf pea and 70 nM in tall pea. The number of binding sites (n) was estimated to be 0.66 and 0.43 pmole mg{sup {minus}1} soluble protein in dwarf pea and in tall pea, respectively. In competition binding assays, biologically active GAs, such as GA{sub 3} and GA{sub 4} could reduce the level of ({sup 3}H)GA{sub 4} binding much more than the biologically inactive GA{sub 4} methyl ester and epi-GA{sub 4}. Changes in gibberellin-binding protein(s) were studied during seed germination. While the Kd of the binding protein(s) for ({sup 3}H)GA{sub 4} remained the same, there was a marked increase in the number of binding sites from 24 h soaked seed to 8-day old seedlings. Also, the Kd and the number of binding sites in the GA-responsive apical part and in the nonresponsive basal part in the epicotyl were similar. The effect of light on gibberellin-binding protein in dwarf pea was also studied. The GA-binding protein in dwarf pea was partially purified by gel filtration and ion exchange chromatography.

Expression of novel rice gibberellin 2-oxidase gene is under homeostatic regulation by biologically active gibberellins.

Science.gov (United States)

Sakai, Miho; Sakamoto, Tomoaki; Saito, Tamio; Matsuoka, Makoto; Tanaka, Hiroshi; Kobayashi, Masatomo

2003-04-01

We have cloned two genes for gibberellin (GA) 2-oxidase from rice ( Oryza sativa L.). Expression of OsGA2ox2 was not observed. The other gene, OsGA2ox3, was expressed in every tissue examined and was enhanced by the application of biologically active GA. Recombinant OsGA2ox3 protein catalyzed the metabolism of GA(1) to GA(8) and GA(20) to GA(29)-catabolite. These results indicate that OsGA2ox3 is involved in the homeostatic regulation of the endogenous level of biologically active GA in rice.

A Gibberellin-Mediated DELLA-NAC Signaling Cascade Regulates Cellulose Synthesis in Rice[OPEN

Science.gov (United States)

Huang, Debao; Wang, Shaogan; Zhang, Baocai; Shang-Guan, Keke; Shi, Yanyun; Zhang, Dongmei; Liu, Xiangling; Wu, Kun; Xu, Zuopeng; Fu, Xiangdong; Zhou, Yihua

2015-01-01

Cellulose, which can be converted into numerous industrial products, has important impacts on the global economy. It has long been known that cellulose synthesis in plants is tightly regulated by various phytohormones. However, the underlying mechanism of cellulose synthesis regulation remains elusive. Here, we show that in rice (Oryza sativa), gibberellin (GA) signals promote cellulose synthesis by relieving the interaction between SLENDER RICE1 (SLR1), a DELLA repressor of GA signaling, and NACs, the top-layer transcription factors for secondary wall formation. Mutations in GA-related genes and physiological treatments altered the transcription of CELLULOSE SYNTHASE genes (CESAs) and the cellulose level. Multiple experiments demonstrated that transcription factors NAC29/31 and MYB61 are CESA regulators in rice; NAC29/31 directly regulates MYB61, which in turn activates CESA expression. This hierarchical regulation pathway is blocked by SLR1-NAC29/31 interactions. Based on the results of anatomical analysis and GA content examination in developing rice internodes, this signaling cascade was found to be modulated by varied endogenous GA levels and to be required for internode development. Genetic and gene expression analyses were further performed in Arabidopsis thaliana GA-related mutants. Altogether, our findings reveal a conserved mechanism by which GA regulates secondary wall cellulose synthesis in land plants and provide a strategy for manipulating cellulose production and plant growth. PMID:26002868

Gibberellins – terpenoid plant hormones: Biological importance and chemical analysis

Czech Academy of Sciences Publication Activity Database

Urbanová, Terezie; Tarkowská, Danuše; Strnad, Miroslav; Hedden, P.

2011-01-01

Roč. 76, č. 12 (2011), s. 1669-1686 ISSN 0010-0765 R&D Projects: GA AV ČR KAN200380801; GA MŠk ED0007/01/01 Keywords : Gibberellins * Biosynthesis * Signaling * Profiling * Extraction * Purification * Mass spectrometry * Liquid chromatography Subject RIV: EF - Botanics Impact factor: 1.283, year: 2011

The rice YABBY1 gene is involved in the feedback regulation of gibberellin metabolism.

Science.gov (United States)

Dai, Mingqiu; Zhao, Yu; Ma, Qian; Hu, Yongfeng; Hedden, Peter; Zhang, Qifa; Zhou, Dao-Xiu

2007-05-01

Gibberellin (GA) biosynthesis is regulated by feedback control providing a mechanism for GA homeostasis in plants. However, regulatory elements involved in the feedback control are not known. In this report, we show that a rice (Oryza sativa) YABBY1 (YAB1) gene had a similar expression pattern as key rice GA biosynthetic genes GA3ox2 and GA20ox2. Overexpression of YAB1 in transgenic rice resulted in a semidwarf phenotype that could be fully rescued by applied GA. Quantification of the endogenous GA content revealed increases of GA(20) and decreases of GA(1) levels in the overexpression plants, in which the transcripts of the biosynthetic gene GA3ox2 were decreased. Cosuppression of YAB1 in transgenic plants induced expression of GA3ox2. The repression of GA3ox2 could be obtained upon treatment by dexamethasone of transgenic plants expressing a YAB1-glucocorticoid receptor fusion. Importantly, we show that YAB1 bound to a GA-responsive element within the GA3ox2 promoter. In addition, the expression of YAB1 was deregulated in GA biosynthesis and signaling mutants and could be either transiently induced by GA or repressed by a GA inhibitor. Finally, either overexpression or cosuppression of YAB1 impaired GA-mediated repression of GA3ox2. These data together suggest that YAB1 is involved in the feedback regulation of GA biosynthesis in rice.

Agrobacterium mediated transient gene silencing (AMTS in Stevia rebaudiana: insights into steviol glycoside biosynthesis pathway.

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Praveen Guleria

Full Text Available Steviol glycoside biosynthesis pathway has emerged as bifurcation from ent-kaurenoic acid, substrate of methyl erythritol phosphate pathway that also leads to gibberellin biosynthesis. However, the genetic regulation of steviol glycoside biosynthesis has not been studied. So, in present study RNA interference (RNAi based Agrobacterium mediated transient gene silencing (AMTS approach was followed. SrKA13H and three SrUGTs (SrUGT85C2, SrUGT74G1 and SrUGT76G1 genes encoding ent-kaurenoic acid-13 hydroxylase and three UDP glycosyltransferases of steviol glycoside biosynthesis pathway were silenced in Stevia rebaudiana to understand its molecular mechanism and association with gibberellins.RNAi mediated AMTS of SrKA13H and three SrUGTs has significantly reduced the expression of targeted endogenous genes as well as total steviol glycoside accumulation. While gibberellins (GA3 content was significantly enhanced on AMTS of SrUGT85C2 and SrKA13H. Silencing of SrKA13H and SrUGT85C2 was found to block the metabolite flux of steviol glycoside pathway and shifted it towards GA3 biosynthesis. Further, molecular docking of three SrUGT proteins has documented highest affinity of SrUGT76G1 for the substrates of alternate pathways synthesizing steviol glycosides. This could be a plausible reason for maximum reduction in steviol glycoside content on silencing of SrUGT76G1 than other genes.SrKA13H and SrUGT85C2 were identified as regulatory genes influencing carbon flux between steviol glycoside and gibberellin biosynthesis. This study has also documented the existence of alternate steviol glycoside biosynthesis route.

Regulation effects of exogenous gibberellin acid (GA 3 ) on the ...

African Journals Online (AJOL)

To fully understand the regulation effects of gibberellin on tomato (Solanum Lycoperscium) ovary locule formation and the fasciated transcription, two varieties: multi-locule 'MLK1' and few- locule 'FL1' which were highly different in locule number and fasciated transcriptional levels, were used in this study. By spraying GA3 ...

Interplay between cytochrome c and gibberellins during Arabidopsis vegetative development

Czech Academy of Sciences Publication Activity Database

Racca, S.; Welchen, E.; Gras, D. E.; Tarkowská, Danuše; Turečková, Veronika; Maurino, V. G.; Gonzalez, D. H.

2018-01-01

Roč. 94, č. 1 (2018), s. 105-121 ISSN 0960-7412 R&D Projects: GA MŠk(CZ) LO1204 Institutional support: RVO:61389030 Keywords : Arabidopsis thaliana * cytochrome c * DELLA protein * gibberellin * mitochondrion Subject RIV: EB - Genetics ; Molecular Biology OBOR OECD: Plant sciences, botany Impact factor: 5.901, year: 2016

Gibberellin-Abscisic Acid Balances during Arbuscular Mycorrhiza Formation in Tomato

Czech Academy of Sciences Publication Activity Database

Martin-Rodriguez, J.A.; Huertas, R.; Ho-Plagaro, T.; Ocampo, J.A.; Turečková, Veronika; Tarkowská, Danuše; Ludwig-Mueller, J.; Garcia-Garrido, J.M.

2016-01-01

Roč. 7, AUG 23 (2016), s. 1273 ISSN 1664-462X R&D Projects: GA ČR GA14-34792S; GA MŠk(CZ) LO1204 Institutional support: RVO:61389030 Keywords : arbuscular mycorrhiza * plant hormones * gibberellins Subject RIV: CB - Analytical Chemistry, Separation Impact factor: 4.298, year: 2016

Retrospectively reported month-to-month variation in sleeping problems of people naturally exposed to high-amplitude annual variation in daylength and/or temperature

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Arcady A. Putilov

Full Text Available Compared to literature on seasonal variation in mood and well-being, reports on seasonality of trouble sleeping are scarce and contradictive. To extend geography of such reports on example of people naturally exposed to high-amplitude annual variation in daylength and/or temperature. Participants were the residents of Turkmenia, West Siberia, South and North Yakutia, Chukotka, and Alaska. Health and sleep-wake adaptabilities, month-to-month variation in sleeping problems, well-being and behaviors were self-assessed. More than a half of 2398 respondents acknowledged seasonality of sleeping problems. Four of the assessed sleeping problems demonstrated three different patterns of seasonal variation. Rate of the problems significantly increased in winter months with long nights and cold days (daytime sleepiness and difficulties falling and staying asleep as well as in summer months with either long days (premature awakening and difficulties falling and staying asleep or hot nights and days (all 4 sleeping problems. Individual differences between respondents in pattern and level of seasonality of sleeping problems were significantly associated with differences in several other domains of individual variation, such as gender, age, ethnicity, physical health, morning-evening preference, sleep quality, and adaptability of the sleep-wake cycle. These results have practical relevance to understanding of the roles playing by natural environmental factors in seasonality of sleeping problems as well as to research on prevalence of sleep disorders and methods of their prevention and treatment in regions with large seasonal differences in temperature and daylength.

Regulation of Strigolactone Biosynthesis by Gibberellin Signaling.

Science.gov (United States)

Ito, Shinsaku; Yamagami, Daichi; Umehara, Mikihisa; Hanada, Atsushi; Yoshida, Satoko; Sasaki, Yasuyuki; Yajima, Shunsuke; Kyozuka, Junko; Ueguchi-Tanaka, Miyako; Matsuoka, Makoto; Shirasu, Ken; Yamaguchi, Shinjiro; Asami, Tadao

2017-06-01

Strigolactones (SLs) are a class of plant hormones that regulate diverse physiological processes, including shoot branching and root development. They also act as rhizosphere signaling molecules to stimulate the germination of root parasitic weeds and the branching of arbuscular mycorrhizal fungi. Although various types of cross talk between SLs and other hormones have been reported in physiological analyses, the cross talk between gibberellin (GA) and SLs is poorly understood. We screened for chemicals that regulate the level of SLs in rice ( Oryza sativa ) and identified GA as, to our knowledge, a novel SL-regulating molecule. The regulation of SL biosynthesis by GA is dependent on the GA receptor GID1 and F-box protein GID2. GA treatment also reduced the infection of rice plants by the parasitic plant witchers weed ( Striga hermonthica ). These data not only demonstrate, to our knowledge, the novel plant hormone cross talk between SL and GA, but also suggest that GA can be used to control parasitic weed infections. © 2017 American Society of Plant Biologists. All Rights Reserved.

Plant-specific Histone Deacetylases HDT½ Regulate GIBBERELLIN 2-OXIDASE 2 Expression to Control Arabidopsis Root Meristem Cell Number

KAUST Repository

Li, Huchen

2017-08-31

Root growth is modulated by environmental factors and depends on cell production in the root meristem (RM). New cells in the meristem are generated by stem cells and transit-amplifying cells, which together determine RM cell number. Transcription factors and chromatin-remodelling factors have been implicated in regulating the switch from stem cells to transit-amplifying cells. Here we show that two Arabidopsis thaliana paralogs encoding plant-specific histone deacetylases, HDT1 and HDT2, regulate a second switch from transit-amplifying cells to expanding cells. Knockdown of HDT½ (hdt1,2i) results in an earlier switch and causes a reduced RM cell number. Our data show that HDT½ negatively regulate the acetylation level of the C19-GIBBERELLIN 2-OXIDASE 2 (GA2ox2) locus and repress the expression of GA2ox2 in the RM and elongation zone. Overexpression of GA2ox2 in the RM phenocopies the hdt1,2i phenotype. Conversely, knockout of GA2ox2 partially rescues the root growth defect of hdt1,2i. These results suggest that by repressing the expression of GA2ox2, HDT½ likely fine-tune gibberellin metabolism and they are crucial for regulating the switch from cell division to expansion to determine RM cell number. We propose that HDT½ function as part of a mechanism that modulates root growth in response to environmental factors.

Gibberellic Acid-Stimulated Arabidopsis6 Serves as an Integrator of Gibberellin, Abscisic Acid, and Glucose Signaling during Seed Germination in Arabidopsis.

Science.gov (United States)

Zhong, Chunmei; Xu, Hao; Ye, Siting; Wang, Shiyi; Li, Lingfei; Zhang, Shengchun; Wang, Xiaojing

2015-11-01

The DELLA protein REPRESSOR OF ga1-3-LIKE2 (RGL2) plays an important role in seed germination under different conditions through a number of transcription factors. However, the functions of the structural genes associated with RGL2-regulated germination are less defined. Here, we report the role of an Arabidopsis (Arabidopsis thaliana) cell wall-localized protein, Gibberellic Acid-Stimulated Arabidopsis6 (AtGASA6), in functionally linking RGL2 and a cell wall loosening expansin protein (Arabidopsis expansin A1 [AtEXPA1]), resulting in the control of embryonic axis elongation and seed germination. AtGASA6-overexpressing seeds showed precocious germination, whereas transfer DNA and RNA interference mutant seeds displayed delayed seed germination under abscisic acid, paclobutrazol, and glucose (Glc) stress conditions. The differences in germination rates resulted from corresponding variation in cell elongation in the hypocotyl-radicle transition region of the embryonic axis. AtGASA6 was down-regulated by RGL2, GLUCOSE INSENSITIVE2, and ABSCISIC ACID-INSENSITIVE5 genes, and loss of AtGASA6 expression in the gasa6 mutant reversed the insensitivity shown by the rgl2 mutant to paclobutrazol and the gin2 mutant to Glc-induced stress, suggesting that it is involved in regulating both the gibberellin and Glc signaling pathways. Furthermore, it was found that the promotion of seed germination and length of embryonic axis by AtGASA6 resulted from a promotion of cell elongation at the embryonic axis mediated by AtEXPA1. Taken together, the data indicate that AtGASA6 links RGL2 and AtEXPA1 functions and plays a role as an integrator of gibberellin, abscisic acid, and Glc signaling, resulting in the regulation of seed germination through a promotion of cell elongation. © 2015 American Society of Plant Biologists. All Rights Reserved.

Agrobacterium Mediated Transient Gene Silencing (AMTS) in Stevia rebaudiana: Insights into Steviol Glycoside Biosynthesis Pathway

Science.gov (United States)

Guleria, Praveen; Yadav, Sudesh Kumar

2013-01-01

Background Steviol glycoside biosynthesis pathway has emerged as bifurcation from ent-kaurenoic acid, substrate of methyl erythritol phosphate pathway that also leads to gibberellin biosynthesis. However, the genetic regulation of steviol glycoside biosynthesis has not been studied. So, in present study RNA interference (RNAi) based Agrobacterium mediated transient gene silencing (AMTS) approach was followed. SrKA13H and three SrUGTs (SrUGT85C2, SrUGT74G1 and SrUGT76G1) genes encoding ent-kaurenoic acid-13 hydroxylase and three UDP glycosyltransferases of steviol glycoside biosynthesis pathway were silenced in Stevia rebaudiana to understand its molecular mechanism and association with gibberellins. Methodology/Principal Findings RNAi mediated AMTS of SrKA13H and three SrUGTs has significantly reduced the expression of targeted endogenous genes as well as total steviol glycoside accumulation. While gibberellins (GA3) content was significantly enhanced on AMTS of SrUGT85C2 and SrKA13H. Silencing of SrKA13H and SrUGT85C2 was found to block the metabolite flux of steviol glycoside pathway and shifted it towards GA3 biosynthesis. Further, molecular docking of three SrUGT proteins has documented highest affinity of SrUGT76G1 for the substrates of alternate pathways synthesizing steviol glycosides. This could be a plausible reason for maximum reduction in steviol glycoside content on silencing of SrUGT76G1 than other genes. Conclusions SrKA13H and SrUGT85C2 were identified as regulatory genes influencing carbon flux between steviol glycoside and gibberellin biosynthesis. This study has also documented the existence of alternate steviol glycoside biosynthesis route. PMID:24023961

Insights into the molecular mechanism of RGL2-mediated inhibition of seed germination in Arabidopsis thaliana

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Stamm Petra

2012-10-01

Full Text Available Abstract Background Seed germination is of immense significance for agriculture and has been studied for centuries. Yet, our understanding of the molecular mechanisms underlying regulation of dormancy and germination is still in its infancy. Gibberellins are the key phytohormones that promote germination, and the DELLA protein RGL2 is the main signalling intermediate involved in this response. Germination is completely inhibited if functional RGL2 is overexpressed and/or stabilized; however, the molecular mechanisms of RGL2 function are still largely unknown. We therefore attempted to shed light onto some of the genetic events downstream of RGL2. Results Gene ontology of the transcriptome differentially regulated by RGL2, as well as extensive cross-comparison with other available microarray data indicates that RGL2-mediated inhibition of germination causes seeds to enter a state of dormancy. RGL2 also appears to differentially regulate a number of transcription factors, many of which are known to be involved in light- or phytohormone-mediated aspects of germination. A promoter analysis of differentially expressed genes identified an enrichment of several motifs that can be bound by specific transcription factors, for example GAMYB, ARF1, or Dof-type zinc fingers. We show that Dof-binding motifs indeed play a role in RGL2-mediated transcription. Using Chromatin Immunoprecipitation (ChIP, we show that RGL2 directly downregulates at least one cell wall modifying enzyme, which is predicted to constrain cell growth thereby leading to inhibition of seed germination. Conclusions Our results reveal that RGL2 controls various aspects of germination. Through the repression of cell wall modifying enzymes, cell growth is directly constrained to inhibit germination. Furthermore, RGL2 likely interacts with various types of proteins to regulate transcription, and differentially regulates several transcription factors. Collectively, our data indicate that

Gibberellins and gravitropism in maize shoots: endogenous gibberellin-like substances and movement and metabolism of [3H]Gibberellin A20

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Rood, S. B.; Kaufman, P. B.; Abe, H.; Pharis, R. P.

1987-01-01

[3H]Gibberellin A20 (GA20) of high specific radioactivity (49.9 gigabecquerel per millimole) was applied equilaterally in a ring of microdrops to the internodal pulvinus of shoots of 3-week-old gravistimulated and vertical normal maize (Zea mays L.), and to a pleiogravitropic (prostrate) maize mutant, lazy (la). All plants converted the [3H]GA20 to [3H]GA1- and [3H]GA29-like metabolites as well as to several metabolites with the partitioning and chromatographic behavior of glucosyl conjugates of [3H]GA1, [3H]GA29, and [3H]GA8. The tentative identification of these putative [3H]GA glucosyl conjugates was further supported by the release of the free [3H]GA moiety after cleavage with cellulase. Within 12 hours of the [3H]GA20 feed, there was a significantly higher proportion of total radioactivity in lower than in upper halves of internode and leaf sheath pulvini in gravistimulated normal maize. Further, there was a significantly higher proportion of putative free GA metabolites of [3H]GA20, especially [3H]GA1, in the lower halves of normal maize relative to upper halves. The differential localization of the metabolites between upper and lower halves was not apparent in the pleiogravitropic mutant, la. Endogenous GA-like substances were also examined in gravistimulated maize shoots. Forty-eight hours after gravistimulation of 3-week-old maize seedlings, endogenous free GA-like substances in upper and lower leaf sheath and internode pulvini halves were extracted, chromatographed, and bioassayed using the "Tanginbozu" dwarf rice microdrop assay. Lower halves contained consistently higher total levels of GA-like activity. The qualitative elution profile of GA-like substances differed consistently, upper halves containing principally a GA20-like substance and lower halves containing principally a GA20-like substance and lower halves containing mainly GA1-like and GA19-like substances. Gibberellins A1 (10 nanograms per gram) and A20 (5 nanograms per gram) were identified

A local maximum in gibberellin levels regulates maize leaf growth by spatial control of cell division.

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Nelissen, Hilde; Rymen, Bart; Jikumaru, Yusuke; Demuynck, Kirin; Van Lijsebettens, Mieke; Kamiya, Yuji; Inzé, Dirk; Beemster, Gerrit T S

2012-07-10

Plant growth rate is largely determined by the transition between the successive phases of cell division and expansion. A key role for hormone signaling in determining this transition was inferred from genetic approaches and transcriptome analysis in the Arabidopsis root tip. We used the developmental gradient at the maize leaf base as a model to study this transition, because it allows a direct comparison between endogenous hormone concentrations and the transitions between dividing, expanding, and mature tissue. Concentrations of auxin and cytokinins are highest in dividing tissues, whereas bioactive gibberellins (GAs) show a peak at the transition zone between the division and expansion zone. Combined metabolic and transcriptomic profiling revealed that this GA maximum is established by GA biosynthesis in the division zone (DZ) and active GA catabolism at the onset of the expansion zone. Mutants defective in GA synthesis and signaling, and transgenic plants overproducing GAs, demonstrate that altering GA levels specifically affects the size of the DZ, resulting in proportional changes in organ growth rates. This work thereby provides a novel molecular mechanism for the regulation of the transition from cell division to expansion that controls organ growth and size. Copyright © 2012 Elsevier Ltd. All rights reserved.

Regulation of Strigolactone Biosynthesis by Gibberellin Signaling1[OPEN

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Ito, Shinsaku; Yamagami, Daichi; Umehara, Mikihisa; Hanada, Atsushi; Sasaki, Yasuyuki; Yajima, Shunsuke; Kyozuka, Junko; Ueguchi-Tanaka, Miyako; Matsuoka, Makoto; Yamaguchi, Shinjiro

2017-01-01

Strigolactones (SLs) are a class of plant hormones that regulate diverse physiological processes, including shoot branching and root development. They also act as rhizosphere signaling molecules to stimulate the germination of root parasitic weeds and the branching of arbuscular mycorrhizal fungi. Although various types of cross talk between SLs and other hormones have been reported in physiological analyses, the cross talk between gibberellin (GA) and SLs is poorly understood. We screened for chemicals that regulate the level of SLs in rice (Oryza sativa) and identified GA as, to our knowledge, a novel SL-regulating molecule. The regulation of SL biosynthesis by GA is dependent on the GA receptor GID1 and F-box protein GID2. GA treatment also reduced the infection of rice plants by the parasitic plant witchers weed (Striga hermonthica). These data not only demonstrate, to our knowledge, the novel plant hormone cross talk between SL and GA, but also suggest that GA can be used to control parasitic weed infections. PMID:28404726

The rice YABBY4 gene regulates plant growth and development through modulating the gibberellin pathway.

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Yang, Chao; Ma, Yamei; Li, Jianxiong

2016-10-01

YABBY genes encode seed plant-specific transcription factors that play pivotal roles in diverse aspects of leaf, shoot, and flower development. Members of the YABBY gene family are primarily expressed in lateral organs in a polar manner and function to specify abaxial cell fate in dicotyledons, but this polar expression is not conserved in monocotyledons. The function of YABBY genes is therefore not well understood in monocotyledons. Here we show that overexpression of the rice (Oryza sativa L.) YABBY4 gene (OsYABBY4) leads to a semi-dwarf phenotype, abnormal development in the uppermost internode, an increased number of floral organs, and insensitivity to gibberellin (GA) treatment. We report on an important role for OsYABBY4 in negative control of the expression of a GA biosynthetic gene by binding to the promoter region of the gibberellin 20-oxidase 2 gene (GA20ox2), which is a direct target of SLR1 (the sole DELLA protein negatively controlling GA responses in rice). OsYABBY4 also suppresses the expression level of SLR1 and interacts with SLR1 protein. The interaction inhibits GA-dependent degradation of SLR1 and therefore leads to GA insensitivity. These data together suggest that OsYABBY4 serves as a DNA-binding intermediate protein for SLR1 and is associated with the GA signaling pathway regulating gene expression during plant growth and development. © The Author 2016. Published by Oxford University Press on behalf of the Society for Experimental Biology. All rights reserved. For permissions, please email: journals.permissions@oup.com.

Exogenous auxin represses soybean seed germination through decreasing the gibberellin/abscisic acid (GA/ABA) ratio.

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Shuai, Haiwei; Meng, Yongjie; Luo, Xiaofeng; Chen, Feng; Zhou, Wenguan; Dai, Yujia; Qi, Ying; Du, Junbo; Yang, Feng; Liu, Jiang; Yang, Wenyu; Shu, Kai

2017-10-03

Auxin is an important phytohormone which mediates diverse development processes in plants. Published research has demonstrated that auxin induces seed dormancy. However, the precise mechanisms underlying the effect of auxin on seed germination need further investigation, especially the relationship between auxins and both abscisic acid (ABA) and gibberellins (GAs), the latter two phytohormones being the key regulators of seed germination. Here we report that exogenous auxin treatment represses soybean seed germination by enhancing ABA biosynthesis, while impairing GA biogenesis, and finally decreasing GA 1 /ABA and GA 4 /ABA ratios. Microscope observation showed that auxin treatment delayed rupture of the soybean seed coat and radicle protrusion. qPCR assay revealed that transcription of the genes involved in ABA biosynthetic pathway was up-regulated by application of auxin, while expression of genes involved in GA biosynthetic pathway was down-regulated. Accordingly, further phytohormone quantification shows that auxin significantly increased ABA content, whereas the active GA 1 and GA 4 levels were decreased, resulting insignificant decreases in the ratiosGA 1 /ABA and GA 4 /ABA.Consistent with this, ABA biosynthesis inhibitor fluridone reversed the delayed-germination phenotype associated with auxin treatment, while paclobutrazol, a GA biosynthesis inhibitor, inhibited soybean seed germination. Altogether, exogenous auxin represses soybean seed germination by mediating ABA and GA biosynthesis.

Effects of protein restriction, melatonin administration, and short daylength on brain benzodiazepine receptors in prepubertal male rats

International Nuclear Information System (INIS)

Kennaway, D.J.; Royles, P.; Webb, H.; Carbone, F.

1988-01-01

The possibility that there are changes in brain benzodiazepine binding sites controlled by photoperiod was investigated in two strains of male rats. The hypothesis was tested by 3H-diazepam binding studies in various brain regions of prepubertal rats maintained in 14 or 10 h of light or treated with late-afternoon injections of melatonin (50 micrograms/day). Protein restriction was applied during the experiment to sensitize the animals to the treatments. Under the conditions employed, rats kept in short daylength throughout or kept on long photoperiod and given late-afternoon melatonin injections showed evidence of delayed puberty (seminal vesicle, ventral prostate, and testis weight decreased by 45%, 55%, and 60% respectively, compared to control rats). Binding measurements were made 1 h before and 2 and 5 h after the onset of darkness in the pubertal (42-day-old) or experimentally prepubertal rats. In the rats of the Porton strain (for which protein restriction was obligatory for the gonadal response) there was no consistent treatment or time effects on specific binding of 3H-diazepam to washed membranes of the hypothalamus, midbrain, or striatum. Similarly, there were no differences in the stimulation of 3H-diazepam binding by 100 microM GABA or the inhibition of binding by 50 microM N-acetyl 5 methoxy kynurenamine. By contrast, in Wistar rats, specific binding to midbrain membranes was reduced 5 h after dark compared to 2 h (37% saline; 20% melatonin) and the extent of stimulation by GABA in the hypothalamus was increased 5 h after darkness (35.6% to 46.7% saline; 37.4% to 50% melatonin). Melatonin treatment resulted in significantly higher specific binding in the hypothalamus 2 h after dark (10%, control fed; 20%, protein restricted) but reduced the GABA induced stimulation of binding in the midbrain (35.5% to 25%, control fed; 33.7% to 23.5%, protein restricted)

Molecular Mechanisms Underlying Abscisic Acid/Gibberellin Balance in the Control of Seed Dormancy and Germination in Cereals

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Pham A. Tuan

2018-05-01

Full Text Available Seed dormancy is an adaptive trait that does not allow the germination of an intact viable seed under favorable environmental conditions. Non-dormant seeds or seeds with low level of dormancy can germinate readily under optimal environmental conditions, and such a trait leads to preharvest sprouting, germination of seeds on the mother plant prior to harvest, which significantly reduces the yield and quality of cereal crops. High level of dormancy, on the other hand, may lead to non-uniform germination and seedling establishment. Therefore, intermediate dormancy is considered to be a desirable trait as it prevents the problems of sprouting and allows uniformity of postharvest germination of seeds. Induction, maintenance, and release of seed dormancy are complex physiological processes that are influenced by a wide range of endogenous and environmental factors. Plant hormones, mainly abscisic acid (ABA and gibberellin (GA, are the major endogenous factors that act antagonistically in the control of seed dormancy and germination; ABA positively regulates the induction and maintenance of dormancy, while GA enhances germination. Significant progress has been made in recent years in the elucidation of molecular mechanisms regulating ABA/GA balance and thereby dormancy and germination in cereal seeds, and this review summarizes the current state of knowledge on the topic.

Molecular Mechanisms Underlying Abscisic Acid/Gibberellin Balance in the Control of Seed Dormancy and Germination in Cereals

Science.gov (United States)

Tuan, Pham A.; Kumar, Rohit; Rehal, Pawanpuneet K.; Toora, Parneet K.; Ayele, Belay T.

2018-01-01

Seed dormancy is an adaptive trait that does not allow the germination of an intact viable seed under favorable environmental conditions. Non-dormant seeds or seeds with low level of dormancy can germinate readily under optimal environmental conditions, and such a trait leads to preharvest sprouting, germination of seeds on the mother plant prior to harvest, which significantly reduces the yield and quality of cereal crops. High level of dormancy, on the other hand, may lead to non-uniform germination and seedling establishment. Therefore, intermediate dormancy is considered to be a desirable trait as it prevents the problems of sprouting and allows uniformity of postharvest germination of seeds. Induction, maintenance, and release of seed dormancy are complex physiological processes that are influenced by a wide range of endogenous and environmental factors. Plant hormones, mainly abscisic acid (ABA) and gibberellin (GA), are the major endogenous factors that act antagonistically in the control of seed dormancy and germination; ABA positively regulates the induction and maintenance of dormancy, while GA enhances germination. Significant progress has been made in recent years in the elucidation of molecular mechanisms regulating ABA/GA balance and thereby dormancy and germination in cereal seeds, and this review summarizes the current state of knowledge on the topic. PMID:29875780

The development of a high performance liquid chromatograph with a sensitive on-stream radioactivity monitor for the analysis of 3H- and 14C-labelled gibberellins

International Nuclear Information System (INIS)

Reeve, D.R.; Yokota, T.; Nash, L.; Crozier, A.

1976-01-01

The development of a high performance liquid chromatograph for the separation of gibberellins is described. The system combines high efficiency, peak capacity, and sample capacity with rapid speed of analysis. In addition, the construction details of a sensitive on-stream radioactivity monitor are outlined. The overall versatility of the chromatograph has been demonstrated by the separation of a range of 3 H- and 14 C-labelled gibberellins and gibberellin precursors. The system also has considerable potential for the analysis of abscisic acid and acidic and neutral indoles. (author)

Gibberellin hormone signal perception: down-regulating DELLA repressors of plant growth and development

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The gibberellin (GA) hormone signal is perceived by a receptor with homology to hormone sensitive lipases, GID1 (GA-INSENSITIVE DWARF1). This leads to GA-stimulated responses including stem elongation, seed germination, and the transition to flowering. GA-binding enables GID1 to interact with and ...

Brassinosteroids antagonize gibberellin- and salicylate-mediated root immunity in rice.

Science.gov (United States)

De Vleesschauwer, David; Van Buyten, Evelien; Satoh, Kouji; Balidion, Johny; Mauleon, Ramil; Choi, Il-Ryong; Vera-Cruz, Casiana; Kikuchi, Shoshi; Höfte, Monica

2012-04-01

Brassinosteroids (BRs) are a unique class of plant steroid hormones that orchestrate myriad growth and developmental processes. Although BRs have long been known to protect plants from a suite of biotic and abiotic stresses, our understanding of the underlying molecular mechanisms is still rudimentary. Aiming to further decipher the molecular logic of BR-modulated immunity, we have examined the dynamics and impact of BRs during infection of rice (Oryza sativa) with the root oomycete Pythium graminicola. Challenging the prevailing view that BRs positively regulate plant innate immunity, we show that P. graminicola exploits BRs as virulence factors and hijacks the rice BR machinery to inflict disease. Moreover, we demonstrate that this immune-suppressive effect of BRs is due, at least in part, to negative cross talk with salicylic acid (SA) and gibberellic acid (GA) pathways. BR-mediated suppression of SA defenses occurred downstream of SA biosynthesis, but upstream of the master defense regulators NONEXPRESSOR OF PATHOGENESIS-RELATED GENES1 and OsWRKY45. In contrast, BR alleviated GA-directed immune responses by interfering at multiple levels with GA metabolism, resulting in indirect stabilization of the DELLA protein and central GA repressor SLENDER RICE1 (SLR1). Collectively, these data favor a model whereby P. graminicola coopts the plant BR pathway as a decoy to antagonize effectual SA- and GA-mediated defenses. Our results highlight the importance of BRs in modulating plant immunity and uncover pathogen-mediated manipulation of plant steroid homeostasis as a core virulence strategy.

Transcriptomic Analysis of Gibberellin- and Paclobutrazol-Treated Rice Seedlings under Submergence

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Jing Xiang

2017-10-01

Full Text Available Submergence stress is a limiting factor for rice growing in rainfed lowland areas of the world. It is known that the phytohormone gibberellin (GA has negative effects on submergence tolerance in rice, while its inhibitor paclobutrazol (PB does the opposite. However, the physiological and molecular basis underlying the GA- and PB-regulated submergence response remains largely unknown. In this study, we reveal that PB could significantly enhance rice seedling survival by retaining a higher level of chlorophyll content and alcohol dehydrogenase activity, and decelerating the consumption of non-structure carbohydrate when compared with the control and GA-treated samples. Further transcriptomic analysis identified 3936 differentially expressed genes (DEGs among the GA- and PB-treated samples and control, which are extensively involved in the submergence and other abiotic stress responses, phytohormone biosynthesis and signaling, photosynthesis, and nutrient metabolism. The results suggested that PB enhances rice survival under submergence through maintaining the photosynthesis capacity and reducing nutrient metabolism. Taken together, the current study provided new insight into the mechanism of phytohormone-regulated submergence response in rice.

A gibberellin-stimulated transcript, OsGASR1, controls seedling growth and α-amylase expression in rice.

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Lee, Sang-Choon; Kim, Soo-Jin; Han, Soon-Ki; An, Gynheung; Kim, Seong-Ryong

2017-07-01

From a T-DNA-tagging population in rice, we identified OsGASR1 (LOC_Os03g55290), a member of the GAST (gibberellin (GA)-Stimulated Transcript) family that is induced by salt stress and ABA treatment. This gene was highly expressed in the regions of cell proliferation and panicle development, as revealed by a GUS assay of the mutant line. In the osgasr1 mutants, the second leaf blades were much longer than those of the segregating wild type due to an increase in cell length. In addition, five α-amylase genes were up-regulated in the mutants, implying that OsGASR1 is a negative regulator of those genes. These results suggest that OsGASR1 plays important roles in seedling growth and α-amylase gene expression. Copyright © 2017 Elsevier GmbH. All rights reserved.

Tall or short? Slender or thick? A plant strategy for regulating elongation growth of roots by low concentrations of gibberellin.

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Tanimoto, Eiichi

2012-07-01

Since the plant hormone gibberellin (GA) was discovered as a fungal toxin that caused abnormal elongation of rice shoots, the physiological function of GA has mainly been investigated in relation to the regulation of plant height. However, an indispensable role for GA in root growth has been elucidated by using severely GA-depleted plants, either with a gene mutation in GA biosynthesis or which have been treated by an inhibitor of GA biosynthesis. The molecular sequence of GA signalling has also been studied to understand GA functions in root growth. This review addresses research progress on the physiological functions of GA in root growth. Concentration-dependent stimulation of elongation growth by GA is important for the regulation of plant height and root length. Thus the endogenous level of GA and/or the GA sensitivity of shoots and roots plays a role in determining the shoot-to-root ratio of the plant body. Since the shoot-to-root ratio is an important parameter for agricultural production, control of GA production and GA sensitivity may provide a strategy for improving agricultural productivity. The sequence of GA signal transduction has recently been unveiled, and some component molecules are suggested as candidate in planta regulatory sites and as points for the artificial manipulation of GA-mediated growth control. This paper reviews: (1) the breakthrough dose-response experiments that show that root growth is regulated by GA in a lower concentration range than is required for shoot growth; (2) research on the regulation of GA biosynthesis pathways that are known predominantly to control shoot growth; and (3) recent research on GA signalling pathways, including GA receptors, which have been suggested to participate in GA-mediated growth regulation. This provides useful information to suggest a possible strategy for the selective control of shoot and root growth, and to explain how GA plays a role in rosette and liana plants with tall or short, and slender

Investigations of the effect of exogenous gibberellin on the electrophoretic repair of plant DNA damaged by the gamma radiation

International Nuclear Information System (INIS)

Kryukova, L.M.; Medvedkova, V.V.

1981-01-01

Effect of the exogenous gibberellin on the DNA of plants irradiated with high doses of γ-radiation is studied. Repair of the molecular weight of DNA can be judged on according to electrophoretic mobility in 1% agar sludge of DNA samples denaturated in alkaline. Investigation results reaffirm that exogenous gibberellin promotes to the repair of the DNA of plants damaged with high doses of radiation. The mechanism of the effect of the hormone is not yet studied, but it is supposed that physiological action of the phytohormone is realized through the ferment systems of plants [ru

Identification of gibberellin acid-responsive proteins in rice leaf sheath using proteomics.

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Gu, Jia-Yu; Wang, Ye; Zhang, Xu; Zhang, Shi-Hua; Gao, Yin; An, Cheng-Cai

2010-06-01

The phytohormone gibberellin acid (GA) controls many aspects of plant development. In this study, we identified proteins that are differentially expressed between the rice (Oryza sativa L.) GA-deficient cultivar, Aijiaonante, and its parental line, Nante. Proteins were extracted from rice leaf sheath and examined by 2DGE. Among more than 1200 protein spots reproducibly detected on each gel, 29 were found to be highly up-regulated by GAs in Nante, and 6 were down-regulated by GAs in Aijiaonante. These 35 proteins were identified by MALDI-TOF MS and were classified into three groups based on their putative function in metabolism, stress/defense processes and signal transduction. These data suggest that metabolic pathways are the main target of regulation by GAs during rice development. Our results provide new information about the involvement of GAs in rice development.

Arabidopsis scaffold protein RACK1A modulates rare sugar D-allose regulated gibberellin signaling.

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Fennell, Herman; Olawin, Abdulquadri; Mizanur, Rahman M; Izumori, Ken; Chen, Jin-Gui; Ullah, Hemayet

2012-11-01

As energy sources and structural components, sugars are the central regulators of plant growth and development. In addition to the abundant natural sugars in plants, more than 50 different kinds of rare sugars exist in nature, several of which show distinct roles in plant growth and development. Recently, one of the rare sugars, D-allose, an epimer of D-glucose at C3, is found to suppress plant hormone gibberellin (GA) signaling in rice. Scaffold protein RACK1A in the model plant Arabidopsis is implicated in the GA pathway as rack1a knockout mutants show insensitivity to GA in GA-induced seed germination. Using genetic knockout lines and a reporter gene, the functional role of RACK1A in the D-allose pathway was investigated. It was found that the rack1a knockout seeds showed hypersensitivity to D-allose-induced inhibition of seed germination, implicating a role for RACK1A in the D-allose mediated suppression of seed germination. On the other hand, a functional RACK1A in the background of the double knockout mutations in the other two RACK1 isoforms, rack1b/rack1c, showed significant resistance to the D-allose induced inhibition of seed germination. The collective results implicate the RACK1A in the D-allose mediated seed germination inhibition pathway. Elucidation of the rare sugar signaling mechanism will help to advance understanding of this less studied but important cellular signaling pathway.

Examination of two lowland rice cultivars reveals that gibberellin-dependent early response to submergence is not necessarily mediated by ethylene.

Science.gov (United States)

Dubois, Vincent; Moritz, Thomas; García-Martínez, José L

2011-01-01

Using two lowland rice (Oryza sativa L.) cultivars we found that in both cases submerged-induced elongation early after germination depends on gibberellins (GAs). Submergence increases the content of the active GA 1 by enhancing the expression of GA biosynthesis genes, thus facilitating the seedlings to escape from the water and preventing asphyxiation. However, the two cultivars differ in their response to ethylene. The cultivar Senia (short), by contrast to cultivar Bomba (tall), does not elongate after ethylene application, and submerged-induced elongation is not negated by an inhibitor of ethylene perception. Also, while ethylene emanation in Senia is not altered by submergence, Bomba seedlings emanate more ethylene upon de-submergence, associated with enhanced expression of the ethylene biosynthesis gene OsACS5. The cultivar Senia thus allows the possibility of clarifying the role of ethylene and other factors as triggers of GA biosynthesis enhancement in rice seedlings under submergence.

Functional Characterization of Gibberellin-Regulated Genes in Rice Using Microarray System

OpenAIRE

Jan, Asad; Komatsu, Setsuko

2006-01-01

Gibberellin (GA) is collectively referred to a group of diterpenoid acids, some of which act as plant hormones and are essential for normal plant growth and development. DNA microarray technology has become the standard tool for the parallel quantification of large numbers of messenger RNA transcripts. The power of this approach has been demonstrated in dissecting plant physiology and development, and in unraveling the underlying cellular signaling pathways. To understand the molecular mechan...

Interactions between ethylene, gibberellins, and brassinosteroids in the development of rhizobial and mycorrhizal symbioses of pea.

Science.gov (United States)

Foo, Eloise; McAdam, Erin L; Weller, James L; Reid, James B

2016-04-01

The regulation of arbuscular mycorrhizal development and nodulation involves complex interactions between the plant and its microbial symbionts. In this study, we use the recently identified ethylene-insensitive ein2 mutant in pea (Pisum sativum L.) to explore the role of ethylene in the development of these symbioses. We show that ethylene acts as a strong negative regulator of nodulation, confirming reports in other legumes. Minor changes in gibberellin1 and indole-3-acetic acid levels in ein2 roots appear insufficient to explain the differences in nodulation. Double mutants produced by crosses between ein2 and the severely gibberellin-deficient na and brassinosteroid-deficient lk mutants showed increased nodule numbers and reduced nodule spacing compared with the na and lk single mutants, but nodule numbers and spacing were typical of ein2 plants, suggesting that the reduced number of nodules innaandlkplants is largely due to the elevated ethylene levels previously reported in these mutants. We show that ethylene can also negatively regulate mycorrhizae development when ethylene levels are elevated above basal levels, consistent with a role for ethylene in reducing symbiotic development under stressful conditions. In contrast to the hormone interactions in nodulation, ein2 does not override the effect of lk or na on the development of arbuscular mycorrhizae, suggesting that brassinosteroids and gibberellins influence this process largely independently of ethylene. © The Author 2016. Published by Oxford University Press on behalf of the Society for Experimental Biology.

QTL analysis of internode elongation in response to gibberellin in deepwater rice

OpenAIRE

Nagai, Keisuke; Kondo, Yuma; Kitaoka, Takuya; Noda, Tomonori; Kuroha, Takeshi; Angeles-Shim, Rosalyn B.; Yasui, Hideshi; Yoshimura, Atsushi; Ashikari, Motoyuki

2014-01-01

Gibberellin (GA) is a plant hormone that has important roles in numerous plant developmental phases. Rice plants known as deepwater rice respond to flooding by elongating their internodes to avoid anoxia. Previous studies reported that GA is essential for internode elongation in deepwater rice. Quantitative trait locus (QTL) analyses identified QTLs regulating internode elongation in response to deepwater conditions. However, the interaction between internode elongation and regulators of GA s...

Features of gas exchange and use of reserve substances in pumpkin seedlings in conditions of skoto- and photomorphogenesis under the influence of gibberellin and chlormequat-chloride

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I. V. Poprotska

2017-02-01

Full Text Available We investigated the effect of gibberellin and the antigibberellic agent chlormequat-chloride on gas exchange and use of reserve substances in pumpkin seedlings during germination in the light and in the dark. We established that an artificial strengthening or growth inhibition of pumpkin seedlings in conditions of skotomorphogenesis caused an increase in of respiration intensity. Gibberellin treatment increased the proportion of assimilation processes in carbon dioxide gas exchange of seedlings, and growth inhibition by retardant caused an increase in respiratory costs when the nutrition type switches in the light from heterotrophic to autotrophic. The formation by seedlings of the demand for reserve assimilates from cotyledons was largely determined by change of activity of subapical meristems, which is manifested in the acceleration of seed germination, enhancing of histogenesis for the actions of gibberellin and in the weakening of these processes under the influence of retardants. Reserve substances used both oil and nitrogen-containing compounds. The content of protein nitrogen in pumpkin cotyledons decreased more in the light than in the dark, moreover growth inhibition by the retardant slowed down and growth increase by gibberellin accelerated this process both in conditions of photomorphogenesis and skotomorphogenesis.

Further identification of endogenous gibberellins in the shoots of pea, line G2

International Nuclear Information System (INIS)

Halinska, A.; Davies, P.J.; Lee, J.W.; Zhu, Yuxian

1989-01-01

To interpret the metabolism of radiolabeled gibberellins A 12 -aldehyde and A 12 in shoots of pea (Pisum sativum L.), the identity of the radiolabeled peaks has to be determined and the endogenous presence of the gibberellins demonstrated. High specific activity [ 14 C]GA 12 and [ 14 C]GA 12 -aldehyde were synthesized using a pumpkin endosperm enzyme preparation, and purified by high performance liquid chromatography (HPLC). [ 14 C]GA 12 was supplied to upper shoots of pea, line G2, to produce radiolabeled metabolites on the 13-OH pathway. Endogenous compounds copurifying with the [ 14 C]GAs on HPLC were analyzed by gas chromatography-mass spectrometry. The endogenous presence of GA 53 , GA 44 , GA 19 and GA 20 was demonstrated and their HPLC peak identity ascertained. The 14 C was progressively diluted in GAs further down the pathway, proportional to the levels found in the tissue and inversely proportional to the speed of metabolism, ranging from 63% in GA 53 to 4% in GA 20 . Calculated levels of GA 20 , GA 19 , GA 44 , and GA 53 were 42, 8, 10, and 0.5 nanograms/gram, respectively

Analysis of gibberellins as free acids by ultra performance liquid chromatography-tandem mass spectrometry

Czech Academy of Sciences Publication Activity Database

Urbanová, Terezie; Tarkowská, Danuše; Novák, Ondřej; Hedden, P.; Strnad, M.

2013-01-01

Roč. 112, č. 2013 (2013), s. 85-94 ISSN 0039-9140 R&D Projects: GA AV ČR KAN200380801 Grant - others:GA MŠk(CZ) ED0007/01/01 Program:ED Institutional research plan: CEZ:AV0Z50380511 Keywords : Gibberellins * Brassica napus * Arabidopsis thaliana Subject RIV: EC - Immunology Impact factor: 3.511, year: 2013

Gibberellins and gravitropism in maize shoots: endogenous gibberellin-like substances and movement and metabolism of [3]gibberellin A

International Nuclear Information System (INIS)

Rood, S.B.; Kaufman, P.B.; Abe, H.; Pharis, R.P.

1987-01-01

[ 3 H]Gibberellin A 20 (GA 20 ) of high specific radioactivity was applied equilaterally in a ring of microdrops to the internodal pulvinus of shoots of 3-week-old vertical normal maize (Zea mays L.), and to a pleiogravitropic (prostrate) maize mutant, lazy (la). All plants converted the [ 3 H]GA 1 - and [ 3 H]GA 29 -like metabolites as well as to several metabolites with the partitioning and chromatographic behavior of glucosyl conjugates of [ 3 H]GA 1 [ 3 H]GA 29 , and [ 3 H]GA 8 . The tentative identification of these putative [ 3 H]GA glucosyl conjugates was further supported by the release of the free [ 3 H]GA moiety after cleavage with cellulase. Within 12 hours of the [ 3 H]GA 20 feed, there was a significantly higher proportion of total radioactivity in lower than in upper halves of internode and leaf sheaf pulvini in gravistimulated normal maize. Further, there was a significantly higher proportion of putative free GA metabolites of [ 3 H]GA 20 , especially [ 3 H] GA 1 , in the lower halves of normal maize relative to upper halves. The differential localization of the metabolites between upper and lower halves was not apparent in the pleiogravitropic mutant, la. Endogenous GA-like substances were also examined in gravistimulated maize shoots. Forty-eight hours after gravistimulation of 3-week-old maize seedlings, endogenous free GA-like substances in upper and lower leaf sheath and internode pulvini halves were extracted, chromatographed, and bioassayed using the Tanginbozu dwarf rice microdroassay. Lower halves contained higher total levels of GA-like activity

Proteomics of Arabidopsis Seed Germination : a Comparative Study of Wild-Type and Gibberellin-Deficient Seeds

NARCIS (Netherlands)

Gallardo, K.; Job, C.; Groot, S.P.C.; Puype, M.; Vandekerckhove, J.; Job, D.

2002-01-01

We examined the role of gibberellins (GAs) in germination of Arabidopsis seeds by a proteomic approach. For that purpose, we used two systems. The first system consisted of seeds of the GA-deficient ga1 mutant, and the second corresponded to wild-type seeds incubated in paclobutrazol, a specific GA

Gibberellin requirement for Arabidopsis seed germination is determined both by testa characteristics and embryonic abscisic acid

NARCIS (Netherlands)

Debeaujon, I.; Koornneef, M.

2000-01-01

The mechanisms imposing a gibberellin (GA) requirement to promote the germination of dormant and non-dormant Arabidopsis seeds were analyzed using the GA-deficient mutant ga1, several seed coat pigmentation and structure mutants, and the abscisic acid (ABA)-deficient mutant aba1. Testa mutants,

Salt Stress Represses Soybean Seed Germination by Negatively Regulating GA Biosynthesis While Positively Mediating ABA Biosynthesis

OpenAIRE

Kai Shu; Ying Qi; Feng Chen; Yongjie Meng; Xiaofeng Luo; Haiwei Shuai; Wenguan Zhou; Jun Ding; Junbo Du; Jiang Liu; Feng Yang; Qiang Wang; Weiguo Liu; Taiwen Yong; Xiaochun Wang

2017-01-01

Soybean is an important and staple oilseed crop worldwide. Salinity stress has adverse effects on soybean development periods, especially on seed germination and post-germinative growth. Improving seed germination and emergence will have positive effects under salt stress conditions on agricultural production. Here we report that NaCl delays soybean seed germination by negatively regulating gibberellin (GA) while positively mediating abscisic acid (ABA) biogenesis, which leads to a decrease i...

The APETALA-2-like transcription factor OsAP2-39 controls key interactions between abscisic acid and gibberellin in rice.

Science.gov (United States)

Yaish, Mahmoud W; El-Kereamy, Ashraf; Zhu, Tong; Beatty, Perrin H; Good, Allen G; Bi, Yong-Mei; Rothstein, Steven J

2010-09-09

The interaction between phytohormones is an important mechanism which controls growth and developmental processes in plants. Deciphering these interactions is a crucial step in helping to develop crops with enhanced yield and resistance to environmental stresses. Controlling the expression level of OsAP2-39 which includes an APETALA 2 (AP2) domain leads to phenotypic changes in rice. Overexpression of OsAP2-39 leads to a reduction in yield by decreasing the biomass and the number of seeds in the transgenic rice lines. Global transcriptome analysis of the OsAP2-39 overexpression transgenic rice revealed the upregulation of a key abscisic acid (ABA) biosynthetic gene OsNCED-I which codes for 9-cis-epoxycarotenoid dioxygenase and leads to an increase in the endogenous ABA level. In addition to OsNCED-1, the gene expression analysis revealed the upregulation of a gene that codes for the Elongation of Upper most Internode (EUI) protein, an enzyme that catalyzes 16α, 17-epoxidation of non-13-hydroxylated GAs, which has been shown to deactivate gibberellins (GAs) in rice. The exogenous application of GA restores the wild-type phenotype in the transgenic line and ABA application induces the expression of EUI and suppresses the expression of OsAP2-39 in the wild-type line. These observations clarify the antagonistic relationship between ABA and GA and illustrate a mechanism that leads to homeostasis of these hormones. In vivo and in vitro analysis showed that the expression of both OsNCED-1 and EUI are directly controlled by OsAP2-39. Together, these results reveal a novel mechanism for the control of the ABA/GA balance in rice which is regulated by OsAP2-39 that in turn regulates plant growth and seed production.

The APETALA-2-like transcription factor OsAP2-39 controls key interactions between abscisic acid and gibberellin in rice.

Directory of Open Access Journals (Sweden)

Mahmoud W Yaish

2010-09-01

Full Text Available The interaction between phytohormones is an important mechanism which controls growth and developmental processes in plants. Deciphering these interactions is a crucial step in helping to develop crops with enhanced yield and resistance to environmental stresses. Controlling the expression level of OsAP2-39 which includes an APETALA 2 (AP2 domain leads to phenotypic changes in rice. Overexpression of OsAP2-39 leads to a reduction in yield by decreasing the biomass and the number of seeds in the transgenic rice lines. Global transcriptome analysis of the OsAP2-39 overexpression transgenic rice revealed the upregulation of a key abscisic acid (ABA biosynthetic gene OsNCED-I which codes for 9-cis-epoxycarotenoid dioxygenase and leads to an increase in the endogenous ABA level. In addition to OsNCED-1, the gene expression analysis revealed the upregulation of a gene that codes for the Elongation of Upper most Internode (EUI protein, an enzyme that catalyzes 16α, 17-epoxidation of non-13-hydroxylated GAs, which has been shown to deactivate gibberellins (GAs in rice. The exogenous application of GA restores the wild-type phenotype in the transgenic line and ABA application induces the expression of EUI and suppresses the expression of OsAP2-39 in the wild-type line. These observations clarify the antagonistic relationship between ABA and GA and illustrate a mechanism that leads to homeostasis of these hormones. In vivo and in vitro analysis showed that the expression of both OsNCED-1 and EUI are directly controlled by OsAP2-39. Together, these results reveal a novel mechanism for the control of the ABA/GA balance in rice which is regulated by OsAP2-39 that in turn regulates plant growth and seed production.

Gibberellin-regulated gene in the basal region of rice leaf sheath encodes basic helix-loop-helix transcription factor.

Science.gov (United States)

Komatsu, Setsuko; Takasaki, Hironori

2009-07-01

Genes regulated by gibberellin (GA) during leaf sheath elongation in rice seedlings were identified using the transcriptome approach. mRNA from the basal regions of leaf sheaths treated with GA3 was analyzed by high-coverage gene expression profiling. 33,004 peaks were detected, and 30 transcripts showed significant changes in the presence of GA3. Among these, basic helix-loop-helix transcription factor (AK073385) was significantly upregulated. Quantitative PCR analysis confirmed that expression of AK073385 was controlled by GA3 in a time- and dose-dependent manner. Basic helix-loop-helix transcription factor (AK073385) is therefore involved in the regulation of gene expression by GA3.

Roles of gibberellin catabolism and signaling in growth and physiological response to drought and short-day photoperiods in Populus trees.

Directory of Open Access Journals (Sweden)

Christine Zawaski

Full Text Available Survival and productivity of perennial plants in temperate zones are dependent on robust responses to prolonged and seasonal cycles of unfavorable conditions. Here we report whole-genome microarray, expression, physiological, and transgenic evidence in hybrid poplar (Populus tremula × Populus alba showing that gibberellin (GA catabolism and repressive signaling mediates shoot growth inhibition and physiological adaptation in response to drought and short-day (SD induced bud dormancy. Both water deprivation and SDs elicited activation of a suite of poplar GA2ox and DELLA encoding genes. Poplar transgenics with up-regulated GA 2-oxidase (GA2ox and DELLA domain proteins showed hypersensitive growth inhibition in response to both drought and SDs. In addition, the transgenic plants displayed greater drought resistance as evidenced by increased pigment concentrations (chlorophyll and carotenoid and reductions in electrolyte leakage (EL. Comparative transcriptome analysis using whole-genome microarray showed that the GA-deficiency and GA-insensitivity, SD-induced dormancy, and drought response in poplar share a common regulon of 684 differentially-expressed genes, which suggest GA metabolism and signaling plays a role in plant physiological adaptations in response to alterations in environmental factors. Our results demonstrate that GA catabolism and repressive signaling represents a major route for control of growth and physiological adaptation in response to immediate or imminent adverse conditions.

Purification and partial amino-acid sequence of gibberellin 20-oxidase from Cucurbita maxima L. endosperm.

Science.gov (United States)

Lange, T

1994-01-01

Gibberellin (GA) 20-oxidase was purified to apparent homogeneity from Cucurbita maxima endosperm by fractionated ammonium-sulphate precipitation, gel-filtration chromatography and anion-exchange and hydrophobic-interaction high-performance liquid chromatography (HPLC). Average purification after the last step was 55-fold with 3.9% of the activity recovered. The purest single fraction was enriched 101-fold with 0.2% overall recovery. Apparent relative molecular mass of the enzyme was 45 kDa, as determined by gel-filtration HPLC and sodium dodecyl sulphate-polyacrylamide gel electrophoresis, indicating that GA 20-oxidase is probably a monomeric enzyme. The purified enzyme degraded on two-dimensional gel electrophoresis, giving two protein spots: a major one corresponding to a molecular mass of 30 kDa and a minor one at 45 kDa. The isoelectric point for both was 5.4. The amino-acid sequences of the amino-terminus of the purified enzyme and of two peptides from a tryptic digest were determined. The purified enzyme catalysed the sequential conversion of [14C]GA12 to [14C]GA15, [14C]GA24 and [14C]GA25, showing that carbon atom 20 was oxidised to the corresponding alcohol, aldehyde and carboxylic acid in three consecutive reactions. [14C]Gibberellin A53 was similarly converted to [14C]GA44, [14C]GA19, [14C]GA17 and small amounts of a fourth product, which was preliminarily identified as [14C]GA20, a C19-gibberellin. All GAs except [14C]GA20 were identified by combined gas chromatography-mass spectrometry. The cofactor requirements in the absence of dithiothreitol were essentially as in its presence (Lange et al., Planta 195, 98-107, 1994), except that ascorbate was essential for enzyme activity and the optimal concentration of catalase was lower.

The Dark Side of Computer-Mediated Control

DEFF Research Database (Denmark)

Cunha, J. V.; Carugati, Andrea; Leclercq, A.

2015-01-01

of computer-mediated control when work and its electronic representation are loosely coupled, because it is employees who report their work in IT systems. Data from a 15-month ethnographic study of the appropriation of a customer relationship management system in the sales department of a large organization......Research on the dark side of computer-mediated control has explained the consequences of computer-mediated control when work is tightly coupled with its electronic representation because information systems record work automatically. Our study complements prior research by addressing the dark side...

Strigolactones Stimulate Internode Elongation Independently of Gibberellins1[C][W

Science.gov (United States)

de Saint Germain, Alexandre; Ligerot, Yasmine; Dun, Elizabeth A.; Pillot, Jean-Paul; Ross, John J.; Beveridge, Christine A.; Rameau, Catherine

2013-01-01

Strigolactone (SL) mutants in diverse species show reduced stature in addition to their extensive branching. Here, we show that this dwarfism in pea (Pisum sativum) is not attributable to the strong branching of the mutants. The continuous supply of the synthetic SL GR24 via the root system using hydroponics can restore internode length of the SL-deficient rms1 mutant but not of the SL-response rms4 mutant, indicating that SLs stimulate internode elongation via RMS4. Cytological analysis of internode epidermal cells indicates that SLs control cell number but not cell length, suggesting that SL may affect stem elongation by stimulating cell division. Consequently, SLs can repress (in axillary buds) or promote (in the stem) cell division in a tissue-dependent manner. Because gibberellins (GAs) increase internode length by affecting both cell division and cell length, we tested if SLs stimulate internode elongation by affecting GA metabolism or signaling. Genetic analyses using SL-deficient and GA-deficient or DELLA-deficient double mutants, together with molecular and physiological approaches, suggest that SLs act independently from GAs to stimulate internode elongation. PMID:23943865

Real-time Control Mediation in Agile Distributed Software Development

DEFF Research Database (Denmark)

Persson, John Stouby; Aaen, Ivan; Mathiassen, Lars

2008-01-01

Agile distributed environments pose particular challenges related to control of quality and collaboration in software development. Moreover, while face-to-face interaction is fundamental in agile development, distributed environments must rely extensively on mediated interactions. On this backdrop...... control was mediated over distance by technology through real-time exchanges. Contrary to previous research, the analysis suggests that both formal and informal elements of real-time mediated control were used; that evolving goals and adjustment of expectations were two of the main issues in real......-time mediated control exchanges; and, that the actors, despite distances in space and culture, developed a clan-like pattern mediated by technology to help control quality and collaboration in software development....

Exogenous gibberellins inhibit coffee (Coffea arabica cv. Rubi) seed germination and cause cell death in the embryo

NARCIS (Netherlands)

Silva, Da E.A.A.; Toorop, P.E.; Nijsse, J.; Bewley, J.D.; Hilhorst, H.W.M.

2005-01-01

The mechanism of inhibition of coffee (Coffea arabica cv. Rubi) seed germination by exogenous gibberellins (GAs) and the requirement of germination for endogenous GA were studied. Exogenous GA4+7 inhibited coffee seed germination. The response to GA4+7 showed two sensitivity thresholds: a lower one

Hormonal regulation of seed development and germination in tomato : studies on abscisic acid- and gibberellin-deficient mutants

NARCIS (Netherlands)

Groot, S.P.C.

1987-01-01

The role of endogenous gibberellins (GAs) and abscisic acid (ABA) in seed development and germination of tomato, was studied with the use of GA- and/or ABA-deficient mutants.

GAs are indispensable for the development of fertile flowers. Fertility of GA-deficient flowers is restored

Trajectories of late-life change in God-mediated control.

Science.gov (United States)

Hayward, R David; Krause, Neal

2013-01-01

To track within-individual change during late life in the sense of personal control and God-mediated control (the belief that one can work collaboratively with God to achieve one's goals and exercise control over life events) and to evaluate the hypothesis that this element of religion is related to declining personal control. A longitudinal survey representative of older White and Black adults in the United States tracked changes in personal and God-mediated control in four waves over the course of 7 years. Growth curve analysis found that the pattern of change differed by race. White adults had less sense of God-mediated control at younger ages, which increased among those who were highly religious but decreased among those who were less religious. Black adults had higher God-mediated control, which increased over time among those with low personal control. These results indicate that God-mediated control generally increases during older adulthood, but that its relationships with personal control and religious commitment are complex and differ between Black and White adults.

Enterobacter sp. I-3, a bio-herbicide inhibits gibberellins biosynthetic pathway and regulates abscisic acid and amino acids synthesis to control plant growth.

Science.gov (United States)

Radhakrishnan, Ramalingam; Park, Jae-Man; Lee, In-Jung

2016-12-01

Very few bacterial species were identified as bio-herbicides for weed control. The present research was focused to elucidate the plant growth retardant properties of Enterobacter sp. I-3 during their interaction by determining the changes in endogenous photosynthetic pigments, plant hormones and amino acids. The two bacterial isolates I-4-5 and I-3 were used to select the superior bacterium for controlling weed seeds (Echinochloa crus-galli L. and Portulaca oleracea L.) germination. The post-inoculation of I-3 (Enterobacter sp. I-3) significantly inhibited the weeds seed germination than their controls. The mechanism of bacterium induced plant growth reduction was identified in lettuce treated with I-3 bacterium and compared their effects with known chemical herbicide, trinexapac-ethyl (TE). The treatment of I-3 and TE showed a significant inhibitory effect on shoot length, leaf number, leaf length, leaf width, shoot weight, root weight and chlorophyll content in lettuce seedlings. The endogenous gibberellins (GAs) and abscisic acid (ABA) analysis showed that Enterobacter sp. I-3 treated plants had lower levels of GAs (GA 12 , GA 19 , GA 20 and GA 8 ) and GAs/ABA ratio and then, the higher level of ABA when compared to their controls. Indeed, the individual amino acids ie., aspartic acid, glutamic acid, glycine, threonine, alanine, serine, leucine, isoleucine and tyrosine were declined in TE and I-3 exposed plants. Our results suggest that the utilization of Enterobacter sp. I-3 inhibits the GAs pathway and amino acids synthesis in weeds to control their growth can be an alternative to chemical herbicides. Copyright © 2016 Elsevier GmbH. All rights reserved.

Seasonal timing of diapause induction limits the effective range of Diorhabda elongata deserticola (Coleoptera: Chrysomelidae) as a biological control agent for tamarisk (Tamarix spp.).

Science.gov (United States)

Bean, Daniel W; Dudley, Tom L; Keller, Julie C

2007-02-01

The leaf beetle Diorhabda elongata Brullé subspecies deserticola Chen, collected in northwestern China, has been released in the western United States to control tamarisk (Tamarix spp.). While beetle establishment and saltcedar defoliation have been noted at northern study sites, this species has not established at latitudes south of the 38th parallel. Critical daylength for diapause induction was measured in the laboratory and ranged between 14 h 50 min to 15 h 08 min, depending on temperature, and adults were shown to cease reproduction and enter diapause at daylengths of 14 h 30 min or less. Critical daylength in the field was measured at approximately 14 h 39 min and occurred 13 d before 50% of the population reached diapause. South of 36 degrees 20' N, the longest days of the year are shorter than 14 h 39 min, making the beetles univoltine in the southern United States. North of 36 degrees 20' N, a window of reproductive activity opens 13 d after the critical daylength is reached in the spring and closes 13 d after it is passed in the summer, allowing at least a partial second summer generation. It is predicted that south of the 38th parallel, premature diapause will increase mortality and disrupt synchrony between the life cycle of the beetle and host plant availability. This could hinder establishment and help explain the failure of this population south of the 38th parallel, providing a rationale for testing other populations of D. elongata in the southern range of Tamarix in North America.

Interactive Effects of Jasmonic Acid, Salicylic Acid, and Gibberellin on Induction of Trichomes in Arabidopsis1

Science.gov (United States)

Traw, M. Brian; Bergelson, Joy

2003-01-01

Leaf trichomes protect plants from attack by insect herbivores and are often induced following damage. Hormonal regulation of this plant induction response has not been previously studied. In a series of experiments, we addressed the effects of artificial damage, jasmonic acid, salicylic acid, and gibberellin on induction of trichomes in Arabidopsis. Artificial damage and jasmonic acid caused significant increases in trichome production of leaves. The jar1-1 mutant exhibited normal trichome induction following treatment with jasmonic acid, suggesting that adenylation of jasmonic acid is not necessary. Salicylic acid had a negative effect on trichome production and consistently reduced the effect of jasmonic acid, suggesting negative cross-talk between the jasmonate and salicylate-dependent defense pathways. Interestingly, the effect of salicylic acid persisted in the nim1-1 mutant, suggesting that the Npr1/Nim1 gene is not downstream of salicylic acid in the negative regulation of trichome production. Last, we found that gibberellin and jasmonic acid had a synergistic effect on the induction of trichomes, suggesting important interactions between these two compounds. PMID:14551332

Comparison of Effect of Brassinosteroid and Gibberellin Biosynthesis Inhibitors on Growth of Rice Seedlings

OpenAIRE

Matusmoto, Tadashi; Yamada, Kazuhiro; Yoshizawa, Yuko; Oh, Keimei

2016-01-01

Brassinosteroid (BR) and gibberellin (GA) are two predominant plant hormones that regulate plant cell elongation. Mutants disrupt the biosynthesis of these hormones and display different degrees of dwarf phenotypes in rice. Although the role of each plant hormone in promoting the longitudinal growth of plants has been extensively studied using genetic methods, their relationship is still poorly understood. In this study, we used two specific inhibitors targeting BR and GA biosynthesis to inve...

An N-terminal region of a Myb-like protein is involved in its intracellular localization and activation of a gibberellin-inducible proteinase gene in germinated rice seeds.

Science.gov (United States)

Sutoh, Keita; Washio, Kenji; Imai, Ryozo; Wada, Masamitsu; Nakai, Tomonori; Yamauchi, Daisuke

2015-01-01

The expression of the gene for a proteinase (Rep1) is upregulated by gibberellins. The CAACTC regulatory element (CARE) of the Rep1 promoter is involved in the gibberellin response. We isolated a cDNA for a CARE-binding protein containing a Myb domain in its carboxyl-terminal region and designated the gene Carboxyl-terminal Myb1 (CTMyb1). This gene encodes two polypeptides of two distinctive lengths, CTMyb1L and CTMyb1S, which include or exclude 213 N-terminal amino acid residues, respectively. CTMyb1S transactivated the Rep1 promoter in the presence of OsGAMyb, but not CTMyb1L. We observed an interaction between CTMyb1S and the rice prolamin box-binding factor (RPBF). A bimolecular fluorescence complex analysis detected the CTMyb1S and RPBF complex in the nucleus, but not the CTMyb1L and RPBF complex. The results suggest that the arrangement of the transfactors is involved in gibberellin-inducible expression of Rep1.

Reduction of gibberellin by low temperature disrupts pollen development in rice.

Science.gov (United States)

Sakata, Tadashi; Oda, Susumu; Tsunaga, Yuta; Shomura, Hikaru; Kawagishi-Kobayashi, Makiko; Aya, Koichiro; Saeki, Kenichi; Endo, Takashi; Nagano, Kuniaki; Kojima, Mikiko; Sakakibara, Hitoshi; Watanabe, Masao; Matsuoka, Makoto; Higashitani, Atsushi

2014-04-01

Microsporogenesis in rice (Oryza sativa) plants is susceptible to moderate low temperature (LT; approximately 19°C) that disrupts pollen development and causes severe reductions in grain yields. Although considerable research has been invested in the study of cool-temperature injury, a full understanding of the molecular mechanism has not been achieved. Here, we show that endogenous levels of the bioactive gibberellins (GAs) GA4 and GA7, and expression levels of the GA biosynthesis genes GA20ox3 and GA3ox1, decrease in the developing anthers by exposure to LT. By contrast, the levels of precursor GA12 were higher in response to LT. In addition, the expression of the dehydration-responsive element-binding protein DREB2B and SLENDER RICE1 (SLR1)/DELLA was up-regulated in response to LT. Mutants involved in GA biosynthetic and response pathways were hypersensitive to LT stress, including the semidwarf mutants sd1 and d35, the gain-of-function mutant slr1-d, and gibberellin insensitive dwarf1. The reduction in the number of sporogenous cells and the abnormal enlargement of tapetal cells occurred most severely in the GA-insensitive mutant. Application of exogenous GA significantly reversed the male sterility caused by LT, and simultaneous application of exogenous GA with sucrose substantially improved the extent of normal pollen development. Modern rice varieties carrying the sd1 mutation are widely cultivated, and the sd1 mutation is considered one of the greatest achievements of the Green Revolution. The protective strategy achieved by our work may help sustain steady yields of rice under global climate change.

CHR729 Is a CHD3 Protein That Controls Seedling Development in Rice.

Science.gov (United States)

Ma, Xiaoding; Ma, Jian; Zhai, Honghong; Xin, Peiyong; Chu, Jinfang; Qiao, Yongli; Han, Longzhi

2015-01-01

CHD3 is one of the chromatin-remodeling factors that contribute to controlling the expression of genes associated with plant development. Loss-of-function mutants display morphological and growth defects. However, the molecular mechanisms underlying CHD3 regulation of plant development remain unclear. In this study, a rice CHD3 protein, CHR729, was identified. The corresponding mutant line (t483) exhibited late seed germination, low germination rate, dwarfism, low tiller number, root growth inhibition, adaxial albino leaves, and short and narrow leaves. CHR729 encoded a nuclear protein and was expressed in almost all organs. RNA-sequencing analysis showed that several plant hormone-related genes were up- or down-regulated in t483 compared to wild type. In particular, expression of the gibberellin synthetase gibberellin 20 oxidase 4 gene was elevated in the mutant. Endogenous gibberellin assays demonstrated that the content of bioactive GA3 was reduced in t483 compared to wild type. Moreover, the seedling dwarfism, late seed germination, and short root length phenotypes of t483 were partially rescued by treatment with exogenous GA3. These results suggest that the rice CHD3 protein CHR729 plays an important role in many aspects of seedling development and controls this development via the gibberellin pathway.

CHR729 Is a CHD3 Protein That Controls Seedling Development in Rice.

Directory of Open Access Journals (Sweden)

Xiaoding Ma

Full Text Available CHD3 is one of the chromatin-remodeling factors that contribute to controlling the expression of genes associated with plant development. Loss-of-function mutants display morphological and growth defects. However, the molecular mechanisms underlying CHD3 regulation of plant development remain unclear. In this study, a rice CHD3 protein, CHR729, was identified. The corresponding mutant line (t483 exhibited late seed germination, low germination rate, dwarfism, low tiller number, root growth inhibition, adaxial albino leaves, and short and narrow leaves. CHR729 encoded a nuclear protein and was expressed in almost all organs. RNA-sequencing analysis showed that several plant hormone-related genes were up- or down-regulated in t483 compared to wild type. In particular, expression of the gibberellin synthetase gibberellin 20 oxidase 4 gene was elevated in the mutant. Endogenous gibberellin assays demonstrated that the content of bioactive GA3 was reduced in t483 compared to wild type. Moreover, the seedling dwarfism, late seed germination, and short root length phenotypes of t483 were partially rescued by treatment with exogenous GA3. These results suggest that the rice CHD3 protein CHR729 plays an important role in many aspects of seedling development and controls this development via the gibberellin pathway.

Genome-Wide Analysis of the Biosynthesis and Deactivation of Gibberellin-Dioxygenases Gene Family in Camellia sinensis (L. O. Kuntze

Directory of Open Access Journals (Sweden)

Cheng Pan

2017-09-01

Full Text Available Gibberellins (GAs, a class of diterpenoid phytohormones, play a key role in regulating diverse processes throughout the life cycle of plants. Bioactive GA levels are rapidly regulated by Gibberellin-dioxygenases (GAox, which are involved in the biosynthesis and deactivation of gibberellin. In this manuscript, a comprehensive genome-wide analysis was carried out to find all GAox in Camellia sinensis. For the first time in a tea plant, 14 CsGAox genes, containing two domains, DIOX_N (PF14226 and 2OG-FeII_Oxy, were identified (PF03171. These genes all belong to 2-oxoglutarate-dependent dioxygenases (2-ODD, including four CsGA20ox (EC: 1.14.11.12, three CsGA3ox (EC: 1.14.11.15, and seven CsGA2ox (EC: 1.14.11.13. According to the phylogenetic classification as in Arabidopsis, the CsGAox genes spanned five subgroups. Each CsGAox shows tissue-specific expression patterns, although these vary greatly. Some candidate genes, which may play an important role in response to external abiotic stresses, have been identified with regards to patterns, such as CsGA20ox2, CsGA3ox2, CsGA3ox3, CsGA2ox1, CsGA2ox2, and CsGA2ox4. The bioactive GA levels may be closely related to the GA20ox, GA3ox and GA2ox genes. In addition, the candidate genes could be used as marker genes for abiotic stress resistance breeding in tea plants.

God-Mediated Control and Change in Self-Rated Health.

Science.gov (United States)

Krause, Neal

2010-10-01

The purpose of this study was to see if feelings of God-mediated control are associated with change in self-rated health over time. In the process, an effort was made to see if a sense of meaning in life and optimism mediated the relationship between God-mediated control and change in health. The following hypothesized relationships were contained in the conceptual model that was developed to evaluate these issues: (1) people who go to church more often tend to have stronger God-mediated control beliefs than individuals who do not attend worship services as often; (2) people with a strong sense of God-mediated control are more likely to find a sense of meaning in life and be more optimistic than individuals who do not have a strong sense of God-mediated control; (3) people who are optimistic and who have a strong sense of meaning in life will rate their health more favorably over time than individuals who are not optimistic, as well as individuals who have not found a sense of meaning in life. Data from a longitudinal nationwide survey of older adults provided support for each of these hypotheses.

OsGSR1 is involved in crosstalk between gibberellins and brassinosteroids in rice.

Science.gov (United States)

Wang, Li; Wang, Zhen; Xu, Yunyuan; Joo, Se-Hwan; Kim, Seong-Ki; Xue, Zhen; Xu, Zhihong; Wang, Zhiyong; Chong, Kang

2009-02-01

Gibberellins (GAs) and brassinosteroids (BRs), two growth-promoting phytohormones, regulate many common physiological processes. Their interactions at the molecular level remain unclear. Here, we demonstrate that OsGSR1, a member of the GAST (GA-stimulated transcript) gene family, is induced by GA and repressed by BR. RNA interference (RNAi) transgenic rice plants with reduced OsGSR1 expression show phenotypes similar to plants deficient in BR, including short primary roots, erect leaves and reduced fertility. The OsGSR1 RNAi transgenic rice shows a reduced level of endogenous BR, and the dwarf phenotype could be rescued by the application of brassinolide. The yeast two-hybrid assay revealed that OsGSR1 interacts with DIM/DWF1, an enzyme that catalyzes the conversion from 24-methylenecholesterol to campesterol in BR biosynthesis. These results suggest that OsGSR1 activates BR synthesis by directly regulating a BR biosynthetic enzyme at the post-translational level. Furthermore, OsGSR1 RNAi plants show a reduced sensitivity to GA treatment, an increased expression of the GA biosynthetic gene OsGA20ox2, which is feedback inhibited by GA signaling, and an elevated level of endogenous GA: together, these suggest that OsGSR1 is a positive regulator of GA signaling. These results demonstrate that OsGSR1 plays important roles in both BR and GA pathways, and also mediates an interaction between the two signaling pathways.

Role of gibberellins and cytokinins in regulation of germination during development and ripening of Triticale caryopses

Directory of Open Access Journals (Sweden)

Stanisław Weidner

2014-01-01

Full Text Available The germination of caryopses of M-T3 Triticale generation, which were freshly harvested in different growth and developmental phases has been studied. A significant influence of the abscisic acid (ABA accumulation on the increment of number of germinating caryopses has been found. Already in the first phase af the embryogenesis considerable stimulating effects of kinetin and gibberellin-A3 (GA3 on the germination of embryos which were isolated from freshly collected grains have been shown. When both stimulators were used together marked synergetic reaction occurred. It has been also determined that in the initial period of embryogensis premature germination occurs, to a higher extent, under the action of cytokinins than! Whether in the further phases of the caryopse development, when embryo develop mainly through the cell elongation, mostly gibberellins seem to be responsible for the activation of germination processes. The more mature were seeds the quicker germinated whole caryopses and embryos isolated from them at different ripeness, after 3-month storage. The highest stimulation of germination by phytohormones has been found for the most mature caryopses. The action of gibberellic acid has been particulary strong.

Developmental landmarks during floral ontogeny of jalapeño chili pepper (Capsicum annuum L.) and the effect of gibberellin on ovary growth.

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Sandoval-Oliveros, R; Guevara-Olvera, L; Beltrán, J P; Gómez-Mena, C; Acosta-García, G

2017-09-01

Pepper (Capsicum annuum L.) is an important horticultural crop in many regions of the world. The final shape and size of the fruit are known to be determined at a very early step of flower development. During flower development hormonal treatments using gibberellins seem to promote growth resulting in higher yield and fruit quality. However, the morphological changes that occur in the pepper flowers after these treatments are largely unknown. In the present study, we provide a description of floral development landmarks of jalapeño chili pepper (cultivar Huichol), divided in nine representative stages from its initiation until the opening of the bud. We established a correlation among external flower development and the time and pattern of reproductive organogenesis. Male and female gametogenesis progression was used to define specific landmarks during flower maturation. The pattern of expression of key genes involved in gibberellin metabolism and response was also evaluated in the nine flower stages. The proposed development framework was used to analyze the effect of gibberellin treatments in the development of the flower. We observed both an effect of the treatment in the histology of the ovary tissue and an increase in the level of expression of CaGA2ox1 and CaGID1b genes. The developmental stages we defined for this species are very useful to analyze the molecular and morphological changes after hormonal treatments.

Chemical screening and development of novel gibberellin mimics.

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Jiang, Kai; Shimotakahara, Hiroaki; Luo, Ming; Otani, Masato; Nakamura, Hidemitsu; Moselhy, Said Salama; Abualnaja, Khalid Omer; Al-Malki, Abdulrahman Labeed; Kumosani, Taha Abduallah; Kitahata, Nobutaka; Nakano, Takeshi; Nakajima, Masatoshi; Asami, Tadao

2017-08-15

Gibberellin (GA) plays versatile roles in the regulation of plant growth and development and therefore is widely used as a regulator in agriculture. We performed a chemical library screening and identified a chemical, named 67D, as a stimulator of seed germination that was suppressed by paclobutrazol (PAC), a GA biosynthesis inhibitor. In vitro binding assays indicated that 67D binds to the GID1 receptor. Further studies on the structure-activity relationship identified a chemical, named chemical 6, that strongly promoted seed germination suppressed by PAC. Chemical 6 was further confirmed to promote the degradation of RGA (for repressor of ga1-3), a DELLA protein, and suppress the expression levels of GA3ox1 in the same manner as GA does. 67D and its analogs are supposed to be agonists of GID1 and are expected to be utilized in agriculture and basic research as an alternative to GA. Copyright © 2017 Elsevier Ltd. All rights reserved.

Transformation of a Dwarf "Arabidopsis" Mutant Illustrates Gibberellin Hormone Physiology and the Function of a Green Revolution Gene

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Molina, Isabel; Weber, Katrin; Alves Cursino dos Santos, Deborah Y.; Ohlrogge, John

2009-01-01

The introduction of dwarfing traits into crops was a major factor in increased grain yields during the "Green Revolution." In most cases those traits were the consequence of altered synthesis or response to the gibberellin (GA) plant hormones. Our current understanding of GA synthesis and physiology has been facilitated by the characterization of…

Gibberellin A3 Is Biosynthesized from Gibberellin A20 via Gibberellin A5 in Shoots of Zea mays L. 1

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Fujioka, Shozo; Yamane, Hisakazu; Spray, Clive R.; Phinney, Bernard O.; Gaskin, Paul; MacMillan, Jake; Takahashi, Nobutaka

1990-01-01

[17-13C,3H]-Labeled gibberellin A20 (GA20), GA5, and GA1 were fed to homozygous normal (+/+), heterozygous dominant dwarf (D8/+), and homozygous dominant dwarf (D8/D8) seedlings of Zea mays L. (maize). 13C-Labeled GA29, GA8, GA5, GA1, and 3-epi-GA1, as well as unmetabolized [13C]GA20, were identified by gas chromatography-selected ion monitoring (GC-SIM) from feeds of [17-13C, 3H]GA20 to all three genotypes. 13C-Labeled GA8 and 3-epi-G1, as well as unmetabolized [13C]GA1, were identified by GC-SIM from feeds of [17-13C, 3H]GA1 to all three genotypes. From feeds of [17-13C, 3H]GA5, 13C-labeled GA3 and the GA3-isolactone, as well as unmetabolized [13C]GA5, were identified by GC-SIM from +/+ and D8/D8, and by full scan GC-MS from D8/+. No evidence was found for the metabolism of [17-13C, 3H]GA5 to [13C]GA1, either by full scan GC-mass spectrometry or by GC-SIM. The results demonstrate the presence in maize seedlings of three separate branches from GA20, as follows: (a) GA20 → GA1 → GA8; (b) GA20 → GA5 → GA3; and (c) GA20 → GA29. The in vivo biogenesis of GA3 from GA5, as well as the origin of GA5 from GA20, are conclusively established for the first time in a higher plant (maize shoots). PMID:16667678

CvADH1, a member of short-chain alcohol dehydrogenase family, is inducible by gibberellin and sucrose in developing watermelon seeds.

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Kim, Joonyul; Kang, Hong-Gyu; Jun, Sung-Hoon; Lee, Jinwon; Yim, Jieun; An, Gynheung

2003-01-01

To understand the molecular mechanisms that control seed formation, we selected a seed-preferential gene (CvADH1) from the ESTs of developing watermelon seeds. RNA blot analysis and in situ localization showed that CvADH1 was preferentially expressed in the nucellar tissue. The CvADH1 protein shared about 50% homology with short-chain alcohol dehydrogenase including ABA2 in Arabidopsis thaliana, stem secoisolariciresinol dehydrogenase in Forsythia intermedia, and 3beta-hydroxysterol dehydrogenase in Digitalis lanata. We investigated gene-expression levels in seeds from both normally pollinated fruits and those made parthenocarpic via N-(2-chloro-4-pyridyl)-N'-phenylurea treatment, the latter of which lack zygotic tissues. Whereas the transcripts of CvADH1 rapidly started to accumulate from about the pre-heart stage in normal seeds, they were not detectable in the parthenocarpic seeds. Treating the parthenogenic fruit with GA(3) strongly induced gene expression, up to the level accumulated in pollinated seeds. These results suggest that the CvADH1 gene is induced in maternal tissues by signals made in the zygotic tissues, and that gibberellin might be one of those signals. We also observed that CvADH1 expression was induced by sucrose in the parthenocarpic seeds. Therefore, we propose that the CvADH1 gene is inducible by gibberellin, and that sucrose plays an important role in the maternal tissues of watermelon during early seed development.

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

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

Thyroidectomy and the termination of juvenile refractoriness in the red-legged partridge (Alectoris graeca chukar)

International Nuclear Information System (INIS)

Creighton, J.A.

1988-01-01

The role of thyroid hormones in the maintenance of juvenile refractoriness was studied in the red-legged partridge hybrid, Alectoris graeca chukar. Juvenile partridges, maintained on long (20L:4D) daylengths from hatch, were radiothyroidectomized at 6 1/2 weeks of age, and after 2 weeks were either held on long days or transferred to short (8L:16D) daylengths. Short-day thyroidectomized birds showed no evidence of gonadal growth 18 weeks after thyroidectomy, and neither did euthyroid controls on either short or long daylengths. Thyroidectomized birds held on long daylengths did show significant gonadal growth at this point. Further treatment with low levels of thyroxine (10 micrograms/bird) led to even greater testicular development in long-day thyroidectomized birds, but had no effect on the gonads of short-day thyroidectomized or euthyroid birds

Arabidopsis scaffold protein RACK1A modulates rare sugar D-allose regulated gibberellin signaling

OpenAIRE

Fennell, Herman; Olawin, Abdulquadri; Mizanur, Rahman M.; Izumori, Ken; Chen, Jin-Gui; Ullah, Hemayet

2012-01-01

As energy sources and structural components, sugars are the central regulators of plant growth and development. In addition to the abundant natural sugars in plants, more than 50 different kinds of rare sugars exist in nature, several of which show distinct roles in plant growth and development. Recently, one of the rare sugars, D-allose, an epimer of D-glucose at C3, is found to suppress plant hormone gibberellin (GA) signaling in rice. Scaffold protein RACK1A in the model plant Arabidopsis ...

CYP714B1 and CYP714B2 encode gibberellin 13-oxidases that reduce gibberellin activity in rice.

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Magome, Hiroshi; Nomura, Takahito; Hanada, Atsushi; Takeda-Kamiya, Noriko; Ohnishi, Toshiyuki; Shinma, Yuko; Katsumata, Takumi; Kawaide, Hiroshi; Kamiya, Yuji; Yamaguchi, Shinjiro

2013-01-29

Bioactive gibberellins (GAs) control many aspects of growth and development in plants. GA(1) has been the most frequently found bioactive GA in various tissues of flowering plants, but the enzymes responsible for GA(1) biosynthesis have not been fully elucidated due to the enzymes catalyzing the 13-hydroxylation step not being identified. Because of the lack of mutants defective in this enzyme, biological significance of GA 13-hydroxylation has been unknown. Here, we report that two cytochrome P450 genes, CYP714B1 and CYP714B2, encode GA 13-oxidase in rice. Transgenic Arabidopsis plants that overexpress CYP714B1 or CYP714B2 show semidwarfism. There was a trend that the levels of 13-OH GAs including GA(1) were increased in these transgenic plants. Functional analysis using yeast or insect cells shows that recombinant CYP714B1 and CYP714B2 proteins can convert GA(12) into GA(53) (13-OH GA(12)) in vitro. Moreover, the levels of 13-OH GAs including GA(1) were decreased, whereas those of 13-H GAs including GA(4) (which is more active than GA(1)) were increased, in the rice cyp714b1 cyp714b2 double mutant. These results indicate that CYP714B1 and CYP714B2 play a predominant role in GA 13-hydroxylation in rice. The double mutant plants appear phenotypically normal until heading, but show elongated uppermost internode at the heading stage. Moreover, CYP714B1 and CYP714B2 expression was up-regulated by exogenous application of bioactive GAs. Our results suggest that GA 13-oxidases play a role in fine-tuning plant growth by decreasing GA bioactivity in rice and that they also participate in GA homeostasis.

Seasonal adaptations to day length in ecotypes of Diorhabda spp. (Coleoptera: Chrysomelidae) inform selection of agents against saltcedars (Tamarix spp.).

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Dalin, Peter; Bean, Daniel W; Dudley, Tom L; Carney, Vanessa A; Eberts, Debra; Gardner, Kevin T; Hebertson, Elizabeth; Jones, Erin N; Kazmer, David J; Michels, G J; O'Meara, Scott A; Thompson, David C

2010-10-01

Seasonal adaptations to daylength often limit the effective range of insects used in biological control of weeds. The leaf beetle Diorhabda carinulata (Desbrochers) was introduced into North America from Fukang, China (latitude 44° N) to control saltcedars (Tamarix spp.), but failed to establish south of 38° N latitude because of a mismatched critical daylength response for diapause induction. The daylength response caused beetles to enter diapause too early in the season to survive the duration of winter at southern latitudes. Using climate chambers, we characterized the critical daylength response for diapause induction (CDL) in three ecotypes of Diorhabda beetles originating from 36, 38, and 43° N latitudes in Eurasia. In a field experiment, the timing of reproductive diapause and voltinism were compared among ecotypes by rearing the insects on plants in the field. CDL declined with latitude of origin among Diorhabda ecotypes. Moreover, CDL in southern (42° N latitude) ecotypes, however, CDL was relatively insensitive to temperature. The southern ecotypes produced up to four generations when reared on plants in the field at sites south of 38° N, whereas northern ecotypes produced only one or two generations. The study reveals latitudinal variation in how Diorhabda ecotypes respond to daylength for diapause induction and how these responses affect insect voltinism across the introduced range.

Microarray and Proteomic Analysis of Brassinosteroid- and Gibberellin-Regulated Gene and Protein Expression in Rice

OpenAIRE

Yang, Guangxiao; Komatsu, Setsuko

2016-01-01

Brassinosteroid (BR) and gibberellin (GA) are two groups of plant growth regulators essential for normal plant growth and development. To gain insight into the molecular mechanism by which BR and GA regulate the growth and development of plants, especially the monocot plant rice, it is necessary to identify and analyze more genes and proteins that are regulated by them. With the availability of draft sequences of two major types, japonica and indica rice, it has become possible to analyze exp...

A negative regulator encoded by a rice WRKY gene represses both abscisic acid and gibberellins signaling in aleurone cells.

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Zhang, Zhong-Lin; Shin, Margaret; Zou, Xiaolu; Huang, Jianzhi; Ho, Tun-hua David; Shen, Qingxi J

2009-05-01

Abscisic acid (ABA) and gibberellins (GAs) control several developmental processes including seed maturation, dormancy, and germination. The antagonism of these two hormones is well-documented. However, recent data from transcription profiling studies indicate that they can function as agonists in regulating the expression of many genes although the underlying mechanism is unclear. Here we report a rice WRKY gene, OsWRKY24, which encodes a protein that functions as a negative regulator of both GA and ABA signaling. Overexpression of OsWRKY24 via particle bombardment-mediated transient expression in aleurone cells represses the expression of two reporter constructs: the beta-glucuronidase gene driven by the GA-inducible Amy32b alpha-amylase promoter (Amy32b-GUS) and the ABA-inducible HVA22 promoter (HVA22-GUS). OsWRKY24 is unlikely a general repressor because it has little effect on the expression of the luciferase reporter gene driven by a constitutive ubiquitin promoter (UBI-Luciferase). As to the GA signaling, OsWRKY24 differs from OsWRKY51 and -71, two negative regulators specifically function in the GA signaling pathway, in several ways. First, OsWRKY24 contains two WRKY domains while OsWRKY51 and -71 have only one; both WRKY domains are essential for the full repressing activity of OsWRKY24. Second, binding of OsWRKY24 to the Amy32b promoter appears to involve sequences in addition to the TGAC cores of the W-boxes. Third, unlike OsWRKY71, OsWRKY24 is stable upon GA treatment. Together, these data demonstrate that OsWRKY24 is a novel type of transcriptional repressor that inhibits both GA and ABA signaling.

Transient gibberellin application promotes Arabidopsis thaliana hypocotyl cell elongation without maintaining transverse orientation of microtubules on the outer tangential wall of epidermal cells

KAUST Repository

Sauret-Gü eto, Susanna; Calder, Grant; Harberd, Nicholas P.

2011-01-01

The phytohormone gibberellin (GA) promotes plant growth by stimulating cellular expansion. Whilst it is known that GA acts by opposing the growth-repressing effects of DELLA proteins, it is not known how these events promote cellular expansion. Here

Wpływ intensyiuności światła i długości dnia na produkcję biomasy siewek zbóż w uprawie hydroponicznej [Influence of light intensity and daylength on biomass production by cereal seedlings in hydroponic culture

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J. Telżyńska

2015-06-01

Full Text Available The influence of light intensity, daylength and of the duration of the cultivation cycle on biomass production was investigated in the case of wheat, rye, oats and barley seedlings reared in hydroponic culture in the glasshouse. The investigations performed show together with the literature data that there is a possibility of obtaining very high yields from a very small surface area if the cultivation cycles are appropriately schemed, and the technical installations and suitable light combinations are applied.

Melanopsin gene variations interact with season to predict sleep onset and chronotype.

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Roecklein, Kathryn A; Wong, Patricia M; Franzen, Peter L; Hasler, Brant P; Wood-Vasey, W Michael; Nimgaonkar, Vishwajit L; Miller, Megan A; Kepreos, Kyle M; Ferrell, Robert E; Manuck, Stephen B

2012-10-01

The human melanopsin gene has been reported to mediate risk for seasonal affective disorder (SAD), which is hypothesized to be caused by decreased photic input during winter when light levels fall below threshold, resulting in differences in circadian phase and/or sleep. However, it is unclear if melanopsin increases risk of SAD by causing differences in sleep or circadian phase, or if those differences are symptoms of the mood disorder. To determine if melanopsin sequence variations are associated with differences in sleep-wake behavior among those not suffering from a mood disorder, the authors tested associations between melanopsin gene polymorphisms and self-reported sleep timing (sleep onset and wake time) in a community sample (N = 234) of non-Hispanic Caucasian participants (age 30-54 yrs) with no history of psychological, neurological, or sleep disorders. The authors also tested the effect of melanopsin variations on differences in preferred sleep and activity timing (i.e., chronotype), which may reflect differences in circadian phase, sleep homeostasis, or both. Daylength on the day of assessment was measured and included in analyses. DNA samples were genotyped for melanopsin gene polymorphisms using fluorescence polarization. P10L genotype interacted with daylength to predict self-reported sleep onset (interaction p sleep onset among those with the TT genotype was later in the day when individuals were assessed on longer days and earlier in the day on shorter days, whereas individuals in the other genotype groups (i.e., CC and CT) did not show this interaction effect. P10L genotype also interacted in an analogous way with daylength to predict self-reported morningness (interaction p sleep onset and chronotype as a function of daylength, whereas other genotypes at P10L do not seem to have effects that vary by daylength. A better understanding of how melanopsin confers heightened responsivity to daylength may improve our understanding of a broad range of

Comparison of signaling interactions determining annual and perennial plant growth in response to low temperature

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Astrid eWingler

2015-01-01

Full Text Available Low temperature inhibits plant growth despite the fact that considerable rates of photosynthetic activity can be maintained. Instead of lower rates of photosynthesis, active inhibition of cell division and expansion is primarily responsible for reduced growth. This results in sink limitation and enables plants to accumulate carbohydrates that act as compatible solutes or are stored throughout the winter to enable re-growth in spring. Regulation of growth in response to temperature therefore requires coordination with carbon metabolism, e.g. via the signaling metabolite trehalose-6-phosphate. The phytohormones gibberellins (GA and jasmonate (JA play an important role in regulating growth in response to temperature. Growth restriction at low temperature is mainly mediated by DELLA proteins, whose degradation is promoted by GA. For annual plants, it has been shown that the GA/DELLA pathway interacts with JA signaling and C-repeat binding factor (CBF dependent cold acclimation, but these interactions have not been explored in detail for perennials. Growth regulation in response to seasonal factors is, however, particularly important in perennials, especially at high latitudes. In autumn, growth cessation in trees is caused by shortening of the daylength in interaction with phytohormone signaling. In perennial grasses seasonal differences in the sensitivity to GA may enable enhanced growth in spring. This review provides an overview of the signaling interactions that determine plant growth at low temperature and highlights gaps in our knowledge, especially concerning the seasonality of signaling responses in perennial plants.

Synergism between demethylation inhibitor fungicides or gibberellin inhibitor plant growth regulators and bifenthrin in a pyrethroid-resistant population of Listronotus maculicollis (Coleoptera: Curculionidae).

Science.gov (United States)

Ramoutar, D; Cowles, R S; Requintina, E; Alm, S R

2010-10-01

In 2007-2008, the "annual bluegrass weevil," Listronotus maculicollis Kirby (Coleoptera: Curculionidae), a serious pest of Poa annua L. (Poales: Poaceae) on U.S. golf courses, was shown to be resistant to two pyrethroids, bifenthrin and lambda-cyhalothrin. In 2008, we showed that bifenthrin resistance was principally mediated by oxidase detoxification (cytochrome P450 [P450]). P450s can be inhibited by demethylation inhibitor fungicides and gibberellin inhibitor plant growth regulators, both of which are commonly used on golf courses. We tested these compounds for synergistic activity with bifenthin against a pyrethroid-resistant population of L. maculicollis. The LD50 value for bifenthrin was significantly reduced from 87 ng per insect (without synergists) to 9.6-40 ng per insect after exposure to the fungicides fenarimol, fenpropimorph, prochloraz, propiconazole, and pyrifenox and the plant growth regulators flurprimidol, paclobutrazol, and trinexapac-ethyl. Simulated field exposure with formulated products registered for use on turf revealed enhanced mortality when adult weevils were exposed to bifenthrin (25% mortality, presented alone) combined with field dosages of propiconizole, fenarimol, flurprimidol, or trinexapac-ethyl (range, 49-70% mortality).

Enterococcus faecium LKE12 Cell-Free Extract Accelerates Host Plant Growth via Gibberellin and Indole-3-Acetic Acid Secretion.

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Lee, Ko-Eun; Radhakrishnan, Ramalingam; Kang, Sang-Mo; You, Young-Hyun; Joo, Gil-Jae; Lee, In-Jung; Ko, Jae-Hwan; Kim, Jin-Ho

2015-09-01

The use of microbial extracts containing plant hormones is a promising technique to improve crop growth. Little is known about the effect of bacterial cell-free extracts on plant growth promotion. This study, based on phytohormonal analyses, aimed at exploring the potential mechanisms by which Enterococcus faecium LKE12 enhances plant growth in oriental melon. A bacterial strain, LKE12, was isolated from soil, and further identified as E. faecium by 16S rDNA sequencing and phylogenetic analysis. The plant growth-promoting ability of an LKE12 bacterial culture was tested in a gibberellin (GA)-deficient rice dwarf mutant (waito-C) and a normal GA biosynthesis rice cultivar (Hwayongbyeo). E. faecium LKE12 significantly improved the length and biomass of rice shoots in both normal and dwarf cultivars through the secretion of an array of gibberellins (GA1, GA3, GA7, GA8, GA9, GA12, GA19, GA20, GA24, and GA53), as well as indole-3-acetic acid (IAA). To the best of our knowledge, this is the first study indicating that E. faecium can produce GAs. Increases in shoot and root lengths, plant fresh weight, and chlorophyll content promoted by E. faecium LKE12 and its cell-free extract inoculated in oriental melon plants revealed a favorable interaction of E. faecium LKE12 with plants. Higher plant growth rates and nutrient contents of magnesium, calcium, sodium, iron, manganese, silicon, zinc, and nitrogen were found in cell-free extract-treated plants than in control plants. The results of the current study suggest that E. faecium LKE12 promotes plant growth by producing GAs and IAA; interestingly, the exogenous application of its cell-free culture extract can be a potential strategy to accelerate plant growth.

Evolutionary rate patterns of the Gibberellin pathway genes

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Zhang Fu-min

2009-08-01

Full Text Available Abstract Background Analysis of molecular evolutionary patterns of different genes within metabolic pathways allows us to determine whether these genes are subject to equivalent evolutionary forces and how natural selection shapes the evolution of proteins in an interacting system. Although previous studies found that upstream genes in the pathway evolved more slowly than downstream genes, the correlation between evolutionary rate and position of the genes in metabolic pathways as well as its implications in molecular evolution are still less understood. Results We sequenced and characterized 7 core structural genes of the gibberellin biosynthetic pathway from 8 representative species of the rice tribe (Oryzeae to address alternative hypotheses regarding evolutionary rates and patterns of metabolic pathway genes. We have detected significant rate heterogeneity among 7 GA pathway genes for both synonymous and nonsynonymous sites. Such rate variation is mostly likely attributed to differences of selection intensity rather than differential mutation pressures on the genes. Unlike previous argument that downstream genes in metabolic pathways would evolve more slowly than upstream genes, the downstream genes in the GA pathway did not exhibited the elevated substitution rate and instead, the genes that encode either the enzyme at the branch point (GA20ox or enzymes catalyzing multiple steps (KO, KAO and GA3ox in the pathway had the lowest evolutionary rates due to strong purifying selection. Our branch and codon models failed to detect signature of positive selection for any lineage and codon of the GA pathway genes. Conclusion This study suggests that significant heterogeneity of evolutionary rate of the GA pathway genes is mainly ascribed to differential constraint relaxation rather than the positive selection and supports the pathway flux theory that predicts that natural selection primarily targets enzymes that have the greatest control on fluxes.

Gibberellin deficiency pleiotropically induces culm bending in sorghum: an insight into sorghum semi-dwarf breeding

OpenAIRE

Ordonio, Reynante L.; Ito, Yusuke; Hatakeyama, Asako; Ohmae-Shinohara, Kozue; Kasuga, Shigemitsu; Tokunaga, Tsuyoshi; Mizuno, Hiroshi; Kitano, Hidemi; Matsuoka, Makoto; Sazuka, Takashi

2014-01-01

Regulation of symmetrical cell growth in the culm is important for proper culm development. So far, the involvement of gibberellin (GA) in this process has not yet been demonstrated in sorghum. Here, we show that GA deficiency resulting from any loss-of-function mutation in four genes (SbCPS1, SbKS1, SbKO1, SbKAO1) involved in the early steps of GA biosynthesis, not only results in severe dwarfism but also in abnormal culm bending. Histological analysis of the bent culm revealed that the intr...

Passion, Trait Self-Control, and Wellbeing: Comparing Two Mediation Models Predicting Wellbeing.

Science.gov (United States)

Briki, Walid

2017-01-01

Research has found that passion and trait self-control represented key determinants of wellbeing. Yet, no study to date has attempted to investigate the mediating influences of trait self-control and passion for accounting for the relationships between passion, trait self-control, and wellbeing (dependent variable). Using different frameworks, such as the dualistic model of passion and the neo-socioanalytic theory, the present study proposed two mediation models, considering either trait self-control (model 1) or passion (model 2) as the mediating variable. Five hundred nine volunteers from the United States (326 females and 183 males; M age = 31.74, SD age = 11.05, from 18 to 70 years old), who reported being passionate about a specific activity (e.g., fishing, swimming, blogging; M passion = 5.94, SD passion = 0.89), answered questionnaires assessing harmonious and obsessive passion, trait self-control, and wellbeing (measured through hedonic and eudaimonic wellbeing scales). Preliminary analyses revealed that both models were significant ( model 1: absolute GoF = 0.366, relative GoF = 0.971, outer model GoF = 0.997, inner model GoF = 0.973, R 2 = 18.300%, p passion, trait self-control, and wellbeing, and no relationships of obsessive passion with trait self-control and wellbeing. Mediation analyses revealed that trait self-control significantly mediated the relationship between harmonious passion and wellbeing (i.e., partial mediation, VAF = 33.136%). Harmonious passion appeared to significantly mediate the positive effect of trait self-control on wellbeing; however, the size of the mediating effect indicated that (almost) no mediation would take place (i.e., VAF = 11.144%). The present study is the first to examine the relationships between passion, trait self-control, and wellbeing, and supports the view that trait self-control and harmonious passion represent not only adaptive and powerful constructs, but also key determinants of wellbeing. Implications for

Gibberellins inhibit adventitious rooting in hybrid aspen and Arabidopsis by affecting auxin transport.

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Mauriat, Mélanie; Petterle, Anna; Bellini, Catherine; Moritz, Thomas

2014-05-01

Knowledge of processes involved in adventitious rooting is important to improve both fundamental understanding of plant physiology and the propagation of numerous plants. Hybrid aspen (Populus tremula × tremuloïdes) plants overexpressing a key gibberellin (GA) biosynthesis gene (AtGA20ox1) grow rapidly but have poor rooting efficiency, which restricts their clonal propagation. Therefore, we investigated the molecular basis of adventitious rooting in Populus and the model plant Arabidopsis. The production of adventitious roots (ARs) in tree cuttings is initiated from the basal stem region, and involves the interplay of several endogenous and exogenous factors. The roles of several hormones in this process have been characterized, but the effects of GAs have not been fully investigated. Here, we show that a GA treatment negatively affects the numbers of ARs produced by wild-type hybrid aspen cuttings. Furthermore, both hybrid aspen plants and intact Arabidopsis seedlings overexpressing AtGA20ox1, PttGID1.1 or PttGID1.3 genes (with a 35S promoter) produce few ARs, although ARs develop from the basal stem region of hybrid aspen and the hypocotyl of Arabidopsis. In Arabidopsis, auxin and strigolactones are known to affect AR formation. Our data show that the inhibitory effect of GA treatment on adventitious rooting is not mediated by perturbation of the auxin signalling pathway, or of the strigolactone biosynthetic and signalling pathways. Instead, GAs appear to act by perturbing polar auxin transport, in particular auxin efflux in hybrid aspen, and both efflux and influx in Arabidopsis. © 2014 The Authors The Plant Journal © 2014 John Wiley & Sons Ltd.

The Effect of Salicylic Acid and Gibberellin on Seed Reserve Utilization, Germination and Enzyme Activity of Sorghum (Sorghum bicolor L. Seeds Under Drought Stress

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Roghayyeh Sheykhbaglou

2014-03-01

Full Text Available Seed priming methods have been used to increases germination characteristics under stress conditions. The study aimed was to determine the effect of salicylic acid and gibberellin on seed reserve utilization, germination and enzyme activity of sorghum (Sorghum bicolor L. seeds under drought stress. Factorial experiment was carried out in completely randomized design with three replications. The first factor was the seed treatments (unpriming, salicylic acid and gibberellin and the second factor was drought stress (0, -4, -8 and -12 bar. The results indicated that for these traits: germination percentage, germination index, weight of utilized (mobilized seed, seed reserve utilization efficiency, seedling dry weight and seed reserve depletion percentage was a significant treatment Ч drought interaction. Thus priming improved study traits in Sorghum (Sorghum bicolor L. seeds under drought stress. Also, priming improves enzyme activity as compared to the unprimed seeds.

Brassinosteroids Antagonize Gibberellin- and Salicylate-Mediated Root Immunity in Rice1[C][W][OA

Science.gov (United States)

De Vleesschauwer, David; Van Buyten, Evelien; Satoh, Kouji; Balidion, Johny; Mauleon, Ramil; Choi, Il-Ryong; Vera-Cruz, Casiana; Kikuchi, Shoshi; Höfte, Monica

2012-01-01

Brassinosteroids (BRs) are a unique class of plant steroid hormones that orchestrate myriad growth and developmental processes. Although BRs have long been known to protect plants from a suite of biotic and abiotic stresses, our understanding of the underlying molecular mechanisms is still rudimentary. Aiming to further decipher the molecular logic of BR-modulated immunity, we have examined the dynamics and impact of BRs during infection of rice (Oryza sativa) with the root oomycete Pythium graminicola. Challenging the prevailing view that BRs positively regulate plant innate immunity, we show that P. graminicola exploits BRs as virulence factors and hijacks the rice BR machinery to inflict disease. Moreover, we demonstrate that this immune-suppressive effect of BRs is due, at least in part, to negative cross talk with salicylic acid (SA) and gibberellic acid (GA) pathways. BR-mediated suppression of SA defenses occurred downstream of SA biosynthesis, but upstream of the master defense regulators NONEXPRESSOR OF PATHOGENESIS-RELATED GENES1 and OsWRKY45. In contrast, BR alleviated GA-directed immune responses by interfering at multiple levels with GA metabolism, resulting in indirect stabilization of the DELLA protein and central GA repressor SLENDER RICE1 (SLR1). Collectively, these data favor a model whereby P. graminicola coopts the plant BR pathway as a decoy to antagonize effectual SA- and GA-mediated defenses. Our results highlight the importance of BRs in modulating plant immunity and uncover pathogen-mediated manipulation of plant steroid homeostasis as a core virulence strategy. PMID:22353574

Melanopsin-Mediated Acute Light Responses Measured in Winter and in Summer: Seasonal Variations in Adults with and without Cataracts

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Mirjam Münch

2017-09-01

Full Text Available Seasonal adaptation is a ubiquitous behavior seen in many species on both global hemispheres and is conveyed by changing photoperiods. In humans this seasonal adaptation is less apparent, in part because changes in daylength are masked by the use of electrical lighting at night. On the other hand, cataracts which reduce light transmission, may compound seasonal changes related to the reduced daylength of winter. To better understand the effects of different photoperiod lengths in healthy adults without and with cataracts, we tested their melanopsin-mediated light responses in summer vs. winter. Fifty-two participants (mean age 67.4 years; 30 with bilateral cataracts and 22 age-matched controls with clear lenses; pseudophakes were tested twice, once in summer and once in winter. At each test session we assessed the electroretinogram and pupil responses during daytime and we determined melatonin suppression, subjective sleepiness and mood in response to light exposure in the evening. Circadian rest-activity cycles and sleep from activity recordings were also analyzed for both seasons. Both groups had similar visual function. There were no seasonal differences in the electroretinogram. For the pupil responses to bright blue light, the post-illumination pupil response (PIPR was greater in winter than summer in pseudophakes, but not in cataract participants, whereas melatonin suppression to acute light exposure showed no differences between both groups and seasons. Overall, intra-daily variability of rest-activity was worse in winter but participants felt sleepier and reported worse mood at the laboratory in evening time in the summer. Those with cataracts had poorer sleep quality with lower sleep efficiency, and higher activity during sleep in winter than summer. In this study, the PIPR showed a seasonal variation in which a larger response was found during winter. This variation was only detected in participants with a clear intraocular lens. In

Reduction of Gibberellin by Low Temperature Disrupts Pollen Development in Rice1[W][OPEN

Science.gov (United States)

Sakata, Tadashi; Oda, Susumu; Tsunaga, Yuta; Shomura, Hikaru; Kawagishi-Kobayashi, Makiko; Aya, Koichiro; Saeki, Kenichi; Endo, Takashi; Nagano, Kuniaki; Kojima, Mikiko; Sakakibara, Hitoshi; Watanabe, Masao; Matsuoka, Makoto; Higashitani, Atsushi

2014-01-01

Microsporogenesis in rice (Oryza sativa) plants is susceptible to moderate low temperature (LT; approximately 19°C) that disrupts pollen development and causes severe reductions in grain yields. Although considerable research has been invested in the study of cool-temperature injury, a full understanding of the molecular mechanism has not been achieved. Here, we show that endogenous levels of the bioactive gibberellins (GAs) GA4 and GA7, and expression levels of the GA biosynthesis genes GA20ox3 and GA3ox1, decrease in the developing anthers by exposure to LT. By contrast, the levels of precursor GA12 were higher in response to LT. In addition, the expression of the dehydration-responsive element-binding protein DREB2B and SLENDER RICE1 (SLR1)/DELLA was up-regulated in response to LT. Mutants involved in GA biosynthetic and response pathways were hypersensitive to LT stress, including the semidwarf mutants sd1 and d35, the gain-of-function mutant slr1-d, and gibberellin insensitive dwarf1. The reduction in the number of sporogenous cells and the abnormal enlargement of tapetal cells occurred most severely in the GA-insensitive mutant. Application of exogenous GA significantly reversed the male sterility caused by LT, and simultaneous application of exogenous GA with sucrose substantially improved the extent of normal pollen development. Modern rice varieties carrying the sd1 mutation are widely cultivated, and the sd1 mutation is considered one of the greatest achievements of the Green Revolution. The protective strategy achieved by our work may help sustain steady yields of rice under global climate change. PMID:24569847

Mapping of a Cellulose-Deficient Mutant Named dwarf1-1 in Sorghum bicolor to the Green Revolution Gene gibberellin20-oxidase Reveals a Positive Regulatory Association between Gibberellin and Cellulose Biosynthesis.

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Petti, Carloalberto; Hirano, Ko; Stork, Jozsef; DeBolt, Seth

2015-09-01

Here, we show a mechanism for expansion regulation through mutations in the green revolution gene gibberellin20 (GA20)-oxidase and show that GAs control biosynthesis of the plants main structural polymer cellulose. Within a 12,000 mutagenized Sorghum bicolor plant population, we identified a single cellulose-deficient and male gametophyte-dysfunctional mutant named dwarf1-1 (dwf1-1). Through the Sorghum propinquum male/dwf1-1 female F2 population, we mapped dwf1-1 to a frameshift in GA20-oxidase. Assessment of GAs in dwf1-1 revealed ablation of GA. GA ablation was antagonistic to the expression of three specific cellulose synthase genes resulting in cellulose deficiency and growth dwarfism, which were complemented by exogenous bioactive gibberellic acid application. Using quantitative polymerase chain reaction, we found that GA was positively regulating the expression of a subset of specific cellulose synthase genes. To cross reference data from our mapped Sorghum sp. allele with another monocotyledonous plant, a series of rice (Oryza sativa) mutants involved in GA biosynthesis and signaling were isolated, and these too displayed cellulose deficit. Taken together, data support a model whereby suppressed expansion in green revolution GA genes involves regulation of cellulose biosynthesis. © 2015 American Society of Plant Biologists. All Rights Reserved.

Attentional control mediates the effect of social anxiety on positive affect☆

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Morrison, Amanda S.; Heimberg, Richard G.

2015-01-01

The goal of the present studies was to examine whether attentional control, a self-regulatory attentional mechanism, mediates the effect of social anxiety on positive affect. We tested this mediation in two studies using undergraduate students selected to represent a broad range of severity of social anxiety. Self-report assessments of social anxiety, attentional control, and positive affect were collected in a cross-sectional design (Study 1) and in a longitudinal design with three assessment points (Study 2). Results of both studies supported the hypothesized mediational model. Specifically, social anxiety was inversely related to attentional control, which itself positively predicted positive affect. This mediation remained significant even when statistically controlling for the effects of depression. Additionally, the hypothesized model provided superior model fit to theoretically-grounded equivalent models in both studies. Implications of these findings for understanding diminished positive affect in social anxiety are discussed. PMID:23254261

Heterosis in rice seedlings: its relationship to gibberellin content and expression of gibberellin metabolism and signaling genes.

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Ma, Qian; Hedden, Peter; Zhang, Qifa

2011-08-01

Despite the accumulation of data on the genetic and molecular understanding of heterosis, there is little information on the regulation of heterosis at the physiological level. In this study, we performed a quantitative analysis of endogenous gibberellin (GA) content and expression profiling of the GA metabolism and signaling genes to investigate the possible relationship between GA signaling and heterosis for seedling development in rice (Oryza sativa). The materials used were an incomplete diallele set of 3 × 3 crosses and the six parents. In the growing shoots of the seedlings at 20 d after sowing, significant positive correlations between the contents of some GA species and performance and heterosis based on shoot dry mass were detected. Expression analyses of GA-related genes by real-time reverse transcription-polymerase chain reaction revealed that 13 out of the 16 GA-related genes examined exhibited significant differential expression among the F1 hybrid and its parents, acting predominantly in the modes of overdominance and positive dominance. Expression levels of nine genes in the hybrids displayed significant positive correlations with the heterosis of shoot dry mass. These results imply that GAs play a positive role in the regulation of heterosis for rice seedling development. In shoots plus root axes of 4-d-old germinating seeds that had undergone the deetiolation, mimicking normal germination in soil, the axis dry mass was positively correlated with the content of GA₂₉ but negatively correlated with that of GA₁₉. Our findings provide supporting evidence for GAs playing an important regulatory role in heterosis for rice seedling development.

Comparison of Effect of Brassinosteroid and Gibberellin Biosynthesis Inhibitors on Growth of Rice Seedlings

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Tadashi Matusmoto

2016-01-01

Full Text Available Brassinosteroid (BR and gibberellin (GA are two predominant plant hormones that regulate plant cell elongation. Mutants disrupt the biosynthesis of these hormones and display different degrees of dwarf phenotypes in rice. Although the role of each plant hormone in promoting the longitudinal growth of plants has been extensively studied using genetic methods, their relationship is still poorly understood. In this study, we used two specific inhibitors targeting BR and GA biosynthesis to investigate the roles of BR and GA in growth of rice seedlings. Yucaizol, a specific inhibitor of BR biosynthesis, and Trinexapac-ethyl, a commercially available inhibitor of GA biosynthesis, were used. The effect of Yucaizol on rice seedlings indicated that Yucaizol significantly retarded stem elongation. The IC50 value was found to be approximately 0.8 μmol/L. Yucaizol also induced small leaf angle phenocopy in rice seedlings, similarly to BR-deficient rice, while Trinexapac-ethyl did not. When Yucaizol combined with Trinexapac-ethyl was applied to the rice plants, the mixture of these two inhibitors retarded stem elongation of rice at lower doses. Our results suggest that the use of a BR biosynthesis inhibitor combined with a GA biosynthesis inhibitor may be useful in the development of new technologies for controlling rice plant height.

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

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Kai Shu

2013-06-01

Full Text Available 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

AtGA3ox2, a key gene responsible for bioactive gibberellin biosynthesis, is regulated during embryogenesis by LEAFY COTYLEDON2 and FUSCA3 in Arabidopsis

NARCIS (Netherlands)

Curaba, J.; Moritz, T.; Blervaque, R.; Parcy, F.; Raz, V.; Herzog, M.; Vachon, G.

2004-01-01

Embryonic regulators LEC2 (LEAFY COTYLEDON2) and FUS3 (FUSCA3) are involved in multiple aspects of Arabidopsis (Arabidopsis thaliana) seed development, including repression of leaf traits and premature germination and activation of seed storage protein genes. In this study, we show that gibberellin

Plant growth enhancement and associated physiological responses are coregulated by ethylene and gibberellin in response to harpin protein Hpa1

OpenAIRE

Li, Xiaojie; Han, Bing; Xu, Manyu; Han, Liping; Zhao, Yanying; Liu, Zhilan; Dong, Hansong; Zhang, Chunling

2014-01-01

The harpin protein Hpa1 produced by the bacterial blight pathogen of rice induces several growth-promoting responses in plants, activating the ethylene signaling pathway, increasing photosynthesis rates and EXPANSIN (EXP) gene expression levels, and thereby enhancing the vegetative growth. This study was attempted to analyze any mechanistic connections among the above and the role of gibberellin in these responses. Hpa1-induced growth enhancement was evaluated in Arabidopsis, tomato, and rice...

Association genetics and transcriptome analysis reveal a gibberellin-responsive pathway involved in regulating photosynthesis.

Science.gov (United States)

Xie, Jianbo; Tian, Jiaxing; Du, Qingzhang; Chen, Jinhui; Li, Ying; Yang, Xiaohui; Li, Bailian; Zhang, Deqiang

2016-05-01

Gibberellins (GAs) regulate a wide range of important processes in plant growth and development, including photosynthesis. However, the mechanism by which GAs regulate photosynthesis remains to be understood. Here, we used multi-gene association to investigate the effect of genes in the GA-responsive pathway, as constructed by RNA sequencing, on photosynthesis, growth, and wood property traits, in a population of 435 Populus tomentosa By analyzing changes in the transcriptome following GA treatment, we identified many key photosynthetic genes, in agreement with the observed increase in measurements of photosynthesis. Regulatory motif enrichment analysis revealed that 37 differentially expressed genes related to photosynthesis shared two essential GA-related cis-regulatory elements, the GA response element and the pyrimidine box. Thus, we constructed a GA-responsive pathway consisting of 47 genes involved in regulating photosynthesis, including GID1, RGA, GID2, MYBGa, and 37 photosynthetic differentially expressed genes. Single nucleotide polymorphism (SNP)-based association analysis showed that 142 SNPs, representing 40 candidate genes in this pathway, were significantly associated with photosynthesis, growth, and wood property traits. Epistasis analysis uncovered interactions between 310 SNP-SNP pairs from 37 genes in this pathway, revealing possible genetic interactions. Moreover, a structural gene-gene matrix based on a time-course of transcript abundances provided a better understanding of the multi-gene pathway affecting photosynthesis. The results imply a functional role for these genes in mediating photosynthesis, growth, and wood properties, demonstrating the potential of combining transcriptome-based regulatory pathway construction and genetic association approaches to detect the complex genetic networks underlying quantitative traits. © The Author 2016. Published by Oxford University Press on behalf of the Society for Experimental Biology. All rights

Processes mediating expertise in air traffic control

NARCIS (Netherlands)

Van Meeuwen, Ludo; Jarodzka, Halszka; Brand-Gruwel, Saskia; Van Merriënboer, Jeroen; De Bock, Jeano; Kirschner, Paul A.

2011-01-01

Van Meeuwen, L. W., Jarodzka, H., Brand-Gruwel, S., Van Merriënboer, J. J. G., De Bock, J. J. P. R., & Kirschner, P. A. (2010, September). Processes mediating expertise in air traffic control. Poster presented at the European Association for Aviation Psychology Conference, Budapest.

Stress and adult smartphone addiction: Mediation by self-control, neuroticism, and extraversion.

Science.gov (United States)

Cho, Hea-Young; Kim, Dai Jin; Park, Jae Woo

2017-12-01

This study employed descriptive statistics and correlation analysis to examine the influence of stress on smartphone addiction as well as the mediating effects of self-control, neuroticism, and extraversion using 400 men and women in their 20s to 40s followed by structural equation analysis. Our findings indicate that stress had a significant influence on smartphone addiction, and self-control mediates the influence of stress on smartphone addiction. As stress increases, self-control decreases, which subsequently leads to increased smartphone addiction. Self-control was confirmed as an important factor in the prevention of smartphone addiction. Finally, among personality factors, neuroticism, and extraversion mediate the influence of stress on smartphone addiction. Copyright © 2017 John Wiley & Sons, Ltd.

Nitroxide-mediated controlled radical polymerisation: towards control of molar mass Controlled Radical Polymerisation

NARCIS (Netherlands)

Bon, S.A.F.; Bergman, F.A.C.; Es, van J.J.G.S.; Klumperman, B.; German, A.L.; Matyjaszewski, K.

1998-01-01

The mechanism of the TEMPO-mediated controlled radical polymerization of styrene in bulk is discussed. It is shown that the isotropic correlation time (tc) of a nitroxide can be used as a measure of the diffusive rate coefficient of trapping (ketD). A general empirical relationship for the density

Identification and characterization of a gibberellin-regulated protein, which is ASR5, in the basal region of rice leaf sheaths.

Science.gov (United States)

Takasaki, Hironori; Mahmood, Tariq; Matsuoka, Makoto; Matsumoto, Hiroshi; Komatsu, Setsuko

2008-04-01

Gibberellins (GAs) regulate growth and development in higher plants. To identify GA-regulated proteins during rice leaf sheath elongation, a proteomic approach was used. Proteins from the basal region of leaf sheath in rice seedling treated with GA(3) were analyzed by fluorescence two-dimensional difference gel electrophoresis. The levels of abscisic acid-stress-ripening-inducible 5 protein (ASR5), elongation factor-1 beta, translationally controlled tumor protein, fructose-bisphosphate aldolase and a novel protein increased; whereas the level of RuBisCO subunit binding-protein decreased by GA(3) treatment. ASR5 out of these six proteins was significantly regulated by GA(3) at the protein level but not at the mRNA level in the basal region of leaf sheaths. Since this protein is regulated not only by abscisic acid but also by GA(3), these results indicate that ASR5 might be involved in plant growth in addition to stress in the basal regions of leaf sheaths.

Mediator subunit18 controls flowering time and floral organ identity in Arabidopsis.

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Zhengui Zheng

Full Text Available Mediator is a conserved multi-protein complex that plays an important role in regulating transcription by mediating interactions between transcriptional activator proteins and RNA polymerase II. Much evidence exists that Mediator plays a constitutive role in the transcription of all genes transcribed by RNA polymerase II. However, evidence is mounting that specific Mediator subunits may control the developmental regulation of specific subsets of RNA polymerase II-dependent genes. Although the Mediator complex has been extensively studied in yeast and mammals, only a few reports on Mediator function in flowering time control of plants, little is known about Mediator function in floral organ identity. Here we show that in Arabidopsis thaliana, MEDIATOR SUBUNIT 18 (MED18 affects flowering time and floral organ formation through FLOWERING LOCUS C (FLC and AGAMOUS (AG. A MED18 loss-of-function mutant showed a remarkable syndrome of later flowering and altered floral organ number. We show that FLC and AG mRNA levels and AG expression patterns are altered in the mutant. Our results support parallels between the regulation of FLC and AG and demonstrate a developmental role for Mediator in plants.

Low temperature sensing in tulip (Tulipa gesneriana L.) is mediated through an increased response to auxin.

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Rietveld, P L; Wilkinson, C; Franssen, H M; Balk, P A; van der Plas, L H; Weisbeek, P J; Douwe de Boer, A

2000-03-01

Tulip (Tulipa gesneriana L.) is a bulbous plant species that requires a period of low temperature for proper growth and flowering. The mechanism of sensing the low temperature period is unknown. The study presented in this paper shows that the essential developmental change in tulip bulbs during cold treatment is an increase in sensitivity to the phytohormone auxin. This is demonstrated using a model system consisting of isolated internodes grown on tissue culture medium containing different combinations of the phytohormones auxin and gibberellin. Using mathematical modelling, equations taken from the field of enzyme kinetics were fitted through the data. By doing so it became apparent that longer periods of low temperature resulted in an increased maximum response at a lower auxin concentration. Besides the cold treatment, gibberellin also enhances the response to auxin in the internodes in this in vitro system. A working model describing the relationship between the cold requirement, gibberellin action and auxin sensitivity is put forward. Possible analogies with other cold-requiring processes such as vernalization and stratification, and the interaction of auxin and gibberellin in the stalk elongation process in other plant species are discussed.

Self-control mediates the relationship between time perspective and BMI.

Science.gov (United States)

Price, Menna; Higgs, Suzanne; Lee, Michelle

2017-01-01

Trait future time perspective measures the extent to which behaviour is dominated by a striving for future goals and rewards. Trait present time perspective measures orientation towards immediate pleasure. Previous research has explored the relationship between future and present time perspective and BMI with mixed findings. In addition, the psychological mechanism underlying this relationship is unclear. Self-control is a likely candidate, as it has been related to both BMI and time perspective, but the relationship between all of these concepts has not been examined in a single study. Therefore, the aim of this study was to examine if trait self-control mediates the relationship between time perspective (future and present) and BMI. Self-report time perspective (ZTPI), self-control (SCS) and height/weight data were collected using an online survey from a mixed student and community sample (N = 218) with wide ranging age (mean 29, SD 11, range 18-73 years) and BMI (mean 24, SD 4, range 15-43). The results of a structural equation model including both facets of time perspective suggested that the traits are related yet distinct measures that independently predict BMI through changes in self-control. Bootstrap mediation analysis showed that self-control mediated the relationship between both future time perspective (95% CI, -0.10 to -0.02) and present time perspective (95% CI, 0.03 to 0.17), and BMI in opposite directions. Participants with higher future time perspective scores (higher present time perspective scores) had higher (lower) self-control, which predicted lower (higher) BMI. These results are consistent with previous research suggesting an important role for time perspective in health outcomes. Self-control likely mediates the relationship between temporal perspectives and BMI, suggesting that time perspective may be a target for individualised interventions. Copyright © 2016 Elsevier Ltd. All rights reserved.

Gibberellins in shoots and developing capsules of Populus species.

Science.gov (United States)

Pearce, David W; Hutt, Oliver E; Rood, Stewart B; Mander, Lewis N

2002-03-01

Extracts of stems of growing shoots of Populus deltoides and P. trichocarpa, and developing capsules of P. deltoides were analysed for gibberellins (GAs) by gas chromatography-mass spectrometry. The following known GAs were identified by comparison of their Kovats retention indices (KRIs) and mass spectra with those of standards: GA1, GA8, GA9, GA19, GA20, 16 beta,17-dihydro-17-hydroxy GA20, GA23, GA28, GA29, GA34, GA44, and GA97. Several of these have not been previously reported from Populus. In addition, two new GAs were identified as 12 beta-hydroxy GA53 (GA127) and 16 beta,17-dihydro-17-hydroxy GA53 and their structures were confirmed by partial synthesis. Evidence was found of 16,17-dihydro-16,17-dihydroxy GA9, 16,17-dihydro-16,17-dihydroxy GA12, 12-hydroxy GA14, and GA34-catabolite by comparison of mass spectra and KRIs with published data. Several putative GAs (hydroxy- and dihydroxy-GA12-like) were also found. The catabolites of active GAs or of key precursors, hydroxylated at C-2 in stems and either C-2, C-12, C-17, or C-16,17 in capsules, were the major proportion of the GAs.

Increased Air Temperature during Simulated Autumn Conditions Does Not Increase Photosynthetic Carbon Gain But Affects the Dissipation of Excess Energy in Seedlings of the Evergreen Conifer Jack Pine1[OA

Science.gov (United States)

Busch, Florian; Hüner, Norman P.A.; Ensminger, Ingo

2007-01-01

Temperature and daylength act as environmental signals that determine the length of the growing season in boreal evergreen conifers. Climate change might affect the seasonal development of these trees, as they will experience naturally decreasing daylength during autumn, while at the same time warmer air temperature will maintain photosynthesis and respiration. We characterized the down-regulation of photosynthetic gas exchange and the mechanisms involved in the dissipation of energy in Jack pine (Pinus banksiana) in controlled environments during a simulated summer-autumn transition under natural conditions and conditions with altered air temperature and photoperiod. Using a factorial design, we dissected the effects of daylength and temperature. Control plants were grown at either warm summer conditions with 16-h photoperiod and 22°C or conditions representing a cool autumn with 8 h/7°C. To assess the impact of photoperiod and temperature on photosynthesis and energy dissipation, plants were also grown under either cold summer (16-h photoperiod/7°C) or warm autumn conditions (8-h photoperiod/22°C). Photosynthetic gas exchange was affected by both daylength and temperature. Assimilation and respiration rates under warm autumn conditions were only about one-half of the summer values but were similar to values obtained for cold summer and natural autumn treatments. In contrast, photosynthetic efficiency was largely determined by temperature but not by daylength. Plants of different treatments followed different strategies for dissipating excess energy. Whereas in the warm summer treatment safe dissipation of excess energy was facilitated via zeaxanthin, in all other treatments dissipation of excess energy was facilitated predominantly via increased aggregation of the light-harvesting complex of photosystem II. These differences were accompanied by a lower deepoxidation state and larger amounts of β-carotene in the warm autumn treatment as well as by changes in

Increased air temperature during simulated autumn conditions does not increase photosynthetic carbon gain but affects the dissipation of excess energy in seedlings of the evergreen conifer Jack pine.

Science.gov (United States)

Busch, Florian; Hüner, Norman P A; Ensminger, Ingo

2007-03-01

Temperature and daylength act as environmental signals that determine the length of the growing season in boreal evergreen conifers. Climate change might affect the seasonal development of these trees, as they will experience naturally decreasing daylength during autumn, while at the same time warmer air temperature will maintain photosynthesis and respiration. We characterized the down-regulation of photosynthetic gas exchange and the mechanisms involved in the dissipation of energy in Jack pine (Pinus banksiana) in controlled environments during a simulated summer-autumn transition under natural conditions and conditions with altered air temperature and photoperiod. Using a factorial design, we dissected the effects of daylength and temperature. Control plants were grown at either warm summer conditions with 16-h photoperiod and 22 degrees C or conditions representing a cool autumn with 8 h/7 degrees C. To assess the impact of photoperiod and temperature on photosynthesis and energy dissipation, plants were also grown under either cold summer (16-h photoperiod/7 degrees C) or warm autumn conditions (8-h photoperiod/22 degrees C). Photosynthetic gas exchange was affected by both daylength and temperature. Assimilation and respiration rates under warm autumn conditions were only about one-half of the summer values but were similar to values obtained for cold summer and natural autumn treatments. In contrast, photosynthetic efficiency was largely determined by temperature but not by daylength. Plants of different treatments followed different strategies for dissipating excess energy. Whereas in the warm summer treatment safe dissipation of excess energy was facilitated via zeaxanthin, in all other treatments dissipation of excess energy was facilitated predominantly via increased aggregation of the light-harvesting complex of photosystem II. These differences were accompanied by a lower deepoxidation state and larger amounts of beta-carotene in the warm autumn

Processes mediating expertise in air traffic control

NARCIS (Netherlands)

Van Meeuwen, Ludo; Jarodzka, Halszka; Brand-Gruwel, Saskia; Van Merriënboer, Jeroen; De Bock, Jeano; Kirschner, Paul A.

2010-01-01

Van Meeuwen, L., Jarodzka, H., Brand-Gruwel, S., Van Merriënboer, J. J. G., De Bock, J. J. P. R., & Kirschner, P. A. (2010, August). Processes mediating expertise in air traffic control. Meeting of the EARLI SIG6/7 Instructional Design and Learning and Instruction with Computers, Ulm, Germany.

Resilience of Penicillium resedanum LK6 and exogenous gibberellin in improving Capsicum annuum growth under abiotic stresses.

Science.gov (United States)

Khan, Abdul Latif; Waqas, Muhammad; Lee, In-Jung

2015-03-01

Understanding how endophytic fungi mitigate abiotic stresses in plants will be important in a changing global climate. A few endophytes can produce phytohormones, but their ability to induce physiological changes in host plants during extreme environmental conditions are largely unexplored. In the present study, we investigated the ability of Penicillium resedanum LK6 to produce gibberellins and its role in improving the growth of Capsicum annuum L. under salinity, drought, and heat stresses. These effects were compared with exogenous application of gibberellic acid (GA3). Endophyte treatment significantly increased shoot length, biomass, chlorophyll content, and the photosynthesis rate compared with the uninfected control during abiotic stresses. The endophyte and combined endophyte + GA3 treatments significantly ameliorated the negative effects of stresses compared with the control. Stress-responsive endogenous abscisic acid and its encoding genes, such as zeaxanthin epoxidase, 9-cis-epoxycarotenoid dioxygenase 3, and ABA aldehyde oxidase 3, were significantly reduced in endophyte-treated plants under stress. Conversely, salicylic acid and biosynthesis-related gene (isochorismate synthase) had constitutive expressions while pathogenesis related (PR1 and PR5) genes showed attenuated responses during endophyte treatment under abiotic stresses. The present findings suggest that endophytes have effects comparable to those of exogenous GA3; both can significantly increase plant growth and yield under changing environmental conditions by reprogramming the host plant's physiological responses.

Cloning of gibberellin 3 beta-hydroxylase cDNA and analysis of endogenous gibberellins in the developing seeds in watermelon.

Science.gov (United States)

Kang, Hong-Gyu; Jun, Sung-Hoon; Kim, Joonyul; Kawaide, Hiroshi; Kamiya, Yuji; An, Gynheung

2002-02-01

We have isolated Cv3h, a cDNA clone from the developing seeds of watermelon, and have demonstrated significant amino acid homology with gibberellin (GA) 3 beta-hydroxylases. This cDNA clone was expressed in Escherichia coli as a fusion protein that oxidized GA(9) and GA(12) to GA(4) and GA(14), respectively. The Cv3h protein had the highest similarity with pumpkin GA 2 beta,3 beta-hydroxylase, but did not possess 2 beta-hydroxylation function. RNA blot analysis showed that the gene was expressed primarily in the inner parts of developing seeds, up to 10 d after pollination (DAP). In the parthenocarpic fruits induced by treatment with 1-(2-chloro-4-pyridyl)-3-phenylurea (CPPU), the embryo and endosperm of the seeds were undeveloped, whereas the integumental tissues, of maternal origin, showed nearly normal development. Cv3h mRNA was undetectable in the seeds of CPPU-treated fruits, indicating that the GA 3 beta-hydroxylase gene was expressed in zygotic cells. In our analysis of endogenous GAs from developing seeds, GA(9) and GA(4) were detected at high levels but those of GA(20) and GA(1) were very low. This demonstrates that GA biosynthesis in seeds prefers a non-13-hydroxylation pathway over an early 13-hydroxylation pathway. We also analyzed endogenous GAs from seeds of the parthenocarpic fruits. The level of bioactive GA(4 )was much lower there than in normal seeds, indicating that bioactive GAs, unconnected with Cv3h, exist in integumental tissues during early seed development.

In vitro gibberellin A1 binding in Zea mays L

International Nuclear Information System (INIS)

Keith, B.; Rappaport, L.

1987-01-01

The first and second leaf sheaths of Zea mays L. cv Golden Jubilee were extracted and the extract centrifuged at 100,000g to yield a supernatant or cytosol fraction. Binding of [ 3 H]gibberellin A 1 (GA 1 ) to a soluble macromolecular component present in the cytosol was demonstrated at 4 0 C by Sephadex G-200 chromatography. The binding component was of high molecular weight (HMW) and greater than 500 kilodaltons. The HMW component was shown to be a protein and the 3 H-activity bound to this protein was largely [ 3 H]GA 1 and not a metabolite. Binding was pH sensitive but only a small percentage (20%) appeared to be exchangeable on addition of unlabeled GA 1 . Both biologically active and inactive GAs and non-GAs were able to inhibit GA 1 binding. [ 3 H]GA 1 binding to an intermediate molecular weight (IMW) fraction (40-100 kilodaltons) was also detected, provided cytosol was first desalted using Sephadex G-200 chromatography. Gel filtration studies suggest that the HMW binding component is an aggregate derived from the IMW fraction. The HMW binding fraction can be separated into two components using anion exchange chromatography

Mechanism of internal browning of pineapple: The role of gibberellins catabolism gene (AcGA2ox) and GAs

Science.gov (United States)

Zhang, Qin; Rao, Xiuwen; Zhang, Lubin; He, Congcong; Yang, Fang; Zhu, Shijiang

2016-01-01

Internal browning (IB), a physiological disorder (PD) that causes severe losses in harvested pineapple, can be induced by exogenous gibberellins (GAs). Over the years, studies have focused on roles of Gibberellin 2-oxidase (GA2oxs), the major GAs catabolic enzyme in plants, in the regulation of changes in morphology or biomass. However, whether GA2oxs could regulate PD has not been reported. Here, a full-length AcGA2ox cDNA was isolated from pineapple, with the putative protein sharing 23.59% to 72.92% identity with GA2oxs from five other plants. Pineapples stored at 5 °C stayed intact, while those stored at 20 °C showed severe IB. Storage at 5 °C enhanced AcGA2ox expression and decreased levels of a GAs (GA4) ‘compared with storage at 20 °C. However, at 20 °C, exogenous application of abscisic acid (ABA) significantly suppressed IB. ABA simultaneously upregulated AcGA2ox and reduced GA4. Ectopic expression of AcGA2ox in Arabidopsis resulted in reduced GA4, lower seed germination, and shorter hypocotyls and roots, all of which were restored by exogenous GA4/7. Moreover, in pineapple, GA4/7 upregulated polyphenol oxidase, while storage at 5 °C and ABA downregulated it. These results strongly suggest the involvement of AcGA2ox in regulation of GAs levels and a role of AcGA2ox in regulating IB. PMID:27982026

Effect of the growth retardant Cycocel® in controlling the growth of ...

African Journals Online (AJOL)

STORAGESEVER

2010-07-19

Jul 19, 2010 ... Hydroponic culture of Gladiolus tristis: Application of paclobutrazol for flowering and height control. Afr. J. Biotechnol. 7(3): 239-243. Ninnemann H, Zeevaart JAD, Kende H, Lang A (1964). The plant growth retardant CCC as an inhibitor of gibberellin biosynthesis in. Fusarium moniliforme. Planta (Bert.) ...

Polarization control of intermediate state absorption in resonance-mediated multi-photon absorption process

International Nuclear Information System (INIS)

Xu, Shuwu; Yao, Yunhua; Jia, Tianqing; Ding, Jingxin; Zhang, Shian; Sun, Zhenrong; Huang, Yunxia

2015-01-01

We theoretically and experimentally demonstrate the control of the intermediate state absorption in an (n + m) resonance-mediated multi-photon absorption process by the polarization-modulated femtosecond laser pulse. An analytical solution of the intermediate state absorption in a resonance-mediated multi-photon absorption process is obtained based on the time-dependent perturbation theory. Our theoretical results show that the control efficiency of the intermediate state absorption by the polarization modulation is independent of the laser intensity when the transition from the intermediate state to the final state is coupled by the single-photon absorption, but will be affected by the laser intensity when this transition is coupled by the non-resonant multi-photon absorption. These theoretical results are experimentally confirmed via a two-photon fluorescence control in (2 + 1) resonance-mediated three-photon absorption of Coumarin 480 dye and a single-photon fluorescence control in (1 + 2) resonance-mediated three-photon absorption of IR 125 dye. (paper)

Heterosis in Rice Seedlings: Its Relationship to Gibberellin Content and Expression of Gibberellin Metabolism and Signaling Genes1[W][OA

Science.gov (United States)

Ma (马谦), Qian; Hedden, Peter; Zhang (张启发), Qifa

2011-01-01

Despite the accumulation of data on the genetic and molecular understanding of heterosis, there is little information on the regulation of heterosis at the physiological level. In this study, we performed a quantitative analysis of endogenous gibberellin (GA) content and expression profiling of the GA metabolism and signaling genes to investigate the possible relationship between GA signaling and heterosis for seedling development in rice (Oryza sativa). The materials used were an incomplete diallele set of 3 × 3 crosses and the six parents. In the growing shoots of the seedlings at 20 d after sowing, significant positive correlations between the contents of some GA species and performance and heterosis based on shoot dry mass were detected. Expression analyses of GA-related genes by real-time reverse transcription-polymerase chain reaction revealed that 13 out of the 16 GA-related genes examined exhibited significant differential expression among the F1 hybrid and its parents, acting predominantly in the modes of overdominance and positive dominance. Expression levels of nine genes in the hybrids displayed significant positive correlations with the heterosis of shoot dry mass. These results imply that GAs play a positive role in the regulation of heterosis for rice seedling development. In shoots plus root axes of 4-d-old germinating seeds that had undergone the deetiolation, mimicking normal germination in soil, the axis dry mass was positively correlated with the content of GA29 but negatively correlated with that of GA19. Our findings provide supporting evidence for GAs playing an important regulatory role in heterosis for rice seedling development. PMID:21693671

Achievement goals and emotions: The mediational roles of perceived progress, control, and value.

Science.gov (United States)

Hall, Nathan C; Sampasivam, Lavanya; Muis, Krista R; Ranellucci, John

2016-06-01

The link between achievement goals and achievement emotions is well established; however, research exploring potential mediators of this relationship is lacking. The control-value theory of achievement emotions (Pekrun, 2006, Educational Psychology Review, 18, 315) posits that perceptions of control and value mediate the relationship between achievement goals and achievement emotions, whereas the bidirectional theory of affect (Linnenbrink & Pintrich, 2002, Educational Psychologist, 37, 69) proposes that perceived progress mediates this relationship. The present study empirically evaluated three hypothesized mediators of the effects of achievement goals on learning-related emotions as proposed in the control-value theory and the bidirectional theory of affect. Undergraduate students (N = 273) from humanities, social science, and STEM disciplines participated. Participants completed web-based questionnaires evaluating academic achievement goals, perceptions of control, perceived task value, and achievement emotions. Results provided empirical support primarily for perceived progress as a mediator of mastery-approach goal effects on positive emotions (enjoyment, hope), showing indirect effects of mastery- and performance-approach goals on outcome-related emotions (hope, anxiety) via perceived control. Indirect effects of mastery- and performance-approach goals were further observed on anxiety via perceived value, with higher value levels predicting greater anxiety. Study findings partially support Linnenbrink and Pintrich's (2002, Educational Psychologist, 37, 69) bidirectional theory of affect while underscoring the potential for indirect effects of goals on emotions through perceived control as proposed by Pekrun (2006, Educational Psychology Review, 18, 315). © 2016 The British Psychological Society.

Myrigalone A Inhibits Lepidium sativum Seed Germination by Interference with Gibberellin Metabolism and Apoplastic Superoxide Production Required for Embryo Extension Growth and Endosperm Rupture

Czech Academy of Sciences Publication Activity Database

Oracz, K.; Voegele, A.; Tarkowská, Danuše; Jacquemoud, D.; Turečková, Veronika; Urbanová, Terezie; Strnad, Miroslav; Sliwinska, E.; Leubner-Metzger, G.

2012-01-01

Roč. 53, č. 1 (2012), s. 81-95 ISSN 0032-0781 R&D Projects: GA AV ČR KAN200380801; GA MŠk ED0007/01/01; GA ČR GD522/08/H003 Keywords : Embryo cell extension growth * Endoreduplication * Endosperm rupture * Gibberellin metabolism * Lepidium sativum * Myrica gale * Phytotoxicity * Reactive oxygen species Subject RIV: EF - Botanics Impact factor: 4.134, year: 2012

Callous-Unemotional Traits and Effortful Control Mediate the Effect of Parenting Intervention on Preschool Conduct Problems.

Science.gov (United States)

Elizur, Yoel; Somech, Lior Y

2018-02-24

Parenting intervention (PI) is an effective treatment for children's conduct problems (CP) that has been shown to be mediated by improved parenting practices and parenting self-efficacy. Recently, Hitkashrut's randomized controlled trial demonstrated that ineffective parenting (IP) mediated effects on callous-unemotional (CU) traits and effortful control (EC), while controlling for more general treatment effects on CP. These temperament and personality-based features predict the formation of early-onset antisocial trajectories with poor long-term prognosis. The objective of this study was to use Hitkashrut's 3-wave dataset to test posttreatment EC and CU mediation of treatment effect on 1-year follow-up CP, and to determine whether mediation by each child-level potential mediator remains significant when tested concurrently with the parenting mediator. Parents of 209 3-5 year-old preschoolers (163 boys; 46 girls), with subclinical-clinical range CP were assigned to 14-session co-parent training groups (n = 140 couples), or to minimal intervention control groups (n = 69 couples). Assessments were based on both parents' questionnaires. An intent-to-treat analysis showed that EC and CU traits simultaneously mediated treatment effects on CP in one EC/CU mediational model. The concurrent testing of child- and parent-level mediators showed mediation by IP and CU traits in the CU/IP model, and IP mediation in the EC/IP model. Similar results were obtained in mediational analyses that controlled for the shared variance between the mediators and CP at T2. Overall, the findings support an intervention model of coaching parents of high-CP children to promote moral self-regulatory competencies while concurrently applying behavioral methods that directly target CP.

Imidazoline and imidazolidine nitroxides as controlling agents in nitroxide-mediated pseudoliving radical polymerization

Science.gov (United States)

Edeleva, M. V.; Marque, S. R. A.; Bagryanskaya, E. G.

2018-04-01

Controlled, or pseudoliving, radical polymerization provides unique opportunities for the synthesis of structurally diverse polymers with a narrow molecular-weight distribution. These reactions occur under relatively mild conditions with broad tolerance to functional groups in the monomers. The nitroxide-mediated pseudoliving radical polymerization is of particular interest for the synthesis of polymers for biomedical applications. This review briefly describes one of the mechanisms of controlled radical polymerization. The studies dealing with the use of imidazoline and imidazolidine nitroxides as controlling agents for nitroxide-mediated pseudoliving radical polymerization of various monomers are summarized and analyzed. The publications addressing the key steps of the controlled radical polymerization in the presence of imidazoline and imidazolidine nitroxides and new approaches to nitroxide-mediated polymerization based on protonation of both nitroxides and monomers are considered. The bibliography includes 154 references.

Safety aid use and social anxiety symptoms: The mediating role of perceived control.

Science.gov (United States)

Korte, Kristina J; Unruh, Amanda S; Oglesby, Mary E; Schmidt, Norman B

2015-08-30

The use of safety aids, cognitive or behavioral strategies used to reduce or cope with anxiety, has emerged as a key construct of interest in anxiety disorders due to their role in the development and maintenance of anxiety symptoms. It has been suggested that individuals with anxiety engage in safety aid use to reduce their anxiety and feel more in control of a situation; however, no studies to date have examined the association between perceived control, that is, perceived level of control over internal events in anxiety provoking situations, and the use of safety aids. The purpose of the present study was to examine the association of perceived control, the use of safety aids, and symptoms of social anxiety. It was predicted that the association between safety aid use and social anxiety symptoms would be mediated by perceived control. This prediction was examined in a large sample of 281 participants. As predicted, perceived control was a significant mediator of the association between the use of safety aids and social anxiety symptoms. This effect remained significant after running a multiple mediation model with distress tolerance added as a competing mediator. Implications for future research are discussed. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

Global efficiency of structural networks mediates cognitive control in Mild Cognitive Impairment

Directory of Open Access Journals (Sweden)

Rok Berlot

2016-12-01

Full Text Available Background: Cognitive control has been linked to both the microstructure of individual tracts and the structure of whole-brain networks, but their relative contributions in health and disease remain unclear. Objective: To determine the contribution of both localised white matter tract damage and disruption of global network architecture to cognitive control, in older age and Mild Cognitive Impairment (MCI.Methods: 25 patients with MCI and 20 age, sex and intelligence-matched healthy volunteers were investigated with 3 Tesla structural magnetic resonance imaging (MRI. Cognitive control and episodic memory were evaluated with established tests. Structural network graphs were constructed from diffusion MRI-based whole-brain tractography. Their global measures were calculated using graph theory. Regression models utilized both global network metrics and microstructure of specific connections, known to be critical for each domain, to predict cognitive scores. Results: Global efficiency and the mean clustering coefficient of networks were reduced in MCI. Cognitive control was associated with global network topology. Episodic memory, in contrast, correlated with individual temporal tracts only. Relationships between cognitive control and network topology were attenuated by addition of single tract measures to regression models, consistent with a partial mediation effect. The mediation effect was stronger in MCI than healthy volunteers, explaining 23-36% of the effect of cingulum microstructure on cognitive control performance. Network clustering was a significant mediator in the relationship between tract microstructure and cognitive control in both groups. Conclusions: The status of critical connections and large-scale network topology are both important for maintenance of cognitive control in MCI. Mediation via large-scale networks is more important in patients with MCI than healthy volunteers. This effect is domain-specific, and true for cognitive

Gibberellins regulate iron deficiency-response by influencing iron transport and translocation in rice seedlings (Oryza sativa).

Science.gov (United States)

Wang, Baolan; Wei, Haifang; Xue, Zhen; Zhang, Wen-Hao

2017-04-01

Gibberellins (GAs) are a class of plant hormones with diverse functions. However, there has been little information on the role of GAs in response to plant nutrient deficiency. To evaluate the roles of GAs in regulation of Fe homeostasis, the effects of GA on Fe accumulation and Fe translocation in rice seedlings were investigated using wild-type, a rice mutant ( eui1 ) displaying enhnaced endogenous GA concentrations due to a defect in GA deactivation, and transgenic rice plants overexpressing OsEUI . Exposure to Fe-deficient medium significantly reduced biomass of rice plants. Both exogenous application of GA and an endogenous increase of bioactive GA enhanced Fe-deficiency response by exaggerating foliar chlorosis and reducing growth. Iron deficiency significantly suppressed production of GA 1 and GA 4 , the biologically active GAs in rice. Exogenous application of GA significantly decreased leaf Fe concentration regardless of Fe supply. Iron concentration in shoot of eui1 mutants was lower than that of WT plants under both Fe-sufficient and Fe-deficient conditions. Paclobutrazol, an inhibitor of GA biosynthesis, alleviated Fe-deficiency responses, and overexpression of EUI significantly increased Fe concentration in shoots and roots. Furthermore, both exogenous application of GA and endogenous increase in GA resulting from EUI mutation inhibited Fe translocation within shoots by suppressing OsYSL2 expression, which is involved in Fe transport and translocation. The novel findings provide compelling evidence to support the involvement of GA in mediation of Fe homeostasis in strategy II rice plants by negatively regulating Fe transport and translocation. © The Author 2017. Published by Oxford University Press on behalf of the Annals of Botany Company. All rights reserved. For Permissions, please email: journals.permissions@oup.com

Adventitious staminate flower formation in gibberellin treated gynoecious cucumber plants

International Nuclear Information System (INIS)

Fuchs, E.; Atsmon, D.; Halevy, A.H.

1977-01-01

Single gibberellin (A sub(4 + 7)) treatments induced the appearance of staminate floral buds in several consecutive nodes on the main stem of genetically female cucumber (Cucumis sativus L.). The staminate buds appeared next to pistillate buds which showed various degrees of degeneration. Similarly, repeated GA treatments induced the appearance of staminate flowers in otherwise strictly hermaphrodite plants, next to bisexual flowers. However, the bisexual buds, unlike the pistillate ones, did not show any deleterious effects of the GA treatment. Therefore, it is inferred that the hormonally induced staminate buds did not develop by sexual reversion of would-be pistillate or bisexual buds, but rather, represent adventitious buds which, in normally grown female or hermaphrodite plants, never develop. It thus seems that predetermined pistillate or bisexual buds do not change into staminate ones, while change in the reverse direction has been demonstrated in the past (at least for the gynoecious ones). The effectiveness of the GA treatment in the gynoecious plants showed an acropetal gradient both within the affected region, as well as along the main stem. Autoradiographic histological examinations showed that the course of development of the induced staminate floral bud did not differ from that of normally developing buds. (auth.)

[Mutual Effect on Determination of Gibberellins and Glyphosate in Groundwater by Spectrophotometry].

Science.gov (United States)

Zhang, Li; Chen, Liang; Liu, Fei

2015-04-01

In the present study, a spectrophotometry method for the simultaneous determination of gibberellins (GA3) and glyphosate in groundwater was established and optimized. In addition, the mutual effect on simultaneous determination of GA3 and glyphosate was studied. Based on the experiment, good linearity (R2 > 0.99) was obtained for GA3 in the range of 0-20 and 0-100 µg and for glyphosate in the range of 0-8 and 5-15 µg. The method's detection limit (MDL) of GA3 and glyphosate was 0.48 and 0.82 µg, respectively; and the recovery rates of 15 to 150 µg GA3 and 3 to 10 µg glyphosate in all samples at a spiked level were 71.3% ± 1.9% and 98.4% ± 8.1%, respectively. No obvious influence of glyphosate (0-100 mg · L(-1)) on the recovery rates of GA3 was observed, but the presence of glyphosate could cause slight determination precision decrease of GA3. Meanwhile, adding 2 mg · L(-1) GA3 can increase the recovery rate of glyphosate.

Overexpression of rice LRK1 restricts internode elongation by down-regulating OsKO2.

Science.gov (United States)

Yang, Mengfei; Qi, Weiwei; Sun, Fan; Zha, Xiaojun; Chen, Mingluan; Huang, Yunqing; Feng, Yu-Qi; Yang, Jinshui; Luo, Xiaojin

2013-01-01

Rice (Oryza sativa) has the potential to undergo rapid internodal elongation which determines plant height. Gibberellin is involved in internode elongation. Leucine-rich repeat receptor-like kinases (LRR-RLKs) are the largest subfamily of transmembrane receptor-like kinases in plants. LRR-RLKs play important functions in mediating a variety of cellular processes and regulating responses to environmental signals. LRK1, a PSK receptor homolog, is a member of the LRR-RLK family. In the present study, differences in ectopic expression of LRK1 were consistent with extent of rice internode elongation. Analyses of gene expression demonstrated that LRK1 restricts gibberellin biosynthesis during the internode elongation process by down-regulation of the gibberellin biosynthetic gene coding for ent-kaurene oxidase.

Parental behavioral and psychological control and problematic internet use among Chinese adolescents: the mediating role of self-control.

Science.gov (United States)

Li, Xian; Li, Dongping; Newman, Joan

2013-06-01

Previous research has reported contradictory effects of parental control on adolescents' problematic Internet use (PIU). To reconcile the discrepant findings, the current study examined the differential effects of parental behavioral control (solicitation and restriction) and psychological control (guilt induction, love withdrawal, and authority assertion) on adolescents' PIU. The mediating effect of self-control on the relationships between parental control and PIU was also examined. A total of 694 Chinese adolescents (M=13.67 years) completed questionnaire measures of parental behavioral control, psychological control, self-control, and PIU. After adjusting for age, gender, and family financial status, it was found that parental restriction (a form of behavioral control) was negatively associated with PIU, whereas love withdrawal (a form of psychological control) was positively associated with PIU. Increased self-control was associated with decreased PIU, and changes in self-control at least partially mediated the differential effects of parental behavioral and psychological control on PIU. Theoretical and practical implications of these findings are discussed.

The mediating effect of sustainability control system on reverse ...

African Journals Online (AJOL)

This paper analyses part of the viability of green supply chain management practices created for fisheries industry to implement sustainability control system adoption as mediating on reverse logistics innovation and customer environmental collaboration towards sustainability performance. It examines reverse logistics ...

Seasonal prolactin secretion and its role in seasonal reproduction: a review.

Science.gov (United States)

Curlewis, J D

1992-01-01

also under photoperiodic control. It is likely therefore that a seasonal pattern of prolactin secretion is only evidence of neuroendocrine sensitivity to changing photoperiod. Depending upon the species, this sensitivity to the seasonal changes in daylength may or may not be accompanied by seasonal changes in a biological endpoint such as seasonal reproduction or indeed other adaptations. Whether the seasonal change in prolactin secretion is an endocrine mediator of such adaptations remains in contention. Certainly in some species this signal does have a role in reproduction. For example, in species with an obligate seasonal embryonic diapause, the seasonal increase in prolactin can act as a luteotrophin (mink and western spotted skunk) or luteostatin (Bennett's and tammar wallabies.(ABSTRACT TRUNCATED AT 400 WORDS)

Inhibitory Control Mediates the Association between Perceived Stress and Secure Relationship Quality

Directory of Open Access Journals (Sweden)

Toria Herd

2018-02-01

Full Text Available Past research has demonstrated negative associations between exposure to stressors and quality of interpersonal relationships among children and adolescents. Nevertheless, underlying mechanisms of this association remain unclear. Chronic stress has been shown to disrupt prefrontal functioning in the brain, including inhibitory control abilities, and evidence is accumulating that inhibitory control may play an important role in secure interpersonal relationship quality, including peer problems and social competence. In this prospective longitudinal study, we examine whether changes in inhibitory control, measured at both behavioral and neural levels, mediate the association between stress and changes in secure relationship quality with parents and peers. The sample included 167 adolescents (53% males who were first recruited at age 13 or 14 years and assessed annually three times. Adolescents’ inhibitory control was measured by their behavioral performance and brain activities, and adolescents self-reported perceived stress levels and relationship quality with mothers, fathers, and peers. Results suggest that behavioral inhibitory control mediates the association between perceived stress and adolescent’s secure relationship quality with their mothers and fathers, but not their peers. In contrast, given that stress was not significantly correlated with neural inhibitory control, we did not further test the mediation path. Our results highlight the role of inhibitory control as a process through which stressful life experiences are related to impaired secure relationship quality between adolescents and their mothers and fathers.

Inhibitory Control Mediates the Association between Perceived Stress and Secure Relationship Quality.

Science.gov (United States)

Herd, Toria; Li, Mengjiao; Maciejewski, Dominique; Lee, Jacob; Deater-Deckard, Kirby; King-Casas, Brooks; Kim-Spoon, Jungmeen

2018-01-01

Past research has demonstrated negative associations between exposure to stressors and quality of interpersonal relationships among children and adolescents. Nevertheless, underlying mechanisms of this association remain unclear. Chronic stress has been shown to disrupt prefrontal functioning in the brain, including inhibitory control abilities, and evidence is accumulating that inhibitory control may play an important role in secure interpersonal relationship quality, including peer problems and social competence. In this prospective longitudinal study, we examine whether changes in inhibitory control, measured at both behavioral and neural levels, mediate the association between stress and changes in secure relationship quality with parents and peers. The sample included 167 adolescents (53% males) who were first recruited at age 13 or 14 years and assessed annually three times. Adolescents' inhibitory control was measured by their behavioral performance and brain activities, and adolescents self-reported perceived stress levels and relationship quality with mothers, fathers, and peers. Results suggest that behavioral inhibitory control mediates the association between perceived stress and adolescent's secure relationship quality with their mothers and fathers, but not their peers. In contrast, given that stress was not significantly correlated with neural inhibitory control, we did not further test the mediation path. Our results highlight the role of inhibitory control as a process through which stressful life experiences are related to impaired secure relationship quality between adolescents and their mothers and fathers.

The role of gibberellins in improving the resistance of tebuconazole-coated maize seeds to chilling stress by microencapsulation.

Science.gov (United States)

Yang, Lijuan; Yang, Daibin; Yan, Xiaojing; Cui, Li; Wang, Zhenying; Yuan, Huizhu

2016-11-07

Chilling stress during germination often causes severe injury. In the present study, maize seed germination and shoot growth under chilling stress were negatively correlated with the dose of tebuconazole in an exponential manner as predicted by the model Y = A + B × e (-x/k) . Microencapsulation was an effective means of eliminating potential phytotoxic risk. The gibberellins (GAs) contents were higher after microencapsulation treatment than after conventional treatment when the dose of tebuconazole was higher than 0.12 g AI (active ingredient) kg -1 seed. Further analysis indicated that microencapsulation can stimulate ent-kaurene oxidase (KO) activity to some extent, whereas GA 3-oxidase (GA3ox) and GA 2-oxidase (GA2ox) activities remained similar to those in the control. Genes encoding GA metabolic enzymes exhibited different expression patterns. Transcript levels of ZmKO1 increased in the microcapsule treatments compared to the control. Even when incorporated into microcapsules, tebuconazole led to the upregulation of ZmGA3ox1 at doses of less than 0.12 g AI kg -1 seed and to the upregulation of ZmGA3ox2 when the dose was higher than 0.12 g AI kg -1 seed. With increasing doses of microencapsulated tebuconazole, the transcript levels of ZmGA2ox4, ZmGA2ox5 and ZmGA2ox6 exhibited upward trends, whereas the transcript levels of ZmGA2ox7 exhibited a downward trend.

Enzymatic and structural characterization of hydrolysis of gibberellin A4 glucosyl ester by a rice β-D-glucosidase.

Science.gov (United States)

Hua, Yanling; Sansenya, Sompong; Saetang, Chiraporn; Wakuta, Shinji; Ketudat Cairns, James R

2013-09-01

In order to identify a rice gibberellin ester β-D-glucosidase, gibberellin A4 β-D-glucosyl ester (GA4-GE) was synthesized and used to screen rice β-glucosidases. Os3BGlu6 was found to have the highest hydrolysis activity to GA4-GE among five recombinantly expressed rice glycoside hydrolase family GH1 enzymes from different phylogenic clusters. The kinetic parameters of Os3BGlu6 and its mutants E178Q, E178A, E394D, E394Q and M251N for hydrolysis of p-nitrophenyl β-D-glucopyranoside (pNPGlc) and GA4-GE confirmed the roles of the catalytic acid/base and nucleophile for hydrolysis of both substrates and suggested M251 contributes to binding hydrophobic aglycones. The activities of the Os3BGlu6 E178Q and E178A acid/base mutants were rescued by azide, which they transglucosylate to produce β-D-glucopyranosyl azide, in a pH-dependent manner, while acetate also rescued Os3BGlu6 E178A at low pH. High concentrations of sodium azide (200-400 mM) inhibited Os3BGlu6 E178Q but not Os3BGlu6 E178A. The structures of Os3BGlu6 E178Q crystallized with either GA4-GE or pNPGlc had a native α-D-glucosyl moiety covalently linked to the catalytic nucleophile, E394, which showed the hydrogen bonding to the 2-hydroxyl in the covalent intermediate. These data suggest that a GH1 β-glucosidase uses the same retaining catalytic mechanism to hydrolyze 1-O-acyl glucose ester and glucoside. Copyright © 2013 Elsevier Inc. All rights reserved.

Isolation and characterisation of a dwarf rice mutant exhibiting defective gibberellins biosynthesis.

Science.gov (United States)

Ji, S H; Gururani, M A; Lee, J W; Ahn, B-O; Chun, S-C

2014-03-01

We have isolated a severe dwarf mutant derived from a Ds (Dissociation) insertion mutant rice (Oryza sativa var. japonica c.v. Dongjin). This severe dwarf phenotype, has short and dark green leaves, reduced shoot growth early in the seedling stage, and later severe dwarfism with failure to initiate flowering. When treated with bioactive GA3 , mutants are restored to the normal wild-type phenotype. Reverse transcription PCR analyses of 22 candidate genes related to the gibberellin (GA) biosynthesis pathway revealed that among 22 candidate genes tested, a dwarf mutant transcript was not expressed only in one OsKS2 gene. Genetic analysis revealed that the severe dwarf phenotype was controlled by recessive mutation of a single nuclear gene. The putative OsKS2 gene was a chromosome 4-located ent-kaurene synthase (KS), encoding the enzyme that catalyses an early step of the GA biosynthesis pathway. Sequence analysis revealed that osks2 carried a 1-bp deletion in the ORF region of OsKS2, which led to a loss-of-function mutation. The expression pattern of OsKS2 in wild-type cv Dongjin, showed that it is expressed in all organs, most prominently in the stem and floral organs. Morphological characteristics of the dwarf mutant showed dramatic modifications in internal structure and external morphology. We propose that dwarfism in this mutant is caused by a point mutation in OsKS2, which plays a significant role in growth and development of higher plants. Further investigation on OsKS2 and other OsKS-like proteins is underway and may yield better understanding of the putative role of OsKS in severe dwarf mutants. © 2013 German Botanical Society and The Royal Botanical Society of the Netherlands.

Governance and control as mediating instruments in an inter-firm relationship : Towards collaboration or transactions?

NARCIS (Netherlands)

Zahir-Ul-Hassan, Muhammad Kaleem; Minnaar, Reinald A.; Vosselman, E.G.J.

2016-01-01

This paper explores the mediation of governance and control structures in an inter-firm relationship between a semiconductor producer and its contractor. As mediating instruments the contract and the control structures are not just pre-given results of distanced managerial decision-making, but are

Governance and control as mediating instruments in an inter-firm relationship: towards collaboration or transactions?

NARCIS (Netherlands)

Zahir-ul-Hassan, M.K.; Minnaar, R.A.; Vosselman, E.G.J.

2016-01-01

This paper explores the mediation of governance and control structures in an inter-firm relationship between a semiconductor producer and its contractor. As mediating instruments the contract and the control structures are not just pre-given results of distanced managerial decision-making, but are

Methylation of Gibberellins by Arabidopsis GAMT1 and GAMT2

Energy Technology Data Exchange (ETDEWEB)

Varbanova,M.; Yamaguchi, S.; Yang, Y.; McKelvey, K.; Hanada, A.; Borochov, R.; Yu, F.; Jikumaru, Y.; Ross, J.; et al

2007-01-01

Arabidopsis thaliana GAMT1 and GAMT2 encode enzymes that catalyze formation of the methyl esters of gibberellins (GAs). Ectopic expression of GAMT1 or GAMT2 in Arabidopsis, tobacco (Nicotiana tabacum), and petunia (Petunia hybrida) resulted in plants with GA deficiency and typical GA deficiency phenotypes, such as dwarfism and reduced fertility. GAMT1 and GAMT2 are both expressed mainly in whole siliques (including seeds), with peak transcript levels from the middle until the end of silique development. Within whole siliques, GAMT2 was previously shown to be expressed mostly in developing seeds, and we show here that GAMT1 expression is also localized mostly to seed, suggesting a role in seed development. Siliques of null single GAMT1 and GAMT2 mutants accumulated high levels of various GAs, with particularly high levels of GA1 in the double mutant. Methylated GAs were not detected in wild-type siliques, suggesting that methylation of GAs by GAMT1 and GAMT2 serves to deactivate GAs and initiate their degradation as the seeds mature. Seeds of homozygous GAMT1 and GAMT2 null mutants showed reduced inhibition of germination, compared with the wild type, when placed on plates containing the GA biosynthesis inhibitor ancymidol, with the double mutant showing the least inhibition. These results suggest that the mature mutant seeds contained higher levels of active GAs than wild-type seeds.

Brassinosteroid regulates cell elongation by modulating gibberellin metabolism in rice.

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Tong, Hongning; Xiao, Yunhua; Liu, Dapu; Gao, Shaopei; Liu, Linchuan; Yin, Yanhai; Jin, Yun; Qian, Qian; Chu, Chengcai

2014-11-01

Brassinosteroid (BR) and gibberellin (GA) are two predominant hormones regulating plant cell elongation. A defect in either of these leads to reduced plant growth and dwarfism. However, their relationship remains unknown in rice (Oryza sativa). Here, we demonstrated that BR regulates cell elongation by modulating GA metabolism in rice. Under physiological conditions, BR promotes GA accumulation by regulating the expression of GA metabolic genes to stimulate cell elongation. BR greatly induces the expression of D18/GA3ox-2, one of the GA biosynthetic genes, leading to increased GA1 levels, the bioactive GA in rice seedlings. Consequently, both d18 and loss-of-function GA-signaling mutants have decreased BR sensitivity. When excessive active BR is applied, the hormone mostly induces GA inactivation through upregulation of the GA inactivation gene GA2ox-3 and also represses BR biosynthesis, resulting in decreased hormone levels and growth inhibition. As a feedback mechanism, GA extensively inhibits BR biosynthesis and the BR response. GA treatment decreases the enlarged leaf angles in plants with enhanced BR biosynthesis or signaling. Our results revealed a previously unknown mechanism underlying BR and GA crosstalk depending on tissues and hormone levels, which greatly advances our understanding of hormone actions in crop plants and appears much different from that in Arabidopsis thaliana. © 2014 American Society of Plant Biologists. All rights reserved.

Motivation toward Physical Exercise and Subjective Wellbeing: The Mediating Role of Trait Self-Control

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Walid Briki

2016-10-01

Full Text Available Motivation toward physical exercise (MPE and trait self-control (TSC were identified as key predictors of subjective wellbeing (SWB. However, there has not been any research designed to examine the mediating role of TSC in the relationship between MPE and SWB. The present study utilizes self-determination theory, control-process theory of self-regulation, and theory of multiple pathways of TSC in order to examine whether TSC mediates the relationships of autonomous MPE (A-MPE, controlled MPE (C-MPE, and impersonal MPE (NO-MPE with SWB using structural equation modeling (XLSTAT PLS. Three hundred seventeen adult American individuals (Mage = 32.97, SDage = 11.30, who reported to be regular exercisers, voluntarily answered questionnaires assessing MPE, TSC, and SWB. Correlational analyses revealed positive relationships between A-MPE, TSC, and SWB, and negative relationships of C-MPE and NO-MPE with TSC and SWB. Mediation analyses revealed that TSC mediated the relationships of A-MPE (partial mediation and C-MPE (full mediation with SWB, but did not mediate the relationship between NO-MPE and SWB. The estimates of the quality of the hypothesized model were acceptable (outer model GoF = .935; absolute GoF = .330; relative GoF = .942; inner model GoF = 1.008; R2 = 36.947%. Finally, this study supports the view that MPE can influence SWB through TSC, and incites to pursue the examination of the relationships between self-determined motivation, self-regulation mechanisms, and health-related outcomes.

Mediating effects of emotional exhaustion on the relationship between job demand–control model and mental health.

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Huang, Yu-Hwa; Du, Pey-Ian; Chen, Chin-Hui; Yang, Chin-Ann; Huang, Ing-Chung

2011-04-01

This study attempted to investigate the role of emotional exhaustion as a mediator on the relationship between job demands-control (JDC) model and mental health. Three-wave data from 297 employees were collected. The results showed that job demands were positively related to emotional exhaustion, and increasing job demands will increase the level of emotional exhaustion. Job control was negatively associated with emotional exhaustion; therefore, increasing job control will decrease the level of emotional exhaustion. Emotional exhaustion was negatively related to mental health. Emotional exhaustion fully mediated the relationship between job demands and mental health, and partially mediated the positive relationship between job control and mental health. In addition, job control was positively associated with mental health directly. The remarkable finding of the present study was that emotional exhaustion served as the key mediator between the JDC model and mental health. Theoretical and managerial implications and limitations were discussed.

SALT-RESPONSIVE ERF1 is a negative regulator of grain filling and gibberellin-mediated seedling establishment in rice.

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Schmidt, Romy; Schippers, Jos H M; Mieulet, Delphine; Watanabe, Mutsumi; Hoefgen, Rainer; Guiderdoni, Emmanuel; Mueller-Roeber, Bernd

2014-02-01

Grain quality is an important agricultural trait that is mainly determined by grain size and composition. Here, we characterize the role of the rice transcription factor (TF) SALT-RESPONSIVE ERF1 (SERF1) during grain development. Through genome-wide expression profiling and chromatin immunoprecipitation, we found that SERF1 directly regulates RICE PROLAMIN-BOX BINDING FACTOR (RPBF), a TF that functions as a positive regulator of grain filling. Loss of SERF1 enhances RPBF expression resulting in larger grains with increased starch content, while SERF1 overexpression represses RPBF resulting in smaller grains. Consistently, during grain filling, starch biosynthesis genes such as GRANULE-BOUND STARCH SYNTHASEI (GBSSI), STARCH SYNTHASEI (SSI), SSIIIa, and ADP-GLUCOSE PYROPHOSPHORYLASE LARGE SUBUNIT2 (AGPL2) are up-regulated in SERF1 knockout grains. Moreover, SERF1 is a direct upstream regulator of GBSSI. In addition, SERF1 negatively regulates germination by controlling RPBF expression, which mediates the gibberellic acid (GA)-induced expression of RICE AMYLASE1A (RAmy1A). Loss of SERF1 results in more rapid seedling establishment, while SERF1 overexpression has the opposite effect. Our study reveals that SERF1 represents a negative regulator of grain filling and seedling establishment by timing the expression of RPBF.

Human GW182 Paralogs Are the Central Organizers for RNA-Mediated Control of Transcription.

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Hicks, Jessica A; Li, Liande; Matsui, Masayuki; Chu, Yongjun; Volkov, Oleg; Johnson, Krystal C; Corey, David R

2017-08-15

In the cytoplasm, small RNAs can control mammalian translation by regulating the stability of mRNA. In the nucleus, small RNAs can also control transcription and splicing. The mechanisms for RNA-mediated nuclear regulation are not understood and remain controversial, hindering the effective application of nuclear RNAi and investigation of its natural regulatory roles. Here, we reveal that the human GW182 paralogs TNRC6A/B/C are central organizing factors critical to RNA-mediated transcriptional activation. Mass spectrometry of purified nuclear lysates followed by experimental validation demonstrates that TNRC6A interacts with proteins involved in protein degradation, RNAi, the CCR4-NOT complex, the mediator complex, and histone-modifying complexes. Functional analysis implicates TNRC6A, NAT10, MED14, and WDR5 in RNA-mediated transcriptional activation. These findings describe protein complexes capable of bridging RNA-mediated sequence-specific recognition of noncoding RNA transcripts with the regulation of gene transcription. Copyright © 2017 The Authors. Published by Elsevier Inc. All rights reserved.

Maladaptive perfectionism as mediator among psychological control, eating disorders, and exercise dependence symptoms in habitual exerciser.

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Costa, Sebastiano; Hausenblas, Heather A; Oliva, Patrizia; Cuzzocrea, Francesca; Larcan, Rosalba

2016-03-01

Background and aims The current study examined the mediating role of maladaptive perfectionism among parental psychological control, eating disorder symptoms, and exercise dependence symptoms by gender in habitual exercisers. Methods Participants were 348 Italian exercisers (n = 178 men and n = 170 women; M age = 20.57, SD = 1.13) who completed self-report questionnaires assessing their parental psychological control, maladaptive perfectionism, eating disorder symptoms, and exercise dependence symptoms. Results Results of the present study confirmed the mediating role of maladaptive perfectionism for eating disorder and exercise dependence symptoms for the male and female exercisers in the maternal data. In the paternal data, maladaptive perfectionism mediated the relationships between paternal psychological control and eating disorder and exercise dependence symptoms as full mediator for female participants and as partial mediator for male participants. Discussion Findings of the present study suggest that it may be beneficial to consider dimensions of maladaptive perfectionism and parental psychological control when studying eating disorder and exercise dependence symptoms in habitual exerciser.

Strategic larval decision-making in a bivoltine butterfly.

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Friberg, Magne; Dahlerus, Josefin; Wiklund, Christer

2012-07-01

In temperate areas, insect larvae must decide between entering winter diapause or developing directly and reproducing in the same season. Long daylength and high temperature promote direct development, which is generally associated with a higher growth rate. In this work, we investigated whether the larval pathway decision precedes the adjustment of growth rate (state-independent), or whether the pathway decision is conditional on the individual's growth rate (state-dependent), in the butterfly Pieris napi. This species typically makes the pathway decision in the penultimate instar. We measured growth rate throughout larval development under two daylengths: slightly shorter and slightly longer than the critical daylength. Results indicate that the pathway decision can be both state-independent and state-dependent; under the shorter daylength condition, most larvae entered diapause, and direct development was chosen exclusively by a small subset of larvae showing the highest growth rates already in the early instars; under the longer daylength condition, most larvae developed directly, and the diapause pathway was chosen exclusively by a small subset of slow-growing individuals. Among the remainder, the choice of pathway was independent of the early growth rate; larvae entering diapause under the short daylength grew as fast as or faster than the direct developers under the longer daylength in the early instars, whereas the direct developers grew faster than the diapausers only in the ultimate instar. Hence, the pathway decision was state-dependent in a subset with a very high or very low growth rate, whereas the decision was state-independent in the majority of the larvae, which made the growth rate adjustment downstream from the pathway decision.

More than resisting temptation: Beneficial habits mediate the relationship between self-control and positive life outcomes.

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Galla, Brian M; Duckworth, Angela L

2015-09-01

Why does self-control predict such a wide array of positive life outcomes? Conventional wisdom holds that self-control is used to effortfully inhibit maladaptive impulses, yet this view conflicts with emerging evidence that self-control is associated with less inhibition in daily life. We propose that one of the reasons individuals with better self-control use less effortful inhibition, yet make better progress on their goals is that they rely on beneficial habits. Across 6 studies (total N = 2,274), we found support for this hypothesis. In Study 1, habits for eating healthy snacks, exercising, and getting consistent sleep mediated the effect of self-control on both increased automaticity and lower reported effortful inhibition in enacting those behaviors. In Studies 2 and 3, study habits mediated the effect of self-control on reduced motivational interference during a work-leisure conflict and on greater ability to study even under difficult circumstances. In Study 4, homework habits mediated the effect of self-control on classroom engagement and homework completion. Study 5 was a prospective longitudinal study of teenage youth who participated in a 5-day meditation retreat. Better self-control before the retreat predicted stronger meditation habits 3 months after the retreat, and habits mediated the effect of self-control on successfully accomplishing meditation practice goals. Finally, in Study 6, study habits mediated the effect of self-control on homework completion and 2 objectively measured long-term academic outcomes: grade point average and first-year college persistence. Collectively, these results suggest that beneficial habits-perhaps more so than effortful inhibition-are an important factor linking self-control with positive life outcomes. (c) 2015 APA, all rights reserved).

More than Resisting Temptation: Beneficial Habits Mediate the Relationship between Self-Control and Positive Life Outcomes

Science.gov (United States)

Galla, Brian M.; Duckworth, Angela L.

2015-01-01

Why does self-control predict such a wide array of positive life outcomes? Conventional wisdom holds that self-control is used to effortfully inhibit maladaptive impulses, yet this view conflicts with emerging evidence that self-control is associated with less inhibition in daily life. We propose that one of the reasons individuals with better self-control use less effortful inhibition, yet make better progress on their goals is that they rely on beneficial habits. Across six studies (total N = 2,274), we found support for this hypothesis. In Study 1, habits for eating healthy snacks, exercising, and getting consistent sleep mediated the effect of self-control on both increased automaticity and lower reported effortful inhibition in enacting those behaviors. In Studies 2 and 3, study habits mediated the effect of self-control on reduced motivational interference during a work-leisure conflict and on greater ability to study even under difficult circumstances. In Study 4, homework habits mediated the effect of self-control on classroom engagement and homework completion. Study 5 was a prospective longitudinal study of teenage youth who participated in a five-day meditation retreat. Better self-control before the retreat predicted stronger meditation habits three months after the retreat, and habits mediated the effect of self-control on successfully accomplishing meditation practice goals. Finally, in Study 6, study habits mediated the effect of self-control on homework completion and two objectively measured long-term academic outcomes: grade point average and first-year college persistence. Collectively, these results suggest that beneficial habits--perhaps more so than effortful inhibition--are an important factor linking self-control with positive life outcomes. PMID:25643222

Gibberellins Promote Brassinosteroids Action and Both Increase Heterosis for Plant Height in Maize (Zea mays L.

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Songlin Hu

2017-06-01

Full Text Available Brassinosteroids (BRs and Gibberellins (GAs are two classes of plant hormones affecting plant height (PHT. Thus, manipulation of BR and GA levels or signaling enables optimization of crop grain and biomass yields. We established backcross (BC families, selected for increased PHT, in two elite maize inbred backgrounds. Various exotic accessions used in the germplasm enhancement in maize project served as donors. BC1-derived doubled haploid lines in the same two elite maize inbred backgrounds established without selection for plant height were included for comparison. We conducted genome-wide association studies to explore the genetic control of PHT by BR and GA. In addition, we used BR and GA inhibitors to compare the relationship between PHT, BR, and GA in inbred lines and heterozygotes from a physiological and biological perspective. A total of 73 genomic loci were discovered to be associated with PHT, with seven co-localized with GA, and two co-localized with BR candidate genes. PHT determined in field trials was significantly correlated with seedling stage BR and GA inhibitor responses. However, this observation was only true for maize heterozygotes, not for inbred lines. Path analysis results suggest that heterozygosity increases GA levels, which in turn promote BR levels. Thus, at least part of heterosis for PHT in maize can be explained by increased GA and BR levels, and seedling stage hormone inhibitor response is promising to predict heterosis for PHT.

Effortless Inhibition: Habit Mediates the Relation Between Self-Control and Unhealthy Snack Consumption

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Marieke eAdriaanse

2014-05-01

Full Text Available In contrast to prevailing beliefs, recent research suggests that trait self-control promotes health behavior not because those high in self-control are more successful at resisting single temptations, but rather because they develop adaptive habits. The present paper presents a first empirical test of this novel suggestion by investigating the mediating role of habit in explaining the relation between self-control and unhealthy snacking behavior. Results showed that self-control was negatively associated with unhealthy snack consumption and unhealthy snacking habits. As hypothesized, the relation between self-control and unhealthy snack intake was mediated by habit strength. Self-control was not associated with fruit consumption or fruit consumption habits. These results provide the first evidence for the notion that high self-control may influence the formation of habits and in turn affect behavior. Moreover, results imply that self-control may be particularly influential in case of inhibiting unhealthy food intake rather than promoting healthy food intake.

Gibberellin regulates pollen viability and pollen tube growth in rice.

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Chhun, Tory; Aya, Koichiro; Asano, Kenji; Yamamoto, Eiji; Morinaka, Yoichi; Watanabe, Masao; Kitano, Hidemi; Ashikari, Motoyuki; Matsuoka, Makoto; Ueguchi-Tanaka, Miyako

2007-12-01

Gibberellins (GAs) play many biological roles in higher plants. We collected and performed genetic analysis on rice (Oryza sativa) GA-related mutants, including GA-deficient and GA-insensitive mutants. Genetic analysis of the mutants revealed that rice GA-deficient mutations are not transmitted as Mendelian traits to the next generation following self-pollination of F1 heterozygous plants, although GA-insensitive mutations are transmitted normally. To understand these differences in transmission, we examined the effect of GA on microsporogenesis and pollen tube elongation in rice using new GA-deficient and GA-insensitive mutants that produce semifertile flowers. Phenotypic analysis revealed that the GA-deficient mutant reduced pollen elongation1 is defective in pollen tube elongation, resulting in a low fertilization frequency, whereas the GA-insensitive semidominant mutant Slr1-d3 is mainly defective in viable pollen production. Quantitative RT-PCR revealed that GA biosynthesis genes tested whose mutations are transmitted to the next generation at a lower frequency are preferentially expressed after meiosis during pollen development, but expression is absent or very low before the meiosis stage, whereas GA signal-related genes are actively expressed before meiosis. Based on these observations, we predict that the transmission of GA-signaling genes occurs in a sporophytic manner, since the protein products and/or mRNA transcripts of these genes may be introduced into pollen-carrying mutant alleles, whereas GA synthesis genes are transmitted in a gametophytic manner, since these genes are preferentially expressed after meiosis.

College drinking behaviors: mediational links between parenting styles, impulse control, and alcohol-related outcomes.

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Patock-Peckham, Julie A; Morgan-Lopez, Antonio A

2006-06-01

Mediational links between parenting styles (authoritative, authoritarian, permissive), impulsiveness (general control), drinking control (specific control), and alcohol use and abuse were tested. A pattern-mixture approach (for modeling non-ignorable missing data) with multiple-group structural equation models with 421 (206 female, 215 male) college students was used. Gender was examined as a potential moderator of parenting styles on control processes related to drinking. Specifically, the parent-child gender match was found to have implications for increased levels of impulsiveness (a significant mediator of parenting effects on drinking control). These findings suggest that a parent with a permissive parenting style who is the same gender as the respondent can directly influence control processes and indirectly influence alcohol use and abuse.

Stamen-derived bioactive gibberellin is essential for male flower development of Cucurbita maxima L.

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Pimenta Lange, Maria João; Knop, Nicole; Lange, Theo

2012-04-01

Gibberellin (GA) signalling during pumpkin male flower development is highly regulated, including biosynthetic, perception, and transduction pathways. GA 20-oxidases, 3-oxidases, and 2-oxidases catalyse the final part of GA synthesis. Additionally, 7-oxidase initiates this part of the pathway in some cucurbits including Cucurbita maxima L. (pumpkin). Expression patterns for these GA-oxidase-encoding genes were examined by competitive reverse transcription-PCR (RT-PCR) and endogenous GA levels were determined during pumpkin male flower development. In young flowers, GA20ox3 transcript levels are high in stamens, followed by high levels of the GA precursor GA(9). Later, just before flower opening, transcript levels for GA3ox3 and GA3ox4 increase in the hypanthium and stamens, respectively. In the stamen, following GA3ox4 expression, bioactive GA(4) levels rise dramatically. Accordingly, catabolic GA2ox2 and GA2ox3 transcript levels are low in developing flowers, and increase in mature flowers. Putative GA receptor GID1b and DELLA repressor GAIPb transcript levels do not change in developing flowers, but increase sharply in mature flowers. Emasculation arrests floral development completely and leads to abscission of premature flowers. Application of GA(4) (but not of its precursors GA(12)-aldehyde or GA(9)) restores normal growth of emasculated flowers. These results indicate that de novo GA(4) synthesis in the stamen is under control of GA20ox3 and GA3ox4 genes just before the rapid flower growth phase. Stamen-derived bioactive GA is essential and sufficient for male flower development, including the petal and the pedicel growth.

Dormancy in Peach (Prunus persica L.) Flower Buds : I. Floral Morphogenesis and Endogenous Gibberellins at the End of the Dormancy Period.

Science.gov (United States)

Luna, V; Lorenzo, E; Reinoso, H; Tordable, M C; Abdala, G; Pharis, R P; Bottini, R

1990-05-01

Flower buds of peach (Prunus persica L.) trees, cv Novedad de Cordoba (Argentina), were collected near the end of the dormant period and immediately before anthesis. After removal of scale leaves, morphological observations of representative buds, made on transverse and longitudinal microtome sections, showed that all verticils making up the flower are present in an undifferentiated form during the dormant period (June). Flower buds collected at the end of dormant period (August) showed additional growth and differentiation, at which time formation of two ovules was beginning in the unicarpelar gynoecium. Dehiscence of anthers had not yet occurred 10 days before full bloom, and the ovules were still developing. Free endogenous gibberellin (GA)-like substances were quantified by bioassay (Tan-ginbozu dwarf rice microdrop) after SiO(2) partition column chromatography, reversed phase C18-high performance liquid chromatography, and finally Nucleosil [N(CH(3))(2)]high performance liquid chromatography. Bioactive fractions were then subjected to capillary gas chromatography-mass spectrometry-selected ion monitoring (GC-MS-SIM). Gibberellins A(1), A(3), and A(8) were tentatively identified in peach flower buds using GC-SIM and Kovat's retention indices, and relative amounts approximated by GC-SIM (2:8:6 for GA(1), GA(3), and GA(8), respectively). The highest concentration (330 nanograms per gram dry weight) of free GA(1)/GA(3) was found in dormant buds (June) and diminished thereafter. The concentration free of GA(1)/GA(3) did not increase immediately prior to bud break. However, high GA(1)/GA(3) concentrations occurred during stages where rate of growth and cellular differentiation of (mainly fertile) verticils can be influenced.

Gibberellin overproduction promotes sucrose synthase expression and secondary cell wall deposition in cotton fibers.

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Wen-Qin Bai

Full Text Available Bioactive gibberellins (GAs comprise an important class of natural plant growth regulators and play essential roles in cotton fiber development. To date, the molecular base of GAs' functions in fiber development is largely unclear. To address this question, the endogenous bioactive GA levels in cotton developing fibers were elevated by specifically up-regulating GA 20-oxidase and suppressing GA 2-oxidase via transgenic methods. Higher GA levels in transgenic cotton fibers significantly increased micronaire values, 1000-fiber weight, cell wall thickness and cellulose contents of mature fibers. Quantitative RT-PCR and biochemical analysis revealed that the transcription of sucrose synthase gene GhSusA1 and sucrose synthase activities were significantly enhanced in GA overproducing transgenic fibers, compared to the wild-type cotton. In addition, exogenous application of bioactive GA could promote GhSusA1 expression in cultured fibers, as well as in cotton hypocotyls. Our results suggested that bioactive GAs promoted secondary cell wall deposition in cotton fibers by enhancing sucrose synthase expression.

Self-reported impulsivity, but not behavioral approach or inhibition, mediates the relationship between stress and self-control.

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Hamilton, Kristen R; Sinha, Rajita; Potenza, Marc N

2014-11-01

Stress has been associated with poor self-control. Individual differences in impulsivity and other behavioral tendencies may influence the relationship of stress with self-control, although this possibility has not been examined to date. The present research investigated whether cumulative stress is associated with poor self-control, and whether this relationship is mediated by impulsivity, behavioral approach, and behavioral inhibition in men and women. A community sample of 566 adults (319 women and 247 men) was assessed on the Cumulative Adversity Interview, Brief Self-control Scale, Barratt Impulsivity Scale, and Behavioral Activation System and Behavioral Inhibition System Scale (BIS/BAS). Data were analyzed using regression and bootstrapping techniques. In the total sample, the effects of cumulative stress on self-control were mediated by impulsivity. Neither behavioral inhibition nor behavioral approach mediated the association between cumulative stress and self-control in the total sample. Results were similar when men and women were considered separately, with impulsivity, but not behavioral inhibition or approach, mediating the association between cumulative stress and self-control. Impulsive individuals might benefit preferentially from interventions focusing on stress management and strategies for improving self-control. Copyright © 2014 Elsevier Ltd. All rights reserved.

Search for possible latitudinal ecotypes in Dumontia contorta (Rhodophyta)

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Rietema, H.; van den Hoek, C.

1984-09-01

Effects of daylength and temperature on the formation of erect fronds (macrothalli) from crusts (microthalli) of Dumontia contorta (S. G. Gmel.) Rupr. from three localities in Nova Scotia and one locality in Southern Iceland were investigated and compared to such effects shown by strains from three different East Atlantic localities (Isle of Man; Zeeland, S. W. Netherlands; and Roscoff, Brittany, France). Although these strains showed small differences in their temperature-daylength responses, these could not be interpreted as latitudinal adaptations, and consequently no latitudinal ecotypes could be found for Dumontia contorta in the N. Atlantic Ocean. Upright fronds are formed at a broad temperature range of about 4°-18°C and at daylengths ≤ 13 h. Only in the southernmost part of its distribution area can high autumnal temperatures be expected to block the reappearance of upright fronds after passage of the critical daylength in September. In the larger part of the distribution area even summer temperatures are not high enough to block formation of uprights and here apparently only short daylengths initiate the reappearance of young upright fronds in autumn. The consequences of these aspects of the life history regulation for the geographic distribution are discussed.

CHANGES IN THE CHARACTERISTICS OF ‘PRATA’ BANANA TREATED WITH CYTOKININ AND GIBBERELLIN

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JULIANA DOMINGUES LIMA

Full Text Available ABSTRACT Plant growth regulators can influence fruit yield and quality. This study aimed to evaluate the effect of cytokinin and gibberelin on the agronomic and physicochemical characteristics of banana fruits cv. ‘Prata’ (Musa spp. AAB, according to the formation period and position in the bunch. The experiment was conducted in a completely randomized 2 x 5 factorial design, two periods of bunch development (summer and winter, five treatments and ten replicates. To study the effect of position in the bunch, split plot was adopted, considering in the plot, 2 x 5 factorial and in subplots, hand 1, hand 4 and last hand. Treatments consisted of 2 pulverizations with water, 150 mg L-1 cytokinin, 200 mg L-1 of gibberellic acid, 100 mg L-1 of cytokinin plus 200 mg L-1 of gibberellic acid and 200 mg L-1 of cytokinin plus 200 mg L-1 of gibberellic acid, applied from the fourth to the last hand of the bunch. Cytokinin and gibberellin, alone or associated, regardless of formation period and position, did not affect the size and physicochemical characteristics of fruits, only delayed the bunch harvest.

Assessing the relationships among stress, god-mediated control, and psychological distress/well-being: Does the level of education matter?

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Krause, Neal

2018-01-24

One of the primary functions of religion is to help people cope with stressful life events. The purpose of the current study is to see if God-mediated control beliefs perform this stress-buffering function. God-mediated control refers to the belief that people work together with God to reduce the effects of unwanted stressors in their lives. An effort is made to probe this relationship more deeply by seeing whether the stress moderating function of God-mediated control beliefs varies across levels of educational attainment. Findings from a recent nationwide survey suggest that strong God-mediated control beliefs reduce the magnitude of the relationship between stress and depressive symptoms, anxiety, happiness, and hope, but only among more highly educated study participants. In contrast, God-mediated control beliefs do not appear to influence the relationship between stress and distress/well-being among study participants with lower levels of educational attainment.

Religiousness and aggression in adolescents: The mediating roles of self-control and compassion.

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Shepperd, James A; Miller, Wendi A; Smith, Colin Tucker

2015-01-01

Although people have used religion to justify aggression, evidence suggests that greater religiousness corresponds with less aggression. We explored two explanations for the religion-aggression link. First, most major religions teach self-control (e.g., delaying gratification, resisting temptation), which diminishes aggression. Second, most major religions emphasize compassionate beliefs and behavior (i.e., perspective taking, forgiveness, a broader love of humanity) that are incompatible with aggression. We tested whether self-control and compassion mediated the relationship between religion and aggression (direct and indirect) in a longitudinal study of 1,040 adolescents in the United States. Structural equation analyses revealed that self-control and compassion together completely mediated the religion-aggression relationship for both types of aggression. © 2015 Wiley Periodicals, Inc.

The influence of external factors on the growth and development of spinach cultivars (Spinacia oleracea L.)

NARCIS (Netherlands)

Parlevliet, J.E.

1967-01-01

Influences of genotype (cultivar), temperature, light intensity, gibberellic acid (GA ₃ ) and daylength on stem elongation and flowering of spinach were investigated. Most cultivars reacted quantitatively to long days (LD) both for stem and flower formation. Daylength requirements varied

Exploring the relationship between socioeconomic status, control beliefs and exercise behavior: a multiple mediator model.

Science.gov (United States)

Murray, Terra C; Rodgers, Wendy M; Fraser, Shawn N

2012-02-01

The purpose of this study was to examine the relationship between control beliefs, socioeconomic status and exercise intentions and behavior. Specifically, we examined whether distal and proximal control beliefs mediated the association between socioeconomic status and exercise intentions and behavior. A one time, cross sectional mail out survey (N = 350) was conducted in a large urban Canadian city. Distal (i.e., personal constraints) and proximal (i.e., scheduling self-efficacy) control beliefs mediated the association between socioeconomic status and exercise, explaining approximately 30% of the variance. Proximal control beliefs (i.e., scheduling self-efficacy) partially mediated the association between socioeconomic status and intentions, with the models explaining approximately 50% of the variance. Compared to individuals with lower socioeconomic status, individuals with higher socioeconomic status reported more exercise and stronger intentions to exercise. This was at least partly because higher socioeconomic status respondents reported fewer barriers in their lives, and were more confident to cope with the scheduling demands of exercise.

Gibberellin-induced change in the structure of chromatin in wheat sprouts: decrease in the accessibility of DNA in preparations of soluble chromatin to the action of EcoRII methylase

International Nuclear Information System (INIS)

Noskov, V.A.; Kintsurashvili, L.N.; Smirnova, T.A.; Manamsh'yan, T.A.; Kir'yanov, G.I.; Vanyushin, B.F.

1986-01-01

A method has been perfected for producing soluble chromatin from whole wheat sprouts at low ionic strength. The chromatin preparations isolated possess a native structure: they have a nucleosome organization. Under identical conditions the soluble wheat chromatin undergoes more profound degradation by DNase I and staphylococcal nuclease than the chromatin from the rat liver. The DNA contained in the isolated chromatin is capable of accepting CHnumber groups from S-[methyl- 3 H]-adenosylmethionine during incubation with DNA methylase EcoRII; not all the CC A/T GG sequences in DNA are methylated in vivo. Chromatin from gibberellin A 3 -treated wheat sprout DNA accepts 40% fewer CH 3 groups than that from the control sprouts, which is probably due to the greater compactness of the chromatin. In the case of longer incubation, the level of methylation of the chromatin falls, which may be associated with the presence of DNA-demethylating activity

Can Job Control Ameliorate Work-family Conflict and Enhance Job Satisfaction among Chinese Registered Nurses? A Mediation Model.

Science.gov (United States)

Ding, Xiaotong; Yang, Yajuan; Su, Dan; Zhang, Ting; Li, Lunlan; Li, Huiping

2018-04-01

Low job satisfaction is the most common cause of nurses' turnover and influences the quality of nursing service. Moreover, we have no idea regarding whether job control, as an individual factor, can play a role in the relationship. To explore the relationship between work-family conflict and job satisfaction among Chinese registered nurses and the mediating role of job control in this relationship. From August 2015 to November 2016, 487 Chinese registered nurses completed a survey. The study used work-family conflict scale, job control scale, job satisfaction scale, as well as general information. Multiple regression analysis was used to explore the independent factors of job satisfaction. Structural equation model was used to explore the mediating role of job control. Work-family conflict was negatively correlated with job satisfaction (r ‑0.432, pjob control was positively related to job satisfaction (r 0.567, pjob control had significant predictive effects on job satisfaction. Job control partially mediated the relationship between work-family conflict and job satisfaction. Work-family conflict affected job satisfaction and job control was a mediator in this relationship among Chinese registered nurses. Job control could potentially improve nurses' job satisfaction.

Rice homeobox transcription factor HOX1a positively regulates gibberellin responses by directly suppressing EL1.

Science.gov (United States)

Wen, Bi-Qing; Xing, Mei-Qing; Zhang, Hua; Dai, Cheng; Xue, Hong-Wei

2011-11-01

Homeobox transcription factors are involved in various aspects of plant development, including maintenance of the biosynthesis and signaling pathways of different hormones. However, few direct targets of homeobox proteins have been identified. We here show that overexpression of rice homeobox gene HOX1a resulted in enhanced gibberellin (GA) response, indicating a positive effect of HOX1a in GA signaling. HOX1a is induced by GA and encodes a homeobox transcription factor with transcription repression activity. In addition, HOX1a suppresses the transcription of early flowering1 (EL1), a negative regulator of GA signaling, and further electrophoretic mobility shift assay and chromatin immunoprecipitation analysis revealed that HOX1a directly bound to the promoter region of EL1 to suppress its expression and stimulate GA signaling. These results demonstrate that HOX1a functions as a positive regulator of GA signaling by suppressing EL1, providing informative hints on the study of GA signaling. © 2011 Institute of Botany, Chinese Academy of Sciences.

A Novel Gibberellin-Induced Gene from Rice and Its Potential Regulatory Role in Stem Growth1

Science.gov (United States)

van der Knaap, Esther; Kim, Jeong Hoe; Kende, Hans

2000-01-01

Os-GRF1 (Oryza sativa-GROWTH-REGULATING FACTOR1) was identified in a search for genes that are differentially expressed in the intercalary meristem of deepwater rice (Oryza sativa L.) internodes in response to gibberellin (GA). Os-GRF1 displays general features of transcription factors, contains a functional nuclear localization signal, and has three regions with similarities to sequences in the database. One of these regions is similar to a protein interaction domain of SWI2/SNF2, which is a subunit of a chromatin-remodeling complex in yeast. The two other domains are novel and found only in plant proteins of unknown function. To study its role in plant growth, Os-GRF1 was expressed in Arabidopsis. Stem elongation of transformed plants was severely inhibited, and normal growth could not be recovered by the application of GA. Our results indicate that Os-GRF1 belongs to a novel class of plant proteins and may play a regulatory role in GA-induced stem elongation. PMID:10712532

Mother-adolescent conflict as a mediator between adolescent problem behaviors and maternal psychological control.

Science.gov (United States)

Steeger, Christine M; Gondoli, Dawn M

2013-04-01

This study examined mother-adolescent conflict as a mediator of longitudinal reciprocal relations between adolescent aggression and depressive symptoms and maternal psychological control. Motivated by family systems theory and the transactions that occur between individual and dyadic levels of the family system, we examined the connections among these variables during a developmental period when children and parents experience significant psychosocial changes. Three years of self-report data were collected from 168 mother-adolescent dyads, beginning when the adolescents (55.4% girls) were in 6th grade. Models were tested using longitudinal path analysis. Results indicated that the connection between adolescent aggression (and depressive symptoms) and maternal psychological control was best characterized as adolescent-driven, indirect, and mediated by mother-adolescent conflict; there were no indications of parent-driven indirect effects. That is, prior adolescent aggression and depressive symptoms were associated with increased conflict. In turn, conflict was associated with increased psychological control. Within our mediation models, reciprocal direct effects between both problem behaviors and conflict and between conflict and psychological control were also found. Additionally, exploratory analyses regarding the role of adolescent gender as a moderator of variable relations were conducted. These analyses revealed no gender-related patterns of moderation, whether moderated mediation or specific path tests for moderation were considered. This study corroborates prior research finding support for child effects on parenting behaviors during early adolescence. (PsycINFO Database Record (c) 2013 APA, all rights reserved).

Divergence and adaptive evolution of the gibberellin oxidase genes in plants.

Science.gov (United States)

Huang, Yuan; Wang, Xi; Ge, Song; Rao, Guang-Yuan

2015-09-29

The important phytohormone gibberellins (GAs) play key roles in various developmental processes. GA oxidases (GAoxs) are critical enzymes in GA synthesis pathway, but their classification, evolutionary history and the forces driving the evolution of plant GAox genes remain poorly understood. This study provides the first large-scale evolutionary analysis of GAox genes in plants by using an extensive whole-genome dataset of 41 species, representing green algae, bryophytes, pteridophyte, and seed plants. We defined eight subfamilies under the GAox family, namely C19-GA2ox, C20-GA2ox, GA20ox,GA3ox, GAox-A, GAox-B, GAox-C and GAox-D. Of these, subfamilies GAox-A, GAox-B, GAox-C and GAox-D are described for the first time. On the basis of phylogenetic analyses and characteristic motifs of GAox genes, we demonstrated a rapid expansion and functional divergence of the GAox genes during the diversification of land plants. We also detected the subfamily-specific motifs and potential sites of some GAox genes, which might have evolved under positive selection. GAox genes originated very early-before the divergence of bryophytes and the vascular plants and the diversification of GAox genes is associated with the functional divergence and could be driven by positive selection. Our study not only provides information on the classification of GAox genes, but also facilitates the further functional characterization and analysis of GA oxidases.

2-Oxoglutarate: linking TCA cycle function with amino acid, glucosinolate, flavonoid, alkaloid, and gibberellin biosynthesis.

Science.gov (United States)

Araújo, Wagner L; Martins, Auxiliadora O; Fernie, Alisdair R; Tohge, Takayuki

2014-01-01

The tricarboxylic acid (TCA) cycle intermediate 2-oxoglutarate (2-OG) is used as an obligatory substrate in a range of oxidative reactions catalyzed by 2-OG-dependent dioxygenases. These enzymes are widespread in nature being involved in several important biochemical processes. We have recently demonstrated that tomato plants in which the TCA cycle enzyme 2-OG dehydrogenase (2-ODD) was antisense inhibited were characterized by early senescence and modified fruit ripening associated with differences in the levels of bioactive gibberellin (GA). Accordingly, there is now compelling evidence that the TCA cycle plays an important role in modulating the rate of flux from 2-OG to amino acid metabolism. Here we discuss recent advances in the biochemistry and molecular biology of 2-OG metabolism occurring in different biological systems indicating the importance of 2-OG and 2-OG dependent dioxygenases not only in glucosinolate, flavonoid and alkaloid metabolism but also in GA and amino acid metabolism. We additionally summarize recent findings regarding the impact of modification of 2-OG metabolism on biosynthetic pathways involving 2-ODDs.

Characterization of ent-kaurene synthase and kaurene oxidase involved in gibberellin biosynthesis from Scoparia dulcis.

Science.gov (United States)

Yamamura, Yoshimi; Taguchi, Yukari; Ichitani, Kei; Umebara, Io; Ohshita, Ayako; Kurosaki, Fumiya; Lee, Jung-Bum

2018-03-01

Gibberellins (GAs) are ubiquitous diterpenoids in higher plants, whereas some higher plants produce unique species-specific diterpenoids. In GA biosynthesis, ent-kaurene synthase (KS) and ent-kaurene oxidase (KO) are key players which catalyze early step(s) of the cyclization and oxidation reactions. We have studied the functional characterization of gene products of a KS (SdKS) and two KOs (SdKO1 and SdKO2) involved in GA biosynthesis in Scoparia dulcis. Using an in vivo heterologous expression system of Escherichia coli, we found that SdKS catalyzed a cyclization reaction from ent-CPP to ent-kaurene and that the SdKOs oxidized ent-kaurene to ent-kaurenoic acid after modification of the N-terminal region for adaptation to the E. coli expression system. The real-time PCR results showed that the SdKS, SdKO1 and SdKO2 genes were mainly expressed in the root and lateral root systems, which are elongating tissues. Based on these results, we suggest that these three genes may be responsible for the metabolism of GAs in S. dulcis.

Transcription factor YY1 can control AID-mediated mutagenesis in mice.

Science.gov (United States)

Zaprazna, Kristina; Basu, Arindam; Tom, Nikola; Jha, Vibha; Hodawadekar, Suchita; Radova, Lenka; Malcikova, Jitka; Tichy, Boris; Pospisilova, Sarka; Atchison, Michael L

2018-02-01

Activation-induced cytidine deminase (AID) is crucial for controlling the immunoglobulin (Ig) diversification processes of somatic hypermutation (SHM) and class switch recombination (CSR). AID initiates these processes by deamination of cytosine, ultimately resulting in mutations or double strand DNA breaks needed for SHM and CSR. Levels of AID control mutation rates, and off-target non-Ig gene mutations can contribute to lymphomagenesis. Therefore, factors that control AID levels in the nucleus can regulate SHM and CSR, and may contribute to disease. We previously showed that transcription factor YY1 can regulate the level of AID in the nucleus and Ig CSR. Therefore, we hypothesized that conditional knock-out of YY1 would lead to reduction in AID localization at the Ig locus, and reduced AID-mediated mutations. Using mice that overexpress AID (IgκAID yy1 f/f ) or that express normal AID levels (yy1 f/f ), we found that conditional knock-out of YY1 results in reduced AID nuclear levels, reduced localization of AID to the Sμ switch region, and reduced AID-mediated mutations. We find that the mechanism of YY1 control of AID nuclear accumulation is likely due to YY1-AID physical interaction which blocks AID ubiquitination. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Overexpression of Jatropha Gibberellin 2-oxidase 6 (JcGA2ox6 Induces Dwarfism and Smaller Leaves, Flowers and Fruits in Arabidopsis and Jatropha

Directory of Open Access Journals (Sweden)

Ying-Xiong Hu

2017-12-01

Full Text Available Gibberellins (GAs are plant hormones that play fundamental roles in plant growth and development. Gibberellin 2-oxidase (GA2ox plays a direct role in determining the levels of bioactive GAs by catalyzing bioactive GAs or their immediate precursors to inactive forms. In this study, a GA2ox gene, designated JcGA2ox6, was isolated from Jatropha curcas. JcGA2ox6 is expressed in all tissues of adult Jatropha, with the highest expression level in male flowers and the lowest expression level in young leaves. Overexpression of JcGA2ox6 in Arabidopsis resulted in a typical dwarf phenotype, along with late flowering, smaller leaves and flowers, shorter siliques and smaller seeds. Similarly, when JcGA2ox6 was overexpressed in Jatropha, the transgenic plants exhibited a dwarf phenotype with dark-green leaves and smaller inflorescences, flowers, fruits and seeds. However, the flowering time of Jatropha was not affected by overexpression of JcGA2ox6, unlike that in the transgenic Arabidopsis. Moreover, the number of flowers per inflorescence, the weight of 10 seeds and the seed oil content were significantly decreased in transgenic Jatropha. The results indicated that overexpression of JcGA2ox6 had a great impact on the vegetative and reproductive growth of transgenic Jatropha. Furthermore, we found that the dwarf phenotype of transgenic Jatropha was caused by a decrease in endogenous bioactive GA4, which was correlated with the degree of dwarfism.

The rice dwarf virus P2 protein interacts with ent-kaurene oxidases in vivo, leading to reduced biosynthesis of gibberellins and rice dwarf symptoms.

Science.gov (United States)

Zhu, Shifeng; Gao, Feng; Cao, Xuesong; Chen, Mao; Ye, Gongyin; Wei, Chunhong; Li, Yi

2005-12-01

The mechanisms of viral diseases are a major focus of biology. Despite intensive investigations, how a plant virus interacts with host factors to cause diseases remains poorly understood. The Rice dwarf virus (RDV), a member of the genus Phytoreovirus, causes dwarfed growth phenotypes in infected rice (Oryza sativa) plants. The outer capsid protein P2 is essential during RDV infection of insects and thus influences transmission of RDV by the insect vector. However, its role during RDV infection within the rice host is unknown. By yeast two-hybrid and coimmunoprecipitation assays, we report that P2 of RDV interacts with ent-kaurene oxidases, which play a key role in the biosynthesis of plant growth hormones gibberellins, in infected plants. Furthermore, the expression of ent-kaurene oxidases was reduced in the infected plants. The level of endogenous GA1 (a major active gibberellin in rice vegetative tissues) in the RDV-infected plants was lower than that in healthy plants. Exogenous application of GA3 to RDV-infected rice plants restored the normal growth phenotypes. These results provide evidence that the P2 protein of RDV interferes with the function of a cellular factor, through direct physical interactions, that is important for the biosynthesis of a growth hormone leading to symptom expression. In addition, the interaction between P2 and rice ent-kaurene oxidase-like proteins may decrease phytoalexin biosynthesis and make plants more competent for virus replication. Moreover, P2 may provide a novel tool to investigate the regulation of GA metabolism for plant growth and development.

Can Job Control Ameliorate Work-family Conflict and Enhance Job Satisfaction among Chinese Registered Nurses? A Mediation Model

Directory of Open Access Journals (Sweden)

Xiaotong Ding

2018-04-01

Full Text Available Background: Low job satisfaction is the most common cause of nurses' turnover and influences the quality of nursing service. Moreover, we have no idea regarding whether job control, as an individual factor, can play a role in the relationship. Objective: To explore the relationship between work-family conflict and job satisfaction among Chinese registered nurses and the mediating role of job control in this relationship. Methods: From August 2015 to November 2016, 487 Chinese registered nurses completed a survey. The study used work-family conflict scale, job control scale, job satisfaction scale, as well as general information. Multiple regression analysis was used to explore the independent factors of job satisfaction. Structural equation model was used to explore the mediating role of job control. Results: Work-family conflict was negatively correlated with job satisfaction (r ‑0.432, p<0.01. In addition, job control was positively related to job satisfaction (r 0.567, p<0.01. Work-family conflict and job control had significant predictive effects on job satisfaction. Job control partially mediated the relationship between work-family conflict and job satisfaction. Conclusion: Work-family conflict affected job satisfaction and job control was a mediator in this relationship among Chinese registered nurses. Job control could potentially improve nurses' job satisfaction.

Gibberellin modulates anther development in rice via the transcriptional regulation of GAMYB.

Science.gov (United States)

Aya, Koichiro; Ueguchi-Tanaka, Miyako; Kondo, Maki; Hamada, Kazuki; Yano, Kentaro; Nishimura, Mikio; Matsuoka, Makoto

2009-05-01

Gibberellins (GAs) play important roles in regulating reproductive development, especially anther development. Our previous studies revealed that the MYB transcriptional factor GAMYB, an important component of GA signaling in cereal aleurone cells, is also important for anther development. Here, we examined the physiological functions of GA during anther development through phenotypic analyses of rice (Oryza sativa) GA-deficient, GA-insensitive, and gamyb mutants. The mutants exhibited common defects in programmed cell death (PCD) of tapetal cells and formation of exine and Ubisch bodies. Microarray analysis using anther RNAs of these mutants revealed that rice GAMYB is involved in almost all instances of GA-regulated gene expression in anthers. Among the GA-regulated genes, we focused on two lipid metabolic genes, a cytochrome P450 hydroxylase CYP703A3 and beta-ketoacyl reductase, both of which might be involved in providing a substrate for exine and Ubisch body. GAMYB specifically interacted with GAMYB binding motifs in the promoter regions in vitro, and mutation of these motifs in promoter-beta-glucuronidase (GUS) transformants caused reduced GUS expression in anthers. Furthermore, a knockout mutant for CYP703A3 showed gamyb-like defects in exine and Ubisch body formation. Together, these results suggest that GA regulates exine formation and the PCD of tapetal cells and that direct activation of CYP703A3 by GAMYB is key to exine formation.

Smartphone Addiction and School Life Adjustment Among High School Students: The Mediating Effect of Self-Control.

Science.gov (United States)

Heo, YoungJin; Lee, Kyunghee

2018-05-08

Previous studies have reported associations among smartphone addiction, school adjustment, and self-control. However, the causal relationship between smartphone addiction and school adjustment has not been clearly demonstrated. The current study examined the association between smartphone addiction and school adjustment and investigated the mediating effect of self-control in this association. A total of 790 students from five high schools in Daegu City, South Korea, were asked to provide demographic information and complete a self-diagnostic smartphone addiction scale and validated Korean version of a self-control scale. Among at-risk students, self-control did not mediate the relation between smartphone addiction and school adjustment; among those not at risk, there was a partial mediating effect. To improve school adjustment among high school students, prevention of smartphone addiction seems important. Smartphone addiction could be managed by strengthening self-control to promote healthy use of smartphones. The current results can serve as groundwork for the development of programs to improve school adjustment among high school students. [Journal of Psychosocial Nursing and Mental Health Services, xx(x), xx-xx.]. Copyright 2018, SLACK Incorporated.

The decision to germinate is regulated by divergent molecular networks in spores and seeds

DEFF Research Database (Denmark)

Vesty, Eleanor F.; Saidi, Younousse; Moody, Laura A.

2016-01-01

, the role of abscisic acid and diterpenes (gibberellins) in germination assumed much greater importance as land plant evolution progressed. We conclude that the endogenous hormone signalling networks mediating germination in response to the environment may have evolved independently in spores and seeds...

Job autonomy in relation to work engagement and workaholism: Mediation of autonomous and controlled work motivation.

Science.gov (United States)

Malinowska, Diana; Tokarz, Aleksandra; Wardzichowska, Anna

2018-02-07

This study integrates the Self Determination Theory and the Job Demands-Resource model in explaining motivational antecedents of 2 forms of excessive work: work engagement and workaholism. It specifically examines the relationship between job autonomy, situational work motivation, work engagement, and workaholism. The sample comprised 318 full-time employees of an international outsourcing company located in Poland. The mediation analysis was used for testing hypotheses about the mediation of autonomous and controlled motivation in the relationship between job autonomy, work engagement, and workaholism. The results have confirmed that autonomous motivation mediates the relationship between job autonomy and work engagement. The assumption about the mediation role of controlled motivation in the relationship between job autonomy and workaholism has not been confirmed; however, external regulation (i.e., controlled motivation) is a significant predictor of workaholism. Giving employees more job autonomy might increase their intrinsic and identified regulation and may therefore lead to more energetic, enthusiastic, and dedicated engagement with their jobs. Workaholism may be predicted by external regulation, and work characteristics other than job autonomy may play an important role in enhancing this controlled type of motivation. This work is available in Open Access model and licensed under a CC BY-NC 3.0 PL license.

Control of Dog Mediated Human Rabies in Haiti: No Time to Spare.

Directory of Open Access Journals (Sweden)

Max F Millien

Full Text Available The American region has pledged to eliminate dog-mediated human rabies by 2015. As part of these efforts, we describe the findings of a desk and field mission review of Haiti's rabies situation by the end of 2013. While government officials recognize the importance of dog-mediated rabies control, and the national rabies plan adequately contemplates the basic capacities to that effect, regular and sufficient implementation, for example, of dog vaccination, is hampered by limited funding. Compounding insufficient funding and human resources, official surveillance figures do not accurately reflect the risk to the population, as evidenced by the large number of rabid dogs detected by focalized and enhanced surveillance activities conducted by the Ministry of Agriculture, Natural Resources and Rural Development (MARNDR and the Health and Population Ministry (MSPP with the technical assistance of the United States Centers for Disease Control and Prevention. Although international support is common, either in the form of on-the-ground technical support or donations of immunobiologicals, it is not comprehensive. In addition, there is limited coordination with MARNDR/MSPP and with other actors at the strategic or operational level due to human resources limitations. Given these findings, the 2015 elimination goal in the region is compromised by the situation in Haiti where control of the disease is not yet in sight despite the best efforts of the resolute national officials. More importantly, dog-mediated rabies is still a threat to the Haitian population.

The LEGO toolbox: Supramolecular building blocks by nitroxide-mediated controlled radical polymerization

NARCIS (Netherlands)

Lohmeijer, B.G.G.; Schubert, U.S.

2005-01-01

A terpyridine-functionalized alkoxyamine unimolecular initiator was used for the nitroxide-mediated controlled living radical polymerization of n-butylacrylate, N,N-dimethylacrylamide, 4-vinylpyridine, 2-vinylpyridine, and isoprene. For the former three monomers, the kinetics were studied. All

Effect of Plant Growth Regulators and Cold on Improvement of Morphological Characteristics of Cineraria (Pericallis × hybrida

Directory of Open Access Journals (Sweden)

Kazem Bashiri

2017-12-01

Full Text Available Introduction: The climate of every region does not let to have year-round production of crops. Use of plant growth regulators allows to produce the flowers out of season and improve their quality and yield. Gibberellin is one of the plant growth regulators which can substitute cold requirement of plants, while cytokinin is another plant growth regulator to stimulate floral initials. Paclobutrazol is a triazole compound that inhibits gibberellin synthesis. Cineraria (Pericallis × hybrida as a prominent flowering pot plant has a growing demand during the spring festivals especially Nowrouz, which needs further improvement of quality and yield. In this regard a study was designed to examine the morphological characteristics of cineraria using gibberellin, cytokinin, paclobutrazol and cold. Materials and Methods: Seeds of cineraria (Pericallis × hybrida cv. Satellite( were sown in plug trays at the research greenhouse of college of agriculture, Shiraz University. A study was carried out with a completely randomized design and five replications. Control plants were transferred to incubators at eight leaves stage to receive six weeks of cold. Spraying treatments consisted of control (water, 100 mg/L gibberellin at three times (before cold, middle of cold and after cold, combinations of cold and/or gibberellin (100, 200 mg/L with benzyl adenine (150, 300 mg/L and/or paclobutrazol (250, 500 mg/L. In order to better understand the effects of paclobutrazol, its treatments were applied two weeks after gibberellin treatments. Data analysis was done by SAS 9.1 software and means were compared by LSD at 5 percent probability level. Results and Discussions: Gibberellin can be used as a replacement for cold. The maximum acceleration of full flowering (32 days and the greatest delay of full bloom (14 days were observed in 100 mg/L gibberellin + 250 mg/L paclobutrazol and 200 mg/L gibberellin + 300 mg/L benzyl adenine, respectively. These results were

Effortless inhibition: habit mediates the relation between self-control and unhealthy snack consumption

OpenAIRE

Adriaanse, Marieke A.; Kroese, Floor M.; Gillebaart, Marleen; De Ridder, Denise T. D.

2014-01-01

In contrast to prevailing beliefs, recent research suggests that trait self-control promotes health behavior not because those high in self-control are more successful at resisting single temptations, but rather because they develop adaptive habits. The present paper presents a first empirical test of this novel suggestion by investigating the mediating role of habit in explaining the relation between self-control and unhealthy snacking behavior. Results showed that self-control was negativel...

Proactive sustainability strategy and corporate sustainability performance: The mediating effect of sustainability control systems.

Science.gov (United States)

Wijethilake, Chaminda

2017-07-01

This study examines to what extent corporations use sustainability control systems (SCS) to translate proactive sustainability strategy into corporate sustainability performance. The study investigates the mediating effect of SCS on the relationship between proactive sustainability strategy and corporate sustainability performance. Survey data were collected from top managers in 175 multinational and local corporations operating in Sri Lanka and analyzed using Partial Least Squares Structural Equation Modeling (PLS-SEM). SCS were observed to only partially mediate the relationship between proactive sustainability strategy and corporate sustainability performance. The mediating effect of SCS is further examined under three sustainability strategies; environmental and social strategies reveal a partial mediation, while the economic strategy exhibits no mediation. The study also finds that (i) a proactive sustainability strategy is positively associated with SCS and corporate sustainability performance and (ii) SCS are positively associated with corporate sustainability performance. Copyright © 2017 Elsevier Ltd. All rights reserved.

The Rice Dwarf Virus P2 Protein Interacts with ent-Kaurene Oxidases in Vivo, Leading to Reduced Biosynthesis of Gibberellins and Rice Dwarf Symptoms1

Science.gov (United States)

Zhu, Shifeng; Gao, Feng; Cao, Xuesong; Chen, Mao; Ye, Gongyin; Wei, Chunhong; Li, Yi

2005-01-01

The mechanisms of viral diseases are a major focus of biology. Despite intensive investigations, how a plant virus interacts with host factors to cause diseases remains poorly understood. The Rice dwarf virus (RDV), a member of the genus Phytoreovirus, causes dwarfed growth phenotypes in infected rice (Oryza sativa) plants. The outer capsid protein P2 is essential during RDV infection of insects and thus influences transmission of RDV by the insect vector. However, its role during RDV infection within the rice host is unknown. By yeast two-hybrid and coimmunoprecipitation assays, we report that P2 of RDV interacts with ent-kaurene oxidases, which play a key role in the biosynthesis of plant growth hormones gibberellins, in infected plants. Furthermore, the expression of ent-kaurene oxidases was reduced in the infected plants. The level of endogenous GA1 (a major active gibberellin in rice vegetative tissues) in the RDV-infected plants was lower than that in healthy plants. Exogenous application of GA3 to RDV-infected rice plants restored the normal growth phenotypes. These results provide evidence that the P2 protein of RDV interferes with the function of a cellular factor, through direct physical interactions, that is important for the biosynthesis of a growth hormone leading to symptom expression. In addition, the interaction between P2 and rice ent-kaurene oxidase-like proteins may decrease phytoalexin biosynthesis and make plants more competent for virus replication. Moreover, P2 may provide a novel tool to investigate the regulation of GA metabolism for plant growth and development. PMID:16299167

Investigation of plant hormone level changes in shoot tips of longan (Dimocarpus longan Lour.) treated with potassium chlorate by liquid chromatography-electrospray ionization mass spectrometry.

Science.gov (United States)

Susawaengsup, Chanthana; Rayanakorn, Mongkon; Wongpornchai, Sugunya; Wangkarn, Sunanta

2011-08-15

The endogenous levels of indole-3-acetic acid (IAA), gibberellins (GAs), abscisic acid (ABA) and cytokinins (CKs) and their changes were investigated in shoot tips of ten longan (Dimocarpus longan Lour.) trees for off-season flowering until 60 days after potassium chlorate treatment in comparison with those of ten control (untreated) longan trees. These analytes were extracted and interfering matrices removed with a single mixed-mode solid phase extraction under optimum conditions. The recoveries at three levels of concentration were in the range of 72-112%. The endogenous plant hormones were separated and quantified by liquid chromatography-electrospray ionization-mass spectrometry (LC-ESI-MS). Detection limits based on the signal-to-noise ratio ranged from 10 ng mL(-1) for gibberellin A4 (GA4) to 200 ng mL(-1) for IAA. Within the first week after potassium chlorate treatment, dry weight (DW) amounts in the treated longan shoot tips of four gibberellins, namely: gibberellin A1(GA1), gibberellic acid (GA3), gibberellin A19 (GA19) and gibberellin A20 (GA20), were found to increase to approximately 25, 50, 20 and 60 ng g(-1) respectively, all of which were significantly higher than those of the controls. In contrast, gibberellin A8 (GA8) obtained from the treated longan was found to decrease to approximately 20 ng g(-1)DW while that of the control increased to around 80 ng g(-1)DW. Certain CKs which play a role in leaf bud induction, particularly isopentenyl adenine (iP), isopentenyl adenosine (iPR) and dihydrozeatin riboside (DHZR), were found to be present in amounts of approximately 20, 50 and 60 ng g(-1)DW in the shoot tips of the control longan. The analytical results obtained from the two-month off-season longan flowering period indicate that high GA1, GA3, GA19 and GA20 levels in the longan shoot tips contribute to flower bud induction while high levels of CKs, IAA and ABA in the control longan contribute more to the vegetative development. Copyright © 2011

Bioherbicides: Current knowledge on weed control mechanism.

Science.gov (United States)

Radhakrishnan, Ramalingam; Alqarawi, Abdulaziz A; Abd Allah, Elsayed Fathi

2018-04-17

Weed control is a challenging event during crop cultivation. Integrated management, including the application of bioherbicides, is an emerging method for weed control in sustainable agriculture. Plant extracts, allelochemicals and some microbes are utilized as bioherbicides to control weed populations. Bioherbicides based on plants and microbes inhibit the germination and growth of weeds; however,few studies conducted in weed physiology. This review ascribes the current knowledge of the physiological changes in weeds that occur during the exposure to bioherbicides. Plant extracts or metabolites are absorbed by weed seeds, which initiates damage to the cell membrane, DNA, mitosis, amylase activity and other biochemical processes and delays or inhibits seed germination. The growth of weeds is also retarded due to low rates of root-cell division, nutrient uptake, photosynthetic pigment synthesis, and plant growth hormone synthesis, while the productions of reactive oxygen species (ROS) and stress-mediated hormones increase, including irregular antioxidant activity. However, lytic enzymes and toxic substances secreted from microbes degrade the weed seed coat and utilize the endosperm for survival, which inhibits seed germination. The microbes grow through the intercellular spaces to reach the root core, and the deposition of toxins in the cells affects cell division and cellular functions. Some of the metabolites of deleterious microbes cause disease, necrosis and chlorosis,which inhibit the germination and growth of weed seeds by suppressing photosynthesis and gibberellin activities and enhancing ROS, abscisic acid and ethylene. This review explains the effects of bioherbicides (derived from plants and microbes) on weed-plant physiology to elucidate their modes of action. Copyright © 2018 Elsevier Inc. All rights reserved.

Activation of gibberellin 2-oxidase 6 decreases active gibberellin levels and creates a dominant semi-dwarf phenotype in rice (Oryza sativa L.).

Science.gov (United States)

Huang, Jian; Tang, Ding; Shen, Yi; Qin, Baoxiang; Hong, Lilan; You, Aiqing; Li, Ming; Wang, Xin; Yu, Hengxiu; Gu, Minghong; Cheng, Zhukuan

2010-01-01

Gibberellin (GA) 2-oxidase plays a key role in the GA catabolic pathway through 2beta-hydroxylation. In the present study, we isolated a CaMV 35S-enhancer activation tagged mutant, H032. This mutant exhibited a dominant dwarf and GA-deficient phenotype, with a final stature that was less than half of its wild-type counterpart. The endogenous bioactive GAs are markedly decreased in the H032 mutant, and application of bioactive GAs (GA(3) or GA(4)) can reverse the dwarf phenotype. The integrated T-DNA was detected 12.8 kb upstream of the OsGA2ox6 in the H032 genome by TAIL-PCR. An increased level of OsGA2ox6 mRNA was detected at a high level in the H032 mutant, which might be due to the enhancer role of the CaMV 35S promoter. RNAi and ectopic expression analysis of OsGA2ox6 indicated that the dwarf trait and the decreased levels of bioactive GAs in the H032 mutant were a result of the up-regulation of the OsGA2ox6 gene. BLASTP analysis revealed that OsGA2ox6 belongs to the class III of GA 2-oxidases, which is a novel type of GA2ox that uses C20-GAs (GA(12) and/or GA(53)) as the substrates. Interestingly, we found that a GA biosynthesis inhibitor, paclobutrazol, positively regulated the OsGA2ox6 gene. Unlike the over-expression of OsGA2ox1, which led to a high rate of seed abortion, the H032 mutant retained normal flowering and seed production. These results indicate that OsGA2ox6 mainly affects plant stature, and the dominant dwarf trait of the H032 mutant can be used as an efficient dwarf resource in rice breeding. Copyright 2010 Institute of Genetics and Developmental Biology and the Genetics Society of China. Published by Elsevier Ltd. All rights reserved.

Work stress and emotional exhaustion in nurses: the mediating role of internal locus of control.

Science.gov (United States)

Partlak Günüşen, Neslihan; Ustün, Besti; Erdem, Sabri

2014-01-01

Burnout is a major problem for nursing. There is a strong relationship between work stress and emotional exhaustion. Although studies report a negative correlation between the internal locus of control and emotional exhaustion and work stress, the number of studies available on the subject is limited. This study intends to examine the extent to which the relationship between work stress and emotional exhaustion is mediated by nurses' internal locus of control. The study adopted a cross-sectional survey design. The data were analyzed using structural equation modeling techniques. The study sample consisted of 347 nurses who worked in a university hospital in Izmir, Turkey and who agreed to participate in the study. The Work-Related Strain Inventory was used to evaluate the nurses' work stress level, Maslach Burnout Inventory was used to evaluate their emotional exhaustion levels, and the Locus of Control Scale was used to evaluate the internal locus of control. The variables of the study were based on the Neuman Systems Model. Work stress was positively related to internal locus of control (β3 = .21, p 0.1). Internal locus of control was negatively related to emotional exhaustion (β = -.14, p Work stress is directly (β = .87, p Work stress is directly (β = .87, p work stress was mediated, the impact of internal locus of control was limited. It is recommended that different variables be included in future studies so that they can mediate the relationship between work stress and emotional exhaustion.

The dampening effect of employees' future orientation on cyberloafing behaviors: the mediating role of self-control.

Science.gov (United States)

Zhang, Heyun; Zhao, Huanhuan; Liu, Jingxuan; Xu, Yan; Lu, Hui

2015-01-01

Previous studies on reducing employees' cyberloafing behaviors have primarily examined the external control factors but seldomly taken individual internal subjective factors into consideration. Future orientation, an important individual factor, is defined as the extent to which one plans for future time and considers future consequences of one's current behavior. To explore further whether and how employees' future orientation can dampen their cyberloafing behaviors, two studies were conducted to examine the relationship between employees' future orientation and cyberloafing behaviors. The mediation effect of employees' objective and subjective self-control between them was also examined. In Study 1, a set of questionnaires was completed, and the results revealed that the relationship between employees' future orientation and cyberloafing behaviors was negative, and objective self-control mediated the relationship. Next, we conducted a priming experiment (Study 2) to examine the causal relationship and psychological mechanism between employees' future orientation and cyberloafing behaviors. The results demonstrated that employees' future-orientation dampened their attitudes and intentions to engage in cyberloafing, and subjective self-control mediated this dampening effect. Theoretical and practical implications of these findings are also discussed.

The Mediator subunit SFR6/MED16 controls defence gene expression mediated by salicylic acid and jasmonate responsive pathways.

Science.gov (United States)

Wathugala, Deepthi L; Hemsley, Piers A; Moffat, Caroline S; Cremelie, Pieter; Knight, Marc R; Knight, Heather

2012-07-01

• Arabidopsis SENSITIVE TO FREEZING6 (SFR6) controls cold- and drought-inducible gene expression and freezing- and osmotic-stress tolerance. Its identification as a component of the MEDIATOR transcriptional co-activator complex led us to address its involvement in other transcriptional responses. • Gene expression responses to Pseudomonas syringae, ultraviolet-C (UV-C) irradiation, salicylic acid (SA) and jasmonic acid (JA) were investigated in three sfr6 mutant alleles by quantitative real-time PCR and susceptibility to UV-C irradiation and Pseudomonas infection were assessed. • sfr6 mutants were more susceptible to both Pseudomonas syringae infection and UV-C irradiation. They exhibited correspondingly weaker PR (pathogenesis-related) gene expression than wild-type Arabidopsis following these treatments or after direct application of SA, involved in response to both UV-C and Pseudomonas infection. Other genes, however, were induced normally in the mutants by these treatments. sfr6 mutants were severely defective in expression of plant defensin genes in response to JA; ectopic expression of defensin genes was provoked in wild-type but not sfr6 by overexpression of ERF5. • SFR6/MED16 controls both SA- and JA-mediated defence gene expression and is necessary for tolerance of Pseudomonas syringae infection and UV-C irradiation. It is not, however, a universal regulator of stress gene transcription and is likely to mediate transcriptional activation of specific regulons only. © 2012 The Authors. New Phytologist © 2012 New Phytologist Trust.

Action of Gibberellins on Growth and Metabolism of Arabidopsis Plants Associated with High Concentration of Carbon Dioxide1[W

Science.gov (United States)

Ribeiro, Dimas M.; Araújo, Wagner L.; Fernie, Alisdair R.; Schippers, Jos H.M.; Mueller-Roeber, Bernd

2012-01-01

Although the positive effect of elevated CO2 concentration [CO2] on plant growth is well known, it remains unclear whether global climate change will positively or negatively affect crop yields. In particular, relatively little is known about the role of hormone pathways in controlling the growth responses to elevated [CO2]. Here, we studied the impact of elevated [CO2] on plant biomass and metabolism in Arabidopsis (Arabidopsis thaliana) in relation to the availability of gibberellins (GAs). Inhibition of growth by the GA biosynthesis inhibitor paclobutrazol (PAC) at ambient [CO2] (350 µmol CO2 mol−1) was reverted by elevated [CO2] (750 µmol CO2 mol−1). Thus, we investigated the metabolic adjustment and modulation of gene expression in response to changes in growth of plants imposed by varying the GA regime in ambient and elevated [CO2]. In the presence of PAC (low-GA regime), the activities of enzymes involved in photosynthesis and inorganic nitrogen assimilation were markedly increased at elevated [CO2], whereas the activities of enzymes of organic acid metabolism were decreased. Under ambient [CO2], nitrate, amino acids, and protein accumulated upon PAC treatment; however, this was not the case when plants were grown at elevated [CO2]. These results suggest that only under ambient [CO2] is GA required for the integration of carbohydrate and nitrogen metabolism underlying optimal biomass determination. Our results have implications concerning the action of the Green Revolution genes in future environmental conditions. PMID:23090585

Reduced Inhibitory Control Mediates the Relationship Between Cortical Thickness in the Right Superior Frontal Gyrus and Body Mass Index.

Science.gov (United States)

Lavagnino, Luca; Mwangi, Benson; Bauer, Isabelle E; Cao, Bo; Selvaraj, Sudhakar; Prossin, Alan; Soares, Jair C

2016-08-01

Unhealthy eating behaviors often develop in the setting of inadequate inhibitory control, a function broadly ascribed to the prefrontal cortex (PFC). Regulation of inhibitory control by the PFC and its anatomical components and their contribution to increasing body mass index (BMI) are poorly understood. To study the role of PFC in the regulation of inhibitory control and body weight, we examined measures of cortical thickness in PFC sub-regions, inhibitory control (color-word interference task (CWIT)), and BMI in 91 healthy volunteers. We tested the predictive effect of PFC sub-regional cortical thickness on BMI and mediation by inhibitory control measured with CWIT. Measures of depression (BDI-II), anxiety (STAI-T) and trauma-related symptoms (TSC-40) were collected; the disinhibition scale of the three-factor eating questionnaire (TFEQ) was used to assess disinhibited eating. We then tested the relationship between BD-II, STAI-T, TSC-40, TFEQ, CWIT, and BMI with correlation analyses. Right superior frontal gyrus cortical thickness significantly predicted BMI (β=-0.91; t=-3.2; p=0.002). Mediation analysis showed a significant indirect effect of cortical thickness on BMI mediated by inhibitory control (95% CI=-6.1, -0.67). BMI was unrelated to BDI-II, STAI-T, TSC-40, or TFEQ scores. We found an inverse relationship between cortical thickness in the right-superior frontal gyrus and BMI, which was fully mediated by inhibitory control neurocognitive performance. Our results suggest possible targets for neuromodulation in obesity (ie superior frontal gyrus) and a quantifiable mediator of their effects (ie inhibitory control).

A rice gid1 suppressor mutant reveals that gibberellin is not always required for interaction between its receptor, GID1, and DELLA proteins.

Science.gov (United States)

Yamamoto, Yuko; Hirai, Takaaki; Yamamoto, Eiji; Kawamura, Mayuko; Sato, Tomomi; Kitano, Hidemi; Matsuoka, Makoto; Ueguchi-Tanaka, Miyako

2010-11-01

To investigate gibberellin (GA) signaling using the rice (Oryza sativa) GA receptor GIBBERELLIN-INSENSITIVE DWARF1 (GID1) mutant gid1-8, we isolated a suppressor mutant, Suppressor of gid1-1 (Sgd-1). Sgd-1 is an intragenic mutant containing the original gid1-8 mutation (L45F) and an additional amino acid substitution (P99S) in the loop region. GID1(P99S) interacts with the rice DELLA protein SLENDER RICE1 (SLR1), even in the absence of GA. Substitution of the 99th Pro with other amino acids revealed that substitution with Ala (P99A) caused the highest level of GA-independent interaction. Physicochemical analysis using surface plasmon resonance revealed that GID1(P99A) has smaller K(a) (association) and K(d) (dissociation) values for GA(4) than does wild-type GID1. This suggests that the GID1(P99A) lid is at least partially closed, resulting in both GA-independent and GA-hypersensitive interactions with SLR1. One of the three Arabidopsis thaliana GID1s, At GID1b, can also interact with DELLA proteins in the absence of GA, so we investigated whether GA-independent interaction of At GID1b depends on a mechanism similar to that of rice GID1(P99A). Substitution of the loop region or a few amino acids of At GID1b with those of At GID1a diminished its GA-independent interaction with GAI while maintaining the GA-dependent interaction. Soybean (Glycine max) and Brassica napus also have GID1s similar to At GID1b, indicating that these unique GID1s occur in various dicots and may have important functions in these plants.

An unusual spliced variant of DELLA protein, a negative regulator of gibberellin signaling, in lettuce.

Science.gov (United States)

Sawada, Yoshiaki; Umetsu, Asami; Komatsu, Yuki; Kitamura, Jun; Suzuki, Hiroyuki; Asami, Tadao; Fukuda, Machiko; Honda, Ichiro; Mitsuhashi, Wataru; Nakajima, Masatoshi; Toyomasu, Tomonobu

2012-01-01

DELLA proteins are negative regulators of the signaling of gibberellin (GA), a phytohormone regulating plant growth. DELLA degradation is triggered by its interaction with GID1, a soluble GA receptor, in the presence of bioactive GA. We isolated cDNA from a spliced variant of LsDELLA1 mRNA in lettuce, and named it LsDELLA1sv. It was deduced that LsDELLA1sv encodes truncated LsDELLA1, which has DELLA and VHYNP motifs at the N terminus but lacks part of the C-terminal GRAS domain. The recombinant LsDELLA1sv protein interacted with both Arabidopsis GID1 and lettuce GID1s in the presence of GA. A yeast two-hybrid assay suggested that LsDELLA1sv interacted with LsDELLA1. The ratio of LsDELLA1sv to LsDELLA1 transcripts was higher in flower samples at the late reproductive stage and seed samples (dry seeds and imbibed seeds) than in the other organ samples examined. This study suggests that LsDELLA1sv is a possible modulator of GA signaling in lettuce.

Expression Studies of Gibberellin Oxidases in Developing Pumpkin Seeds1

Science.gov (United States)

Frisse, Andrea; Pimenta, Maria João; Lange, Theo

2003-01-01

Two cDNA clones, 3-ox and 2-ox, have been isolated from developing pumpkin (Cucurbita maxima) embryos that show significant amino acid homology to gibberellin (GA) 3-oxidases and 2-oxidases, respectively. Recombinant fusion protein of clone 3-ox converted GA12-aldehyde, GA12, GA15, GA24, GA25, and GA9 to GA14-aldehyde, GA14, GA37, GA36, GA13, and GA4, respectively. Recombinant 2-ox protein oxidized GA9, GA4, and GA1 to GA51, GA34, and GA8, respectively. Previously cloned GA 7-oxidase revealed additional 3β-hydroxylation activity of GA12. Transcripts of this gene were identified in endosperm and embryo of the developing seed by quantitative reverse transcriptase-polymerase chain reaction and localized in protoderm, root apical meristem, and quiescent center by in situ hybridization. mRNA of the previously cloned GA 20-oxidase from pumpkin seeds was localized in endosperm and in tissues of protoderm, ground meristem, and cotyledons of the embryo. However, transcripts of the recently cloned GA 20-oxidase from pumpkin seedlings were found all over the embryo, and in tissues of the inner seed coat at the micropylar end. Previously cloned GA 2β,3β-hydroxylase mRNA molecules were specifically identified in endosperm tissue. Finally, mRNA molecules of the 3-ox and 2-ox genes were found in the embryo only. 3-ox transcripts were localized in tissues of cotyledons, protoderm, and inner cell layers of the root apical meristem, and 2-ox transcripts were found in all tissues of the embryo except the root tips. These results indicate tissue-specific GA-biosynthetic pathways operating within the developing seed. PMID:12644672

Brassinosteroid Regulates Cell Elongation by Modulating Gibberellin Metabolism in Rice[C][W][OPEN

Science.gov (United States)

Tong, Hongning; Xiao, Yunhua; Liu, Dapu; Gao, Shaopei; Liu, Linchuan; Yin, Yanhai; Jin, Yun; Qian, Qian; Chu, Chengcai

2014-01-01

Brassinosteroid (BR) and gibberellin (GA) are two predominant hormones regulating plant cell elongation. A defect in either of these leads to reduced plant growth and dwarfism. However, their relationship remains unknown in rice (Oryza sativa). Here, we demonstrated that BR regulates cell elongation by modulating GA metabolism in rice. Under physiological conditions, BR promotes GA accumulation by regulating the expression of GA metabolic genes to stimulate cell elongation. BR greatly induces the expression of D18/GA3ox-2, one of the GA biosynthetic genes, leading to increased GA1 levels, the bioactive GA in rice seedlings. Consequently, both d18 and loss-of-function GA-signaling mutants have decreased BR sensitivity. When excessive active BR is applied, the hormone mostly induces GA inactivation through upregulation of the GA inactivation gene GA2ox-3 and also represses BR biosynthesis, resulting in decreased hormone levels and growth inhibition. As a feedback mechanism, GA extensively inhibits BR biosynthesis and the BR response. GA treatment decreases the enlarged leaf angles in plants with enhanced BR biosynthesis or signaling. Our results revealed a previously unknown mechanism underlying BR and GA crosstalk depending on tissues and hormone levels, which greatly advances our understanding of hormone actions in crop plants and appears much different from that in Arabidopsis thaliana. PMID:25371548

A collapsin response mediator protein 2 isoform controls myosin II-mediated cell migration and matrix assembly by trapping ROCK II

DEFF Research Database (Denmark)

Yoneda, Atsuko; Morgan-Fisher, Marie; Wait, Robin

2012-01-01

Collapsin response mediator protein 2 (CRMP-2) is known as a regulator of neuronal polarity and differentiation through microtubule assembly and trafficking. Here, we show that CRMP-2 is ubiquitously expressed and a splice variant (CRMP-2L), which is expressed mainly in epithelial cells among...... nonneuronal cells, regulates myosin II-mediated cellular functions, including cell migration. While the CRMP-2 short form (CRMP-2S) is recognized as a substrate of the Rho-GTP downstream kinase ROCK in neuronal cells, a CRMP-2 complex containing 2L not only bound the catalytic domain of ROCK II through two......-2L but not -2S inhibited fibronectin matrix assembly in fibroblasts. Underlying these responses, CRMP-2L regulated the kinase activity of ROCK II but not ROCK I, independent of GTP-RhoA levels. This study provides a new insight into CRMP-2 as a controller of myosin II-mediated cellular functions...

Influence of water table decline on growth allocation and endogenous gibberellins in black cottonwood

Energy Technology Data Exchange (ETDEWEB)

Rood, S.B.; Zanewich, K.; Stefura, C. [Lethbridge Univ., Lethbridge, AB (Canada). Dept. of Biological Sciences; Mahoney, J.M. [Alberta Environmental Protection, Lethbridge, AB (Canada)

2000-06-01

Cottonwoods have shown an adaptation to the riparian zone by coordinating root elongation to maintain contact with the water table, whose depth varies with the elevation of the adjacent river. The rate of water decline on growth allocation and concentrations of endogenous gibberellins (GAs) in black cottonwood saplings were studied at the University of Lethbridge, Alberta. Water declines were achieved by using rhizopods, and root elongation approximately doubled in response whereas leaf area was reduced. At some point, a greater water decline rate led to water stress resulting in reduced growth, increased leaf diffusive resistance, decreased water potential, and leaf senescence and abscission. After extraction of endogenous GAs, they were purified and analysed by gas chromatography-selected ion monitoring with internal ({sup 2}H{sub 2})GA standards. The results showed that GAs were higher in shoot tips and sequentially lower in basal stems, root tips, leaves and upper roots. Noticeable relationships did not appear between GA concentration and growth allocation across the water decline treatments. Only GA{sub 8} showed a consistent reduction in plants experiencing water table decline. This research did not permit the authors to conclude whether endogenous GAs play a primary role in the regulation of root elongation in response to water table decline. 7 figs., 25 refs.

Chloride (Cl−) ion-mediated shape control of palladium nanoparticles

International Nuclear Information System (INIS)

Nalajala, Naresh; Chakraborty, Arup; Bera, Bapi; Neergat, Manoj

2016-01-01

The shape control of Pd nanoparticles is investigated using chloride (Cl − ) ions as capping agents in an aqueous medium in the temperature range of 60–100 °C. With weakly adsorbing and strongly etching Cl − ions, oxygen plays a crucial role in shape control. The experimental factors considered are the concentration of the capping agents, reaction time and reaction atmosphere. Thus, Pd nanoparticles of various shapes with high selectivity can be synthesized. Moreover, the removal of Cl − ions from the nanoparticle surface is easier than that of Br − ions (moderately adsorbing and etching) and I − ions (strongly adsorbing and weakly etching). The cleaned Cl − ion-mediated shape-controlled Pd nanoparticles are electrochemically characterized and the order of the half-wave potential of the oxygen reduction reaction in oxygen-saturated 0.1 M HClO 4 solution is of the same order as that observed with single-crystal Pd surfaces. (paper)

Alcohol-specific parenting, adolescents' self-control, and alcohol use: a moderated mediation model.

Science.gov (United States)

Koning, Ina M; van den Eijnden, Regina J J M; Vollebergh, Wilma A M

2014-01-01

There is convincing evidence that parental rules about alcohol are important in curbing adolescents' alcohol use. However, little is known about the mechanisms through which the direct link between alcohol-specific parenting and alcohol use is obtained. In this study, we investigated the mediating effect of adolescent self-control on the relationship between alcohol-specific rules and adolescents' drinking behavior and whether this mediation effect depends on the level of quality of communication. A total of 883 adolescents participated in this longitudinal study at ages 13, 14, and 15 years. Strict rules predicted lower rates of drinking, but no direct effect of the quality of communication on adolescents' alcohol use was found. A higher level of self-control was related to lower rates of drinking in adolescents. The indirect effect of rules about alcohol through adolescents' self-control was statistically significant, yet only in adolescents with high qualitative parent-child communication about alcohol. In adolescents with low quality of parent-child communication, self-control was not related to drinking. These findings imply that strict rule setting in combination with qualitative parent-child communication is an important target for prevention. In addition, findings point at the importance of high qualitative parent-child communication for adolescents' motivation to engage in self-control to avoid drinking.

Isolation and characterization of a Ds-tagged rice (Oryza sativa L.) GA-responsive dwarf mutant defective in an early step of the gibberellin biosynthesis pathway.

Science.gov (United States)

Margis-Pinheiro, Marcia; Zhou, Xue-Rong; Zhu, Qian-Hao; Dennis, Elizabeth S; Upadhyaya, Narayana M

2005-03-01

We have isolated a severe dwarf transposon (Ds) insertion mutant in rice (Oryza sativa L.), which could be differentiated early in the seedling stage by reduced shoot growth and dark green leaves, and later by severe dwarfism and failure to initiate flowering. These mutants, however, showed normal seed germination and root growth. One of the sequences flanking Ds, rescued from the mutant, was of a chromosome 4-located putative ent-kaurene synthase (KS) gene, encoding the enzyme catalyzing the second step of the gibberellin (GA) biosynthesis pathway. Dwarf mutants were always homozygous for this Ds insertion and no normal plants homozygous for this mutation were recovered in the segregating progeny, indicating that the Ds insertion mutation is recessive. As mutations in three recently reported rice GA-responsive dwarf mutant alleles and the dwarf mutation identified in this study mapped to the same locus, we designate the corresponding gene OsKS1. The osks1 mutant seedlings were responsive to exogenous gibberellin (GA3). OsKS1 transcripts of about 2.3 kb were detected in leaves and stem of wild-type plants, but not in germinating seeds or roots, suggesting that OsKS1 is not involved in germination or root growth. There are at least five OsKS1-like genes in the rice genome, four of which are also represented in rice expressed sequence tag (EST) databases. All OsKS1-like genes are transcribed with different expression patterns. ESTs corresponding to all six OsKS genes are represented in other cereal databases including barley, wheat and maize, suggesting that they are biologically active.

The dampening effect of employees’ future orientation on cyberloafing behaviors: the mediating role of self-control

Science.gov (United States)

Zhang, Heyun; Zhao, Huanhuan; Liu, Jingxuan; Xu, Yan; Lu, Hui

2015-01-01

Previous studies on reducing employees’ cyberloafing behaviors have primarily examined the external control factors but seldomly taken individual internal subjective factors into consideration. Future orientation, an important individual factor, is defined as the extent to which one plans for future time and considers future consequences of one’s current behavior. To explore further whether and how employees’ future orientation can dampen their cyberloafing behaviors, two studies were conducted to examine the relationship between employees’ future orientation and cyberloafing behaviors. The mediation effect of employees’ objective and subjective self-control between them was also examined. In Study 1, a set of questionnaires was completed, and the results revealed that the relationship between employees’ future orientation and cyberloafing behaviors was negative, and objective self-control mediated the relationship. Next, we conducted a priming experiment (Study 2) to examine the causal relationship and psychological mechanism between employees’ future orientation and cyberloafing behaviors. The results demonstrated that employees’ future-orientation dampened their attitudes and intentions to engage in cyberloafing, and subjective self-control mediated this dampening effect. Theoretical and practical implications of these findings are also discussed. PMID:26483735

The dampening effect of employees’ future orientation on cyberloafing behaviors: The mediating role of self-control

Directory of Open Access Journals (Sweden)

Heyun eZhang

2015-09-01

Full Text Available Previous studies on reducing employees’ cyberloafing behaviors have primarily examined the external control factors but seldomly taken individual internal subjective factors into consideration. Future orientation, an important individual factor, is defined as the extent to which one plans for future time and considers future consequences of one’s current behavior. To explore further whether and how employees’ future orientation can dampen their cyberloafing behaviors, two studies were conducted to examine the relationship between employees’ future orientation and cyberloafing behaviors. The mediation effect of employees’ objective and subjective self-control between them was also examined. In Study 1, a set of questionnaires was completed, and the results revealed that the relationship between employees’ future orientation and cyberloafing behaviors was negative, and objective self-control mediated the relationship. Next, we conducted a priming experiment (Study 2 to examine the causal relationship and psychological mechanism between employees’ future orientation and cyberloafing behaviors. The results demonstrated that employees’ future-orientation dampened their attitudes and intentions to engage in cyberloafing, and subjective self-control mediated this dampening effect. Theoretical and practical implications of these findings are also discussed.

Cloning and molecular analyses of a gibberellin 20-oxidase gene expressed specifically in developing seeds of watermelon.

Science.gov (United States)

Kang, H G; Jun, S H; Kim, J; Kawaide, H; Kamiya, Y; An, G

1999-10-01

To understand the biosynthesis and functional role of gibberellins (GAs) in developing seeds, we isolated Cv20ox, a cDNA clone from watermelon (Citrullus lanatus) that shows significant amino acid homology with GA 20-oxidases. The complementary DNA clone was expressed in Escherichia coli as a fusion protein, which oxidized GA(12) at C-20 to the C(19) compound GA(9), a precursor of bioactive GAs. RNA-blot analysis showed that the Cv20ox gene was expressed specifically in developing seeds. The gene was strongly expressed in the integument tissues, and it was also expressed weakly in inner seed tissues. In parthenocarpic fruits induced by 1-(2-chloro-4-pyridyl)-3-phenylurea treatment, the expression pattern of Cv20ox did not change, indicating that the GA 20-oxidase gene is expressed primarily in the maternal cells of developing seeds. The promoter of Cv20ox was isolated and fused to the beta-glucuronidase (GUS) gene. In a transient expression system, beta-glucuronidase staining was detectable only in the integument tissues of developing watermelon seeds.

Fate control and well-being in Chinese rural people living with HIV: mediation effect of resilience.

Science.gov (United States)

Yu, Nancy Xiaonan; Zhang, Jianxin; Chow, Amy Y M; Chan, Celia H Y; Chan, Cecilia L W

2017-01-01

Fate control has been often misconceptualized as a superstitious belief and overlooked in health psychology. It is not known how this cultural belief might impact the well-being of Chinese people living with HIV. This study examined the protective role of fate control for well-being and the potential mediation effect of resilience. Participants in this study were rural patients who contracted HIV via commercial blood donation. In this cross-sectional survey, 250 participants completed measures of fate control, well-being, and resilience. The results showed that fate control and resilience were positively associated with well-being. Resilience mediated the association between fate control and well-being. Our findings provide insight into the adaptive function of fate control as a cognitive defensive mechanism and highlight the need to incorporate this cultural belief in developing culturally sensitive intervention programs for resilience enhancement tailored for this understudied population infected with HIV living in rural China.

To what extent can the age at sexual maturity of broiler breeders be ...

African Journals Online (AJOL)

Mean egg weight was unaffected, but the number of unsettable eggs was increased by 2.6. Using 12 h rather than 16-h daylengths during the laying period resulted in a significant increase (7) in number of eggs laid. In the second trial, birds were transferred from 8 to 16-h daylengths at 10, 11, 12, 14, 16 or 18 weeks to ...

Regulation of wheat seed dormancy by after-ripening is mediated by specific transcriptional switches that induce changes in seed hormone metabolism and signaling.

Directory of Open Access Journals (Sweden)

Aihua Liu

Full Text Available Treatments that promote dormancy release are often correlated with changes in seed hormone content and/or sensitivity. To understand the molecular mechanisms underlying the role of after-ripening (seed dry storage in triggering hormone related changes and dormancy decay in wheat (Triticum aestivum, temporal expression patterns of genes related to abscisic acid (ABA, gibberellin (GA, jasmonate and indole acetic acid (IAA metabolism and signaling, and levels of the respective hormones were examined in dormant and after-ripened seeds in both dry and imbibed states. After-ripening mediated developmental switch from dormancy to germination appears to be associated with declines in seed sensitivity to ABA and IAA, which are mediated by transcriptional repressions of PROTEIN PHOSPHATASE 2C, SNF1-RELATED PROTEIN KINASE2, ABA INSENSITIVE5 and LIPID PHOSPHATE PHOSPHTASE2, and AUXIN RESPONSE FACTOR and RELATED TO UBIQUITIN1 genes. Transcriptomic analysis of wheat seed responsiveness to ABA suggests that ABA inhibits the germination of wheat seeds partly by repressing the transcription of genes related to chromatin assembly and cell wall modification, and activating that of GA catabolic genes. After-ripening induced seed dormancy decay in wheat is also associated with the modulation of seed IAA and jasmonate contents. Transcriptional control of members of the ALLENE OXIDE SYNTHASE, 3-KETOACYL COENZYME A THIOLASE, LIPOXYGENASE and 12-OXOPHYTODIENOATE REDUCTASE gene families appears to regulate seed jasmonate levels. Changes in the expression of GA biosynthesis genes, GA 20-OXIDASE and GA 3-OXIDASE, in response to after-ripening implicate this hormone in enhancing dormancy release and germination. These findings have important implications in the dissection of molecular mechanisms underlying regulation of seed dormancy in cereals.

Rice early flowering1, a CKI, phosphorylates DELLA protein SLR1 to negatively regulate gibberellin signalling.

Science.gov (United States)

Dai, Cheng; Xue, Hong-Wei

2010-06-02

The plant hormone gibberellin (GA) is crucial for multiple aspects of plant growth and development. To study the relevant regulatory mechanisms, we isolated a rice mutant earlier flowering1, el1, which is deficient in a casein kinase I that has critical roles in both plants and animals. el1 had an enhanced GA response, consistent with the suppression of EL1 expression by exogenous GA(3). Biochemical characterization showed that EL1 specifically phosphorylates the rice DELLA protein SLR1, proving a direct evidence for SLR1 phosphorylation. Overexpression of SLR1 in wild-type plants caused a severe dwarf phenotype, which was significantly suppressed by EL1 deficiency, indicating the negative effect of SLR1 on GA signalling requires the EL1 function. Further studies showed that the phosphorylation of SLR1 is important for maintaining its activity and stability, and mutation of the candidate phosphorylation site of SLR1 results in the altered GA signalling. This study shows EL1 a novel and key regulator of the GA response and provided important clues on casein kinase I activities in GA signalling and plant development.

Locus of control, self-efficacy, and the mediating effect of outcome control: predicting course-level and global outcomes in an academic context.

Science.gov (United States)

Au, Evelyn W M

2015-01-01

The current study utilizes Skinner's framework to examine the unique contributions of internal locus of control, self-efficacy, and perceived outcome control over course performance on students' academic experiences. Undergraduate students (N = 225) took part in a longitudinal study and completed two surveys (Time 1: just before their mid-term exams; Time 2: just before their final exam in the same semester). Both locus of control and self-efficacy at Time 1 predicted course-level perceived control over course performance at Time 2. Student-level perceived control over course performance at Time 2 mediated the relationship between self-efficacy at Time 1 and course-level perseverance, course-specific stress, and course enjoyment at Time 2. For global perceived stress and life satisfaction measured at Time 2, both locus of control and self-efficacy at Time 1 had only a direct effect on global perceived stress at Time 2, but only self-efficacy at Time 1 predicted life satisfaction at Time 2. Both locus of control and self-efficacy uniquely contribute to students' academic experiences. Student-level perceived control plays an important mediating role between locus of control and self-efficacy at Time 1, and course-level perseverance, course-specific stress, and course enjoyment at Time 2.

Gibberellin biosynthesis and signal transduction is essential for internode elongation in deepwater rice.

Science.gov (United States)

Ayano, Madoka; Kani, Takahiro; Kojima, Mikiko; Sakakibara, Hitoshi; Kitaoka, Takuya; Kuroha, Takeshi; Angeles-Shim, Rosalyn B; Kitano, Hidemi; Nagai, Keisuke; Ashikari, Motoyuki

2014-10-01

Under flooded conditions, the leaves and internodes of deepwater rice can elongate above the water surface to capture oxygen and prevent drowning. Our previous studies showed that three major quantitative trait loci (QTL) regulate deepwater-dependent internode elongation in deepwater rice. In this study, we investigated the age-dependent internode elongation in deepwater rice. We also investigated the relationship between deepwater-dependent internode elongation and the phytohormone gibberellin (GA) by physiological and genetic approach using a QTL pyramiding line (NIL-1 + 3 + 12). Deepwater rice did not show internode elongation before the sixth leaf stage under deepwater condition. Additionally, deepwater-dependent internode elongation occurred on the sixth and seventh internodes during the sixth leaf stage. These results indicate that deepwater rice could not start internode elongation until the sixth leaf stage. Ultra-performance liquid chromatography tandem mass-spectrometry (UPLC-MS/MS) method for the phytohormone contents showed a deepwater-dependent GA1 and GA4 accumulation in deepwater rice. Additionally, a GA inhibitor abolished deepwater-dependent internode elongation in deepwater rice. On the contrary, GA feeding mimicked internode elongation under ordinary growth conditions. However, mutations in GA biosynthesis and signal transduction genes blocked deepwater-dependent internode elongation. These data suggested that GA biosynthesis and signal transduction are essential for deepwater-dependent internode elongation in deepwater rice. © 2014 The Authors. Plant, Cell & Environment published by John Wiley & Sons Ltd.

Interventional effects for mediation analysis with multiple mediators

OpenAIRE

Vansteelandt, Stijn; Daniel, Rhian M.

2017-01-01

The mediation formula for the identification of natural (in)direct effects has facilitated mediation analyses that better respect the nature of the data, with greater consideration of the need for confounding control. The default assumptions on which it relies are strong, however. In particular, they are known to be violated when confounders of the mediator–outcome association are affected by the exposure. This complicates extensions of counterfactual-based mediation analysis to settings that...

Diabetes-specific emotional distress mediates the association between depressive symptoms and glycaemic control in Type 1 and Type 2 diabetes

DEFF Research Database (Denmark)

van Bastelaar, Kim M P; Pouwer, F; Geelhoed-Duijvestijn, P H L M

2010-01-01

and diabetes-specific emotional distress respectively. Linear regression was performed to examine the mediating effect of diabetes-distress. RESULTS: Complete data were available for 627 outpatients with Type 1 (n = 280) and Type 2 (n = 347) diabetes. Analyses showed that diabetes-distress mediated......OBJECTIVES: To investigate whether diabetes-specific emotional distress mediates the relationship between depression and glycaemic control in patients with Type 1 and Type 2 diabetes. RESEARCH DESIGN AND METHODS: Data were derived from the baseline assessment of a depression in diabetes screening...... and glycaemic control, diabetes-specific emotional distress appears to be an important mediator. Addressing diabetes-specific emotional problems as part of depression treatment in diabetes patients may help improve glycaemic outcomes....

A Rice gid1 Suppressor Mutant Reveals That Gibberellin Is Not Always Required for Interaction between Its Receptor, GID1, and DELLA Proteins[W][OA

Science.gov (United States)

Yamamoto, Yuko; Hirai, Takaaki; Yamamoto, Eiji; Kawamura, Mayuko; Sato, Tomomi; Kitano, Hidemi; Matsuoka, Makoto; Ueguchi-Tanaka, Miyako

2010-01-01

To investigate gibberellin (GA) signaling using the rice (Oryza sativa) GA receptor GIBBERELLIN-INSENSITIVE DWARF1 (GID1) mutant gid1-8, we isolated a suppressor mutant, Suppressor of gid1-1 (Sgd-1). Sgd-1 is an intragenic mutant containing the original gid1-8 mutation (L45F) and an additional amino acid substitution (P99S) in the loop region. GID1P99S interacts with the rice DELLA protein SLENDER RICE1 (SLR1), even in the absence of GA. Substitution of the 99th Pro with other amino acids revealed that substitution with Ala (P99A) caused the highest level of GA-independent interaction. Physicochemical analysis using surface plasmon resonance revealed that GID1P99A has smaller Ka (association) and Kd (dissociation) values for GA4 than does wild-type GID1. This suggests that the GID1P99A lid is at least partially closed, resulting in both GA-independent and GA-hypersensitive interactions with SLR1. One of the three Arabidopsis thaliana GID1s, At GID1b, can also interact with DELLA proteins in the absence of GA, so we investigated whether GA-independent interaction of At GID1b depends on a mechanism similar to that of rice GID1P99A. Substitution of the loop region or a few amino acids of At GID1b with those of At GID1a diminished its GA-independent interaction with GAI while maintaining the GA-dependent interaction. Soybean (Glycine max) and Brassica napus also have GID1s similar to At GID1b, indicating that these unique GID1s occur in various dicots and may have important functions in these plants. PMID:21098733

Gibberellins producing Bacillus methylotrophicus KE2 supports plant growth and enhances nutritional metabolites and food values of lettuce.

Science.gov (United States)

Radhakrishnan, Ramalingam; Lee, In-Jung

2016-12-01

The nutritional quality of green leafy vegetables can be enhanced by application of plant beneficial micro-organisms. The present study was aimed to increase the food values of lettuce leaves by bacterial treatment. We isolated bacterial strain KE2 from Kimchi food and identified as Bacillus methylotrophicus by phylogenetic analysis. The beneficial effect of B. methylotrophicus KE2 on plants was confirmed by increasing the percentage of seed germination of Lactuca sativa L., Cucumis melo L., Glycine max L. and Brassica juncea L. It might be the secretion of array of gibberellins (GA 1 , GA 3 , GA 7 , GA 8 , GA 9 , GA 12 , GA 19 , GA 20 , GA 24 , GA 34 and GA 53 ) and indole-acetic acid from B. methylotrophicus KE2. The mechanism of plant growth promotion via their secreted metabolites was confirmed by a significant increase of GA deficient mutant rice plant growth. Moreover, the bacterial association was favor to enhance shoot length, shoot fresh weight and leaf width of lettuce. The higher concentration of protein, amino acids (Asp, Thr, Ser, Glu, Gly, Ala, Leu, Tyr and His), gama-aminobutric acid and fructose was found in bacterial culture (KE2) applied plants. The macro and micro minerals such as K, Mg, Na, P, Fe, Zn and N were also detected as significantly higher quantities in bacteria treated plants than untreated control plants. In addition, the carotenoids and chlorophyll a were also increased in lettuce at bacterial inoculation. The results of this study suggest that B. methylotrophicus KE2 application to soil helps to increase the plant growth and food values of lettuce. Copyright © 2016 Elsevier Masson SAS. All rights reserved.

Interventional Effects for Mediation Analysis with Multiple Mediators.

Science.gov (United States)

Vansteelandt, Stijn; Daniel, Rhian M

2017-03-01

The mediation formula for the identification of natural (in)direct effects has facilitated mediation analyses that better respect the nature of the data, with greater consideration of the need for confounding control. The default assumptions on which it relies are strong, however. In particular, they are known to be violated when confounders of the mediator-outcome association are affected by the exposure. This complicates extensions of counterfactual-based mediation analysis to settings that involve repeatedly measured mediators, or multiple correlated mediators. VanderWeele, Vansteelandt, and Robins introduced so-called interventional (in)direct effects. These can be identified under much weaker conditions than natural (in)direct effects, but have the drawback of not adding up to the total effect. In this article, we adapt their proposal to achieve an exact decomposition of the total effect, and extend it to the multiple mediator setting. Interestingly, the proposed effects capture the path-specific effects of an exposure on an outcome that are mediated by distinct mediators, even when-as often-the structural dependence between the multiple mediators is unknown, for instance, when the direction of the causal effects between the mediators is unknown, or there may be unmeasured common causes of the mediators.

Map-Based Cloning of Seed Dormancy1-2 Identified a Gibberellin Synthesis Gene Regulating the Development of Endosperm-Imposed Dormancy in Rice.

Science.gov (United States)

Ye, Heng; Feng, Jiuhuan; Zhang, Lihua; Zhang, Jinfeng; Mispan, Muhamad S; Cao, Zhuanqin; Beighley, Donn H; Yang, Jianchang; Gu, Xing-You

2015-11-01

Natural variation in seed dormancy is controlled by multiple genes mapped as quantitative trait loci in major crop or model plants. This research aimed to clone and characterize the Seed Dormancy1-2 (qSD1-2) locus associated with endosperm-imposed dormancy and plant height in rice (Oryza sativa). qSD1-2 was delimited to a 20-kb region, which contains OsGA20ox2 and had an additive effect on germination. Naturally occurring or induced loss-of-function mutations of the gibberellin (GA) synthesis gene enhanced seed dormancy and also reduced plant height. Expression of this gene in seeds (including endospermic cells) during early development increased GA accumulation to promote tissue morphogenesis and maturation programs. The mutant allele prevalent in semidwarf cultivars reduced the seed GA content by up to 2-fold at the early stage, which decelerated tissue morphogenesis including endosperm cell differentiation, delayed abscisic acid accumulation by a shift in the temporal distribution pattern, and postponed dehydration, physiological maturity, and germinability development. As the endosperm of developing seeds dominates the moisture equilibrium and desiccation status of the embryo in cereal crops, qSD1-2 is proposed to control primary dormancy by a GA-regulated dehydration mechanism. Allelic distribution of OsGA20ox2, the rice Green Revolution gene, was associated with the indica and japonica subspeciation. However, this research provided no evidence that the primitive indica- and common japonica-specific alleles at the presumably domestication-related locus functionally differentiate in plant height and seed dormancy. Thus, the evolutionary mechanism of this agriculturally important gene remains open for discussion. © 2015 American Society of Plant Biologists. All Rights Reserved.

Aggregation control of quantum dots through ion-mediated hydrogen bonding shielding.

Science.gov (United States)

Liu, Jianbo; Yang, Xiaohai; Wang, Kemin; He, Xiaoxiao; Wang, Qing; Huang, Jin; Liu, Yan

2012-06-26

Nanoparticle stabilization against detrimental aggregation is a critical parameter that needs to be well controlled. Herein, we present a facile and rapid ion-mediated dispersing technique that leads to hydrophilic aggregate-free quantum dots (QDs). Because of the shielding of the hydrogen bonds between cysteamine-capped QDs, the presence of F(-) ions disassembled the aggregates of QDs and afforded their high colloidal stability. The F(-) ions also greatly eliminated the nonspecific adsorption of the QDs on glass slides and cells. Unlike the conventional colloidal stabilized method that requires the use of any organic ligand and/or polymer for the passivation of the nanoparticle surface, the proposed approach adopts the small size and large diffusion coefficient of inorganic ions as dispersant, which offers the disaggregation a fast reaction dynamics and negligible influence on their intrinsic surface functional properties. Therefore, the ion-mediated dispersing strategy showed great potential in chemosensing and biomedical applications.

Microwave synthesis of gibberellin acid 3 magnetic molecularly imprinted polymer beads for the trace analysis of gibberellin acids in plant samples by liquid chromatography-mass spectrometry detection.

Science.gov (United States)

Zhang, Zhuomin; Tan, Wei; Hu, Yuling; Li, Gongke; Zan, Song

2012-02-21

In this study, novel GA3 magnetic molecularly imprinted polymer (mag-MIP) beads were synthesized by a microwave irradiation method, and the beads were applied for the trace analysis of gibberellin acids (GAs) in plant samples including rice and cucumber coupled with high performance liquid chromatography-mass spectrometry (HPLC-MS). The microwave synthetic procedure was optimized in detail. In particular, the interaction between GA3 and functional monomers was further studied for the selection of the optimal functional monomers during synthesis. It can be seen that the interaction between GA3 and acrylamide (AM) finally selected was stronger than that between GA3 and other functional monomers. GA3 mag-MIP beads were characterized by a series of physical tests. GA3 mag-MIP beads had a porous and homogeneous surface morphology with stable chemical, thermal and magnetic properties. Moreover, GA3 mag-MIP beads demonstrated selective and specific absorption behavior for the target compounds during unsaturated extraction, which resulted in a higher extraction capacity (∼708.4 pmol for GA3) and selectivity than GA3 mag-non-imprinted polymer beads. Finally, an analytical method of GA3 mag-AM-MIP bead extraction coupled with HPLC-MS detection was established and applied for the determination of trace GA1, GA3, GA4 and GA7 in rice and cucumber samples. It was satisfactory that GA4 could be actually found to be 121.5 ± 1.4 μg kg(-1) in real rice samples by this novel analytical method. The recoveries of spiked rice and cucumber samples were found to be 76.0-109.1% and 79.9-93.6% with RSDs of 2.8-8.8% and 3.1-7.7% (n = 3), respectively. The proposed method is efficient and applicable for the trace analysis of GAs in complicated plant samples.

Epimorphin mediates mammary luminal morphogenesis through control of C/EBPbeta

International Nuclear Information System (INIS)

Hirai, Yohei; Radisky, Derek; Boudreau, Rosanne; Simian, Marina; Stevens, Mary E.; Oka, Yumiko; Takebe, Kyoko; Niwa, Shinichiro; Bissell, Mina J.

2002-01-01

We have previously shown that epimorphin, a protein expressed on the surface of myoepithelial and fibroblast cells of the mammary gland, acts as a multifunctional morphogen of mammary epithelial cells. Here, we present the molecular mechanism by which epimorphin mediates luminal morphogenesis. Treatment of cells with epimorphin to induce lumen formation greatly increases the overall expression of transcription factor CCAAT/enhancer binding protein beta (C/EBPbeta) and alters the relative expression of its two principal isoforms, LIP and LAP. These alterations were shown to be essential for the morphogenetic activities, as constitutive expression of LIP was sufficient to produce lumen formation, while constitutive expression of LAP blocked epimorphin-mediated luminal morphogenesis. Furthermore, in a transgenic mouse model in which epimorphin expression was expressed in an apolar fashion on the surface of mammary epithelial cells, we found increased expression of C/EBPbeta, increased relative expression of LIP to LAP, and enlarged ductal lumina. Together, our studies demonstrate a role for epimorphin in luminal morphogenesis through control of C/EBPbeta expression

Cloning and Molecular Analyses of a Gibberellin 20-Oxidase Gene Expressed Specifically in Developing Seeds of Watermelon1

Science.gov (United States)

Kang, Hong-Gyu; Jun, Sung-Hoon; Kim, Junyul; Kawaide, Hiroshi; Kamiya, Yuji; An, Gynheung

1999-01-01

To understand the biosynthesis and functional role of gibberellins (GAs) in developing seeds, we isolated Cv20ox, a cDNA clone from watermelon (Citrullus lanatus) that shows significant amino acid homology with GA 20-oxidases. The complementary DNA clone was expressed in Escherichia coli as a fusion protein, which oxidized GA12 at C-20 to the C19 compound GA9, a precursor of bioactive GAs. RNA-blot analysis showed that the Cv20ox gene was expressed specifically in developing seeds. The gene was strongly expressed in the integument tissues, and it was also expressed weakly in inner seed tissues. In parthenocarpic fruits induced by 1-(2-chloro-4-pyridyl)-3-phenylurea treatment, the expression pattern of Cv20ox did not change, indicating that the GA 20-oxidase gene is expressed primarily in the maternal cells of developing seeds. The promoter of Cv20ox was isolated and fused to the β-glucuronidase (GUS) gene. In a transient expression system, β-glucuronidase staining was detectable only in the integument tissues of developing watermelon seeds. PMID:10517828

Right ventrolateral prefrontal cortex mediates individual differences in conflict-driven cognitive control

Science.gov (United States)

Egner, Tobias

2013-01-01

Conflict adaptation – a conflict-triggered improvement in the resolution of conflicting stimulus or response representations – has become a widely used probe of cognitive control processes in both healthy and clinical populations. Previous functional magnetic resonance imaging (fMRI) studies have localized activation foci associated with conflict resolution to dorsolateral prefrontal cortex (dlPFC). The traditional group-analysis approach employed in these studies highlights regions that are, on average, activated during conflict resolution, but does not necessarily reveal areas mediating individual differences in conflict resolution, because between-subject variance is treated as noise. Here, we employed a complementary approach in order to elucidate the neural bases of variability in the proficiency of conflict-driven cognitive control. We analyzed two independent fMRI data sets of face-word Stroop tasks by using individual variability in the behavioral expression of conflict adaptation as the metric against which brain activation was regressed, while controlling for individual differences in mean reaction time and Stroop interference. Across the two experiments, a replicable neural substrate of individual variation in conflict adaptation was found in ventrolateral prefrontal cortex (vlPFC), specifically, in the right inferior frontal gyrus, pars orbitalis (BA 47). Unbiased regression estimates showed that variability in activity in this region accounted for ~40% of the variance in behavioral expression of conflict adaptation across subjects, thus documenting a heretofore unsuspected key role for vlPFC in mediating conflict-driven adjustments in cognitive control. We speculate that vlPFC plays a primary role in conflict control that is supplemented by dlPFC recruitment under conditions of suboptimal performance. PMID:21568631

Effect of gibberellin, auxin and kinetin treatments combined with foliar applied NPK on the yield of Capsicum annuum L. fruits and their capsaicin content

Directory of Open Access Journals (Sweden)

Tomasz J. Nowak

2013-12-01

Full Text Available The Wrocław version of hydroponic culture was applied. Under optimal conditions of root fertilization the plants were sprayed with growth regulators sueh as gibberellins, auxins and kinetins, and .their mixtures. Each growth regulator treatment was applied with or without NPK added. The influence of these treatments on the fresh and dry weight of the fruit, percentage of ripe fruits and content and yield of capsaicin was studied. The highest yield of fruits and capsaicin. was obtained from plants sprayed with gibberellic acid and kinetin (in concentrations of 10 and 5 mg/l, respectively together with NPK foliar application. No influence of ,growth regulators and foliar-applied NPK was noted on capsaicin content and dry weight of fruits.

Computer-mediated communication in adults with high-functioning autism spectrum disorders and controls

NARCIS (Netherlands)

van der Aa, Christine; Pollmann, Monique; Plaat, Aske; van der Gaag, Rutger Jan

2016-01-01

It has been suggested that people with Autism Spectrum Disorders (ASD) are attracted to computer-mediated communication (CMC). In this study, we compare CMC use in adults with high-functioning ASD (N = 113) and a control group (N = 72). We find that people with ASD spend more time on CMC than

Control of the first flowering in forest trees

Energy Technology Data Exchange (ETDEWEB)

Chalupka, W. [Inst. od Dendrology, Kornik (Poland); Cecich, R.A. [U.S.D.A.-Forest Service, Columbia, MO (United States). North Central Forest Experiment Station

1997-04-01

Precocious flowering provides opportunities to shorten a breeding cycle. A tree may flower for the first time when sufficient crown development has occurred and there are enough meristems to support both vegetative and reproductive buds. Precocious flowering can be promoted through the use of cultural techniques, such as photoperiod, accelerated growth, gibberellins and water stress. The length of the juvenile phase is dependent on genetic and environmental variables that affect achievement of a minimum size, and is positively correlated with the height of the plants within a family. Selection pressure can be applied successfully to the precocious flowering character, and crossed or inbred lines of precocious flowering progeny can be developed. Various levels and amounts of genetic control have been implicated in the control of precocious flowering. 90 refs, 1 tab

No mediating effects of glycemic control and inflammation on the association between vitamin D and lung function in the general population.

Science.gov (United States)

Kaul, Anne; Gläser, Sven; Hannemann, Anke; Stubbe, Beate; Felix, Stefan B; Nauck, Matthias; Ewert, Ralf; Friedrich, Nele

2017-04-01

Vitamin D deficiency is discussed to be associated with lung health. While former studies focused on subjects suffering from pulmonary diseases, we aimed to investigate the association of 25-hydroxy vitamin D [25(OH)D] with lung function in the general population and examined whether mediating effects of inflammation, glycemic control or renal function exist. 1404 participants from the Study of Health in Pomerania with pulmonary function testing assessed by expiratory volume in 1 s (FEV 1 ), forced vital capacity (FVC), total lung capacity and Krogh index were used. Adjusted analysis of variance, linear regression models and mediation analyses were performed. Significant positive associations between 25(OH)D levels and FEV 1 , FVC and Krogh index were found. Mediator analyses revealed no mediating effect of inflammation (fibrinogen), glycemic control (HbA1c) or renal function (eGFR) on associations with FEV 1 or FVC. With respect to Krogh-Index, the association to 25(OH)D was slightly mediated by fibrinogen with a proportion mediated of 9.7%. Significant positive associations of 25(OH)D with lung function were revealed in a general population. The proposed mediating effects of inflammation, glycemic control and renal function on these relations were not confirmed. Further studies examining the causality of the association between 25(OH)D and lung function are necessary. Copyright © 2017 Elsevier Ltd. All rights reserved.

The Effects of Subjective Loss of Control on Risk-taking Behavior: The Mediating Role of Anger

Directory of Open Access Journals (Sweden)

Birgit M. Beisswingert

2015-06-01

Full Text Available Based on the Appraisal Tendency Framework on the antecedents and consequences of emotions two experimental studies examined the relationship between externally caused loss of control experiences and risk-taking behavior, as well as the assumed mediation of this relationship by the emotion anger. An experimental paradigm for inducing externally caused and consequently externally attributed loss of control which should lead to experiences of anger was developed and pretested in a Pilot Study. The relationship between loss of control experiences, anger and risk-taking behavior was investigated using two separate student samples from Germany (N = 84, 54% female and China (N = 125; 64% female. In line with our hypotheses, results showed that anger mediated the link between subjective loss of control experiences and increasing risk-taking behavior. Multiple group comparisons revealing similar patterns in both samples affirmed the results’ cross-cultural generalizability. These results implicate that anger makes people less risk averse in the process of economic decision making.

The effects of subjective loss of control on risk-taking behavior: the mediating role of anger

Science.gov (United States)

Beisswingert, Birgit M.; Zhang, Keshun; Goetz, Thomas; Fang, Ping; Fischbacher, Urs

2015-01-01

Based on the Appraisal Tendency Framework on the antecedents and consequences of emotions two experimental studies examined the relationship between externally caused loss of control experiences and risk-taking behavior, as well as the assumed mediation of this relationship by the emotion anger. An experimental paradigm for inducing externally caused and consequently externally attributed loss of control which should lead to experiences of anger was developed and pretested in a Pilot Study. The relationship between loss of control experiences, anger, and risk-taking behavior was investigated using two separate student samples from Germany (N = 84, 54% female) and China (N = 125; 64% female). In line with our hypotheses, results showed that anger mediated the link between subjective loss of control experiences and increasing risk-taking behavior. Multiple group comparisons revealing similar patterns in both samples affirmed the results’ cross-cultural generalizability. These results implicate that anger makes people less risk averse in the process of economic decision making. PMID:26217244

Parenting Styles and Bullying at School: The Mediating Role of Locus of Control

Science.gov (United States)

Georgiou, Stelios N.; Ioannou, Myria; Stavrinides, Panayiotis

2017-01-01

The current study examined the mediating role of children's locus of control in the relation between parenting styles and bully-victim experiences at school. Participants were 447 students aged 10 and 11 years old from 13 different elementary, urban, and rural schools in Cyprus. Analyses using structural equation modeling showed that parenting…

Perceived discrimination and psychological well-being: the mediating and moderating role of sense of control.

Science.gov (United States)

Jang, Yuri; Chiriboga, David A; Small, Brent J

2008-01-01

Being discriminated against is an unpleasant and stressful experience, and its connection to reduced psychological well-being is well-documented. The present study hypothesized that a sense of control would serve as both mediator and moderator in the dynamics of perceived discrimination and psychological well-being. In addition, variations by age, gender, and race in the effects of perceived discrimination were explored. Data from the Midlife Development in the United States (MIDUS) survey (N=1554; age range = 45 to 74) provided supportive evidence for the hypotheses. The relationships between perceived discrimination and positive and negative affect were reduced when sense of control was controlled, demonstrating the role of sense of control as a mediator. The moderating role of sense of control was also supported, but only in the analysis for negative affect: the combination of a discriminatory experience and low sense of control markedly increased negative affect. In addition, age and gender variations were observed: the negative impact of perceived discrimination on psychological well-being was more pronounced among younger adults and females compared to their counterparts. The findings elucidated the mechanisms by which perceived discrimination manifested its psychological outcomes, and suggest ways to reduce adverse consequences associated with discriminatory experiences.

The U-box E3 ubiquitin ligase TUD1 functions with a heterotrimeric G α subunit to regulate Brassinosteroid-mediated growth in rice.

Directory of Open Access Journals (Sweden)

Xingming Hu

Full Text Available Heterotrimeric G proteins are an important group of signaling molecules found in eukaryotes. They function with G-protein-coupled-receptors (GPCRs to transduce various signals such as steroid hormones in animals. Nevertheless, their functions in plants are not well-defined. Previous studies suggested that the heterotrimeric G protein α subunit known as D1/RGA1 in rice is involved in a phytohormone gibberellin-mediated signaling pathway. Evidence also implicates D1 in the action of a second phytohormone Brassinosteroid (BR and its pathway. However, it is unclear how D1 functions in this pathway, because so far no partner has been identified to act with D1. In this study, we report a D1 genetic interactor Taihu Dwarf1 (TUD1 that encodes a functional U-box E3 ubiquitin ligase. Genetic, phenotypic, and physiological analyses have shown that tud1 is epistatic to d1 and is less sensitive to BR treatment. Histological observations showed that the dwarf phenotype of tud1 is mainly due to decreased cell proliferation and disorganized cell files in aerial organs. Furthermore, we found that D1 directly interacts with TUD1. Taken together, these results demonstrate that D1 and TUD1 act together to mediate a BR-signaling pathway. This supports the idea that a D1-mediated BR signaling pathway occurs in rice to affect plant growth and development.

The U-Box E3 Ubiquitin Ligase TUD1 Functions with a Heterotrimeric G α Subunit to Regulate Brassinosteroid-Mediated Growth in Rice

Science.gov (United States)

Hu, Xingming; Qian, Qian; Xu, Ting; Zhang, Yu'e; Dong, Guojun; Gao, Ting; Xie, Qi; Xue, Yongbiao

2013-01-01

Heterotrimeric G proteins are an important group of signaling molecules found in eukaryotes. They function with G-protein-coupled-receptors (GPCRs) to transduce various signals such as steroid hormones in animals. Nevertheless, their functions in plants are not well-defined. Previous studies suggested that the heterotrimeric G protein α subunit known as D1/RGA1 in rice is involved in a phytohormone gibberellin-mediated signaling pathway. Evidence also implicates D1 in the action of a second phytohormone Brassinosteroid (BR) and its pathway. However, it is unclear how D1 functions in this pathway, because so far no partner has been identified to act with D1. In this study, we report a D1 genetic interactor Taihu Dwarf1 (TUD1) that encodes a functional U-box E3 ubiquitin ligase. Genetic, phenotypic, and physiological analyses have shown that tud1 is epistatic to d1 and is less sensitive to BR treatment. Histological observations showed that the dwarf phenotype of tud1 is mainly due to decreased cell proliferation and disorganized cell files in aerial organs. Furthermore, we found that D1 directly interacts with TUD1. Taken together, these results demonstrate that D1 and TUD1 act together to mediate a BR-signaling pathway. This supports the idea that a D1-mediated BR signaling pathway occurs in rice to affect plant growth and development. PMID:23526892

Controlled/living photopolymerization of methyl methacrylate in miniemulsion mediated by HTEMPO

Institute of Scientific and Technical Information of China (English)

Xiaoxuan LIU; Yanni JING; Yingkun BAI

2008-01-01

Controlled/living photopolymerization of methyl methacrylate (MMA) in miniemulsion mediated by 4-hydroxy-2,2,6,6-tetramethyl-piperidinyloxy (HTEMPO) was carried out at ambient temperatures. MMA miniemulsion was prepared by using an anionic surfactant with cetylalcohol as a co-stabilizer. The photopolymerization led to stable lattices and they were obtained with no coagulation during synthesis and no destabilization over time. It was found that the obtained MMA homopolymers exhibited relatively narrow mole-cular weight distribution (PDI = 1.27- 1.36) which was characterized by GPC. The plots of number-average molecular weight in (Mn) vs. Conversion and ln([MO]/[M]) vs. Time both were linear indicating that the reaction was a controlled/living free radical polymerization.

Increased air temperature during simulated autumn conditions does not increase photosynthetic carbon gain but affects the dissipation of excess energy in seedlings of the evergreen Conifer Jack Pine

OpenAIRE

Busch, F.; Huner, N.; Ensminger, I.

2007-01-01

Temperature and daylength act as environmental signals that determine the length of the growing season in boreal evergreen conifers. Climate change might affect the seasonal development of these trees, as they will experience naturally decreasing daylength during autumn, while at the same time warmer air temperature will maintain photosynthesis and respiration. We characterized the down-regulation of photosynthetic gas exchange and the mechanisms involved in the dissipation of energy in Jack ...

Map-Based Cloning of Seed Dormancy1-2 Identified a Gibberellin Synthesis Gene Regulating the Development of Endosperm-Imposed Dormancy in Rice1

Science.gov (United States)

Ye, Heng; Feng, Jiuhuan; Zhang, Lihua; Zhang, Jinfeng; Mispan, Muhamad S.; Cao, Zhuanqin; Beighley, Donn H.; Yang, Jianchang; Gu, Xing-You

2015-01-01

Natural variation in seed dormancy is controlled by multiple genes mapped as quantitative trait loci in major crop or model plants. This research aimed to clone and characterize the Seed Dormancy1-2 (qSD1-2) locus associated with endosperm-imposed dormancy and plant height in rice (Oryza sativa). qSD1-2 was delimited to a 20-kb region, which contains OsGA20ox2 and had an additive effect on germination. Naturally occurring or induced loss-of-function mutations of the gibberellin (GA) synthesis gene enhanced seed dormancy and also reduced plant height. Expression of this gene in seeds (including endospermic cells) during early development increased GA accumulation to promote tissue morphogenesis and maturation programs. The mutant allele prevalent in semidwarf cultivars reduced the seed GA content by up to 2-fold at the early stage, which decelerated tissue morphogenesis including endosperm cell differentiation, delayed abscisic acid accumulation by a shift in the temporal distribution pattern, and postponed dehydration, physiological maturity, and germinability development. As the endosperm of developing seeds dominates the moisture equilibrium and desiccation status of the embryo in cereal crops, qSD1-2 is proposed to control primary dormancy by a GA-regulated dehydration mechanism. Allelic distribution of OsGA20ox2, the rice Green Revolution gene, was associated with the indica and japonica subspeciation. However, this research provided no evidence that the primitive indica- and common japonica-specific alleles at the presumably domestication-related locus functionally differentiate in plant height and seed dormancy. Thus, the evolutionary mechanism of this agriculturally important gene remains open for discussion. PMID:26373662

Salinity Inhibits Rice Seed Germination by Reducing α-Amylase Activity via Decreased Bioactive Gibberellin Content

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Li Liu

2018-03-01

Full Text Available Seed germination plays important roles in the establishment of seedlings and their subsequent growth; however, seed germination is inhibited by salinity, and the inhibitory mechanism remains elusive. Our results indicate that NaCl treatment inhibits rice seed germination by decreasing the contents of bioactive gibberellins (GAs, such as GA1 and GA4, and that this inhibition can be rescued by exogenous bioactive GA application. To explore the mechanism of bioactive GA deficiency, the effect of NaCl on GA metabolic gene expression was investigated, revealing that expression of both GA biosynthetic genes and GA-inactivated genes was up-regulated by NaCl treatment. These results suggest that NaCl-induced bioactive GA deficiency is caused by up-regulated expression of GA-inactivated genes, and the up-regulated expression of GA biosynthetic genes might be a consequence of negative feedback regulation of the bioactive GA deficiency. Moreover, we provide evidence that NaCl-induced bioactive GA deficiency inhibits rice seed germination by decreasing α-amylase activity via down-regulation of α-amylase gene expression. Additionally, exogenous bioactive GA rescues NaCl-inhibited seed germination by enhancing α-amylase activity. Thus, NaCl treatment reduces bioactive GA content through promotion of bioactive GA inactivation, which in turn inhibits rice seed germination by decreasing α-amylase activity via down-regulation of α-amylase gene expression.

A Collapsin Response Mediator Protein 2 Isoform Controls Myosin II-Mediated Cell Migration and Matrix Assembly by Trapping ROCK II

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Morgan-Fisher, Marie; Wait, Robin; Couchman, John R.; Wewer, Ulla M.

2012-01-01

Collapsin response mediator protein 2 (CRMP-2) is known as a regulator of neuronal polarity and differentiation through microtubule assembly and trafficking. Here, we show that CRMP-2 is ubiquitously expressed and a splice variant (CRMP-2L), which is expressed mainly in epithelial cells among nonneuronal cells, regulates myosin II-mediated cellular functions, including cell migration. While the CRMP-2 short form (CRMP-2S) is recognized as a substrate of the Rho-GTP downstream kinase ROCK in neuronal cells, a CRMP-2 complex containing 2L not only bound the catalytic domain of ROCK II through two binding domains but also trapped and inhibited the kinase. CRMP-2L protein levels profoundly affected haptotactic migration and the actin-myosin cytoskeleton of carcinoma cells as well as nontransformed epithelial cell migration in a ROCK activity-dependent manner. Moreover, the ectopic expression of CRMP-2L but not -2S inhibited fibronectin matrix assembly in fibroblasts. Underlying these responses, CRMP-2L regulated the kinase activity of ROCK II but not ROCK I, independent of GTP-RhoA levels. This study provides a new insight into CRMP-2 as a controller of myosin II-mediated cellular functions through the inhibition of ROCK II in nonneuronal cells. PMID:22431514

Delay Discounting Mediates Parent-Adolescent Relationship Quality and Risky Sexual Behavior for Low Self-Control Adolescents

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Kahn, Rachel E.; Holmes, Christopher; Farley, Julee P.; Kim-Spoon, Jungmeen

2015-01-01

Parent-adolescent relationship quality and delay discounting may play important roles in adolescents’ sexual decision making processes, and levels of self-control during adolescence could act as a buffer within these factors. This longitudinal study included 219 adolescent (55% male; mean age = 12.66 years at Wave 1; mean age = 15.10 years at Wave 2) and primary caregiver dyads. Structural equation modeling was utilized to determine whether delay discounting mediated the association between parent-adolescent relationship quality and adolescents’ risky sexual behavior and how this mediated association may differ between those with high versus low self-control. The results revealed parent-adolescent relationship quality plays a role in the development of risky sexual behavior indirectly through levels of delay discounting, but only for adolescents with low self-control. These findings could inform sex education policies and health prevention programs that address adolescent risky sexual behavior. PMID:26202153

Harsh parenting and academic achievement in Chinese adolescents: Potential mediating roles of effortful control and classroom engagement.

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Wang, Mingzhong; Deng, Xueli; Du, Xiuxiu

2018-04-01

This study examined (a) the potential mediating roles of effortful control and classroom engagement in the association between harsh parenting and adolescent academic achievement, and (b) the potential moderating role of gender. Sixth through eighth graders in rural China (n=815, mean age=12.55years) reported on harsh parenting, effortful control, and classroom engagement. Parents also reported on each other's harsh parenting. Academic achievement was assessed by students' test scores and teacher-rated academic performance. Results of structural equation modeling revealed gender differences in patterns of association among the model variables. Harsh parenting was negatively and directly associated with academic achievement for both boys and girls. It was also negatively and indirectly associated with academic achievement via effortful control and classroom engagement sequentially, forming a common indirect "path" for boys and girls. The indirect negative effect of harsh parenting on boys' academic achievement was mainly realized through the mediator of effortful control, whereas this same indirect effect for girls was mainly realized through the mediator of classroom engagement. Jointly, effortful control and classroom engagement precipitates more indirect effects for boys than for girls in the association between harsh parenting and academic achievement. The discussion analyzes the potential "paths" from harsh parenting to adolescent academic achievement, as well as gender differences in these "paths." The current study has implications for teachers and parents eager to improve students' classroom engagement and academic achievement. Copyright © 2017. Published by Elsevier Ltd.

Maternal Parenting as a Mediator of the Relationship between Intimate Partner Violence and Effortful Control

OpenAIRE

Gustafsson, Hanna C.; Cox, Martha J.; Blair, Clancy

2011-01-01

The current study examined the relationship between intimate partner violence (IPV), maternal parenting behaviors, and child effortful control in a diverse sample of 705 families living in predominantly low-income, rural communities. Using structural equation modeling, the authors simultaneously tested whether observed sensitive parenting and/or harsh-intrusive parenting over the toddler years mediated the relationship between early IPV and later effortful control. Results suggest that parent...

The Effect of The Locus of Control on Organizational Citizenship Behavior The Mediating Role Perceived Organizationel Support : Case Study of A University

OpenAIRE

Güçel, Cem; Tokmak, İsmail; Turgut, Hakan

2012-01-01

The aim of this study is to examine the effects of locus of control on organizational citizenship behaviors and the mediating effect of the perceived organizational support. For this aim, firstly, the locus of control, then organizational citizenship behaviors and, finally, the mediating effect of the perceived organizational support are explained. In the application part, a questionnaire including the measures of the locus of control, organizational support and organization...

THE EFFECT OF THE LOCUS OF CONTROL ON ORGANIZATIONAL CITIZENSHIP BEHAVIOR THE MEDIATING EFFECT PERCEIVED ORGANIZATIONAL SUPPORT: CASE STUDY OF A UNIVERSITY

OpenAIRE

GUCEL, Cem; TOKMAK, Ismail; TURGUT, Hakan

2012-01-01

The aim of this study is to examine the effects of locus of control on organizational citizenship behaviors and the mediating effect of the perceived organizational support. For this aim, firstly, the locus of control, then organizational citizenship behaviors and, finally, the mediating effect of the perceived organizational support are explained. In the application part, a questionnaire including the measures of the locus of control, organizational support and organizational citizenship beh...

Toehold-mediated internal control to probe the near-field interaction between the metallic nanoparticle and the fluorophore

Science.gov (United States)

Ang, Y. S.; Yung, L. Y. L.

2014-10-01

Metallic nanoparticles (MNPs) are known to alter the emission of vicinal fluorophores through the near-field interaction, leading to either fluorescence quenching or enhancement. Much ambiguity remains in the experimental outcome of such a near-field interaction, particularly for bulk colloidal solution. It is hypothesized that the strong far-field interference from the inner filter effect of the MNPs could mask the true near-field MNP-fluorophore interaction significantly. Thus, in this work, a reliable internal control capable of decoupling the near-field interaction from far-field interference is established by the use of the DNA toehold concept to mediate the in situ assembly and disassembly of the MNP-fluorophore conjugate. A model gold nanoparticle (AuNP)-Cy3 system is used to investigate our proposed toehold-mediated internal control system. The maximum fluorescence enhancement is obtained for large-sized AuNP (58 nm) separated from Cy3 at an intermediate distance of 6.8 nm, while fluorescence quenching is observed for smaller-sized AuNP (11 nm and 23 nm), which is in agreement with the theoretical values reported in the literature. This work shows that the toehold-mediated internal control design can serve as a central system for evaluating the near-field interaction of other MNP-fluorophore combinations and facilitate the rational design of specific MNP-fluorophore systems for various applications.Metallic nanoparticles (MNPs) are known to alter the emission of vicinal fluorophores through the near-field interaction, leading to either fluorescence quenching or enhancement. Much ambiguity remains in the experimental outcome of such a near-field interaction, particularly for bulk colloidal solution. It is hypothesized that the strong far-field interference from the inner filter effect of the MNPs could mask the true near-field MNP-fluorophore interaction significantly. Thus, in this work, a reliable internal control capable of decoupling the near

Hyperglycemic conditions inhibit C3-mediated immunologic control of Staphylococcus aureus

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Hair Pamela S

2012-03-01

Full Text Available Abstract Background Diabetic patients are at increased risk for bacterial infections; these studies provide new insight into the role of the host defense complement system in controlling bacterial pathogens in hyperglycemic environments. Methods The interactions of complement C3 with bacteria in elevated glucose were assayed for complement activation to opsonic forms, phagocytosis and bacterial killing. C3 was analyzed in euglycemic and hyperglycemic conditions by mass spectrometry to measure glycation and structural differences. Results Elevated glucose inhibited S. aureus activation of C3 and deposition of C3b and iC3b on the bacterial surface. S. aureus-generated C5a and serum-mediated phagocytosis by neutrophils were both decreased in elevated glucose conditions. Interestingly, elevated glucose increased the binding of unactivated C3 to S. aureus, which was reversible on return to normal glucose concentrations. In a model of polymicrobial infection, S. aureus in elevated glucose conditions depleted C3 from serum resulting in decreased complement-mediated killing of E. coli. To investigate the effect of differing glucose concentration on C3 structure and glycation, purified C3 incubated with varying glucose concentrations was analyzed by mass spectrometry. Glycation was limited to the same three lysine residues in both euglycemic and hyperglycemic conditions over one hour, thus glycation could not account for observed changes between glucose conditions. However, surface labeling of C3 with sulfo-NHS-biotin showed significant changes in the surface availability of seven lysine residues in response to increasing glucose concentrations. These results suggest that the tertiary structure of C3 changes in response to hyperglycemic conditions leading to an altered interaction of C3 with bacterial pathogens. Conclusions These results demonstrate that hyperglycemic conditions inhibit C3-mediated complement effectors important in the immunological

Mediators of cognitive behavioral therapy for anxiety-disordered children and adolescents: cognition, perceived control, and coping.

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Hogendoorn, Sanne M; Prins, Pier J M; Boer, Frits; Vervoort, Leentje; Wolters, Lidewij H; Moorlag, Harma; Nauta, Maaike H; Garst, Harry; Hartman, Catharina A; de Haan, Else

2014-01-01

The purpose is to investigate whether a change in putative mediators (negative and positive thoughts, coping strategies, and perceived control over anxious situations) precedes a change in anxiety symptoms in anxiety-disordered children and adolescents receiving cognitive behavioral therapy (CBT). Participants were 145 Dutch children (8-18 years old, M = 12.5 years, 57% girls) with a primary anxiety disorder. Assessments were completed pretreatment, in-treatment, posttreatment, and at 3-month follow-up. Sequential temporal dependencies between putative mediators and parent- and child-reported anxiety symptoms were investigated in AMOS using longitudinal Latent Difference Score Modeling. During treatment an increase of positive thoughts preceded a decrease in child-reported anxiety symptoms. An increase in three coping strategies (direct problem solving, positive cognitive restructuring, and seeking distraction) preceded a decrease in parent-reported anxiety symptoms. A reciprocal effect was found for perceived control: A decrease in parent-reported anxiety symptoms both preceded and followed an increase in perceived control. Using a longitudinal design, a temporal relationship between several putative mediators and CBT-outcome for anxious children was explored. The results suggest that a change in positive thoughts, but not negative thoughts, and several coping strategies precedes a change in symptom reduction and, therefore, at least partly support theoretical models of anxiety upon which the anxiety intervention is based.

Effectiveness of Parent-Child Mediation in Improving Family Functioning and Reducing Adolescent Problem Behavior: Results from a Pilot Randomized Controlled Trial.

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Tucker, Joan S; Edelen, Maria Orlando; Huang, Wenjing

2017-03-01

Parent-child mediation programs are intended to resolve or manage disputes and improve family functioning, but rigorous evaluations of their effectiveness are lacking. Families referred to a community-based mediation program (N = 111) were randomized to an intervention or wait-list control group, and completed three surveys over a 12-week period. With the exception of parent-reported child delinquency (which decreased more in the intervention group), this evaluation provides little support for the short-term effectiveness of parent-child mediation for improving family functioning and reducing child problem behaviors in general. Given that this is the first randomized controlled trial of a parent-child mediation program, additional evaluations involving larger samples and longer follow-ups are needed before firm conclusions can be drawn about the effectiveness of this intervention.

Effectiveness of Parent-Child Mediation in Improving Family Functioning and Reducing Adolescent Problem Behavior: Results from a Pilot Randomized Controlled Trial

Science.gov (United States)

Tucker, Joan S.; Edelen, Maria Orlando; Huang, Wenjing

2016-01-01

Parent-child mediation programs are intended to resolve or manage disputes and improve family functioning, but rigorous evaluations of their effectiveness are lacking. Families referred to a community-based mediation program (N=111) were randomized to an intervention or wait-list control group, and completed three surveys over a 12-week period. With the exception of parent-reported child delinquency (which decreased more in the intervention group), this evaluation provides little support for the short-term effectiveness of parent-child mediation for improving family functioning and reducing child problem behaviors in general. Given that this is the first randomized controlled trial of a parent-child mediation program, additional evaluations involving larger samples and longer follow-ups are needed before firm conclusions can be drawn about the effectiveness of this intervention. PMID:26762375

Delay Discounting Mediates Parent-Adolescent Relationship Quality and Risky Sexual Behavior for Low Self-Control Adolescents.

Science.gov (United States)

Kahn, Rachel E; Holmes, Christopher; Farley, Julee P; Kim-Spoon, Jungmeen

2015-09-01

Parent-adolescent relationship quality and delay discounting may play important roles in adolescents' sexual decision making processes, and levels of self-control during adolescence could act as a buffer within these factors. This longitudinal study included 219 adolescent (55 % male; mean age = 12.66 years at Wave 1; mean age = 15.10 years at Wave 2) and primary caregiver dyads. Structural equation modeling (SEM) was utilized to determine whether delay discounting mediated the association between parent-adolescent relationship quality and adolescents' risky sexual behavior and how this mediated association may differ between those with high versus low self-control. The results revealed parent-adolescent relationship quality plays a role in the development of risky sexual behavior indirectly through levels of delay discounting, but only for adolescents with low self-control. These findings could inform sex education policies and health prevention programs that address adolescent risky sexual behavior.

Germination and initial development of aroeira (Myracrodruon urundeuva seedlings

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Silvana de Paula Quintão Scalon

2012-12-01

Full Text Available Aroeira has great economic importance due to its wood useful, tannins extraction and use in the pharmacology. The aim of this work was to evaluate the germination aspects and initial seedlings development of aroeira, under gibberellins, substrata and shading effects, and for that two experiments were led out. In the first one, seeds were previously soaked for 24 hours in water and in 100 mg.L-1 gibberellin solution and were sowed directly in cells trays in the following substrata: land and sand (1:1 and 1:2 and Plantmax . In the second experiment, 15 cm length seedlings were transplanted to polyethylene sacks filled out land+sand+poultry manure (1:1:1 partly decomposed and they were maintained at greenhouse for 15 days. Soon after, seedlings were transferred for the following conditions: shading (50% and full sun and they were 50 mg.L-1 and 150 mg.L-1 gibberellins solutions pulverized, as control seedlings water pulverized. Aroeira seeds should not be previously water or gibberellins imbibed before being sowed. The best substrata for aroeira seeds germination was Plantmax without germinative treatments to reach higher than 80% of seedlings survival. The seedlings developed better at full sun light and the gibberellin. It was observed increment in height, diameter, foliar area and fresh and dry mass from aerial and root part when compared to shading situation. The gibberellins applications did not influence the aroeira seedlings initial growth characteristics.

Job attitudes and well-being among public vs. private physicians: organizational justice and job control as mediators.

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Heponiemi, Tarja; Kuusio, Hannamaria; Sinervo, Timo; Elovainio, Marko

2011-08-01

The present study examined whether there are differences in job-related attitudes and well-being among physicians working in private sector and public sector. In addition, we examined whether psychosocial factors (organizational justice and job control) could mediate these possible differences in different sectors. Cross-sectional survey data from the Finnish Health Professional Study was used. A random sample of Finnish physicians included 1522 women and 1047 men aged 25-65 years. Outcome variables were job satisfaction, organizational commitment, psychological distress, work ability and sleeping problems. Job control and organizational justice were measured using established questionnaires. Series of regression analyses were performed and the mediational effects were tested following the procedures outlined by Baron and Kenny. Physicians working in private sector had higher levels of job satisfaction and organizational commitment and lower levels of psychological distress and sleeping problems when compared with physicians working in public sector. Private physicians also had higher levels of organizational justice, which acted as a mediator behind more positive attitudes and better well-being in private sector. Private physicians had higher levels of job control but it did not act as a mediator. Private physicians feel better than public physicians and this is partly due to higher organizational justice in private sector. Public health care organizations should invest effort to increase the fairness in their organizations and management and pay more attention in improving the well-being of their employees, which could possibly increase the attractiveness of public sector as a career option.

Therapist-Aided Exposure for Women with Lifelong Vaginismus: Mediators of Treatment Outcome: A Randomized Waiting List Control Trial.

Science.gov (United States)

Ter Kuile, Moniek M; Melles, Reinhilde J; Tuijnman-Raasveld, Charlotte C; de Groot, Helen E; van Lankveld, Jacques J D M

2015-08-01

Therapist-aided exposure seems an effective treatment for lifelong vaginismus, but mechanisms of action have not yet been established. The purpose of the present study was to investigate whether treatment outcome of a therapist-aided exposure treatment was mediated by changes in positive and negative penetration beliefs or feelings of sexual disgust. Participants with lifelong vaginismus were allocated at random to a 3-month exposure (n = 35) or a waiting list control condition (n = 35). Full intercourse was assessed daily during 12 weeks. Secondary outcome measures (complaints about vaginismus and coital pain) were assessed at baseline and after 12 weeks. Possible mediators: penetration beliefs (catastrophic pain beliefs, genital incompatibility beliefs, perceived control beliefs) and feelings of sexual disgust were assessed at baseline and 6 weeks. Treatment outcome (coital frequency, symptoms of vaginismus, and coital pain) at 12 weeks was mediated by changes in negative and positive penetration beliefs at 6 weeks, in particular by more pronounced reduction of catastrophic pain penetration beliefs. No evidence was found that changes in feelings of sexual disgust mediated treatment outcome. The results strongly suggest that therapist-aided exposure affects negative penetration beliefs and that these changes in negative penetration beliefs mediate treatment outcome in women with lifelong vaginismus. Implications for treatment are discussed. © 2015 International Society for Sexual Medicine.

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African Journals Online (AJOL)

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Inhibitory Control Mediates the Relationship between Depressed Mood and Overgeneral Memory Recall in Children

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Raes, Filip; Verstraeten, Katrien; Bijttebier, Patricia; Vasey, Michael W.; Dalgleish, Tim

2010-01-01

It has been well established that depressed mood is related to overgeneral memory recall (OGM), which refers to a relative difficulty in retrieving specific information from one's autobiographical memory (AM). The present study examined whether OGM is also related to depressed mood in children and whether lack of inhibitory control mediates this…

GERMINATION STUDIES ON Tabebuia impetiginosa Mart. SEEDS

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Edvaldo Aparecido Amaral da Silva

2004-06-01

Full Text Available Seed germination and seedling production of native forest tree species are an important step in ex situ conservation programs and in the reforestation with ecological purposes. Therefore, understanding seed germination and its regulation is mandatory for the complete success of the conservation programs and revegetation techniques. Thus, morphological studies, temperature requirements for seed germination and its control by gibberellins (GAs were studied in Tabebuia impetiginosa (“ipê-roxo” seeds. The best temperature for germination under constant light was 30oC. The imbibition of T. impetiginosa seeds followed the common triphasic pattern, with most of the seeds attaining phase II at 24 hours and phase III at 72 hours of imbibition. Visible germination, as radicle elongation, started at 30 hours in water-imbibed seeds and at 24 hours in GA-imbibed seeds. Seeds imbibed in Paclobutrazol, an inhibitor of GA biosynthesis, failed to germinate. However, application of exogenous gibberellins overcame inhibition and allowed germination, suggesting that GAs are regulators of Tabebuia impetiginosa seed germination. The results suggested that germination in Tabebuia impetiginosa seeds is controlled by elongation of the radicle and gibberellins may play an important role in regulating it. The possible role of gibberellins is discussed.

Impaired cognitive control mediates the relationship between cortical thickness of the superior frontal gyrus and role functioning in schizophrenia.

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Tully, Laura M; Lincoln, Sarah Hope; Liyanage-Don, Nadia; Hooker, Christine I

2014-02-01

Structural abnormalities in the lateral prefrontal cortex (LPFC) are well-documented in schizophrenia and recent evidence suggests that these abnormalities relate to functional outcome. Cognitive control mechanisms, reliant on the LPFC, are impaired in schizophrenia and predict functional outcome, thus impaired cognitive control could mediate the relationship between neuroanatomical abnormalities in the LPFC and functional outcome. We used surface-based morphometry to investigate relationships between cortical surface characteristics, cognitive control, and measures of social and role functioning in 26 individuals with schizophrenia and 29 healthy controls. Results demonstrate that schizophrenia participants had thinner cortex in a region of the superior frontal gyrus (BA10). Across all participants, decreased cortical thickness in this region related to decreased cognitive control and decreased role functioning. Moreover, cognitive control fully mediated the relationship between cortical thickness in the superior frontal gyrus and role functioning, indicating that neuroanatomical abnormalities in the LPFC adversely impact role functioning via impaired cognitive control processes. Copyright © 2013 Elsevier B.V. All rights reserved.

A randomised controlled trial evaluating family mediated exercise (FAME therapy following stroke

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Stokes Emma

2008-06-01

Full Text Available Abstract Background Stroke is a leading cause of disability among adults worldwide. Evidence suggests that increased duration of exercise therapy following stroke has a positive impact on functional outcome following stroke. The main objective of this randomised controlled trial is to evaluate the impact of additional family assisted exercise therapy in people with acute stroke. Methods/Design A prospective multi-centre single blind randomised controlled trial will be conducted. Forty patients with acute stroke will be randomised into either an experimental or control group. The experimental group will receive routine therapy and additional lower limb exercise therapy in the form of family assisted exercises. The control group will receive routine therapy with no additional formal input from their family members. Participants will be assessed at baseline, post intervention and followed up at three months using a series of standardised outcome measures. A secondary aim of the project is to evaluate the impact of the family mediated exercise programme on the person with stroke and the individual(s assisting in the delivery of exercises using a qualitative methodology. The study has gained ethical approval from the Research Ethics Committees of each of the clinical sites involved in the study. Discussion This study will evaluate a structured programme of exercises that can be delivered to people with stroke by their 'family members/friends'. Given that the progressive increase in the population of older people is likely to lead to an increased prevalence of stroke in the future, it is important to reduce the burden of this illness on the individual, the family and society. Family mediated exercises can maximise the carry over outside formal physiotherapy sessions, giving patients the opportunity for informal practice. Trial Registration The protocol for this study is registered with the US NIH Clinical trials registry (NCT00666744

Mediating Parent Learning to Promote Social Communication for Toddlers with Autism: Effects from a Randomized Controlled Trial

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Schertz, Hannah H.; Odom, Samuel L.; Baggett, Kathleen M.; Sideris, John H.

2018-01-01

A randomized controlled trial was conducted to evaluate effects of the Joint Attention Mediated Learning (JAML) intervention. Toddlers with autism spectrum disorders (ASD) aged 16-30 months (n = 144) were randomized to intervention and community control conditions. Parents, who participated in 32 weekly home-based sessions, followed a mediated…

Predictive Effects of Good Self-Control and Poor Regulation on Alcohol-Related Outcomes: Do Protective Behavioral Strategies Mediate?

Science.gov (United States)

Pearson, Matthew R.; Kite, Benjamin A.; Henson, James M.

2016-01-01

In the present study, we examined whether use of protective behavioral strategies mediated the relationship between self-control constructs and alcohol-related outcomes. According to the two-mode model of self-control, good self-control (planfulness; measured with Future Time Perspective, Problem Solving, and Self-Reinforcement) and poor regulation (impulsivity; measured with Present Time Perspective, Poor Delay of Gratification, Distractibility) are theorized to be relatively independent constructs rather than opposite ends of a single continuum. The analytic sample consisted of 278 college student drinkers (68% women) who responded to a battery of surveys at a single time point. Using a structural equation model based on the two-mode model of self-control, we found that good self-control predicted increased use of three types of protective behavioral strategies (Manner of Drinking, Limiting/Stopping Drinking, and Serious Harm Reduction). Poor regulation was unrelated to use of protective behavioral strategies, but had direct effects on alcohol use and alcohol problems. Further, protective behavioral strategies mediated the relationship between good self-control and alcohol use. The clinical implications of these findings are discussed. PMID:22663345

Characterization and genetic mapping of a Photoperiod-sensitive dwarf 1 locus in rice (Oryza sativa L.).

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Li, Riqing; Xia, Jixing; Xu, Yiwei; Zhao, Xiucai; Liu, Yao-Guang; Chen, Yuanling

2014-01-01

Plant height is an important agronomic trait for crop architecture and yield. Most known factors determining plant height function in gibberellin or brassinosteroid biosynthesis or signal transduction. Here, we report a japonica rice (Oryza sativa ssp. japonica) dominant dwarf mutant, Photoperiod-sensitive dwarf 1 (Psd1). The Psd1 mutant showed impaired cell division and elongation, and a severe dwarf phenotype under long-day conditions, but nearly normal growth in short-day. The plant height of Psd1 mutant could not be rescued by gibberellin or brassinosteroid treatment. Genetic analysis with R1 and F2 populations determined that Psd1 phenotype was controlled by a single dominant locus. Linkage analysis with 101 tall F2 plants grown in a long-day season, which were derived from a cross between Psd1 and an indica cultivar, located Psd1 locus on chromosome 1. Further fine-mapping with 1017 tall F2 plants determined this locus on an 11.5-kb region. Sequencing analysis of this region detected a mutation site in a gene encoding a putative lipid transfer protein; the mutation produces a truncated C-terminus of the protein. This study establishes the genetic foundation for understanding the molecular mechanisms regulating plant cell division and elongation mediated by interaction between genetic and environmental factors.

Effects of abscisic acid, gibberellin, ethylene and their interactions on production of phenolic acids in salvia miltiorrhiza bunge hairy roots.

Science.gov (United States)

Liang, Zongsuo; Ma, Yini; Xu, Tao; Cui, Beimi; Liu, Yan; Guo, Zhixin; Yang, Dongfeng

2013-01-01

Salvia miltiorrhiza is one of the most important traditional Chinese medicinal plants because of its excellent performance in treating coronary heart disease. Phenolic acids mainly including caffeic acid, rosmarinic acid and salvianolic acid B are a group of active ingredients in S. miltiorrhiza. Abscisic acid (ABA), gibberellin (GA) and ethylene are three important phytohormones. In this study, effects of the three phytohormones and their interactions on phenolic production in S. miltiorrhiza hairy roots were investigated. The results showed that ABA, GA and ethylene were all effective to induce production of phenolic acids and increase activities of PAL and TAT in S. miltiorrhiza hairy roots. Effects of phytohormones were reversed by their biosynthetic inhibitors. Antagonistic actions between the three phytohormones played important roles in the biosynthesis of phenolic acids. GA signaling is necessary for ABA and ethylene-induced phenolic production. Yet, ABA and ethylene signaling is probably not necessary for GA3-induced phenolic production. The complex interactions of phytohormones help us reveal regulation mechanism of secondary metabolism and scale-up production of active ingredients in plants.

Climate controls photosynthetic capacity more than leaf nitrogen contents

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Ali, A. A.; Xu, C.; McDowell, N. G.

2013-12-01

Global vegetation models continue to lack the ability to make reliable predictions because the photosynthetic capacity varies a lot with growth conditions, season and among species. It is likely that vegetation models link photosynthetic capacity to concurrent changes in leaf nitrogen content only. To improve the predictions of the vegetation models, there is an urgent need to review species growth conditions and their seasonal response to changing climate. We sampled the global distribution of the Vcmax (maximum carboxylation rates) data of various species across different environmental gradients from the literature and standardized its value to 25 degree Celcius. We found that species explained the largest variation in (1) the photosynthetic capacity and (2) the proportion of nitrogen allocated for rubisco (PNcb). Surprisingly, climate variables explained more variations in photosynthetic capacity as well as PNcb than leaf nitrogen content and/or specific leaf area. The chief climate variables that explain variation in photosynthesis and PNcb were radiation, temperature and daylength. Our analysis suggests that species have the greatest control over photosynthesis and PNcb. Further, compared to leaf nitrogen content and/or specific leaf area, climate variables have more control over photosynthesis and PNcb. Therefore, climate variables should be incorporated in the global vegetation models when making predictions about the photosynthetic capacity.

Cadophora malorum Cs-8-1 as a new fungal strain producing gibberellins isolated from Calystegia soldanella.

Science.gov (United States)

You, Young-Hyun; Yoon, Hyeokjun; Kang, Sang-Mo; Woo, Ju-Ri; Choo, Yeon-Sik; Lee, In-Jung; Shin, Jae-Ho; Kim, Jong-Guk

2013-07-01

Fourteen endophytic fungi with different colony morphologies were isolated from the roots of Calystegia soldanella. Endophytic fungi isolated from C. soldanella were identified by internal transcribed spacer (ITS) region. To verify plant growth promotion (PGP), culture filtrates of isolated endophytic fungi were treated in Waito-c rice (WR) and C. soldanella seedlings. Culture filtrates of Cs-8-1 fungal strain had advanced PGP activity. The presence of physiologically bioactive gibberellins (GA) GA(1) (1.213 ng ml(-1)), GA(3) (1.292 ng ml(-1)), GA(4) (3.6 ng ml(-1)), GA(7) (1.328 ng ml(-1)), other inactive GA(9) (0.796 ng ml(-1)) and GA(12) (0.417 ng ml(-1)), GA(20) (0.302 ng ml(-1)), GA(24) (1.351 ng ml(-1)), GA(34) (0.076 ng ml(-1)), and GA(53) (0.051 ng ml(-1)) in culture filtrates of Cs-8-1 fungal strain was detected. The Cs-8-1 fungal strain was confirmed as a producer of GAs. Molecular analysis of sequences showed high similarity of 99% to Cadophora malorum. Consequentially, the Cs-8-1 fungal strain was identified as a new C. malorum producing GAs. © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Jasmonic Acid, Abscisic Acid, and Salicylic Acid Are Involved in the Phytoalexin Responses of Rice to Fusarium fujikuroi, a High Gibberellin Producer Pathogen.

Science.gov (United States)

Siciliano, Ilenia; Amaral Carneiro, Greice; Spadaro, Davide; Garibaldi, Angelo; Gullino, Maria Lodovica

2015-09-23

Fusarium fujikuroi, the causal agent of bakanae disease, is the main seedborne pathogen on rice. To understand the basis of rice resistance, a quantitative method to simultaneously detect phytohormones and phytoalexins was developed by using HPLC-MS/MS. With this method dynamic profiles and possible interactions of defense-related phytohormones and phytoalexins were investigated on two rice cultivars, inoculated or not with F. fujikuroi. In the resistant cultivar Selenio, the presence of pathogen induced high production of phytoalexins, mainly sakuranetin, and symptoms of bakanae were not observed. On the contrary, in the susceptible genotype Dorella, the pathogen induced the production of gibberellin and abscisic acid and inhibited jasmonic acid production, phytoalexins were very low, and bakanae symptoms were observed. The results suggested that a wide range of secondary metabolites are involved in plant defense against pathogens and phytoalexin synthesis could be an important factor for rice resistance against bakanae disease.

How information about overdetection changes breast cancer screening decisions: a mediation analysis within a randomised controlled trial.

Science.gov (United States)

Hersch, Jolyn; McGeechan, Kevin; Barratt, Alexandra; Jansen, Jesse; Irwig, Les; Jacklyn, Gemma; Houssami, Nehmat; Dhillon, Haryana; McCaffery, Kirsten

2017-10-06

In a randomised controlled trial, we found that informing women about overdetection changed their breast screening decisions. We now present a mediation analysis exploring the psychological pathways through which study participants who received the intervention processed information about overdetection and how this influenced their decision-making. We examined a series of potential mediators in the causal chain between exposure to overdetection information and women's subsequently reported breast screening intentions. Serial multiple mediation analysis within a randomised controlled trial. New South Wales, Australia. 811 women aged 48-50 years with no personal history of breast cancer. Two versions of a decision aid giving women information about breast cancer deaths averted and false positives from mammography screening, either with (intervention) or without (control) information on overdetection. Intentions to undergo breast cancer screening in the next 2-3 years. Knowledge about overdetection, worry about breast cancer, attitudes towards breast screening and anticipated regret. The effect of information about overdetection on women's breast screening intentions was mediated through multiple cognitive and affective processes. In particular, the information led to substantial improvements in women's understanding of overdetection, and it influenced-both directly and indirectly via its effect on knowledge-their attitudes towards having screening. Mediation analysis showed that the mechanisms involving knowledge and attitudes were particularly important in determining women's intentions about screening participation. Even in this emotive context, new information influenced women's decision-making by changing their understanding of possible consequences of screening and their attitudes towards undergoing it. These findings emphasise the need to provide good-quality information on screening outcomes and to communicate this information effectively, so that women can

The relationship between self-control and health: The mediating effect of avoidant coping.

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Boals, Adriel; Vandellen, Michelle R; Banks, Jonathan B

2011-08-01

Trait self-control is related to a number of positive outcomes, including mental health, interpersonal success, academic success and health-related behaviours. This study sought to explore the relationships between self-control, reports of mental and physical health symptoms and coping styles. The results revealed that higher self-control was related to fewer mental and physical health symptoms and less avoidance coping. There was not a significant relationship between self-control and problem-focused or emotion-focused coping styles. Further, the relationships between self-control and mental and physical health outcomes were partially mediated by avoidance coping style. Specifically, the data suggest lower self-control is associated with unhealthy coping strategies (avoidance coping), which in turn are associated with worse mental health outcomes and greater reports of physical health symptoms. Thus lower trait self-control can serve as an indicator, suggesting circumstances in which individuals' tendencies to engage in unhealthy coping strategies are increased. These findings add to a growing body of literature underscoring the importance of trait self-control.

Mediating Mechanisms of Theory-Based Psychosocial Determinants on Behavioral Changes in a Middle School Obesity Risk Reduction Curriculum Intervention, Choice, Control, and Change.

Science.gov (United States)

Gray, Heewon Lee; Contento, Isobel R; Koch, Pamela A; Noia, Jennifer Di

2016-10-01

A limited number of school-based intervention studies have explored mediating mechanisms of theory-based psychosocial variables on obesity risk behavior changes. The current study investigated how theory-based psychosocial determinants mediated changes in energy balance-related behaviors (EBRBs) among urban youth. A secondary analysis study was conducted using data from a cluster randomized controlled trial. Data from students at 10 middle schools in New York City (n = 1136) were used. The intervention, Choice, Control, and Change curriculum, was based on social cognitive and self-determination theories. Theory-based psychosocial determinants (goal intention, cognitive outcome expectations, affective outcome expectations, self-efficacy, perceived barriers, and autonomous motivation) and EBRBs were measured with self-report questionnaires. Mediation mechanisms were examined using structural equation modeling, Results: Mediating mechanisms for daily sugar-sweetened beverage (SSB) consumption and purposeful stair climbing were identified. Models with best fit indices (root mean square error of approximation = 0.039/0.045, normed fit index = 0.916/0.882; comparative fit index = 0.945/0.932; Tucker-Lewis index = 0.896/0.882, respectively) suggested that goal intention and reduced perceived barriers were significant proximal mediators for reducing SSB consumption among both boys and girls or increasing physical activity by stair climbing among boys. Cognitive outcome expectations, affective outcome expectations, self-efficacy, and autonomous motivation indirectly mediated behavioral changes through goal intention or perceived barriers (p behavioral outcome variances. Theory-based psychosocial determinants targeted in Choice, Control, and Change in fact mediated behavior changes in middle school students. Strategies targeting these mediators might benefit future success of behavioral interventions. Further studies are needed to determine other

The Mediating Roles of Primary and Secondary Control in the Relationship between Body Satisfaction and Subjective Well-Being Among Middle-Aged and Older Women.

Science.gov (United States)

Watt, Ashli D; Konnert, Candace A; Speirs, Calandra E C

2017-07-01

This study examined primary and secondary control as mediators in the relationship between body satisfaction and subjective well-being (SWB) and explored age differences in the mediation model. Data from 362 women, aged 40-91 years, assessed (i) the relationships between body satisfaction, age, primary and secondary control strategies (body-specific social comparison, acceptance, and positive reappraisal), and three indices of SWB (positive affect, negative affect, and life satisfaction), (ii) the mediation effects of primary and secondary control on the relationship between body satisfaction and SWB, and (iii) whether mediational relationships were moderated by age. Body satisfaction was unrelated to age but positively related to positive affect and life satisfaction and negatively related to negative affect. Body satisfaction was also related to primary and secondary control strategies. There were significant indirect (mediated) effects of body satisfaction on all outcome variables through acceptance and positive reappraisal. These mediators were significant at all age levels, but exerted their strongest influence among younger women. This study provides new information about the mechanisms that influence the relationship between body satisfaction and SWB among a broad age range of women who are experiencing physical changes that are inconsistent with Western beauty standards. © The Author 2015. Published by Oxford University Press on behalf of The Gerontological Society of America. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

Mediators of cognitive behavioral therapy for anxiety-disordered children and adolescents : cognition, perceived control, and coping

NARCIS (Netherlands)

Hogendoorn, Sanne M; Prins, Pier J M; Boer, Frits; Vervoort, Leentje; Wolters, Lidewij H; Moorlag, Harma; Nauta, Maaike H; Garst, Harry; Hartman, Catharina A; de Haan, Else

2014-01-01

The purpose is to investigate whether a change in putative mediators (negative and positive thoughts, coping strategies, and perceived control over anxious situations) precedes a change in anxiety symptoms in anxiety-disordered children and adolescents receiving cognitive behavioral therapy (CBT).

Rice black streaked dwarf virus P7-2 forms a SCF complex through binding to Oryza sativa SKP1-like proteins, and interacts with GID2 involved in the gibberellin pathway.

Science.gov (United States)

Tao, Tao; Zhou, Cui-Ji; Wang, Qian; Chen, Xiang-Ru; Sun, Qian; Zhao, Tian-Yu; Ye, Jian-Chun; Wang, Ying; Zhang, Zong-Ying; Zhang, Yong-Liang; Guo, Ze-Jian; Wang, Xian-Bing; Li, Da-Wei; Yu, Jia-Lin; Han, Cheng-Gui

2017-01-01

As a core subunit of the SCF complex that promotes protein degradation through the 26S proteasome, S-phase kinase-associated protein 1 (SKP1) plays important roles in multiple cellular processes in eukaryotes, including gibberellin (GA), jasmonate, ethylene, auxin and light responses. P7-2 encoded by Rice black streaked dwarf virus (RBSDV), a devastating viral pathogen that causes severe symptoms in infected plants, interacts with SKP1 from different plants. However, whether RBSDV P7-2 forms a SCF complex and targets host proteins is poorly understood. In this study, we conducted yeast two-hybrid assays to further explore the interactions between P7-2 and 25 type I Oryza sativa SKP1-like (OSK) proteins, and found that P7-2 interacted with eight OSK members with different binding affinity. Co-immunoprecipitation assay further confirmed the interaction of P7-2 with OSK1, OSK5 and OSK20. It was also shown that P7-2, together with OSK1 and O. sativa Cullin-1, was able to form the SCF complex. Moreover, yeast two-hybrid assays revealed that P7-2 interacted with gibberellin insensitive dwarf2 (GID2) from rice and maize plants, which is essential for regulating the GA signaling pathway. It was further demonstrated that the N-terminal region of P7-2 was necessary for the interaction with GID2. Overall, these results indicated that P7-2 functioned as a component of the SCF complex in rice, and interaction of P7-2 with GID2 implied possible roles of the GA signaling pathway during RBSDV infection.

Rice black streaked dwarf virus P7-2 forms a SCF complex through binding to Oryza sativa SKP1-like proteins, and interacts with GID2 involved in the gibberellin pathway.

Directory of Open Access Journals (Sweden)

Tao Tao

Full Text Available As a core subunit of the SCF complex that promotes protein degradation through the 26S proteasome, S-phase kinase-associated protein 1 (SKP1 plays important roles in multiple cellular processes in eukaryotes, including gibberellin (GA, jasmonate, ethylene, auxin and light responses. P7-2 encoded by Rice black streaked dwarf virus (RBSDV, a devastating viral pathogen that causes severe symptoms in infected plants, interacts with SKP1 from different plants. However, whether RBSDV P7-2 forms a SCF complex and targets host proteins is poorly understood. In this study, we conducted yeast two-hybrid assays to further explore the interactions between P7-2 and 25 type I Oryza sativa SKP1-like (OSK proteins, and found that P7-2 interacted with eight OSK members with different binding affinity. Co-immunoprecipitation assay further confirmed the interaction of P7-2 with OSK1, OSK5 and OSK20. It was also shown that P7-2, together with OSK1 and O. sativa Cullin-1, was able to form the SCF complex. Moreover, yeast two-hybrid assays revealed that P7-2 interacted with gibberellin insensitive dwarf2 (GID2 from rice and maize plants, which is essential for regulating the GA signaling pathway. It was further demonstrated that the N-terminal region of P7-2 was necessary for the interaction with GID2. Overall, these results indicated that P7-2 functioned as a component of the SCF complex in rice, and interaction of P7-2 with GID2 implied possible roles of the GA signaling pathway during RBSDV infection.

Role of hormones in controlling vascular differentiation and the mechanism of lateral root initiation.

Science.gov (United States)

Aloni, Roni

2013-11-01

The vascular system in plants is induced and controlled by streams of inductive hormonal signals. Auxin produced in young leaves is the primary controlling signal in vascular differentiation. Its polar and non-polar transport pathways and major controlling mechanisms are clarified. Ethylene produced in differentiating protoxylem vessels is the signal that triggers lateral root initiation, while tumor-induced ethylene is a limiting and controlling factor of crown gall development and its vascular differentiation. Gibberellin produced in mature leaves moves non-polarly and promotes elongation, regulates cambium activity and induces long fibers. Cytokinin from the root cap moves upward to promote cambial activity and stimulate shoot growth and branching, while strigolactone from the root inhibits branching. Furthermore, the role of the hormonal signals in controlling the type of differentiating vascular elements and gradients of conduit size and density, and how they regulate plant adaptation and have shaped wood evolution are elucidated.

Intervening to reduce workplace sitting: mediating role of social-cognitive constructs during a cluster randomised controlled trial.

Science.gov (United States)

Hadgraft, Nyssa T; Winkler, Elisabeth A H; Healy, Genevieve N; Lynch, Brigid M; Neuhaus, Maike; Eakin, Elizabeth G; Dunstan, David W; Owen, Neville; Fjeldsoe, Brianna S

2017-03-06

The Stand Up Victoria multi-component intervention successfully reduced workplace sitting time in both the short (three months) and long (12 months) term. To further understand how this intervention worked, we aimed to assess the impact of the intervention on four social-cognitive constructs, and examined whether these constructs mediated intervention effects on workplace sitting time at 3 and 12 months post-baseline. Two hundred and thirty one office-based workers (14 worksites, single government employer) were randomised to intervention or control conditions by worksite. The intervention comprised organisational, environmental, and individual level elements. Participant characteristics and social-cognitive constructs (perceived behavioural control, barrier self-efficacy, perceived organisational norms and knowledge) were measured through a self-administered online survey at baseline, 3 months and 12 months. Workplace sitting time (min/8 h day) was measured with the activPAL3 device. Single multi-level mediation models were performed for each construct at both time points. There were significant intervention effects at 3 months on perceived behavioural control, barrier self-efficacy and perceived organisational norms. Effects on perceived organisational norms were not significant at 12 months. Perceived behavioural control significantly mediated intervention effects at 3 months, accounting for a small portion of the total effect (indirect effect: -8.6 min/8 h day, 95% CI: -18.5, -3.6 min; 7.5% of total effect). At 12 months, barrier self-efficacy significantly mediated the intervention effects on workplace sitting time (indirect effect: -10.3 min/8 h day, 95% CI: -27.3, -2.2; 13.9% of total effect). No significant effects were observed for knowledge at either time point. Strategies that aim to increase workers' perceived control and self-efficacy over their sitting time may be helpful components of sedentary behaviour interventions in the workplace

Coping Styles Mediate the Relationship Between Self-esteem, Health Locus of Control, and Health-Promoting Behavior in Chinese Patients With Coronary Heart Disease.

Science.gov (United States)

Zou, Huijing; Tian, Qian; Chen, Yuxia; Cheng, Cheng; Fan, Xiuzhen

Health-promoting behavior plays an important role in reducing the burden of coronary heart disease. Self-esteem and health locus of control may contribute to health-promoting behavior, and coping styles may mediate these associations. The aims of our study were to examine whether self-esteem and health locus of control are associated with health-promoting behavior and examine the possible mediating effect of coping styles in patients with coronary heart disease. Health-promoting behavior, self-esteem, health locus of control, and coping styles were assessed in 272 hospitalized patients (60 ± 12 years, 61% male) with coronary heart disease. Hierarchical regression analysis was conducted to analyze the relationships between health-promoting behavior and other variables. Mediation effect was examined according to the methods of Baron and Kenny. The mean score for health-promoting behavior was 2.57 ± 0.51; 38.2% of patients (n = 104) scored lower than 2.5. Self-esteem (β = .139, P locus of control and health-promoting behavior. Confrontation plays a mediating role in the association among self-esteem, internal health locus of control, and health-promoting behavior. Strategies should be undertaken to encourage the use of confrontation coping style, which will facilitate health-promoting behavior.

Safety climate and self-reported injury: assessing the mediating role of employee safety control.

Science.gov (United States)

Huang, Yueng-Hsiang; Ho, Michael; Smith, Gordon S; Chen, Peter Y

2006-05-01

To further reduce injuries in the workplace, companies have begun focusing on organizational factors which may contribute to workplace safety. Safety climate is an organizational factor commonly cited as a predictor of injury occurrence. Characterized by the shared perceptions of employees, safety climate can be viewed as a snapshot of the prevailing state of safety in the organization at a discrete point in time. However, few studies have elaborated plausible mechanisms through which safety climate likely influences injury occurrence. A mediating model is proposed to link safety climate (i.e., management commitment to safety, return-to-work policies, post-injury administration, and safety training) with self-reported injury through employees' perceived control on safety. Factorial evidence substantiated that management commitment to safety, return-to-work policies, post-injury administration, and safety training are important dimensions of safety climate. In addition, the data support that safety climate is a critical factor predicting the history of a self-reported occupational injury, and that employee safety control mediates the relationship between safety climate and occupational injury. These findings highlight the importance of incorporating organizational factors and workers' characteristics in efforts to improve organizational safety performance.

Examination of mid-intervention mediating effects on objectively assessed sedentary time among children in the Transform-Us! cluster-randomized controlled trial.

Science.gov (United States)

Carson, Valerie; Salmon, Jo; Arundell, Lauren; Ridgers, Nicola D; Cerin, Ester; Brown, Helen; Hesketh, Kylie D; Ball, Kylie; Chinapaw, Mai; Yildirim, Mine; Daly, Robin M; Dunstan, David W; Crawford, David

2013-05-20

The optimal targets and strategies for effectively reducing sedentary behavior among young people are unknown. Intervention research that explores changes in mediated effects as well as in outcome behaviors is needed to help inform more effective interventions. Therefore, the purpose of this study was to examine the mid-intervention mediating effects on children's objectively assessed classroom and total weekday sedentary time in the Transform-Us! intervention. The results are based on 293 children, aged 7- to 9-years-old at baseline, from 20 schools in Melbourne, Australia. Each school was randomly allocated to one of four groups, which targeted reducing sedentary time in the school and family settings (SB; n = 74), increasing or maintaining moderate- to vigorous-intensity physical activity in the school and family settings (PA; n = 75), combined SB and PA (SB + PA; n = 80), or the current practice control (C; n = 64). Baseline and mid-intervention data (5-9 months) were collected in 2010 and analyzed in 2012. Classroom and total weekday sedentary time was objectively assessed using ActiGraph accelerometers. The hypothesized mediators including, child enjoyment, parent and teacher outcome expectancies, and child perceived access to standing opportunities in the classroom environment, were assessed by questionnaire. The SB + PA group spent 13.3 min/day less in weekday sedentary time at mid-intervention compared to the control group. At mid-intervention, children in the SB group had higher enjoyment of standing in class (0.9 units; 5-unit scale) and all intervention groups had more positive perceptions of access to standing opportunities in the classroom environment (0.3-0.4 units; 3-unit scale), compared to the control group. However, none of the hypothesized mediator variables had an effect on sedentary time; thus, no mediating effects were observed. While beneficial intervention effects were observed on some hypothesized mediating

New approach to increasing rice lodging resistance and biomass yield through the use of high gibberellin producing varieties.

Science.gov (United States)

Okuno, Ayako; Hirano, Ko; Asano, Kenji; Takase, Wakana; Masuda, Reiko; Morinaka, Yoichi; Ueguchi-Tanaka, Miyako; Kitano, Hidemi; Matsuoka, Makoto

2014-01-01

Traditional breeding for high-yielding rice has been dependent on the widespread use of fertilizers and the cultivation of gibberellin (GA)-deficient semi-dwarf varieties. The use of semi-dwarf plants facilitates high grain yield since these varieties possess high levels of lodging resistance, and thus could support the high grain weight. Although this approach has been successful in increasing grain yield, it is desirable to further improve grain production and also to breed for high biomass. In this study, we re-examined the effect of GA on rice lodging resistance and biomass yield using several GA-deficient mutants (e.g. having defects in the biosynthesis or perception of GA), and high-GA producing line or mutant. GA-deficient mutants displayed improved bending-type lodging resistance due to their short stature; however they showed reduced breaking-type lodging resistance and reduced total biomass. In plants producing high amounts of GA, the bending-type lodging resistance was inferior to the original cultivars. The breaking-type lodging resistance was improved due to increased lignin accumulation and/or larger culm diameters. Further, these lines had an increase in total biomass weight. These results show that the use of rice cultivars producing high levels of GA would be a novel approach to create higher lodging resistance and biomass.

Effect of the Application of Gibberellin (GA3 on Tomato Seed Germination (Solanum Lycopersicum L. Variety Santa Cruz

Directory of Open Access Journals (Sweden)

Yuli Alexandra Deaquiz-Oyola

2013-12-01

Full Text Available The tomato is one of the most important vegetable, economical and nutritionally, around the world. For this reason the germination process in the tomato is a vital stage in the growth and development of plants. In this study, the effect of different doses of gibberellin over the germination of Santa Cruz variety tomato seeds was evaluated. The seeds were embedded for 24 hours in different concentrations of gibberellic acid, sown in a peat substrate in the screen house of the UPTC. A complete randomized design was used with 4 treatments corresponding to 0, 100, 200 and 400 mg L-1 of GAs with three replicates, for a total of 12 experimental units (EU, and each unit with 35 seeds. The treatment of 0 mg L-1 had a favorable impact on the mean germination time (GT, average speed of germination (ASG and germination percentage (GP, showing significant differences with respect to the other treatments. The seeds soaked in 400 mg L-1 of GAs presented the lowest values in the variables GT, ASG and GP, attributed to negative effect this type of hormone over this tomato variety, which delayed the death of the embryo and the seed germination.

HLA-A*7401-mediated control of HIV viremia is independent of its linkage disequilibrium with HLA-B*5703

DEFF Research Database (Denmark)

Matthews, Philippa C; Adland, Emily; Listgarten, Jennifer

2011-01-01

-clade-infected subjects. We present evidence that HLA-A*7401 operates an effect that is independent of HLA-B*5703, with which it is in linkage disequilibrium in some populations, to mediate lowered viremia. We describe a novel statistical approach to detecting additive effects between class I alleles in control of HIV-1...... epitopes appear immunodominant. We identify eight novel putative HLA-A*7401-restricted epitopes, of which three have been defined to the optimal epitope. In common with HLA-B alleles linked with slow progression, viremic control through an HLA-A*7401-restricted response appears to be associated...... with the selection of escape mutants within Gag epitopes that reduce viral replicative capacity. These studies highlight the potentially important contribution of an HLA-A allele to immune control of HIV infection, which may have been concealed by a stronger effect mediated by an HLA-B allele with which...

Mother–Adolescent Conflict as a Mediator Between Adolescent Problem Behaviors and Maternal Psychological Control

OpenAIRE

Steeger, Christine M.; Gondoli, Dawn M.

2012-01-01

This study examined mother–adolescent conflict as a mediator of longitudinal reciprocal relations between adolescent aggression and depressive symptoms and maternal psychological control. Motivated by family systems theory and the transactions that occur between individual and dyadic levels of the family system, we examined the connections among these variables during a developmental period when children and parents experience significant psychosocial changes. Three years of self-report data ...

Basic Psychological Needs Satisfaction Mediates the Association between Self-Control Skills and Subjective Well-Being

Directory of Open Access Journals (Sweden)

Hod Orkibi

2017-06-01

Full Text Available Although studies have shown that self-control skills (SCSs are positively linked to both personal and interpersonal outcomes in adolescent students, studies on the putative mechanisms underlying this relationship are scarce. Drawing on Self-Determination Theory and previous studies, we theorized that the association between students’ SCSs and their subjective well-being (SWB in school may be mediated by students’ perceived satisfaction of their basic psychological needs for competence, relatedness, and autonomy. The sample consisted of 1576 Israeli adolescent students (54% girls in grades 10–12 (mean age 16 enrolled in 20 schools. A mediation model was tested with structural equation modeling and a robust bootstrap method for testing indirect effects, controlling for school-level variance. The findings supported the hypothesized model and a post hoc multi-group comparison analysis yielded gender invariance in the model. The findings suggest that both girls and boys with high SCSs may perceive themselves as having greater needs satisfaction in school and consequently higher school-related SWB. Implications for policy and practice are discussed.

Brassinosteroid and gibberellin control of seedling traits in maize (Zea mays L.).

Science.gov (United States)

Hu, Songlin; Sanchez, Darlene L; Wang, Cuiling; Lipka, Alexander E; Yin, Yanhai; Gardner, Candice A C; Lübberstedt, Thomas

2017-10-01

In this study, we established two doubled haploid (DH) libraries with a total of 207 DH lines. We applied BR and GA inhibitors to all DH lines at seedling stage and measured seedling BR and GA inhibitor responses. Moreover, we evaluated field traits for each DH line (untreated). We conducted genome-wide association studies (GWAS) with 62,049 genome wide SNPs to explore the genetic control of seedling traits by BR and GA. In addition, we correlate seedling stage hormone inhibitor response with field traits. Large variation for BR and GA inhibitor response and field traits was observed across these DH lines. Seedling stage BR and GA inhibitor response was significantly correlate with yield and flowering time. Using three different GWAS approaches to balance false positive/negatives, multiple SNPs were discovered to be significantly associated with BR/GA inhibitor responses with some localized within gene models. SNPs from gene model GRMZM2G013391 were associated with GA inhibitor response across all three GWAS models. This gene is expressed in roots and shoots and was shown to regulate GA signaling. These results show that BRs and GAs have a great impact for controlling seedling growth. Gene models from GWAS results could be targets for seeding traits improvement. Copyright © 2017 Elsevier B.V. All rights reserved.

Perceived Academic Control: Mediating the Effects of Optimism and Social Support on College Students' Psychological Health

Science.gov (United States)

Ruthig, Joelle C.; Haynes, Tara L.; Stupnisky, Robert H.; Perry, Raymond P.

2009-01-01

The first year of college presents numerous challenges experienced as overwhelming by some freshmen who may become overly stressed and depressed. This longitudinal study examined perceived academic control (PAC) as a mediator of optimism and social support's buffering effects on freshman students' psychological health. Multiple regressions…

DMPD: Protein kinase C epsilon: a new target to control inflammation andimmune-mediated disorders. [Dynamic Macrophage Pathway CSML Database

Lifescience Database Archive (English)

Full Text Available 14643884 Protein kinase C epsilon: a new target to control inflammation andimmune-m...g) (.html) (.csml) Show Protein kinase C epsilon: a new target to control inflammation andimmune-mediated di...sorders. PubmedID 14643884 Title Protein kinase C epsilon: a new target to contro

Sugars, the clock and transition to flowering

Directory of Open Access Journals (Sweden)

Mohammad Reza eBolouri Moghaddam

2013-02-01

Full Text Available Sugars do not only act as source of energy, but they also act as signals in plants. This mini review summarizes the emerging links between sucrose-mediated signaling and the cellular networks involved in flowering time control and defense. Cross-talks with gibberellin (GA and jasmonate (JA signaling pathways are highlighted. The circadian clock fulfills a crucial role at the heart of cellular networks and the bilateral relation between sugar signaling and the clock is discussed. It is proposed that important factors controlling plant growth (DELLAs, PIFs, invertases and trehalose- 6-phosphate or T6P might fulfill central roles in the transition to flowering as well. The emerging concept of ‘sweet immunity’, modulated by the clock, might at least partly rely on a sucrose-specific signaling pathway that needs further exploration.

Personal Values as a Mediator of Relations Between Perceived Parental Support and Control and Youth Substance Use.

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Borca, Gabriella; Rabaglietti, Emanuela; Roggero, Antonella; Keller, Peggy; Haak, Eric; Begotti, Tatiana

2017-10-15

Tobacco and marijuana smoking are very popular in adolescence and there is a high rate of comorbidity between them, even in young adulthood. Parental support and control may hinder involvement in the use of these substances by promoting conventional values among adolescents. The present study investigates the relations between family functioning (parental support and control) and psychoactive substance use (tobacco and marijuana smoking) and determines whether these relationships are mediated by personal values (in terms of disapproval of deviance and beliefs about the importance of school, health and religion). 175 Italian late adolescents (17 to 20 years old) participated in this two-wave longitudinal study. Data were collected at school through an anonymous questionnaire. Greater parental control and support were directly associated with lower adolescent tobacco and marijuana use; adolescent acceptance of conventional values mediated the association between parenting and adolescent marijuana use. Findings emphasize the influence of family relationships throughout adolescence. The transmission of conventional values to adolescents may be a critical mechanism through which parenting protects adolescents from substance use, especially marijuana use.

Nutrient Control of Yeast Gametogenesis Is Mediated by TORC1, PKA and Energy Availability.

Directory of Open Access Journals (Sweden)

Hilla Weidberg

2016-06-01

Full Text Available Cell fate choices are tightly controlled by the interplay between intrinsic and extrinsic signals, and gene regulatory networks. In Saccharomyces cerevisiae, the decision to enter into gametogenesis or sporulation is dictated by mating type and nutrient availability. These signals regulate the expression of the master regulator of gametogenesis, IME1. Here we describe how nutrients control IME1 expression. We find that protein kinase A (PKA and target of rapamycin complex I (TORC1 signalling mediate nutrient regulation of IME1 expression. Inhibiting both pathways is sufficient to induce IME1 expression and complete sporulation in nutrient-rich conditions. Our ability to induce sporulation under nutrient rich conditions allowed us to show that respiration and fermentation are interchangeable energy sources for IME1 transcription. Furthermore, we find that TORC1 can both promote and inhibit gametogenesis. Down-regulation of TORC1 is required to activate IME1. However, complete inactivation of TORC1 inhibits IME1 induction, indicating that an intermediate level of TORC1 signalling is required for entry into sporulation. Finally, we show that the transcriptional repressor Tup1 binds and represses the IME1 promoter when nutrients are ample, but is released from the IME1 promoter when both PKA and TORC1 are inhibited. Collectively our data demonstrate that nutrient control of entry into sporulation is mediated by a combination of energy availability, TORC1 and PKA activities that converge on the IME1 promoter.

Direct and indirect influences of fate control belief, gambling expectancy bias, and self-efficacy on problem gambling and negative mood among Chinese college students: a multiple mediation analysis.

Science.gov (United States)

Tang, Catherine So-Kum; Wu, Anise M S

2010-12-01

A multiple mediation model was proposed to integrate core concepts of the social axioms framework and the social cognitive theory in order to understand gambling behavior. It was hypothesized that the influence of general fate control belief on problem gambling and negative mood would be mediated by gambling-specific beliefs. Data from 773 Chinese college recreational gamblers were collected. The bootstrapping procedure was used to test the multiple mediation hypotheses. Significant indirect effects of fate control belief on problem gambling and negative mood through two gambling-specific mediators were found. Gambling expectancy bias was a more salient mediator than gambling self-efficacy. Fate control belief was also found to have a significant direct effect on negative mood. In general, a high level of general fate control belief was related to greater gambling expectancy bias and lower self-efficacy in resisting gambling, which were in turn related to problem gambling and negative mood. Limitations and implications of the study were discussed.

Transcription regulation by the Mediator complex.

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Soutourina, Julie

2018-04-01

Alterations in the regulation of gene expression are frequently associated with developmental diseases or cancer. Transcription activation is a key phenomenon in the regulation of gene expression. In all eukaryotes, mediator of RNA polymerase II transcription (Mediator), a large complex with modular organization, is generally required for transcription by RNA polymerase II, and it regulates various steps of this process. The main function of Mediator is to transduce signals from the transcription activators bound to enhancer regions to the transcription machinery, which is assembled at promoters as the preinitiation complex (PIC) to control transcription initiation. Recent functional studies of Mediator with the use of structural biology approaches and functional genomics have revealed new insights into Mediator activity and its regulation during transcription initiation, including how Mediator is recruited to transcription regulatory regions and how it interacts and cooperates with PIC components to assist in PIC assembly. Novel roles of Mediator in the control of gene expression have also been revealed by showing its connection to the nuclear pore and linking Mediator to the regulation of gene positioning in the nuclear space. Clear links between Mediator subunits and disease have also encouraged studies to explore targeting of this complex as a potential therapeutic approach in cancer and fungal infections.

Relational aggression and psychological control in the sibling relationship: mediators of the association between maternal psychological control and adolescents' emotional adjustment.

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Campione-Barr, Nicole; Lindell, Anna K; Greer, Kelly Bassett; Rose, Amanda J

2014-08-01

The association between mothers' psychological control and their children's emotional adjustment problems is well documented. However, processes that may explain this association are not well understood. The present study tested the idea that relational aggression and psychological control within the context of the sibling relationship may help to account for the relation between mothers' psychological control and adolescents' internalizing symptoms. Older (M = 16.46, SD = 1.35 years) and younger (M = 13.67, SD = 1.56 years) siblings from 101 dyads rated the psychological control they received from mothers and siblings, and the relational aggression they received from siblings. Despite some similarities between psychological control and relational aggression, confirmatory factor analyses provided evidence that the two sibling processes are distinct. Maternal psychological control was related to psychological control and relational aggression within the sibling relationship, which were related to adolescents' anxiety and depressed mood. In addition, sibling relational aggression was a more powerful mediator of the relationship between maternal psychological control and adolescent adjustment than sibling psychological control.

The Mediator subunit MED23 couples H2B mono-ubiquitination to transcriptional control and cell fate determination.

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Yao, Xiao; Tang, Zhanyun; Fu, Xing; Yin, Jingwen; Liang, Yan; Li, Chonghui; Li, Huayun; Tian, Qing; Roeder, Robert G; Wang, Gang

2015-12-02

The Mediator complex orchestrates multiple transcription factors with the Pol II apparatus for precise transcriptional control. However, its interplay with the surrounding chromatin remains poorly understood. Here, we analyze differential histone modifications between WT and MED23(-/-) (KO) cells and identify H2B mono-ubiquitination at lysine 120 (H2Bub) as a MED23-dependent histone modification. Using tandem affinity purification and mass spectrometry, we find that MED23 associates with the RNF20/40 complex, the enzyme for H2Bub, and show that this association is critical for the recruitment of RNF20/40 to chromatin. In a cell-free system, Mediator directly and substantially increases H2Bub on recombinant chromatin through its cooperation with RNF20/40 and the PAF complex. Integrative genome-wide analyses show that MED23 depletion specifically reduces H2Bub on a subset of MED23-controlled genes. Importantly, MED23-coupled H2Bub levels are oppositely regulated during myogenesis and lung carcinogenesis. In sum, these results establish a mechanistic link between the Mediator complex and a critical chromatin modification in coordinating transcription with cell growth and differentiation. © 2015 The Authors.

Electrochemiluminescent DNA sensor based on controlled Zn-mediated grafting of diazonium precursors.

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Torréns, Mabel; Ortiz, Mayreli; Bejarano-Nosas, Diego; O'Sullivan, Ciara K

2015-07-01

Controlled Zn-mediated grafting of a thin layer of a diazonium salt was used to functionalise a carbon electrode with ruthenium(II)-tris-bipyridine (Ru)-labelled DNA for use as a capture probe in an electrochemiluminescent genosensor. A secondary reporter probe was labelled with a ferrocene (Fc) molecule, and in the presence of the single-stranded DNA target a genocomplex formed, where the Fc-label effectively quenched the electrochemiluminescence of the signal emitted from the Ru-label. The spacing of the labels for maximum sensitivity and minimum detection limit was optimised, and the signal reproducibility and stability of the method was established.

Identification and characterization of dwarf 62, a loss-of-function mutation in DLT/OsGRAS-32 affecting gibberellin metabolism in rice.

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Li, Wenqiang; Wu, Jianguo; Weng, Shili; Zhang, Yujiang; Zhang, Dapeng; Shi, Chunhai

2010-11-01

A dwarf mutant, dwarf 62 (d62), was isolated from rice cultivar 93-11 by mutagenesis with γ-rays. Under normal growth conditions, the mutant had multiple abnormal phenotypes, such as dwarfism, wide and dark-green leaf blades, reduced tiller numbers, late and asynchronous heading, short roots, partial male sterility, etc. Genetic analysis indicated that the abnormal phenotypes were controlled by the recessive mutation of a single nuclear gene. Using molecular markers, the D62 gene was fine mapped in 131-kb region at the short arm of chromosome 6. Positional cloning of D62 gene revealed that it was the same locus as DLT/OsGRAS-32, which encodes a member of the GRAS family. In previous studies, the DLT/OsGRAS-32 is confirmed to play positive roles in brassinosteroid (BR) signaling. Sequence analysis showed that the d62 carried a 2-bp deletion in ORF region of D62 gene which led to a loss-of-function mutation. The function of D62 gene was confirmed by complementation experiment. RT-PCR analysis and promoter activity analysis showed that the D62 gene expressed in all tested tissues including roots, stems, leaves and panicles of rice plant. The d62 mutant exhibited decreased activity of α-amylase in endosperm and reduced content of endogenous GA(1). The expression levels of gibberellin (GA) biosynthetic genes including OsCPS1, OsKS1, OsKO1, OsKAO, OsGA20ox2/SD1 and OsGA2ox3 were significantly increased in d62 mutant. Briefly, these results demonstrated that the D62 (DLT/OsGRAS-32) not only participated in the regulation of BR signaling, but also influenced GA metabolism in rice.

Oligo-carrageenan kappa-induced reducing redox status and activation of TRR/TRX system increase the level of indole-3-acetic acid, gibberellin A3 and trans-zeatin in Eucalyptus globulus trees.

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González, Alberto; Contreras, Rodrigo A; Zúiga, Gustavo; Moenne, Alejandra

2014-08-20

Eucalyptus globulus trees treated with oligo-carrageenan (OC) kappa showed an increase in NADPH, ascorbate and glutathione levels and activation of the thioredoxin reductase (TRR)/thioredoxin (TRX) system which enhance photosynthesis, basal metabolism and growth. In order to analyze whether the reducing redox status and the activation of thioredoxin reductase (TRR)/thioredoxin (TRX) increased the level of growth-promoting hormones, trees were treated with water (control), with OC kappa, or with inhibitors of ascorbate synthesis, lycorine, glutathione synthesis, buthionine sulfoximine (BSO), NADPH synthesis, CHS-828, and thioredoxin reductase activity, auranofine, and with OC kappa, and cultivated for four additional months. Eucalyptus trees treated with OC kappa showed an increase in the levels of the auxin indole 3-acetic acid (IAA), gibberellin A3 (GA3) and the cytokinin trans-zeatin (t-Z) as well as a decrease in the level of the brassinosteroid epi-brassinolide (EB). In addition, treatment with lycorine, BSO, CHS-828 and auranofine inhibited the increase in IAA, GA3 and t-Z as well as the decrease in EB levels. Thus, the reducing redox status and the activation of TRR/TRX system induced by OC kappa increased the levels of IAA, GA3 and t-Z levels determining, at least in part, the stimulation of growth in Eucalyptus trees.

Photoperiod- and temperature-mediated control of growth cessation and dormancy in trees: a molecular perspective.

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Maurya, Jay P; Bhalerao, Rishikesh P

2017-09-01

How plants adapt their developmental patterns to regular seasonal changes is an important question in biology. The annual growth cycle in perennial long-lived trees is yet another example of how plants can adapt to seasonal changes. The two main signals that plants rely on to respond to seasonal changes are photoperiod and temperature, and these signals have critical roles in the temporal regulation of the annual growth cycle of trees. This review presents the latest findings to provide insight into the molecular mechanisms that underlie how photoperiodic and temperature signals regulate seasonal growth in trees. The results point to a high level of conservation in the signalling pathways that mediate photoperiodic control of seasonal growth in trees and flowering in annual plants such as arabidopsis. Furthermore, the data indicate that symplastic communication may mediate certain aspects of seasonal growth. Although considerable insight into the control of phenology in model plants such as poplar and spruce has been obtained, the future challenge is extending these studies to other, non-model trees. © The Author 2017. Published by Oxford University Press on behalf of the Annals of Botany Company. All rights reserved. For Permissions, please email: journals.permissions@oup.com

Seed-borne endophytic Bacillus amyloliquefaciens RWL-1 produces gibberellins and regulates endogenous phytohormones of Oryza sativa.

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Shahzad, Raheem; Waqas, Muhammad; Khan, Abdul Latif; Asaf, Sajjad; Khan, Muhammad Aaqil; Kang, Sang-Mo; Yun, Byung-Wook; Lee, In-Jung

2016-09-01

Some microorganisms are adapted to an endophytic mode, living symbiotically with plants through vertical transmission in seeds. The role of plant growth-promoting endophytes has been well studied, but those of seed-associated endophytic bacteria are less understood. The current study aimed to isolate and identify bacterial endophytes associated with rice (Oryza sativa L. 'Jin so mi') seeds, their potential to produce gibberellins (GAs), and role in improving host-plant physiology. The isolated bacterial endophyte RWL-1 was identified as Bacillus amyloliquefaciens by using 16S rRNA sequencing and phylogenetic analysis. The pure culture of B. amyloliquefaciens RWL-1, supplied with deuterated internal standards, was subjected to gas chromatography and mass spectrometric selected ion monitoring (GC-MS/SIM) for quantification of GAs. Results showed the presence of GAs in various quantities (ng/mL) viz., GA20 (17.88 ± 4.04), GA36 (5.75 ± 2.36), GA24 (5.64 ± 2.46), GA4 (1.02 ± 0.16), GA53 (0.772 ± 0.20), GA9 (0.12 ± 0.09), GA19 (0.093 ± 0.13), GA5 (0.08 ± 0.04), GA12 (0.014 ± 0.34), and GA8 (0.013 ± 0.01). Since endogenous seed GAs are essential for prolonged seed growth and subsequent plant development, we used exogenous GA3 as a positive control and water as a negative control for comparative analysis of the application of B. amyloliquefaciens RWL-1 to rice plants. The growth parameters of rice plants treated with endophytic bacterial cell application was significantly increased compared to the plants treated with exogenous GA3 and water. This was also revealed by the significant up-regulation of endogenous GA1 (17.54 ± 2.40 ng), GA4 (310 ± 5.41 ng), GA7 (192.60 ± 3.32 ng), and GA9 (19.04 ± 2.49 ng) as compared to results of the positive and negative control treatments. Rice plants inoculated with B. amyloliquefaciens RWL-1 exhibited significantly higher endogenous salicylic acid (1615.06 ± 10.81 μg), whereas

New approach to increasing rice lodging resistance and biomass yield through the use of high gibberellin producing varieties.

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Ayako Okuno

Full Text Available Traditional breeding for high-yielding rice has been dependent on the widespread use of fertilizers and the cultivation of gibberellin (GA-deficient semi-dwarf varieties. The use of semi-dwarf plants facilitates high grain yield since these varieties possess high levels of lodging resistance, and thus could support the high grain weight. Although this approach has been successful in increasing grain yield, it is desirable to further improve grain production and also to breed for high biomass. In this study, we re-examined the effect of GA on rice lodging resistance and biomass yield using several GA-deficient mutants (e.g. having defects in the biosynthesis or perception of GA, and high-GA producing line or mutant. GA-deficient mutants displayed improved bending-type lodging resistance due to their short stature; however they showed reduced breaking-type lodging resistance and reduced total biomass. In plants producing high amounts of GA, the bending-type lodging resistance was inferior to the original cultivars. The breaking-type lodging resistance was improved due to increased lignin accumulation and/or larger culm diameters. Further, these lines had an increase in total biomass weight. These results show that the use of rice cultivars producing high levels of GA would be a novel approach to create higher lodging resistance and biomass.

Method for evaluating multiple mediators: mediating effects of smoking and COPD on the association between the CHRNA5-A3 variant and lung cancer risk.

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Wang, Jian; Spitz, Margaret R; Amos, Christopher I; Wu, Xifeng; Wetter, David W; Cinciripini, Paul M; Shete, Sanjay

2012-01-01

A mediation model explores the direct and indirect effects between an independent variable and a dependent variable by including other variables (or mediators). Mediation analysis has recently been used to dissect the direct and indirect effects of genetic variants on complex diseases using case-control studies. However, bias could arise in the estimations of the genetic variant-mediator association because the presence or absence of the mediator in the study samples is not sampled following the principles of case-control study design. In this case, the mediation analysis using data from case-control studies might lead to biased estimates of coefficients and indirect effects. In this article, we investigated a multiple-mediation model involving a three-path mediating effect through two mediators using case-control study data. We propose an approach to correct bias in coefficients and provide accurate estimates of the specific indirect effects. Our approach can also be used when the original case-control study is frequency matched on one of the mediators. We employed bootstrapping to assess the significance of indirect effects. We conducted simulation studies to investigate the performance of the proposed approach, and showed that it provides more accurate estimates of the indirect effects as well as the percent mediated than standard regressions. We then applied this approach to study the mediating effects of both smoking and chronic obstructive pulmonary disease (COPD) on the association between the CHRNA5-A3 gene locus and lung cancer risk using data from a lung cancer case-control study. The results showed that the genetic variant influences lung cancer risk indirectly through all three different pathways. The percent of genetic association mediated was 18.3% through smoking alone, 30.2% through COPD alone, and 20.6% through the path including both smoking and COPD, and the total genetic variant-lung cancer association explained by the two mediators was 69.1%.

Method for evaluating multiple mediators: mediating effects of smoking and COPD on the association between the CHRNA5-A3 variant and lung cancer risk.

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Jian Wang

Full Text Available A mediation model explores the direct and indirect effects between an independent variable and a dependent variable by including other variables (or mediators. Mediation analysis has recently been used to dissect the direct and indirect effects of genetic variants on complex diseases using case-control studies. However, bias could arise in the estimations of the genetic variant-mediator association because the presence or absence of the mediator in the study samples is not sampled following the principles of case-control study design. In this case, the mediation analysis using data from case-control studies might lead to biased estimates of coefficients and indirect effects. In this article, we investigated a multiple-mediation model involving a three-path mediating effect through two mediators using case-control study data. We propose an approach to correct bias in coefficients and provide accurate estimates of the specific indirect effects. Our approach can also be used when the original case-control study is frequency matched on one of the mediators. We employed bootstrapping to assess the significance of indirect effects. We conducted simulation studies to investigate the performance of the proposed approach, and showed that it provides more accurate estimates of the indirect effects as well as the percent mediated than standard regressions. We then applied this approach to study the mediating effects of both smoking and chronic obstructive pulmonary disease (COPD on the association between the CHRNA5-A3 gene locus and lung cancer risk using data from a lung cancer case-control study. The results showed that the genetic variant influences lung cancer risk indirectly through all three different pathways. The percent of genetic association mediated was 18.3% through smoking alone, 30.2% through COPD alone, and 20.6% through the path including both smoking and COPD, and the total genetic variant-lung cancer association explained by the two

Locus of control fails to mediate between stress and anxiety and depression in parents of children with a developmental disorder.

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Hamlyn-Wright, Sarah; Draghi-Lorenz, Riccardo; Ellis, Jason

2007-11-01

Stress, anxiety and depression are raised amongst parents of children with a developmental disorder. However, the processes by which stress leads to depression and anxiety are poorly understood. In a cross-sectional survey, levels of parental stress, depression and anxiety were compared between parents of children with an autistic disorder, children with Down's syndrome and children with no disorder (N = 619) and the mediational role of locus of control was examined. Anxiety and depression were higher in parents of children with a disorder, and highest in parents of children with autism. Locus of control was more external in parents of children with autism. Locus of control failed to mediate the relationship between stress and both anxiety and depression in parents of children with a disorder. This suggests that help for parents of a child with a disorder may be effective if focused on the sources of stress rather than perceived control over events.

Reactivation of meristem activity and sprout growth in potato tubers require both cytokinin and gibberellin.

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Hartmann, Anja; Senning, Melanie; Hedden, Peter; Sonnewald, Uwe; Sonnewald, Sophia

2011-02-01

Reactivation of dormant meristems is of central importance for plant fitness and survival. Due to their large meristem size, potato (Solanum tuberosum) tubers serve as a model system to study the underlying molecular processes. The phytohormones cytokinins (CK) and gibberellins (GA) play important roles in releasing potato tuber dormancy and promoting sprouting, but their mode of action in these processes is still obscure. Here, we established an in vitro assay using excised tuber buds to study the dormancy-releasing capacity of GA and CK and show that application of gibberellic acid (GA(3)) is sufficient to induce sprouting. In contrast, treatment with 6-benzylaminopurine induced bud break but did not support further sprout growth unless GA(3) was administered additionally. Transgenic potato plants expressing Arabidopsis (Arabidopsis thaliana) GA 20-oxidase or GA 2-oxidase to modify endogenous GA levels showed the expected phenotypical changes as well as slight effects on tuber sprouting. The isopentenyltransferase (IPT) from Agrobacterium tumefaciens and the Arabidopsis cytokinin oxidase/dehydrogenase1 (CKX) were exploited to modify the amounts of CK in transgenic potato plants. IPT expression promoted earlier sprouting in vitro. Strikingly, CKX-expressing tubers exhibited a prolonged dormancy period and did not respond to GA(3). This supports an essential role of CK in terminating tuber dormancy and indicates that GA is not sufficient to break dormancy in the absence of CK. GA(3)-treated wild-type and CKX-expressing tuber buds were subjected to a transcriptome analysis that revealed transcriptional changes in several functional groups, including cell wall metabolism, cell cycle, and auxin and ethylene signaling, denoting events associated with the reactivation of dormant meristems.

Endophytic fungal association via gibberellins and indole acetic acid can improve plant growth under abiotic stress: an example of Paecilomyces formosus LHL10

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Khan Abdul

2012-01-01

Full Text Available Abstract Background Endophytic fungi are little known for exogenous secretion of phytohormones and mitigation of salinity stress, which is a major limiting factor for agriculture production worldwide. Current study was designed to isolate phytohormone producing endophytic fungus from the roots of cucumber plant and identify its role in plant growth and stress tolerance under saline conditions. Results We isolated nine endophytic fungi from the roots of cucumber plant and screened their culture filtrates (CF on gibberellins (GAs deficient mutant rice cultivar Waito-C and normal GAs biosynthesis rice cultivar Dongjin-byeo. The CF of a fungal isolate CSH-6H significantly increased the growth of Waito-C and Dongjin-byeo seedlings as compared to control. Analysis of the CF showed presence of GAs (GA1, GA3, GA4, GA8, GA9, GA12, GA20 and GA24 and indole acetic acid. The endophyte CSH-6H was identified as a strain of Paecilomyces formosus LHL10 on the basis of phylogenetic analysis of ITS sequence similarity. Under salinity stress, P. formosus inoculation significantly enhanced cucumber shoot length and allied growth characteristics as compared to non-inoculated control plants. The hypha of P. formosus was also observed in the cortical and pericycle regions of the host-plant roots and was successfully re-isolated using PCR techniques. P. formosus association counteracted the adverse effects of salinity by accumulating proline and antioxidants and maintaining plant water potential. Thus the electrolytic leakage and membrane damage to the cucumber plants was reduced in the association of endophyte. Reduced content of stress responsive abscisic acid suggest lesser stress convened to endophyte-associated plants. On contrary, elevated endogenous GAs (GA3, GA4, GA12 and GA20 contents in endophyte-associated cucumber plants evidenced salinity stress modulation. Conclusion The results reveal that mutualistic interactions of phytohormones secreting endophytic

Systemic vascular function, measured with forearm flow mediated dilatation, in acute and stable cerebrovascular disease: a case-control study

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Blacker David

2010-10-01

Full Text Available Abstract Background Acute ischaemic stroke is associated with alteration in systemic markers of vascular function. We measured forearm vascular function (using forearm flow mediated dilatation to clarify whether recent acute ischaemic stroke/TIA is associated with impaired systemic vascular function. Methods Prospective case control study enrolling 17 patients with recent acute ischaemic stroke/TIA and 17 sex matched controls with stroke more than two years previously. Forearm vascular function was measured using flow medicated dilatation (FMD. Results Flow mediated dilatation was 6.0 ± 1.1% in acute stroke/TIA patients and 4.7 ± 1.0% among control subjects (p = 0.18. The mean paired difference in FMD between subjects with recent acute stroke and controls was 1.25% (95% CI -0.65, 3.14; p = 0.18. Endothelium independent dilatation was measured in six pairs of participants and was similar in acute stroke/TIA patients (22.6 ± 4.3% and control subjects (19.1 ± 2.6%; p = 0.43. Conclusions Despite the small size of this study, these data indicate that recent acute stroke is not necessarily associated with a clinically important reduction in FMD.

Mediating effect of perceived overweight on the association between actual obesity and intention for weight control; role of race, ethnicity, and gender

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Shervin Assari

2015-01-01

Full Text Available Background: Although obesity is expected to be associated with intention to reduce weight, this effect may be through perceived overweight. This study tested if perceived overweight mediates the association between actual obesity and intention to control weight in groups based on the intersection of race and gender. For this purpose, we compared Non-Hispanic White men, Non-Hispanic White women, African American men, African American women, Caribbean Black men, and Caribbean Black women. Methods: National Survey of American Life, 2001-2003 included 5,810 American adults (3516 African Americans, 1415 Caribbean Blacks, and 879 Non-Hispanic Whites. Weight control intention was entered as the main outcome. In the first step, we fitted race/gender specific logistic regression models with the intention for weight control as outcome, body mass index as predictor and sociodemographics as covariates. In the next step, to test mediation, we added perceived weight to the model. Results: Obesity was positively associated with intention for weight control among all race × gender groups. Perceived overweight fully mediated the association between actual obesity and intention for weight control among Non-Hispanic White women, African American men, and Caribbean Black men. The mediation was only partial for Non-Hispanic White men, African American women, and Caribbean Black women. Conclusions: The complex relation between actual weight, perceived weight, and weight control intentions depends on the intersection of race and gender. Perceived overweight plays a more salient role for Non-Hispanic White women and Black men than White men and Black women. Weight loss programs may benefit from being tailored based on race and gender. This finding also sheds more light to the disproportionately high rate of obesity among Black women in US.

Gratitude mediates quality of life differences between fibromyalgia patients and healthy controls.

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Toussaint, Loren; Sirois, Fuschia; Hirsch, Jameson; Weber, Annemarie; Vajda, Christian; Schelling, Jorg; Kohls, Niko; Offenbacher, Martin

2017-09-01

Despite a growing literature on the benefits of gratitude for adjustment to chronic illness, little is known about gratitude in medical populations compared to healthy populations, or the degree to which potential deficits in gratitude might impact quality of life. The purpose of the present study was to (1) examine levels of gratitude and quality of life in fibromyalgia patients and healthy controls and (2) consider the role of gratitude in explaining quality of life differences between fibromyalgia patients and healthy controls. Participants were 173 fibromyalgia patients and 81 healthy controls. All participants completed measures of gratitude, quality of life, and socio-demographics. Although gratitude was positively associated with quality of life, levels of gratitude and quality of life were lower in the fibromyalgia sample relative to the healthy controls. This difference in gratitude partially mediated differences in quality of life between the two groups after controlling for socio-demographic variables. Our findings suggest that gratitude is a valuable positive psychological trait for quality of life in people with fibromyalgia. Interventions to improve gratitude in this patient population may also bring enhancement in quality of life.

MEDIATOR18 and MEDIATOR20 confer susceptibility to Fusarium oxysporum in Arabidopsis thaliana

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Stiller, Jiri; Davoine, Celine; Björklund, Stefan; Manners, John M.; Kazan, Kemal; Schenk, Peer M.

2017-01-01

The conserved protein complex known as Mediator conveys transcriptional signals by acting as an intermediary between transcription factors and RNA polymerase II. As a result, Mediator subunits play multiple roles in regulating developmental as well as abiotic and biotic stress pathways. In this report we identify the head domain subunits MEDIATOR18 and MEDIATOR20 as important susceptibility factors for Fusarium oxysporum infection in Arabidopsis thaliana. Mutants of MED18 and MED20 display down-regulation of genes associated with jasmonate signaling and biosynthesis while up-regulation of salicylic acid associated pathogenesis related genes and reactive oxygen producing and scavenging genes. We propose that MED18 and MED20 form a sub-domain within Mediator that controls the balance of salicylic acid and jasmonate associated defense pathways. PMID:28441405

The relationship between adult attachment orientation and child self-regulation in eating: The mediating role of persuasive-controlling feeding practices.

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Powell, Elisabeth M; Frankel, Leslie A; Umemura, Tomo; Hazen, Nancy

2017-08-01

The present study examines the hypothesis that adult attachment orientation, specifically anxious attachment, is related to children's diminished ability to self-regulate their food intake, and that this relationship is mediated by parents' persuasive-controlling feeding practices. Two hundred and sixty five mothers and fathers of preschool children completed online questionnaires that included measures of Adult Attachment Orientation, Parental Persuasive-Controlling Feeding Practices, and Child Self-Regulation of Eating. Structural equation modeling revealed a significant relationship between parental anxious attachment and child self-regulatory abilities, which was fully mediated by parental persuasive-controlling feeding. Also as predicted, parents' avoidant attachment was found to be unrelated to persuasive-controlling feeding and child self-regulated eating. Findings suggest that parents with an anxious attachment orientation may be more likely than other parents to try to use persuasive techniques to control their children's food intake, which may impair children's ability to regulate their food intake, increasing their obesity risk. Implications for intervention are discussed. Copyright © 2017 Elsevier Ltd. All rights reserved.

Does self-efficacy mediate functional change in older adults participating in an exercise program after hip fracture? A randomized control trial

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Latham, Nancy K.; Ni, Pengsheng; Jette, Alan M.

2015-01-01

Objectives This study examined whether self-efficacy mediated the effect of the HIP Rehab exercise program on activity limitations in older adults after hip fracture, and whether the mediation effect was different between different gender and age groups. Design Randomized controlled trial (RCT) Setting Community Participants Two hundred and thirty two participants aged 79±9.4 years with hip fracture were randomly assigned to intervention (n=120) or attention control (n=112) groups. Interventions The 6-month intervention, the HIP Rehab, is a functionally-oriented, home-based exercise program. Data was collected at baseline, post-intervention (6 months), and follow-up (9 months). Main outcome measure Activity Measure for Post-Acute Care (AM-PAC) Results The mediation effect of the HIP Rehab exercise program on Basic Mobility function through self-efficacy for exercise was significant at 9 months (βindirect=0.21). Similarly, the mediation effect of the intervention on Daily Activity function through self-efficacy for exercise was significant at 9 months (βindirect=0.49). In subgroup analyses, the mediation effect was significant at 9 months in the younger group (≤79 years old) in comparison to the older group, and was significant in females in comparison to males. Conclusion Self-efficacy may play a partial mediating role for the effect on some longer-term functional outcomes in the HIP Rehab intervention. The results suggest that program components that target self-efficacy should be incorporated in the future hip fracture rehabilitation interventions. Age and gender of the targeted participants may also need to be considered when developing interventions. PMID:25701101

Gender-specific mediational links between parenting styles, parental monitoring, impulsiveness, drinking control, and alcohol-related problems.

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Patock-Peckham, Julie A; King, Kevin M; Morgan-Lopez, Antonio A; Ulloa, Emilio C; Moses, Jennifer M Filson

2011-03-01

Recently, it has been suggested that traits may dynamically change as conditions change. One possible mechanism that may influence impulsiveness is parental monitoring. Parental monitoring reflects a knowledge regarding one's offspring's whereabouts and social connections. The aim of this investigation was to examine potential gender-specific parental influences to impulsiveness (general behavioral control), control over one's own drinking (specific behavioral control), and alcohol-related problems among individuals in a period of emerging adulthood. Direct and mediational links between parenting styles (permissive, authoritarian, and authoritative), parental monitoring, impulsiveness, drinking control, and alcohol-related problems were investigated. A multiple-group, SEM model with (316 women, 265 men) university students was examined. In general, the overall pattern among male and female respondents was distinct. For daughters, perceptions of a permissive father were indirectly linked to more alcohol-related problems through lower levels of monitoring by fathers and more impulsive symptoms. Perceptions of an authoritative father were also indirectly linked to fewer impulsive symptoms through higher levels of monitoring by fathers among daughters. For men, perceptions of a permissive mother were indirectly linked to more alcohol-related problems through lower levels of monitoring by mothers and more impulsive symptoms. For sons, perceptions of mother authoritativeness were indirectly linked to fewer alcohol-related problems through more monitoring by mothers and fewer impulsive symptoms. Monitoring by an opposite-gender parent mediated the link between parenting styles (i.e., permissive, authoritative) on impulsiveness.

Systemic inflammatory mediators in post-traumatic complex regional pain syndrome (CRPS I) - longitudinal investigations and differences to control groups.

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Schinkel, Christian; Scherens, A; Köller, M; Roellecke, G; Muhr, G; Maier, C

2009-03-17

The Complex Regional Pain Syndrome I (CRPS I) is a disease that might affect an extremity after trauma or operation. The pathogenesis remains yet unclear. It has clinical signs of severe local inflammation as a result of an exaggerated inflammatory response but neurogenic dysregulation also contributes to it. Some studies investigated the role inflammatory mediators and cytokines; however, few longitudinal studies exist and control groups except healthy controls were not investigated yet. To get further insights into the role of systemic inflammatory mediators in CRPS I, we investigated a variety of pro-, anti-, or neuro-inflammatory mediators such as C-Reactive Protein (CRP), White Blood Cell Count (WBC), Interleukins 4, 6, 8, 10, 11, 12 (p70), Interferon gamma, Tumor-Necrosis-Factor alpha (TNF-a) and its soluble Receptors I/II, soluble Selectins (E,L,P), Substance-P (SP), and Calcitonin Gene-Related Peptide (CGRP) at different time points in venous blood from patients with acute (AC) and chronic (CC) CRPS I, patients with forearm fractures (FR), with neuralgia (NE), and from healthy volunteers (C). No significant changes for serum parameters investigated in CRPS compared to control groups were found except for CC/C (CGRP p = 0.007), FR/C (CGRP p = 0.048) and AC/CC (IL-12 p = 0.02; TNFRI/II p = 0.01; SP p = 0.049). High interindividual variations were observed. No intra- or interindividual correlation of parameters with clinical course (e.g. chronification) or outcome was detectable. Although clinically appearing as inflammation in acute stages, local rather than systemic inflammatory responses seem to be relevant in CRPS. Variable results from different studies might be explained by unpredictable intermittent release of mediators from local inflammatory processes into the blood combined with high interindividual variabilities. A clinically relevant difference to various control groups was not notable in this pilot study. Determination of systemic inflammatory

Systemic inflammatory mediators in post-traumatic Complex Regional Pain Syndrome (CRPS I - longitudinal investigations and differences to control groups

Directory of Open Access Journals (Sweden)

Schinkel Ch

2009-03-01

Full Text Available Abstract Objectives The Complex Regional Pain Syndrome I (CRPS I is a disease that might affect an extremity after trauma or operation. The pathogenesis remains yet unclear. It has clinical signs of severe local inflammation as a result of an exaggerated inflammatory response but neurogenic dysregulation also contributes to it. Some studies investigated the role inflammatory mediators and cytokines; however, few longitudinal studies exist and control groups except healthy controls were not investigated yet. Methods To get further insights into the role of systemic inflammatory mediators in CRPS I, we investigated a variety of pro-, anti-, or neuro-inflammatory mediators such as C-Reactive Protein (CRP, White Blood Cell Count (WBC, Interleukins 4, 6, 8, 10, 11, 12 (p70, Interferon gamma, Tumor-Necrosis-Factor alpha (TNF-α and its soluble Receptors I/II, soluble Selectins (E, L, P, Substance-P (SP, and Calcitonin Gene-Related Peptide (CGRP at different time points in venous blood from patients with acute (AC and chronic (CC CRPS I, patients with forearm fractures (FR, with neuralgia (NE, and from healthy volunteers (C. Results No significant changes for serum parameters investigated in CRPS compared to control groups were found except for CC/C (CGRP p = 0.007, FR/C (CGRP p = 0.048 and AC/CC (IL-12 p = 0.02; TNFRI/II p = 0.01; SP p = 0.049. High interindividual variations were observed. No intra-or interindividual correlation of parameters with clinical course (e.g. chronification or outcome was detectable. Conclusion Although clinically appearing as inflammation in acute stages, local rather than systemic inflammatory responses seem to be relevant in CRPS. Variable results from different studies might be explained by unpredictable intermittent release of mediators from local inflammatory processes into the blood combined with high interindividual variabilities. A clinically relevant difference to various control groups was not notable in this

Rice PLASTOCHRON genes regulate leaf maturation downstream of the gibberellin signal transduction pathway.

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Mimura, Manaki; Nagato, Yasuo; Itoh, Jun-Ichi

2012-05-01

Rice PLASTOCHRON 1 (PLA1) and PLA2 genes regulate leaf maturation and plastochron, and their loss-of-function mutants exhibit small organs and rapid leaf emergence. They encode a cytochrome P450 protein CYP78A11 and an RNA-binding protein, respectively. Their homologs in Arabidopsis and maize are also associated with plant development/organ size. Despite the importance of PLA genes in plant development, their molecular functions remain unknown. Here, we investigated how PLA1 and PLA2 genes are related to phytohormones. We found that gibberellin (GA) is the major phytohormone that promotes PLA1 and PLA2 expression. GA induced PLA1 and PLA2 expression, and conversely the GA-inhibitor uniconazole suppressed PLA1 and PLA2 expression. In pla1-4 and pla2-1 seedlings, expression levels of GA biosynthesis genes and the signal transduction gene were similar to those in wild-type seedlings. GA treatment slightly down-regulated the GA biosynthesis gene GA20ox2 and up-regulated the GA-catabolizing gene GA2ox4, whereas the GA biosynthesis inhibitor uniconazole up-regulated GA20ox2 and down-regulated GA2ox4 both in wild-type and pla mutants, suggesting that the GA feedback mechanism is not impaired in pla1 and pla2. To reveal how GA signal transduction affects the expression of PLA1 and PLA2, PLA expression in GA-signaling mutants was examined. In GA-insensitive mutant, gid1 and less-sensitive mutant, Slr1-d1, PLA1 and PLA2 expression was down-regulated. On the other hand, the expression levels of PLA1 and PLA2 were highly enhanced in a GA-constitutive-active mutant, slr1-1, causing ectopic overexpression. These results indicate that both PLA1 and PLA2 act downstream of the GA signal transduction pathway to regulate leaf development.

Identification of rice Os4BGlu13 as a β-glucosidase which hydrolyzes gibberellin A4 1-O-β-d-glucosyl ester, in addition to tuberonic acid glucoside and salicylic acid derivative glucosides.

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Hua, Yanling; Ekkhara, Watsamon; Sansenya, Sompong; Srisomsap, Chantragan; Roytrakul, Sittiruk; Saburi, Wataru; Takeda, Ryosuke; Matsuura, Hideyuki; Mori, Haruhide; Ketudat Cairns, James R

2015-10-01

Gibberellin 1-O-β-d-glucose ester hydrolysis activity has been detected in rice seedling extracts, but no enzyme responsible for this activity has ever been purified and identified. Therefore, gibberellin A4 glucosyl ester (GA4-GE) β-d-glucosidase activity was purified from ten-day rice seedling stems and leaves. The family 1 glycoside hydrolase Os4BGlu13 was identified in the final purification fraction. The Os4BGlu13 cDNA was amplified from rice seedlings and expressed as an N-terminal thioredoxin-tagged fusion protein in Escherichia coli. The purified recombinant Os4BGlu13 protein (rOs4BGlu13) had an optimum pH of 4.5, for hydrolysis of p-nitrophenyl β-d-glucopyranoside (pNPGlc), which was the best substrate identified, with a kcat/Km of 637 mM(-1) s(-1). rOs4BGlu13 hydrolyzed helicin best among natural glycosides tested (kcat/Km of 74.4 mM(-1) s(-1)). Os4BGlu13 was previously designated tuberonic acid glucoside (TAG) β-glucosidase (TAGG), and here the kcat/Km of rOsBGlu13 for TAG was 6.68 mM(-1) s(-1), while that for GA4-GE was 3.63 mM(-1) s(-1) and for salicylic acid glucoside (SAG) is 0.88 mM(-1) s(-1). rOs4BGlu13 also hydrolyzed oligosaccharides, with preference for short β-(1 → 3)-linked over β-(1 → 4)-linked glucooligosaccharides. The enzymatic data suggests that Os4BGlu13 may contribute to TAG, SAG, oligosaccharide and GA4-GE hydrolysis in the rice plant, although helicin or a similar compound may be its primary target. Copyright © 2015 Elsevier Inc. All rights reserved.

Compromised virus control and augmented perforin-mediated immunopathology in IFN-gamma-deficient mice infected with lymphocytic choriomeningitis virus

DEFF Research Database (Denmark)

Nansen, A; Jensen, Teis; Christensen, Jan Pravsgaard

1999-01-01

To define the role of IFN-gamma in the control of acute infection with a noncytopathogenic virus, mice with targeted defects of the genes encoding IFN-gamma, perforin, or both were infected i.v. with two strains of lymphocytic choriomeningitis virus differing markedly in their capacity to spread...... in wild-type mice. Our results reveal that IFN-gamma is pivotal to T cell-mediated control of a rapidly invasive stain, whereas it is less important in the acute elimination of a slowly invasive strain. Moreover, the majority of mice infected with the rapidly invasive strain succumb to a wasting syndrome...... mediated by CD8+ effector cells. The primary effector mechanism underlying this disease is perforin-dependent lysis, but other mechanisms are also involved. Wasting disease can be prevented if naive CD8+ cells from mice transgenic for an MHC class I-restricted lymphocytic choriomeningitis virus...

Control of Seed Germination and Plant Development by Carbon and Nitrogen Availability

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Daniel eOsuna

2015-11-01

Full Text Available Little is known about the molecular basis of the influence of external carbon/nitrogen (C/N ratio and other abiotic factors on phytohormones regulation during seed germination and plant developmental processes, and the identification of elements that participate in this response is essential to understand plant nutrient perception and signaling. Sugars (sucrose, glucose and nitrate not only act as nutrients but also as signaling molecules in plant development. A connection between changes in auxin transport and nitrate signal transduction has been reported in Arabidopsis thaliana through the NRT1.1, a nitrate sensor and transporter that also functions as a repressor of lateral root growth under low concentrations of nitrate by promoting auxin transport. Nitrate inhibits the elongation of lateral roots, but this effect is significantly reduced in abscisic acid (ABA-insensitive mutants, what suggests that ABA might mediate the inhibition of lateral root elongation by nitrate. Gibberellin (GA biosynthesis has been also related to nitrate level in seed germination and its requirement is determined by embryonic ABA. These mechanisms connect nutrients and hormones signaling during seed germination and plant development. Thus, the genetic identification of the molecular components involved in nutrients-dependent pathways would help to elucidate the potential crosstalk between nutrients, nitric oxide (NO and phytohormones (ABA, auxins and GAs in seed germination and plant development. In this review we focus on changes in C and N levels and how they control seed germination and plant developmental processes through the interaction with other plant growth regulators, such as phytohormones.

G-computation demonstration in causal mediation analysis

International Nuclear Information System (INIS)

Wang, Aolin; Arah, Onyebuchi A.

2015-01-01

Recent work has considerably advanced the definition, identification and estimation of controlled direct, and natural direct and indirect effects in causal mediation analysis. Despite the various estimation methods and statistical routines being developed, a unified approach for effect estimation under different effect decomposition scenarios is still needed for epidemiologic research. G-computation offers such unification and has been used for total effect and joint controlled direct effect estimation settings, involving different types of exposure and outcome variables. In this study, we demonstrate the utility of parametric g-computation in estimating various components of the total effect, including (1) natural direct and indirect effects, (2) standard and stochastic controlled direct effects, and (3) reference and mediated interaction effects, using Monte Carlo simulations in standard statistical software. For each study subject, we estimated their nested potential outcomes corresponding to the (mediated) effects of an intervention on the exposure wherein the mediator was allowed to attain the value it would have under a possible counterfactual exposure intervention, under a pre-specified distribution of the mediator independent of any causes, or under a fixed controlled value. A final regression of the potential outcome on the exposure intervention variable was used to compute point estimates and bootstrap was used to obtain confidence intervals. Through contrasting different potential outcomes, this analytical framework provides an intuitive way of estimating effects under the recently introduced 3- and 4-way effect decomposition. This framework can be extended to complex multivariable and longitudinal mediation settings

Does self-efficacy mediate functional change in older adults participating in an exercise program after hip fracture? A randomized controlled trial.

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Chang, Feng-Hang; Latham, Nancy K; Ni, Pengsheng; Jette, Alan M

2015-06-01

To examine whether self-efficacy mediated the effect of the Home-based Post-Hip Fracture Rehabilitation program on activity limitations in older adults after hip fracture and whether the mediating effect was different between sex and age groups. Randomized controlled trial. Community. Participants with hip fracture (N=232; mean age ± SD, 79±9.4y) were randomly assigned to intervention (n=120, 51.7%) and attention control (n=112, 48.3%) groups. The 6-month intervention, the Home-based Post-Hip Fracture Rehabilitation, is a functionally oriented, home-based exercise program. Data were collected at baseline, postintervention (6mo), and follow-up (9mo). Activity Measure for Post-Acute Care. The mediating effect of the Home-based Post-Hip Fracture Rehabilitation program on Basic Mobility function through self-efficacy for exercise was significant at 9 months (βindirect=.21). Similarly, the mediating effect of the intervention on Daily Activity function through self-efficacy for exercise was significant at 9 months (βindirect=.49). In subgroup analyses, the mediating effect was significant at 9 months in the younger group (age, ≤79y) in comparison to the older group and was significant in women in comparison to men. Self-efficacy may play a partial mediating role in the effect on some longer-term functional outcomes in the Home-based Post-Hip Fracture Rehabilitation intervention. The results suggest that program components that target self-efficacy should be incorporated in future hip fracture rehabilitation interventions. Age and sex of the targeted participants may also need to be considered when developing interventions. Copyright © 2015 American Congress of Rehabilitation Medicine. Published by Elsevier Inc. All rights reserved.

Effects of chilling and ABA on [3H]gibberellin A4 metabolism in somatic embryos of grape (Vitis vinifera L. x V. rupestris Scheele)

International Nuclear Information System (INIS)

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

1987-01-01

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

GSK3 controls axon growth via CLASP-mediated regulation of growth cone microtubules

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Hur, Eun-Mi; Saijilafu; Lee, Byoung Dae; Kim, Seong-Jin; Xu, Wen-Lin; Zhou, Feng-Quan

2011-01-01

Suppression of glycogen synthase kinase 3 (GSK3) activity in neurons yields pleiotropic outcomes, causing both axon growth promotion and inhibition. Previous studies have suggested that specific GSK3 substrates, such as adenomatous polyposis coli (APC) and collapsin response mediator protein 2 (CRMP2), support axon growth by regulating the stability of axonal microtubules (MTs), but the substrate(s) and mechanisms conveying axon growth inhibition remain elusive. Here we show that CLIP (cytoplasmic linker protein)-associated protein (CLASP), originally identified as a MT plus end-binding protein, displays both plus end-binding and lattice-binding activities in nerve growth cones, and reveal that the two MT-binding activities regulate axon growth in an opposing manner: The lattice-binding activity mediates axon growth inhibition induced by suppression of GSK3 activity via preventing MT protrusion into the growth cone periphery, whereas the plus end-binding property supports axon extension via stabilizing the growing ends of axonal MTs. We propose a model in which CLASP transduces GSK3 activity levels to differentially control axon growth by coordinating the stability and configuration of growth cone MTs. PMID:21937714

Locus of control, quality of life, anxiety, and depression among Malaysian breast cancer patients: The mediating role of uncertainty.

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Pahlevan Sharif, Saeed

2017-04-01

The main objective of this study was to investigate the mediating role of uncertainty in the relationship between locus of control with quality of life, anxiety, and depression. A descriptive and correlational survey was conducted in a private hospital in Kuala Lumpur, Malaysia. A convenience sample of 118 Malaysian breast cancer patients voluntarily participated in the study and responded to a set of questionnaires including: socio-demographic questionnaire, the short form of Locus of Control Scale, the Functional Assessment of Cancer Therapy-Breast (FACT-B), the Hospital Anxiety and Depression Scale (HADS), and the Short-Form Mishel Uncertainty in Illness Scale (SF-MUIS). The results revealed that breast cancer patients with higher internal locus of control and lower external locus of control experience a higher quality of life, lower anxiety, and lower depression. Also, uncertainty mediated the relationship between locus of control with quality of life and depression (quasi-significant). The findings indicated the need for early, targeted psychological interventions seeking to gradually shift cancer patients' locus of control from external to internal in order to improve their quality of life and reduce their depression and anxiety. Moreover, health care providers by providing relevant information to cancer patients, especially for externally oriented patients, can reduce their uncertainty which in turn would improve their quality of life. Copyright © 2017 Elsevier Ltd. All rights reserved.

Improved eating behaviours mediate weight gain prevention of young adults: moderation and mediation results of a randomised controlled trial of TXT2BFiT, mHealth program.

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Partridge, Stephanie R; McGeechan, Kevin; Bauman, Adrian; Phongsavan, Philayrath; Allman-Farinelli, Margaret

2016-04-02

Explanatory evaluation of interventions for prevention of weight gain is required beyond changes in weight, to determine for whom the intervention works and the underlying mechanisms of change. It was hypothesised that participant characteristics moderate intervention effect on weight change and improved eating and physical activity behaviours during the 3-month program mediate the relationship between intervention and weight. In our randomised controlled trial, young adults at risk of weight gain (n = 250) were assigned either to an intervention group that received a 3-month mHealth (TXT2BFiT) program with 6-month maintenance or to a control group. Data were collected via online self-report surveys. Hypothesised moderators and mediators of the intervention effect on weight were independently assessed in PROCESS macro models for 3 and 9-month weight change. Males (P = 0.01), mid-20s age group (P = 0.04), and higher income earners (P = 0.02) moderated intervention effects on weight change at 3-months and males only at 9-months (P = 0.02). Weight change at 3 (-1.12 kg) and 9-months (-1.38 kg) remained significant when 3-month nutrition and physical activity behaviours were specified as mediators (P <0.01 and P = 0.01 respectively). Indirect paths explained 39% (0.72/1.85 kg) and 40 % (0.92/2.3 kg) of total effect on weight change at 3 and 9-months respectively. Increased vegetable intake by intervention group at 3-months accounted for 19 and 17% and decreased sugar-sweetened beverages accounted for 8 and 13% of indirect weight change effects at 3 and 9-months respectively. TXT2BFiT was effective for both young men and women. Small sustained behavioural changes, including increased vegetable intake and decreased sugar-sweetened beverages consumption significantly mediated the intervention's effects on weight change. Improved eating behaviours and increased physical activity accounted for approximately 40% of the weight change. The trial is

Molecular cloning and characterization of a cDNA encoding the gibberellin biosynthetic enzyme ent-kaurene synthase B from pumpkin (Cucurbita maxima L.).

Science.gov (United States)

Yamaguchi, S; Saito, T; Abe, H; Yamane, H; Murofushi, N; Kamiya, Y

1996-08-01

The first committed step in the formation of diterpenoids leading to gibberellin (GA) biosynthesis is the conversion of geranylgeranyl diphosphate (GGDP) to ent-kaurene. ent-Kaurene synthase A (KSA) catalyzes the conversion of GGDP to copalyl diphosphate (CDP), which is subsequently converted to ent-kaurene by ent-kaurene synthase B (KSB). A full-length KSB cDNA was isolated from developing cotyledons in immature seeds of pumpkin (Cucurbita maxima L.). Degenerate oligonucleotide primers were designed from the amino acid sequences obtained from the purified protein to amplify a cDNA fragment, which was used for library screening. The isolated full-length cDNA was expressed in Escherichia coli as a fusion protein, which demonstrated the KSB activity to cyclize [3H]CDP to [3H]ent-kaurene. The KSB transcript was most abundant in growing tissues, but was detected in every organ in pumpkin seedlings. The deduced amino acid sequence shares significant homology with other terpene cyclases, including the conserved DDXXD motif, a putative divalent metal ion-diphosphate complex binding site. A putative transit peptide sequence that may target the translated product into the plastids is present in the N-terminal region.

Mediation Analysis with Multiple Mediators.

Science.gov (United States)

VanderWeele, T J; Vansteelandt, S

2014-01-01

Recent advances in the causal inference literature on mediation have extended traditional approaches to direct and indirect effects to settings that allow for interactions and non-linearities. In this paper, these approaches from causal inference are further extended to settings in which multiple mediators may be of interest. Two analytic approaches, one based on regression and one based on weighting are proposed to estimate the effect mediated through multiple mediators and the effects through other pathways. The approaches proposed here accommodate exposure-mediator interactions and, to a certain extent, mediator-mediator interactions as well. The methods handle binary or continuous mediators and binary, continuous or count outcomes. When the mediators affect one another, the strategy of trying to assess direct and indirect effects one mediator at a time will in general fail; the approach given in this paper can still be used. A characterization is moreover given as to when the sum of the mediated effects for multiple mediators considered separately will be equal to the mediated effect of all of the mediators considered jointly. The approach proposed in this paper is robust to unmeasured common causes of two or more mediators.

One-pot preparation of a mixed-mode organic-silica hybrid monolithic capillary column and its application in determination of endogenous gibberellins in plant tissues.

Science.gov (United States)

Zhang, Zheng; Hao, Yan-Hong; Ding, Jun; Xu, Sheng-Nan; Yuan, Bi-Feng; Feng, Yu-Qi

2015-10-16

A newly improved one-pot method, based on "thiol-ene" click chemistry and sol-gel approach in microemulsion system, was developed for the preparation of C8/PO(OH)2-silica hybrid monolithic capillary column. The prepared monolith possesses large specific surface area, narrow mesopore size distribution and high column efficiency. The monolithic column was demonstrated to have cation exchange/reversed-phase (CX/RP) mixed-mode retention for analytes on nano-liquid chromatography (nano-LC). On the basis of the developed nano-LC system with MS detector coupled to pipette tip solid phase extraction (PT-SPE) and derivatization process, we then realized simultaneous determination of 10 gibberellins (GAs) with low limits of detection (LODs, 0.003-0.025 ng/mL). Furthermore, 6 endogenous GAs in only 5mg rice leaves (fresh weight) were successfully detected and quantified. The developed PT-SPE-nano-LC-MS strategy may offer promising applications in the determination of low abundant bioactive molecules from complex matrix. Copyright © 2015 Elsevier B.V. All rights reserved.

Mediation Analysis: A Practitioner's Guide.

Science.gov (United States)

VanderWeele, Tyler J

2016-01-01

This article provides an overview of recent developments in mediation analysis, that is, analyses used to assess the relative magnitude of different pathways and mechanisms by which an exposure may affect an outcome. Traditional approaches to mediation in the biomedical and social sciences are described. Attention is given to the confounding assumptions required for a causal interpretation of direct and indirect effect estimates. Methods from the causal inference literature to conduct mediation in the presence of exposure-mediator interactions, binary outcomes, binary mediators, and case-control study designs are presented. Sensitivity analysis techniques for unmeasured confounding and measurement error are introduced. Discussion is given to extensions to time-to-event outcomes and multiple mediators. Further flexible modeling strategies arising from the precise counterfactual definitions of direct and indirect effects are also described. The focus throughout is on methodology that is easily implementable in practice across a broad range of potential applications.

Mycobacterium tuberculosis Controls Phagosomal Acidification by Targeting CISH-Mediated Signaling

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Christophe J. Queval

2017-09-01

Full Text Available Pathogens have evolved a range of mechanisms to counteract host defenses, notably to survive harsh acidic conditions in phagosomes. In the case of Mycobacterium tuberculosis, it has been shown that regulation of phagosome acidification could be achieved by interfering with the retention of the V-ATPase complexes at the vacuole. Here, we present evidence that M. tuberculosis resorts to yet another strategy to control phagosomal acidification, interfering with host suppressor of cytokine signaling (SOCS protein functions. More precisely, we show that infection of macrophages with M. tuberculosis leads to granulocyte-macrophage colony-stimulating factor (GM-CSF secretion, inducing STAT5-mediated expression of cytokine-inducible SH2-containing protein (CISH, which selectively targets the V-ATPase catalytic subunit A for ubiquitination and degradation by the proteasome. Consistently, we show that inhibition of CISH expression leads to reduced replication of M. tuberculosis in macrophages. Our findings further broaden the molecular understanding of mechanisms deployed by bacteria to survive.

Lowering Temperature is the Trigger for Glycogen Build-Up and Winter Fasting in Crucian Carp (Carassius carassius).

Science.gov (United States)

Varis, Joonas; Haverinen, Jaakko; Vornanen, Matti

2016-02-01

Seasonal changes in physiology of vertebrate animals are triggered by environmental cues including temperature, day-length and oxygen availability. Crucian carp (Carassius carassius) tolerate prolonged anoxia in winter by using several physiological adaptations that are seasonally activated. This study examines which environmental cues are required to trigger physiological adjustments for winter dormancy in crucian carp. To this end, crucian carp were exposed to changing environmental factors under laboratory conditions: effects of declining water temperature, shortening day-length and reduced oxygen availability, separately and in different combinations, were examined on glycogen content and enzyme activities involved in feeding (alkaline phosphatase, AP) and glycogen metabolism (glycogen synthase, GyS; glycogen phosphorylase, GP). Lowering temperature induced a fall in activity of AP and a rise in glycogen content and rate of glycogen synthesis. Relative mass of the liver, and glycogen concentration of liver, muscle and brain increased with lowering temperature. Similarly activity of GyS in muscle and expression of GyS transcripts in brain were up-regulated by lowering temperature. Shortened day-length and oxygen availability had practically no effects on measured variables. We conclude that lowering temperature is the main trigger in preparation for winter anoxia in crucian carp.

Minimal ancilla mediated quantum computation

International Nuclear Information System (INIS)

Proctor, Timothy J.; Kendon, Viv

2014-01-01

Schemes of universal quantum computation in which the interactions between the computational elements, in a computational register, are mediated by some ancillary system are of interest due to their relevance to the physical implementation of a quantum computer. Furthermore, reducing the level of control required over both the ancillary and register systems has the potential to simplify any experimental implementation. In this paper we consider how to minimise the control needed to implement universal quantum computation in an ancilla-mediated fashion. Considering computational schemes which require no measurements and hence evolve by unitary dynamics for the global system, we show that when employing an ancilla qubit there are certain fixed-time ancilla-register interactions which, along with ancilla initialisation in the computational basis, are universal for quantum computation with no additional control of either the ancilla or the register. We develop two distinct models based on locally inequivalent interactions and we then discuss the relationship between these unitary models and the measurement-based ancilla-mediated models known as ancilla-driven quantum computation. (orig.)

Mediator effect of statistical process control between Total Quality Management (TQM) and business performance in Malaysian Automotive Industry

Science.gov (United States)

Ahmad, M. F.; Rasi, R. Z.; Zakuan, N.; Hisyamudin, M. N. N.

2015-12-01

In today's highly competitive market, Total Quality Management (TQM) is vital management tool in ensuring a company can success in their business. In order to survive in the global market with intense competition amongst regions and enterprises, the adoption of tools and techniques are essential in improving business performance. There are consistent results between TQM and business performance. However, only few previous studies have examined the mediator effect namely statistical process control (SPC) between TQM and business performance. A mediator is a third variable that changes the association between an independent variable and an outcome variable. This study present research proposed a TQM performance model with mediator effect of SPC with structural equation modelling, which is a more comprehensive model for developing countries, specifically for Malaysia. A questionnaire was prepared and sent to 1500 companies from automotive industry and the related vendors in Malaysia, giving a 21.8 per cent rate. Attempts were made at findings significant impact of mediator between TQM practices and business performance showed that SPC is important tools and techniques in TQM implementation. The result concludes that SPC is partial correlation between and TQM and BP with indirect effect (IE) is 0.25 which can be categorised as high moderator effect.

High prevalence of sensitization to gibberellin-regulated protein (peamaclein) in fruit allergies with negative immunoglobulin E reactivity to Bet v 1 homologs and profilin: Clinical pattern, causative fruits and cofactor effect of gibberellin-regulated protein allergy.

Science.gov (United States)

Inomata, Naoko; Miyakawa, Mami; Aihara, Michiko

2017-07-01

Gibberellin-regulated protein (GRP) is a new allergen in peach allergy, with an amino acid sequence very well conserved through several botanical species. We investigated the allergenicity of GRP in fruit allergies other than peaches and identified the clinical characteristics of fruit allergy patients with GRP sensitization. One hundred consecutive Japanese patients with fruit allergies were enrolled in the present study. To identify the features of GRP sensitization, we selected patients with negative ImmunoCAP results for Bet v 1 homologs and profilin, which are marker allergens for pollen-food allergy syndrome (PFAS), or lipid transfer protein. These patients underwent specific immunoglobulin E measurements by enzyme-linked immunosorbent assay (ELISA) and skin prick tests (SPT) using purified nPru p 7. Twenty of 100 consecutive patients with fruit allergies had negative ImmunoCAP results for Bet v 1 homologs and profilin. Thirteen (65.0%) of the 20 patients had positive ELISA and/or SPT results using nPru p 7, whereas one of the 20 patients had positive ImmunoCAP results for Pru p 3. In 13 nPru p 7-sensitized patients, the causative foods were peaches (92.3%), apricots (61.5%), oranges (46.2%) and apples (30.8%). Ten patients (76.9%) had multiple causative fruits. Frequent symptoms included facial edema (92.3%) and laryngeal tightness (66.7%). In eight patients (61.5%), exercise or aspirin intake enhanced the allergic reaction onset as cofactors. The prevalence of GRP sensitization was high in Japanese fruit allergy patients except for PFAS patients. In conclusion, GRP-sensitized patients may have allergies to multiple fruits and may show peculiar characteristics such as facial swelling and cofactor dependence. © 2017 Japanese Dermatological Association.

Resistance Exercise and Inflammation in Breast Cancer Patients Undergoing Adjuvant Radiation Therapy: Mediation Analysis From a Randomized, Controlled Intervention Trial

Energy Technology Data Exchange (ETDEWEB)

Schmidt, Martina E., E-mail: m.schmidt@dkfz.de [Division of Preventive Oncology, National Center for Tumor Diseases and German Cancer Research Center, Heidelberg (Germany); Meynköhn, Anna; Habermann, Nina [Division of Preventive Oncology, National Center for Tumor Diseases and German Cancer Research Center, Heidelberg (Germany); Wiskemann, Joachim [Division of Medical Oncology, National Center for Tumor Diseases and University Hospital, Heidelberg (Germany); Oelmann, Jan; Hof, Holger; Wessels, Sabine [Department of Radiation Oncology, National Center for Tumor Diseases and University Hospital, Heidelberg (Germany); Klassen, Oliver [Division of Preventive Oncology, National Center for Tumor Diseases and German Cancer Research Center, Heidelberg (Germany); Debus, Jürgen; Potthoff, Karin [Department of Radiation Oncology, National Center for Tumor Diseases and University Hospital, Heidelberg (Germany); Steindorf, Karen; Ulrich, Cornelia M. [Division of Preventive Oncology, National Center for Tumor Diseases and German Cancer Research Center, Heidelberg (Germany)

2016-02-01

Purpose: To explore the mediating role of inflammatory parameters in the development of fatigue, pain, and potentially related depressive symptoms during radiation therapy for breast cancer and its mitigation by resistance exercise. Methods and Materials: Breast cancer patients scheduled for adjuvant radiation therapy were randomized to 12-week progressive resistance exercise training (EX) or a relaxation control group. Interleukin-6 (IL-6) and interleukin-1 receptor antagonist (IL-1ra) were measured in serum samples collected before, at the end, and 6 weeks after radiation therapy from 103 chemotherapy-naïve participants. Fatigue was assessed with the multidimensional Fatigue Assessment Questionnaire, pain with the European Organization for Research and Treatment of Cancer QLQ-C30, and depressive symptoms with the Center for Epidemiologic Studies Depression Scale. Analysis of covariance models, partial correlations, Freedman-Schatzkin tests, and R{sup 2} effect-size measures for mediation were calculated. Results: The analysis of covariance models revealed a significant intervention effect on IL-6 (P=.010) and the IL-6/IL-1ra ratio (P=.018), characterized by a marked increase during radiation therapy among controls, but no significant change in EX. Interleukin-1 receptor antagonist did not change significantly in either group (P=.88). Increased IL-6 and IL-6/IL-1ra levels at the end of radiation therapy were significantly associated with increased physical fatigue and pain 6 weeks after radiation. We observed significant partial mediation by IL-6 and IL-6/IL-1ra of the effect of resistance exercise on physical fatigue (Freedman-Schatzkin P=.023 and P<.001) and pain (both P<.001). Hereby IL-6 and IL-6/IL-1ra mediated between 15% and 24% of the variance of physical fatigue and pain explained by the intervention. Conclusions: This randomized, controlled trial showed a significantly increased proinflammatory cytokine level after adjuvant radiation therapy in breast

Resistance Exercise and Inflammation in Breast Cancer Patients Undergoing Adjuvant Radiation Therapy: Mediation Analysis From a Randomized, Controlled Intervention Trial

International Nuclear Information System (INIS)

Schmidt, Martina E.; Meynköhn, Anna; Habermann, Nina; Wiskemann, Joachim; Oelmann, Jan; Hof, Holger; Wessels, Sabine; Klassen, Oliver; Debus, Jürgen; Potthoff, Karin; Steindorf, Karen; Ulrich, Cornelia M.

2016-01-01

Purpose: To explore the mediating role of inflammatory parameters in the development of fatigue, pain, and potentially related depressive symptoms during radiation therapy for breast cancer and its mitigation by resistance exercise. Methods and Materials: Breast cancer patients scheduled for adjuvant radiation therapy were randomized to 12-week progressive resistance exercise training (EX) or a relaxation control group. Interleukin-6 (IL-6) and interleukin-1 receptor antagonist (IL-1ra) were measured in serum samples collected before, at the end, and 6 weeks after radiation therapy from 103 chemotherapy-naïve participants. Fatigue was assessed with the multidimensional Fatigue Assessment Questionnaire, pain with the European Organization for Research and Treatment of Cancer QLQ-C30, and depressive symptoms with the Center for Epidemiologic Studies Depression Scale. Analysis of covariance models, partial correlations, Freedman-Schatzkin tests, and R"2 effect-size measures for mediation were calculated. Results: The analysis of covariance models revealed a significant intervention effect on IL-6 (P=.010) and the IL-6/IL-1ra ratio (P=.018), characterized by a marked increase during radiation therapy among controls, but no significant change in EX. Interleukin-1 receptor antagonist did not change significantly in either group (P=.88). Increased IL-6 and IL-6/IL-1ra levels at the end of radiation therapy were significantly associated with increased physical fatigue and pain 6 weeks after radiation. We observed significant partial mediation by IL-6 and IL-6/IL-1ra of the effect of resistance exercise on physical fatigue (Freedman-Schatzkin P=.023 and P<.001) and pain (both P<.001). Hereby IL-6 and IL-6/IL-1ra mediated between 15% and 24% of the variance of physical fatigue and pain explained by the intervention. Conclusions: This randomized, controlled trial showed a significantly increased proinflammatory cytokine level after adjuvant radiation therapy in breast

The Mediating Effect of Self-Control on Parenting and Delinquency: A Gendered Approach With a Multinational Sample.

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Muftić, Lisa R; Updegrove, Alexander H

2017-08-01

This study aims to clarify the relationships between parenting techniques, low self-control, and juvenile delinquency in Gottfredson and Hirschi's general theory of crime while controlling for alternative explanations of delinquency. We relied on a sample of 35,511 adolescent students from 31 countries from the International Self-Report Delinquency 2 Study. Results indicate that parenting exhibits a direct effect on adolescents' violence perpetration and property offending, and that while self-control weakens the strength of this relationship, it fails to fully mediate it. Males reported lower levels of self-control, exposure to poorer parenting techniques, and higher rates of violence perpetration and property offending. The relationship between parenting, self-control, and juvenile delinquency was similar for females and males. These results provide evidence that parenting has important implications for adolescents' involvement in delinquency above and beyond its influence on their level of self-control.

Novel Strategy to Control Transgene Expression Mediated by a Sendai Virus-Based Vector Using a Nonstructural C Protein and Endogenous MicroRNAs.

Directory of Open Access Journals (Sweden)

Masayuki Sano

Full Text Available Tissue-specific control of gene expression is an invaluable tool for studying various biological processes and medical applications. Efficient regulatory systems have been utilized to control transgene expression in various types of DNA viral or integrating viral vectors. However, existing regulatory systems are difficult to transfer into negative-strand RNA virus vector platforms because of significant differences in their transcriptional machineries. In this study, we developed a novel strategy for regulating transgene expression mediated by a cytoplasmic RNA vector based on a replication-defective and persistent Sendai virus (SeVdp. Because of the capacity of Sendai virus (SeV nonstructural C proteins to specifically inhibit viral RNA synthesis, overexpression of C protein significantly reduced transgene expression mediated by SeVdp vectors. We found that SeV C overexpression concomitantly reduced SeVdp mRNA levels and genomic RNA synthesis. To control C expression, target sequences for an endogenous microRNA were incorporated into the 3' untranslated region of the C genes. Incorporation of target sequences for miR-21 into the SeVdp vector restored transgene expression in HeLa cells by decreasing C expression. Furthermore, the SeVdp vector containing target sequences for let-7a enabled cell-specific control of transgene expression in human fibroblasts and induced pluripotent stem cells. Our findings demonstrate that SeV C can be used as an effective regulator for controlling transgene expression. This strategy will contribute to efficient and less toxic SeVdp-mediated gene transfer in various biological applications.

ELONGATED UPPERMOST INTERNODE Encodes a Cytochrome P450 Monooxygenase That Epoxidizes Gibberellins in a Novel Deactivation Reaction in RiceW⃞

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Zhu, Yongyou; Nomura, Takahito; Xu, Yonghan; Zhang, Yingying; Peng, Yu; Mao, Bizeng; Hanada, Atsushi; Zhou, Haicheng; Wang, Renxiao; Li, Peijin; Zhu, Xudong; Mander, Lewis N.; Kamiya, Yuji; Yamaguchi, Shinjiro; He, Zuhua

2006-01-01

The recessive tall rice (Oryza sativa) mutant elongated uppermost internode (eui) is morphologically normal until its final internode elongates drastically at the heading stage. The stage-specific developmental effect of the eui mutation has been used in the breeding of hybrid rice to improve the performance of heading in male sterile cultivars. We found that the eui mutant accumulated exceptionally large amounts of biologically active gibberellins (GAs) in the uppermost internode. Map-based cloning revealed that the Eui gene encodes a previously uncharacterized cytochrome P450 monooxygenase, CYP714D1. Using heterologous expression in yeast, we found that EUI catalyzed 16α,17-epoxidation of non-13-hydroxylated GAs. Consistent with the tall and dwarfed phenotypes of the eui mutant and Eui-overexpressing transgenic plants, respectively, 16α,17-epoxidation reduced the biological activity of GA4 in rice, demonstrating that EUI functions as a GA-deactivating enzyme. Expression of Eui appeared tightly regulated during plant development, in agreement with the stage-specific eui phenotypes. These results indicate the existence of an unrecognized pathway for GA deactivation by EUI during the growth of wild-type internodes. The identification of Eui as a GA catabolism gene provides additional evidence that the GA metabolism pathway is a useful target for increasing the agronomic value of crops. PMID:16399803

Mediators of the association between narcissism and compulsive buying: the roles of materialism and impulse control.

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Rose, Paul

2007-12-01

Building upon past research about the guiding values and self-regulation difficulties of people with narcissistic personalities, this study tested a model of the association between narcissism and compulsive consumption. In data obtained from a sample of undergraduate consumers (N=238) with varying degrees of spending problems, positive associations emerged between narcissism, materialism, and compulsive buying. Impulse control was negatively correlated with each of these variables. Mediation tests revealed that both impulse control and materialism accounted for significant portions of the shared variance between narcissism and compulsive consumption. These findings highlight the importance of both personal values and impulse control as correlates of addictive buying. They also add to growing evidence that people who are relatively narcissistic are poor self-regulators who may be at risk of developing a variety of addictive behaviors.

Characteristics of the home food environment that mediate immediate and sustained increases in child fruit and vegetable consumption: mediation analysis from the Healthy Habits cluster randomised controlled trial.

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Wyse, Rebecca; Wolfenden, Luke; Bisquera, Alessandra

2015-09-17

The home food environment can influence the development of dietary behaviours in children, and interventions that modify characteristics of the home food environment have been shown to increase children's fruit and vegetable consumption. However to date, interventions to increase children's fruit and vegetable consumption have generally produced only modest effects. Mediation analysis can help in the design of more efficient and effective interventions by identifying the mechanisms through which interventions have an effect. This study aimed to identify characteristics of the home food environment that mediated immediate and sustained increases in children's fruit and vegetable consumption following the 4-week Healthy Habits telephone-based parent intervention. Analysis was conducted using 2-month (immediate) and 12-month (sustained) follow-up data from a cluster randomised control trial of a home food environment intervention to increase the fruit and vegetable consumption of preschool children. Using recursive path analysis, a series of mediation models were created to investigate the direct and indirect effects of immediate and sustained changes to characteristics of the home food environment (fruit and vegetable availability, accessibility, parent intake, parent providing behaviour, role-modelling, mealtime eating practices, child feeding strategies, and pressure to eat), on the change in children's fruit and vegetable consumption. Of the 394 participants in the randomised trial, 357 and 329 completed the 2- and 12-month follow-up respectively. The final mediation model suggests that the effect of the intervention on the children's fruit and vegetable consumption was mediated by parent fruit and vegetable intake and parent provision of these foods at both 2- and 12-month follow-up. Analysis of data from the Healthy Habits trial suggests that two environmental variables (parental intake and parent providing) mediate the immediate and sustained effect of the

RNA- and protein-mediated control of Listeria monocytogenes virulence gene expression

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Lebreton, Alice; Cossart, Pascale

2017-01-01

ABSTRACT The model opportunistic pathogen Listeria monocytogenes has been the object of extensive research, aiming at understanding its ability to colonize diverse environmental niches and animal hosts. Bacterial transcriptomes in various conditions reflect this efficient adaptability. We review here our current knowledge of the mechanisms allowing L. monocytogenes to respond to environmental changes and trigger pathogenicity, with a special focus on RNA-mediated control of gene expression. We highlight how these studies have brought novel concepts in prokaryotic gene regulation, such as the ‘excludon’ where the 5′-UTR of a messenger also acts as an antisense regulator of an operon transcribed in opposite orientation, or the notion that riboswitches can regulate non-coding RNAs to integrate complex metabolic stimuli into regulatory networks. Overall, the Listeria model exemplifies that fine RNA tuners act together with master regulatory proteins to orchestrate appropriate transcriptional programmes. PMID:27217337

Parent Mediation Empowers Sibling Conflict Resolution

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Ross, Hildy S.; Lazinski, Marysia J.

2014-01-01

Research Findings: For the current study, formal mediation procedures were adapted for families and parents were trained and asked to mediate their children's disputes; control group parents intervened as they normally would. Conflict negotiations with parents and their children (ages 3½-11 years) occurring 3 and 7 weeks following training, and…

A Mediation Analysis of Mothers' Dietary Intake: The Entre Familia: Reflejos de Salud Randomized Controlled Trial.

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Horton, Lucy A; Ayala, Guadalupe X; Slymen, Donald J; Ibarra, Leticia; Hernandez, Erika; Parada, Humberto; Rock, Cheryl L; Arredondo, Elva M; Elder, John P

2017-12-01

Examine intervention effects among mothers involved in a healthy eating randomized controlled trial. Furthermore, examine the mediating roles of individual and familial influences on observed outcomes. Between 2009 and 2011, 361 families were recruited; half were assigned to an 11-session community health worker-delivered family-based intervention targeting Spanish-speaking Latino families in Imperial County, California. The intervention was delivered over a 4-month period. Home visits and telephone calls were delivered approximately weekly, with tapering near the end of the intervention to promote independence from the promotora. In this article, mothers' self-reported dietary intake was the primary outcome. Evaluation measures were taken at baseline, 4 months, and 10 months. Daily servings of fruits were higher among intervention versus control mothers (mean = 1.86 vs. mean = 1.47; effect size [ES] = 0.22) at 10 months post-baseline. Mothers in the intervention versus control condition also reported consuming a lower percent energy from fat (mean = 30.0% vs. 31.0%; ES = 0.30) and a higher diet quality (mean = 2.93 vs. mean = 2.67; ES = 0.29). Mediators of improvements were behavioral strategies to increase fiber and lower fat intake, family support for vegetable purchasing, and decreased unhealthy eating behaviors and perceived family barriers to healthy eating. Family-based behavioral interventions are effective for changing the skills and family system needed to improve diet among Latina mothers. Health care providers and other practitioners are encouraged to target skill development and fostering a socially supportive environment.

Mycobacterium tuberculosis Controls Phagosomal Acidification by Targeting CISH-Mediated Signaling.

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Queval, Christophe J; Song, Ok-Ryul; Carralot, Jean-Philippe; Saliou, Jean-Michel; Bongiovanni, Antonino; Deloison, Gaspard; Deboosère, Nathalie; Jouny, Samuel; Iantomasi, Raffaella; Delorme, Vincent; Debrie, Anne-Sophie; Park, Sei-Jin; Gouveia, Joana Costa; Tomavo, Stanislas; Brosch, Roland; Yoshimura, Akihiko; Yeramian, Edouard; Brodin, Priscille

2017-09-26

Pathogens have evolved a range of mechanisms to counteract host defenses, notably to survive harsh acidic conditions in phagosomes. In the case of Mycobacterium tuberculosis, it has been shown that regulation of phagosome acidification could be achieved by interfering with the retention of the V-ATPase complexes at the vacuole. Here, we present evidence that M. tuberculosis resorts to yet another strategy to control phagosomal acidification, interfering with host suppressor of cytokine signaling (SOCS) protein functions. More precisely, we show that infection of macrophages with M. tuberculosis leads to granulocyte-macrophage colony-stimulating factor (GM-CSF) secretion, inducing STAT5-mediated expression of cytokine-inducible SH2-containing protein (CISH), which selectively targets the V-ATPase catalytic subunit A for ubiquitination and degradation by the proteasome. Consistently, we show that inhibition of CISH expression leads to reduced replication of M. tuberculosis in macrophages. Our findings further broaden the molecular understanding of mechanisms deployed by bacteria to survive. Copyright © 2017 The Authors. Published by Elsevier Inc. All rights reserved.

Diabetes-specific emotional distress mediates the association between depressive symptoms and glycaemic control in Type 1 and Type 2 diabetes.

NARCIS (Netherlands)

Bastelaar, K.M. van; Pouwer, F.; Geelhoed-Duijvestijn, P.H.; Tack, C.J.J.; Bazelmans, E.; Beekman, A.T.; Heine, R.J.; Snoek, F.J.

2010-01-01

OBJECTIVES: To investigate whether diabetes-specific emotional distress mediates the relationship between depression and glycaemic control in patients with Type 1 and Type 2 diabetes. RESEARCH DESIGN AND METHODS: Data were derived from the baseline assessment of a depression in diabetes screening

Effect of sports participation on Internet addiction mediated by self-control: A case of Korean adolescents

Directory of Open Access Journals (Sweden)

Jae-Ahm Park

2016-09-01

SEM indicated a significant effect of sports participation on Internet addiction mediated by self-control. The results suggest the effectiveness of and need for sport and physical activity in Internet addiction treatment programs and for other addictions as well. Moreover, sports participation has a wider variety of psychological and physical benefits unlike intervention strategies or pharmacological treatments. Thus, the adoption of sports needs to be broadened from physical development to treating diverse psychological problems among adolescents.

The Relationship Between Poor Quality of Life and Desire to Hasten Death: A Multiple Mediation Model Examining the Contributions of Depression, Demoralization, Loss of Control, and Low Self-worth.

Science.gov (United States)

Robinson, Sophie; Kissane, David W; Brooker, Joanne; Hempton, Courtney; Burney, Susan

2017-02-01

The risk of suicide is elevated in palliative care patients compared with the general population. Various psychological factors, including depression, demoralization, loss of control, and low self-worth, have been associated with a desire to hasten death. The aim of this study was to investigate whether depression, demoralization, loss of control, and low self-worth mediated the relationship between global quality of life and desire to hasten death. A sample of 162 palliative care patients completed measures of global quality of life, depression, demoralization, perceived control, self-worth, and desire to hasten death. A multiple mediation model with bootstrapping sampling tested the total (combined) indirect effect and individual indirect effects of depression, the two subscales of demoralization (Meaning and Purpose, and Distress and Coping Ability), perceived control, and self-worth. Depressive symptoms, loss of meaning and purpose, loss of control, and low self-worth mediated the direct effect of global quality of life on desire to hasten death. The Distress and Coping Ability component of demoralization was not a significant mediator. Depression, loss of meaning and purpose, loss of control, and low self-worth are strong clinical markers for desire to hasten death. Targeting these symptoms through existentially oriented therapies, such as meaning-centered therapy, may ameliorate suicidal thinking. Copyright © 2016 American Academy of Hospice and Palliative Medicine. Published by Elsevier Inc. All rights reserved.

The effects of redox controls mediated by glutathione peroxidases on root architecture in Arabidopsis thaliana.

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Passaia, Gisele; Queval, Guillaume; Bai, Juan; Margis-Pinheiro, Marcia; Foyer, Christine H

2014-03-01

Glutathione peroxidases (GPXs) fulfil important functions in oxidative signalling and protect against the adverse effects of excessive oxidation. However, there has been no systematic characterization of the functions of the different GPX isoforms in plants. The roles of the different members of the Arabidopsis thaliana GPX gene (AtGPX) family were therefore investigated using gpx1, gpx2, gpx3, gpx4, gpx6, gpx7, and gpx8 T-DNA insertion mutant lines. The shoot phenotypes were largely similar in all genotypes, with small differences from the wild type observed only in the gpx2, gpx3, gpx7, and gpx8 mutants. In contrast, all the mutants showed altered root phenotypes compared with the wild type. The gpx1, gpx4, gpx6, gpx7, and gpx8 mutants had a significantly greater lateral root density (LRD) than the wild type. Conversely, the gpx2 and gpx3 mutants had significantly lower LRD values than the wild type. Auxin increased the LRD in all genotypes, but the effect of auxin was significantly greater in the gpx1, gpx4, and gpx7 mutants than in the wild type. The application of auxin increased GPX4 and GPX7 transcripts, but not GPX1 mRNAs in the roots of wild-type plants. The synthetic strigolactone GR24 and abscisic acid (ABA) decreased LRD to a similar extent in all genotypes, except gpx6, which showed increased sensitivity to ABA. These data not only demonstrate the importance of redox controls mediated by AtGPXs in the control of root architecture but they also show that the plastid-localized GPX1 and GPX7 isoforms are required for the hormone-mediated control of lateral root development.

Mediating role of activity level in the depressive realism effect.

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Blanco, Fernando; Matute, Helena; A Vadillo, Miguel

2012-01-01

Several classic studies have concluded that the accuracy of identifying uncontrollable situations depends heavily on depressive mood. Nondepressed participants tend to exhibit an optimistic illusion of control, whereas depressed participants tend to better detect a lack of control. Recently, we suggested that the different activity levels (measured as the probability of responding during a contingency learning task) exhibited by depressed and nondepressed individuals is partly responsible for this effect. The two studies presented in this paper provide further support for this mediational hypothesis, in which mood is the distal cause of the illusion of control operating through activity level, the proximal cause. In Study 1, the probability of responding, P(R), was found to be a mediator variable between the depressive symptoms and the judgments of control. In Study 2, we intervened directly on the mediator variable: The P(R) for both depressed and nondepressed participants was manipulated through instructions. Our results confirm that P(R) manipulation produced differences in the participants' perceptions of uncontrollability. Importantly, the intervention on the mediator variable cancelled the effect of the distal cause; the participants' judgments of control were no longer mood dependent when the P(R) was manipulated. This result supports the hypothesis that the so-called depressive realism effect is actually mediated by the probability of responding.

Identification of highly effective target genes for RNAi-mediated control of emerald ash borer, Agrilus planipennis.

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Rodrigues, Thais B; Duan, Jian J; Palli, Subba R; Rieske, Lynne K

2018-03-22

Recent study has shown that RNA interference (RNAi) is efficient in emerald ash borer (EAB), Agrilus planipennis, and that ingestion of double-stranded RNA (dsRNA) targeting specific genes causes gene silencing and mortality in neonates. Here, we report on the identification of highly effective target genes for RNAi-mediated control of EAB. We screened 13 candidate genes in neonate larvae and selected the most effective target genes for further investigation, including their effect on EAB adults and on a non-target organism, Tribolium castaneum. The two most efficient target genes selected, hsp (heat shock 70-kDa protein cognate 3) and shi (shibire), caused up to 90% mortality of larvae and adults. In EAB eggs, larvae, and adults, the hsp is expressed at higher levels when compared to that of shi. Ingestion of dsHSP and dsSHI caused mortality in both neonate larvae and adults. Administration of a mixture of both dsRNAs worked better than either dsRNA by itself. In contrast, injection of EAB.dsHSP and EAB.dsSHI did not cause mortality in T. castaneum. Thus, the two genes identified cause high mortality in the EAB with no apparent phenotype effects in a non-target organism, the red flour beetle, and could be used in RNAi-mediated control of this invasive pest.

Parent-Mediated Intervention for One-Year-Olds Screened as At-Risk for Autism Spectrum Disorder: A Randomized Controlled Trial

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Watson, Linda R.; Crais, Elizabeth R.; Baranek, Grace T.; Turner-Brown, Lauren; Sideris, John; Wakeford, Linn; Kinard, Jessica; Reznick, J. Steven; Martin, Katrina L.; Nowell, Sallie W.

2017-01-01

Theoretically, interventions initiated with at-risk infants prior to the point in time a definitive autism spectrum disorder (ASD) diagnosis can be made will improve outcomes. Pursuing this idea, we tested the efficacy of a parent-mediated early intervention called Adapted Responsive Teaching (ART) via a randomized controlled trial with 87…

Increased skills usage statistically mediates symptom reduction in self-guided internet-delivered cognitive-behavioural therapy for depression and anxiety: a randomised controlled trial.

Science.gov (United States)

Terides, Matthew D; Dear, Blake F; Fogliati, Vincent J; Gandy, Milena; Karin, Eyal; Jones, Michael P; Titov, Nickolai

2018-01-01

Cognitive-behavioural therapy (CBT) is an effective treatment for clinical and subclinical symptoms of depression and general anxiety, and increases life satisfaction. Patients' usage of CBT skills is a core aspect of treatment but there is insufficient empirical evidence suggesting that skills usage behaviours are a mechanism of clinical change. This study investigated if an internet-delivered CBT (iCBT) intervention increased the frequency of CBT skills usage behaviours and if this statistically mediated reductions in symptoms and increased life satisfaction. A two-group randomised controlled trial was conducted comparing internet-delivered CBT (n = 65) with a waitlist control group (n = 75). Participants were individuals experiencing clinically significant symptoms of depression or general anxiety. Mixed-linear models analyses revealed that the treatment group reported a significantly higher frequency of skills usage, lower symptoms, and higher life satisfaction by the end of treatment compared with the control group. Results from bootstrapping mediation analyses revealed that the increased skills usage behaviours statistically mediated symptom reductions and increased life satisfaction. Although skills usage and symptom outcomes were assessed concurrently, these findings support the notion that iCBT increases the frequency of skills usage behaviours and suggest that this may be an important mechanism of change.

Mediating effects of resistance training skill competency on health-related fitness and physical activity: the ATLAS cluster randomised controlled trial.

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Smith, Jordan J; Morgan, Philip J; Plotnikoff, Ronald C; Stodden, David F; Lubans, David R

2016-01-01

The purpose of this study was to examine the mediating effect of resistance training skill competency on percentage of body fat, muscular fitness and physical activity among a sample of adolescent boys participating in a school-based obesity prevention intervention. Participants were 361 adolescent boys taking part in the Active Teen Leaders Avoiding Screen-time (ATLAS) cluster randomised controlled trial: a school-based program targeting the health behaviours of economically disadvantaged adolescent males considered "at-risk" of obesity. Body fat percentage (bioelectrical impedance), muscular fitness (hand grip dynamometry and push-ups), physical activity (accelerometry) and resistance training skill competency were assessed at baseline and post-intervention (i.e., 8 months). Three separate multi-level mediation models were analysed to investigate the potential mediating effects of resistance training skill competency on each of the study outcomes using a product-of-coefficients test. Analyses followed the intention-to-treat principle. The intervention had a significant impact on the resistance training skill competency of the boys, and improvements in skill competency significantly mediated the effect of the intervention on percentage of body fat and the combined muscular fitness score. No significant mediated effects were found for physical activity. Improving resistance training skill competency may be an effective strategy for achieving improvements in body composition and muscular fitness in adolescent boys.

Training parents to mediate sibling disputes affects children's negotiation and conflict understanding.

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Smith, Julie; Ross, Hildy

2007-01-01

The effects of training parents to use formal mediation procedures in sibling disputes were examined in 48 families with 5- to 10-years-old children, randomly assigned to mediation and control conditions. Children whose parents were trained in mediation were compared with those whose parents intervened normally. Parents reported that children used more constructive conflict resolution strategies, compromised more often, and controlled the outcomes of conflicts more often in mediation families than in control families. Observations indicated less negativity in children's independent negotiations of recurrent conflicts, better understanding of the role of interpretation in assessing blame, and better knowledge of their siblings' perspectives in the mediation group. Thus, both social and social-cognitive gains resulted from experience with constructive conflict resolution.

Self-Efficacy and Social Support Mediate the Relationship between Internal Health Locus of Control and Health Behaviors in College Students

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Marr, Joni; Wilcox, Sara

2015-01-01

Background: Internal health locus of control has been associated with positive health outcomes and behaviors. Understanding the mechanisms of this relationship are key to designing and implementing effective health behavior intervention programs. Purpose: The purpose was to examine whether self-efficacy and social support mediate the relationship…

Ombuds’ corner: Consider mediation - some rules

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Vincent Vuillemin

2013-01-01

Mediation is a structured process in which an external party, called a mediator, helps participants generate and evaluate options that would allow them to reach a mutual agreement. It is an informal and confidential process.   The mediator does not have the power to impose an agreement on the parties, who should find it by themselves. However, the mediator controls the process. He arranges the meetings in agreement with the parties, and coordinates the details (concerning the speaking times, for example) and ensures that the parties respect of the rules which have been agreed on. He also favours advancing of the process towards a solution. The mediation process is centred on the search for a solution and a mutual agreement. In such a process, the mediator takes a neutral and impartial position, and does not advocate for a single party. He favours good communication between the parties, and will ensure that mutual respect is maintained and that the correct language is used during the discussi...

Controls of growth phenology vary in seedlings of three, co-occurring ecologically distinct northern conifers.

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Green, D Scott

2007-08-01

The objective of this study was to investigate the effects of temperature and seed-source elevation on height-growth phenology of three co-occurring and ecologically distinct northern conifers (Pinus contorta Dougl. ex Loud. var. latifolia (lodgepole pine), Picea glauca (Moench) Voss x Picea engelmannii Parry ex Engelm. (interior spruce) and Abies lasiocarpa (Hook.) Nutt. (subalpine fir)). Seed from populations of the three indigenous and co-occurring species was collected across an elevational transect on the southwestern slope of McBride Peak, near Prince George, BC. Collection sites were at elevations of 750 to 1850 m, the latter being close to the tree line. In 2003, seeds were germinated and seedlings raised under favorable growing conditions in a temperature-controlled glasshouse. In 2004, seedlings of each population were grown in natural daylengths at a location within 50 km of the seed collection site both in a temperature-controlled glasshouse and at a nearby field site, and height growth was recorded twice a week throughout the growing season. Species differed in both the date and the accumulated heat sum above 5 degrees C for the initiation and cessation of shoot extension. Growth durations (which integrate growth initiation and growth cessation) were more similar among species in the field than in the glasshouse. This suggests that different mechanisms of phenological control among co-occurring species can result in adaptive "equivalence" under a particular set of climatic conditions.

Depression and pain: testing of serial multiple mediators.

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Wongpakaran, Tinakon; Wongpakaran, Nahathai; Tanchakvaranont, Sitthinant; Bookkamana, Putipong; Pinyopornpanish, Manee; Wannarit, Kamonporn; Satthapisit, Sirina; Nakawiro, Daochompu; Hiranyatheb, Thanita; Thongpibul, Kulvadee

2016-01-01

Despite the fact that pain is related to depression, few studies have been conducted to investigate the variables that mediate between the two conditions. In this study, the authors explored the following mediators: cognitive function, self-sacrificing interpersonal problems, and perception of stress, and the effects they had on pain symptoms among patients with depressive disorders. An analysis was performed on the data of 346 participants with unipolar depressive disorders. The 17-item Hamilton Depression Rating Scale, Mini-Mental State Examination, the pain subscale of the health-related quality of life (SF-36), the self-sacrificing subscale of the Inventory of Interpersonal Problems, and the Perceived Stress Scale were used. Parallel multiple mediator and serial multiple mediator models were used. An alternative model regarding the effect of self-sacrificing on pain was also proposed. Perceived stress, self-sacrificing interpersonal style, and cognitive function were found to significantly mediate the relationship between depression and pain, while controlling for demographic variables. The total effect of depression on pain was significant. This model, with an additional three mediators, accounted for 15% of the explained variance in pain compared to 9% without mediators. For the alternative model, after controlling for the mediators, a nonsignificant total direct effect level of self-sacrificing was found, suggesting that the effect of self-sacrificing on pain was based only on an indirect effect and that perceived stress was found to be the strongest mediator. Serial mediation may help us to see how depression and pain are linked and what the fundamental mediators are in the chain. No significant, indirect effect of self-sacrificing on pain was observed, if perceived stress was not part of the depression and/or cognitive function mediational chain. The results shown here have implications for future research, both in terms of testing the model and in

Intrinsic religiousness and well-being among cancer patients: the mediating role of control-related religious coping and self-efficacy for coping with cancer.

Science.gov (United States)

Pérez, John E; Rex Smith, Amy

2015-04-01

We examined the relationship between intrinsic religiousness and well-being, with control-related religious coping and self-efficacy for coping with cancer as potential mediators of this relationship among cancer patients. In a cross-sectional design, 179 ambulatory cancer patients completed measures of intrinsic religiousness, religious coping, self-efficacy for coping with cancer, well-being, and demographic variables. Type of cancer, stage of cancer, and time since diagnosis were collected from electronic medical charts. In a path model, the positive association between intrinsic religiousness and three types of well-being--physical, functional, and social-was fully mediated by active religious surrender and self-efficacy for coping with cancer. In addition, the negative association between passive religious deferral and all four types of well-being--physical, functional, social, and emotional--was fully mediated by self-efficacy for coping with cancer. Finally, there was a negative direct association between pleading for God's direct intercession and emotional well-being. These findings suggest pathways by which intrinsic religiousness and control-related religious coping are linked to various dimensions of well-being among cancer patients.

Biologically mediated dissolution of volcanic glass in seawater

NARCIS (Netherlands)

Staudigel, H; Yayanos, A; Chastain, R; Davies, G.T.; Verdurmen, E.A Th; Schiffmann, P; Bourcier, R; de Baar, H.J.W.

1998-01-01

We studied the effects of biological mediation on the dissolution of basaltic glass in seawater. Experiments with typical seawater microbial populations were contrasted with a sterile control, and reactions were monitored chemically and isotopically. Biologically mediated experiments produce twice

The Mediator co-activator complex regulates Ty1 retromobility by controlling the balance between Ty1i and Ty1 promoters.

Science.gov (United States)

Salinero, Alicia C; Knoll, Elisabeth R; Zhu, Z Iris; Landsman, David; Curcio, M Joan; Morse, Randall H

2018-02-01

The Ty1 retrotransposons present in the genome of Saccharomyces cerevisiae belong to the large class of mobile genetic elements that replicate via an RNA intermediary and constitute a significant portion of most eukaryotic genomes. The retromobility of Ty1 is regulated by numerous host factors, including several subunits of the Mediator transcriptional co-activator complex. In spite of its known function in the nucleus, previous studies have implicated Mediator in the regulation of post-translational steps in Ty1 retromobility. To resolve this paradox, we systematically examined the effects of deleting non-essential Mediator subunits on the frequency of Ty1 retromobility and levels of retromobility intermediates. Our findings reveal that loss of distinct Mediator subunits alters Ty1 retromobility positively or negatively over a >10,000-fold range by regulating the ratio of an internal transcript, Ty1i, to the genomic Ty1 transcript. Ty1i RNA encodes a dominant negative inhibitor of Ty1 retromobility that blocks virus-like particle maturation and cDNA synthesis. These results resolve the conundrum of Mediator exerting sweeping control of Ty1 retromobility with only minor effects on the levels of Ty1 genomic RNA and the capsid protein, Gag. Since the majority of characterized intrinsic and extrinsic regulators of Ty1 retromobility do not appear to effect genomic Ty1 RNA levels, Mediator could play a central role in integrating signals that influence Ty1i expression to modulate retromobility.

Diffusion-controlled oxygen reduction on multi-copper oxidase-adsorbed carbon aerogel electrodes without mediator

Energy Technology Data Exchange (ETDEWEB)

Tsujimura, S.; Kamitaka, Y.; Kano, K. [Division of Applied Life Sciences, Graduate School of Agriculture, Kyoto University, Sakyo-ku, Kyoto (Japan)

2007-12-15

Bioelectrocatalytic reduction of O{sub 2} into water was archived at diffusion-controlled rate by using enzymes (laccase from Trametes sp. and bilirubin oxidase from Myrothecium verrucaria, which belong to the family of multi-copper oxidase) adsorbed on mesoporous carbon aerogel particle without a mediator. The current density was predominantly controlled by the diffusion of dissolved O{sub 2} in rotating-disk electrode experiments, and reached a value as large as 10 mA cm{sup -2} at 1 atm O{sub 2}, 25 C, and 8,000 rpm on the laccase-adsorbed electrode. The overpotential of the bioelectrocatalytic reduction of O{sub 2} was 0.4-0.55 V smaller than that observed on a Pt disk electrode. Without any optimization, the laccase-adsorbed biocathode showed stable current intensity of the O{sub 2} reduction in an air-saturated buffer at least for 10 days under continuous flow system. (Abstract Copyright [2007], Wiley Periodicals, Inc.)

The Effect of Social Support on Glycemic Control in Patients with Type 2 Diabetes Mellitus: The Mediating Roles of Self-Efficacy and Adherence

Directory of Open Access Journals (Sweden)

Yechang Shao

2017-01-01

Full Text Available Ample evidence suggests that social support, self-efficacy, and adherence significantly, independently, and together affect glycemic control in patients with type 2 diabetes mellitus (T2DM, but the pathway from social support to glycemic control remains unclear. This study hypothesized that the effect of social support on glycemic control was mediated sequentially by self-efficacy and adherence. Patients with T2DM were recruited from two hospitals in Guangzhou, China, from January 1 to July 31, 2014, and their sociodemographic clinical data and their assessments on social support, self-efficacy, and adherence were obtained from medical records and self-completed questionnaires. Of the 532 patients who participated, 35% achieved glycemic control (i.e., HbA1c < 7%. Social support, self-efficacy, and adherence had significant correlations with each other and with glycemic control (P<0.05. Regression analyses and structural equation modeling showed that better social support was associated to better patient self-efficacy, which, in turn, was associated with better medical adherence, which was associated with improved glycemic control, and the relationship between social support and glycemic control was sequentially and completely mediated by self-efficacy and adherence. The five goodness-of-fit indices confirmed that our data fitted the hypothesized pathway model strongly.

Are Metabolic Signatures Mediating the Relationship between Lifestyle Factors and Hepatocellular Carcinoma Risk? Results from a Nested Case-Control Study in EPIC.

Science.gov (United States)

Assi, Nada; Thomas, Duncan C; Leitzmann, Michael; Stepien, Magdalena; Chajès, Véronique; Philip, Thierry; Vineis, Paolo; Bamia, Christina; Boutron-Ruault, Marie-Christine; Sandanger, Torkjel M; Molinuevo, Amaia; Boshuizen, Hendriek C; Sundkvist, Anneli; Kühn, Tilman; Travis, Ruth C; Overvad, Kim; Riboli, Elio; Gunter, Marc J; Scalbert, Augustin; Jenab, Mazda; Ferrari, Pietro; Viallon, Vivian

2018-05-01

Background: The "meeting-in-the-middle" (MITM) is a principle to identify exposure biomarkers that are also predictors of disease. The MITM statistical framework was applied in a nested case-control study of hepatocellular carcinoma (HCC) within European Prospective Investigation into Cancer and Nutrition (EPIC), where healthy lifestyle index (HLI) variables were related to targeted serum metabolites. Methods: Lifestyle and targeted metabolomic data were available from 147 incident HCC cases and 147 matched controls. Partial least squares analysis related 7 lifestyle variables from a modified HLI to a set of 132 serum-measured metabolites and a liver function score. Mediation analysis evaluated whether metabolic profiles mediated the relationship between each lifestyle exposure and HCC risk. Results: Exposure-related metabolic signatures were identified. Particularly, the body mass index (BMI)-associated metabolic component was positively related to glutamic acid, tyrosine, PC aaC38:3, and liver function score and negatively to lysoPC aC17:0 and aC18:2. The lifetime alcohol-specific signature had negative loadings on sphingomyelins (SM C16:1, C18:1, SM(OH) C14:1, C16:1 and C22:2). Both exposures were associated with increased HCC with total effects (TE) = 1.23 (95% confidence interval = 0.93-1.62) and 1.40 (1.14-1.72), respectively, for BMI and alcohol consumption. Both metabolic signatures mediated the association between BMI and lifetime alcohol consumption and HCC with natural indirect effects, respectively, equal to 1.56 (1.24-1.96) and 1.09 (1.03-1.15), accounting for a proportion mediated of 100% and 24%. Conclusions: In a refined MITM framework, relevant metabolic signatures were identified as mediators in the relationship between lifestyle exposures and HCC risk. Impact: The understanding of the biological basis for the relationship between modifiable exposures and cancer would pave avenues for clinical and public health interventions on metabolic mediators

The Arabidopsis SWI/SNF protein BAF60 mediates seedling growth control by modulating DNA accessibility

KAUST Repository

Jé gu, Teddy; Veluchamy, Alaguraj; Ramirez Prado, Juan Sebastian; Rizzi-Paillet, Charley; Perez, Magalie; Lhomme, Anaï s; Latrasse, David; Coleno, Emeline; Vicaire, Serge; Legras, Sté phanie; Jost, Bernard; Rougé e, Martin; Barneche, Fredy; Bergounioux, Catherine; Crespi, Martin; Mahfouz, Magdy M.; Hirt, Heribert; Raynaud, Cé cile; Benhamed, Moussa

2017-01-01

Plant adaptive responses to changing environments involve complex molecular interplays between intrinsic and external signals. Whilst much is known on the signaling components mediating diurnal, light, and temperature controls on plant development, their influence on chromatin-based transcriptional controls remains poorly explored.In this study we show that a SWI/SNF chromatin remodeler subunit, BAF60, represses seedling growth by modulating DNA accessibility of hypocotyl cell size regulatory genes. BAF60 binds nucleosome-free regions of multiple G box-containing genes, opposing in cis the promoting effect of the photomorphogenic and thermomorphogenic regulator Phytochrome Interacting Factor 4 (PIF4) on hypocotyl elongation. Furthermore, BAF60 expression level is regulated in response to light and daily rhythms.These results unveil a short path between a chromatin remodeler and a signaling component to fine-tune plant morphogenesis in response to environmental conditions.

The Arabidopsis SWI/SNF protein BAF60 mediates seedling growth control by modulating DNA accessibility

KAUST Repository

Jégu, Teddy

2017-06-15

Plant adaptive responses to changing environments involve complex molecular interplays between intrinsic and external signals. Whilst much is known on the signaling components mediating diurnal, light, and temperature controls on plant development, their influence on chromatin-based transcriptional controls remains poorly explored.In this study we show that a SWI/SNF chromatin remodeler subunit, BAF60, represses seedling growth by modulating DNA accessibility of hypocotyl cell size regulatory genes. BAF60 binds nucleosome-free regions of multiple G box-containing genes, opposing in cis the promoting effect of the photomorphogenic and thermomorphogenic regulator Phytochrome Interacting Factor 4 (PIF4) on hypocotyl elongation. Furthermore, BAF60 expression level is regulated in response to light and daily rhythms.These results unveil a short path between a chromatin remodeler and a signaling component to fine-tune plant morphogenesis in response to environmental conditions.

Controlled Zn-mediated grafting of thin layers of bipodal diazonium salt on gold and carbon substrates.

Science.gov (United States)

Torréns, Mabel; Ortiz, Mayreli; Turner, Anthony P F; Beni, Valerio; O'Sullivan, Ciara K

2015-01-07

A controlled, rapid, and potentiostat-free method has been developed for grafting the diazonium salt (3,5-bis(4-diazophenoxy)benzoic acid tetrafluoroborate (DCOOH)) on gold and carbon substrates, based on a Zn-mediated chemical dediazonation. The highly stable thin layer organic platforms obtained were characterized by cyclic voltammetry, AFM, impedance, XP, and Raman spectroscopies. A dediazonation mechanism based on radical formation is proposed. Finally, DCOOH was proved as a linker to an aminated electroactive probe. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Function and regulation of the Mediator complex.

Science.gov (United States)

Conaway, Ronald C; Conaway, Joan Weliky

2011-04-01

Over the past few years, advances in biochemical and genetic studies of the structure and function of the Mediator complex have shed new light on its subunit architecture and its mechanism of action in transcription by RNA polymerase II (pol II). The development of improved methods for reconstitution of recombinant Mediator subassemblies is enabling more in-depth analyses of basic features of the mechanisms by which Mediator interacts with and controls the activity of pol II and the general initiation factors. The discovery and characterization of multiple, functionally distinct forms of Mediator characterized by the presence or absence of the Cdk8 kinase module have led to new insights into how Mediator functions in both Pol II transcription activation and repression. Finally, progress in studies of the mechanisms by which the transcriptional activation domains (ADs) of DNA binding transcription factors target Mediator have brought to light unexpected complexities in the way Mediator participates in signal transduction. Copyright © 2011 Elsevier Ltd. All rights reserved.

Mediating role of activity level in the depressive realism effect.

Directory of Open Access Journals (Sweden)

Fernando Blanco

Full Text Available Several classic studies have concluded that the accuracy of identifying uncontrollable situations depends heavily on depressive mood. Nondepressed participants tend to exhibit an optimistic illusion of control, whereas depressed participants tend to better detect a lack of control. Recently, we suggested that the different activity levels (measured as the probability of responding during a contingency learning task exhibited by depressed and nondepressed individuals is partly responsible for this effect. The two studies presented in this paper provide further support for this mediational hypothesis, in which mood is the distal cause of the illusion of control operating through activity level, the proximal cause. In Study 1, the probability of responding, P(R, was found to be a mediator variable between the depressive symptoms and the judgments of control. In Study 2, we intervened directly on the mediator variable: The P(R for both depressed and nondepressed participants was manipulated through instructions. Our results confirm that P(R manipulation produced differences in the participants' perceptions of uncontrollability. Importantly, the intervention on the mediator variable cancelled the effect of the distal cause; the participants' judgments of control were no longer mood dependent when the P(R was manipulated. This result supports the hypothesis that the so-called depressive realism effect is actually mediated by the probability of responding.

Mediating Role of Activity Level in the Depressive Realism Effect

Science.gov (United States)

Blanco, Fernando; Matute, Helena; A. Vadillo, Miguel

2012-01-01

Several classic studies have concluded that the accuracy of identifying uncontrollable situations depends heavily on depressive mood. Nondepressed participants tend to exhibit an optimistic illusion of control, whereas depressed participants tend to better detect a lack of control. Recently, we suggested that the different activity levels (measured as the probability of responding during a contingency learning task) exhibited by depressed and nondepressed individuals is partly responsible for this effect. The two studies presented in this paper provide further support for this mediational hypothesis, in which mood is the distal cause of the illusion of control operating through activity level, the proximal cause. In Study 1, the probability of responding, P(R), was found to be a mediator variable between the depressive symptoms and the judgments of control. In Study 2, we intervened directly on the mediator variable: The P(R) for both depressed and nondepressed participants was manipulated through instructions. Our results confirm that P(R) manipulation produced differences in the participants’ perceptions of uncontrollability. Importantly, the intervention on the mediator variable cancelled the effect of the distal cause; the participants’ judgments of control were no longer mood dependent when the P(R) was manipulated. This result supports the hypothesis that the so-called depressive realism effect is actually mediated by the probability of responding. PMID:23029435

PRMT1-mediated arginine methylation controls ATXN2L localization

Energy Technology Data Exchange (ETDEWEB)

Kaehler, Christian; Guenther, Anika; Uhlich, Anja; Krobitsch, Sylvia, E-mail: krobitsc@molgen.mpg.de

2015-05-15

Arginine methylation is a posttranslational modification that is of importance in diverse cellular processes. Recent proteomic mass spectrometry studies reported arginine methylation of ataxin-2-like (ATXN2L), the paralog of ataxin-2, a protein that is implicated in the neurodegenerative disorder spinocerebellar ataxia type 2. Here, we investigated the methylation state of ATXN2L and its significance for ATXN2L localization. We first confirmed that ATXN2L is asymmetrically dimethylated in vivo, and observed that the nuclear localization of ATXN2L is altered under methylation inhibition. We further discovered that ATXN2L associates with the protein arginine-N-methyltransferase 1 (PRMT1). Finally, we showed that neither mutation of the arginine–glycine-rich motifs of ATXN2L nor methylation inhibition alters ATXN2L localization to stress granules, suggesting that methylation of ATXN2L is probably not mandatory. - Highlights: • ATXN2L is asymmetrically dimethylated in vivo. • ATXN2L interacts with PRMT1 under normal and stress conditions. • PRMT1-mediated dimethylation of ATXN2L controls its nuclear localization. • ATXN2L localization to stress granules appears independent of its methylation state.

cGAS-mediated control of blood-stage malaria promotes Plasmodium-specific germinal center responses.

Science.gov (United States)

Hahn, William O; Butler, Noah S; Lindner, Scott E; Akilesh, Holly M; Sather, D Noah; Kappe, Stefan Hi; Hamerman, Jessica A; Gale, Michael; Liles, W Conrad; Pepper, Marion

2018-01-25

Sensing of pathogens by host pattern recognition receptors is essential for activating the immune response during infection. We used a nonlethal murine model of malaria (Plasmodium yoelii 17XNL) to assess the contribution of the pattern recognition receptor cyclic GMP-AMP synthase (cGAS) to the development of humoral immunity. Despite previous reports suggesting a critical, intrinsic role for cGAS in early B cell responses, cGAS-deficient (cGAS-/-) mice had no defect in the early expansion or differentiation of Plasmodium-specific B cells. As the infection proceeded, however, cGAS-/- mice exhibited higher parasite burdens and aberrant germinal center and memory B cell formation when compared with littermate controls. Antimalarial drugs were used to further demonstrate that the disrupted humoral response was not B cell intrinsic but instead was a secondary effect of a loss of parasite control. These findings therefore demonstrate that cGAS-mediated innate-sensing contributes to parasite control but is not intrinsically required for the development of humoral immunity. Our findings highlight the need to consider the indirect effects of pathogen burden in investigations examining how the innate immune system affects the adaptive immune response.

Gibberellin 20-oxidase gene OsGA20ox3 regulates plant stature and disease development in rice.

Science.gov (United States)

Qin, Xue; Liu, Jun Hua; Zhao, Wen Sheng; Chen, Xu Jun; Guo, Ze Jian; Peng, You Liang

2013-02-01

Gibberellin (GA) 20-oxidase (GA20ox) catalyses consecutive steps of oxidation in the late part of the GA biosynthetic pathway. A T-DNA insertion mutant (17S-14) in rice, with an elongated phenotype, was isolated. Analysis of the flanking sequences of the T-DNA insertion site revealed that an incomplete T-DNA integration resulted in enhanced constitutively expression of downstream OsGA20ox3 in the mutant. The accumulation of bioactive GA(1) and GA(4) were increased in the mutant in comparison with the wild-type plant. Transgenic plants overexpressing OsGA20ox3 showed phenotypes similar to those of the 17S-14 mutant, and the RNA interference (RNAi) lines that had decreased OsGA20ox3 expression exhibited a semidwarf phenotype. Expression of OsGA20ox3 was detected in the leaves and roots of young seedlings, immature panicles, anthers, and pollens, based on β-glucuronidase (GUS) activity staining in transgenic plants expressing the OsGA20ox3 promoter fused to the GUS gene. The OsGA20ox3 RNAi lines showed enhanced resistance against rice pathogens Magnaporthe oryzae (causing rice blast) and Xanthomonas oryzae pv. oryzae (causing bacterial blight) and increased expression of defense-related genes. Conversely, OsGA20ox3-overexpressing plants were more susceptible to these pathogens comparing with the wild-type plants. The susceptibility of wild-type plants to X. oryzae pv. oryzae was increased by exogenous application of GA(3) and decreased by S-3307 treatment. Together, the results provide direct evidence for a critical role of OsGA20ox3 in regulating not only plant stature but also disease resistance in rice.

Detachment of Chain-Forming Neuroblasts by Fyn-Mediated Control of cell-cell Adhesion in the Postnatal Brain.

Science.gov (United States)

Fujikake, Kazuma; Sawada, Masato; Hikita, Takao; Seto, Yayoi; Kaneko, Naoko; Herranz-Pérez, Vicente; Dohi, Natsuki; Homma, Natsumi; Osaga, Satoshi; Yanagawa, Yuchio; Akaike, Toshihiro; García-Verdugo, Jose Manuel; Hattori, Mitsuharu; Sobue, Kazuya; Sawamoto, Kazunobu

2018-05-09

In the rodent olfactory system, neuroblasts produced in the ventricular-subventricular zone of the postnatal brain migrate tangentially in chain-like cell aggregates toward the olfactory bulb (OB) through the rostral migratory stream (RMS). After reaching the OB, the chains are dissociated and the neuroblasts migrate individually and radially toward their final destination. The cellular and molecular mechanisms controlling cell-cell adhesion during this detachment remain unclear. Here we report that Fyn, a nonreceptor tyrosine kinase, regulates the detachment of neuroblasts from chains in the male and female mouse OB. By performing chemical screening and in vivo loss-of-function and gain-of-function experiments, we found that Fyn promotes somal disengagement from the chains and is involved in neuronal migration from the RMS into the granule cell layer of the OB. Fyn knockdown or Dab1 (disabled-1) deficiency caused p120-catenin to accumulate and adherens junction-like structures to be sustained at the contact sites between neuroblasts. Moreover, a Fyn and N-cadherin double-knockdown experiment indicated that Fyn regulates the N-cadherin-mediated cell adhesion between neuroblasts. These results suggest that the Fyn-mediated control of cell-cell adhesion is critical for the detachment of chain-forming neuroblasts in the postnatal OB. SIGNIFICANCE STATEMENT In the postnatal brain, newly born neurons (neuroblasts) migrate in chain-like cell aggregates toward their destination, where they are dissociated into individual cells and mature. The cellular and molecular mechanisms controlling the detachment of neuroblasts from chains are not understood. Here we show that Fyn, a nonreceptor tyrosine kinase, promotes the somal detachment of neuroblasts from chains, and that this regulation is critical for the efficient migration of neuroblasts to their destination. We further show that Fyn and Dab1 (disabled-1) decrease the cell-cell adhesion between chain-forming neuroblasts

The role of mediation in resolving contract disputes

OpenAIRE

Christian, Michael C

1997-01-01

Approved for public release; distribution is unlimited Mediation has emerged as a preferred ADR method among commercial organizations involved in contract disputes. However, its use by the Navy has been rare. Mediation has shown to provide benefits to its commercial users such as: improved business relations, time and cost savings, flexibility and adaptability and superior control over outcomes. This thesis provides information on mediation and examines the differences and similarities bet...

Gibberellins interfere with symbiosis signaling and gene expression and alter colonization by arbuscular mycorrhizal fungi in Lotus japonicus.

Science.gov (United States)

Takeda, Naoya; Handa, Yoshihiro; Tsuzuki, Syusaku; Kojima, Mikiko; Sakakibara, Hitoshi; Kawaguchi, Masayoshi

2015-02-01

Arbuscular mycorrhiza is a mutualistic plant-fungus interaction that confers great advantages for plant growth. Arbuscular mycorrhizal (AM) fungi enter the host root and form symbiotic structures that facilitate nutrient supplies between the symbionts. The gibberellins (GAs) are phytohormones known to inhibit AM fungal infection. However, our transcriptome analysis and phytohormone quantification revealed GA accumulation in the roots of Lotus japonicus infected with AM fungi, suggesting that de novo GA synthesis plays a role in arbuscular mycorrhiza development. We found pleiotropic effects of GAs on the AM fungal infection. In particular, the morphology of AM fungal colonization was drastically altered by the status of GA signaling in the host root. Exogenous GA treatment inhibited AM hyphal entry into the host root and suppressed the expression of Reduced Arbuscular Mycorrhization1 (RAM1) and RAM2 homologs that function in hyphal entry and arbuscule formation. On the other hand, inhibition of GA biosynthesis or suppression of GA signaling also affected arbuscular mycorrhiza development in the host root. Low-GA conditions suppressed arbuscular mycorrhiza-induced subtilisin-like serine protease1 (SbtM1) expression that is required for AM fungal colonization and reduced hyphal branching in the host root. The reduced hyphal branching and SbtM1 expression caused by the inhibition of GA biosynthesis were recovered by GA treatment, supporting the theory that insufficient GA signaling causes the inhibitory effects on arbuscular mycorrhiza development. Most studies have focused on the negative role of GA signaling, whereas our study demonstrates that GA signaling also positively interacts with symbiotic responses and promotes AM colonization of the host root. © 2015 American Society of Plant Biologists. All Rights Reserved.

Candidate Gene Identification of Flowering Time Genes in Cotton

Directory of Open Access Journals (Sweden)

Corrinne E. Grover

2015-07-01

Full Text Available Flowering time control is critically important to all sexually reproducing angiosperms in both natural ecological and agronomic settings. Accordingly, there is much interest in defining the genes involved in the complex flowering-time network and how these respond to natural and artificial selection, the latter often entailing transitions in day-length responses. Here we describe a candidate gene analysis in the cotton genus , which uses homologs from the well-described flowering network to bioinformatically and phylogenetically identify orthologs in the published genome sequence from Ulbr., one of the two model diploid progenitors of the commercially important allopolyploid cottons, L. and L. Presence and patterns of expression were evaluated from 13 aboveground tissues related to flowering for each of the candidate genes using allopolyploid as a model. Furthermore, we use a comparative context to determine copy number variability of each key gene family across 10 published angiosperm genomes. Data suggest a pattern of repeated loss of duplicates following ancient whole-genome doubling events in diverse lineages. The data presented here provide a foundation for understanding both the parallel evolution of day-length neutrality in domesticated cottons and the flowering-time network, in general, in this important crop plant.

Seed-mediated growth and manipulation of Au nanorods via size-controlled synthesis of Au seeds

International Nuclear Information System (INIS)

Liu Juncheng; Duggan, Jennifer N.; Morgan, Joshua; Roberts, Christopher B.

2012-01-01

Seed-mediated growth of gold (Au) nanorods with highly controllable length, width, and aspect ratio was accomplished via carefully size-controlled synthesis of the original Au seeds. A slow dynamic growth of Au nanoparticle seeds was observed after reduction of the Au salt (i.e., hydrogen tetrachloroaurate (III) hydrate) by sodium borohydride (NaBH 4 ) in the presence of cetyltrimethyl ammonium bromide (CTAB). As such, the size of the Au nanoparticle seeds can therefore be manipulated through control over the duration of the reaction period (i.e., aging times of 2, 8, 48, 72, and 144 h were used in this study). These differently sized Au nanoparticles were subsequently used as seeds for the growth of Au nanorods, where the additions of Au salt, CTAB, AgNO 3 , and ascorbic acid were employed. Smaller Au nanoparticle seeds obtained via short growth/aging time resulted in Au nanorods with higher aspect ratio and thus longer longitudinal surface plasmon wavelength (LSPW). The larger Au nanoparticle seeds obtained via longer growth/aging time resulted in Au nanorods with lower aspect ratio and shorter LSPW.

Fluid Intelligence as a Mediator of the Relationship between Executive Control and Balanced Time Perspective.

Science.gov (United States)

Zajenkowski, Marcin; Stolarski, Maciej; Witowska, Joanna; Maciantowicz, Oliwia; Łowicki, Paweł

2016-01-01

This study examined the cognitive foundations of the balanced time perspective (BTP) proposed by Zimbardo and Boyd (1999). Although BTP is defined as the mental ability to switch effectively between different temporal perspectives, its connection with cognitive functioning has not yet been established. We addressed this by exploring the relationships between time perspectives and both fluid intelligence (measured with Raven's and Cattell's tests) and executive control (Go/No-go and anti-saccade tasks). An investigation conducted among Polish adults ( N = 233) revealed that more balanced TP profile was associated with higher fluid intelligence, and higher executive control. Moreover, we found that the relationship between executive control and BTP was completely mediated by fluid intelligence with the effect size (the ratio of the indirect effect to the total effect) of 0.75, which suggests that cognitive abilities play an important role in adoption of temporal balance. The findings have relevance to time perspective theory as they provide valuable insight into the mechanisms involved in assigning human experience to certain time frames.

Surface receptor Toso controls B cell-mediated regulation of T cell immunity.

Science.gov (United States)

Yu, Jinbo; Duong, Vu Huy Hoang; Westphal, Katrin; Westphal, Andreas; Suwandi, Abdulhadi; Grassl, Guntram A; Brand, Korbinian; Chan, Andrew C; Föger, Niko; Lee, Kyeong-Hee

2018-05-01

The immune system is tightly controlled by regulatory processes that allow for the elimination of invading pathogens, while limiting immunopathological damage to the host. In the present study, we found that conditional deletion of the cell surface receptor Toso on B cells unexpectedly resulted in impaired proinflammatory T cell responses, which led to impaired immune protection in an acute viral infection model and was associated with reduced immunopathological tissue damage in a chronic inflammatory context. Toso exhibited its B cell-inherent immunoregulatory function by negatively controlling the pool of IL-10-competent B1 and B2 B cells, which were characterized by a high degree of self-reactivity and were shown to mediate immunosuppressive activity on inflammatory T cell responses in vivo. Our results indicate that Toso is involved in the differentiation/maintenance of regulatory B cells by fine-tuning B cell receptor activation thresholds. Furthermore, we showed that during influenza A-induced pulmonary inflammation, the application of Toso-specific antibodies selectively induced IL-10-competent B cells at the site of inflammation and resulted in decreased proinflammatory cytokine production by lung T cells. These findings suggest that Toso may serve as a novel therapeutic target to dampen pathogenic T cell responses via the modulation of IL-10-competent regulatory B cells.

CD4+ lymphocytes control gut epithelial apoptosis and mediate survival in sepsis.

Science.gov (United States)

Stromberg, Paul E; Woolsey, Cheryl A; Clark, Andrew T; Clark, Jessica A; Turnbull, Isaiah R; McConnell, Kevin W; Chang, Katherine C; Chung, Chun-Shiang; Ayala, Alfred; Buchman, Timothy G; Hotchkiss, Richard S; Coopersmith, Craig M

2009-06-01

Lymphocytes help determine whether gut epithelial cells proliferate or differentiate but are not known to affect whether they live or die. Here, we report that lymphocytes play a controlling role in mediating gut epithelial apoptosis in sepsis but not under basal conditions. Gut epithelial apoptosis is similar in unmanipulated Rag-1(-/-) and wild-type (WT) mice. However, Rag-1(-/-) animals have a 5-fold augmentation in gut epithelial apoptosis following cecal ligation and puncture (CLP) compared to septic WT mice. Reconstitution of lymphocytes in Rag-1(-/-) mice via adoptive transfer decreases intestinal apoptosis to levels seen in WT animals. Subset analysis indicates that CD4(+) but not CD8(+), gammadelta, or B cells are responsible for the antiapoptotic effect of lymphocytes on the gut epithelium. Gut-specific overexpression of Bcl-2 in transgenic mice decreases mortality following CLP. This survival benefit is lymphocyte dependent since gut-specific overexpression of Bcl-2 fails to alter survival when the transgene is overexpressed in Rag-1(-/-) mice. Further, adoptively transferring lymphocytes to Rag-1(-/-) mice that simultaneously overexpress gut-specific Bcl-2 results in improved mortality following sepsis. Thus, sepsis unmasks CD4(+) lymphocyte control of gut apoptosis that is not present under homeostatic conditions, which acts as a key determinant of both cellular survival and host mortality.

LDB1-mediated enhancer looping can be established independent of mediator and cohesin.

Science.gov (United States)

Krivega, Ivan; Dean, Ann

2017-08-21

Mechanistic studies in erythroid cells indicate that LDB1, as part of a GATA1/TAL1/LMO2 complex, brings erythroid-expressed genes into proximity with enhancers for transcription activation. The role of co-activators in establishing this long-range interaction is poorly understood. Here we tested the contributions of the RNA Pol II pre-initiation complex (PIC), mediator and cohesin to establishment of locus control region (LCR)/β-globin proximity. CRISPR/Cas9 editing of the β-globin promoter to eliminate the RNA Pol II PIC by deleting the TATA-box resulted in loss of transcription, but enhancer-promoter interaction was unaffected. Additional deletion of the promoter GATA1 site eliminated LDB1 complex and mediator occupancy and resulted in loss of LCR/β-globin proximity. To separate the roles of LDB1 and mediator in LCR looping, we expressed a looping-competent but transcription-activation deficient form of LDB1 in LDB1 knock down cells: LCR/β-globin proximity was restored without mediator core occupancy. Further, Cas9-directed tethering of mutant LDB1 to the β-globin promoter forced LCR loop formation in the absence of mediator or cohesin occupancy. Moreover, ENCODE data and our chromatin immunoprecipitation results indicate that cohesin is almost completely absent from validated and predicted LDB1-regulated erythroid enhancer-gene pairs. Thus, lineage specific factors largely mediate enhancer-promoter looping in erythroid cells independent of mediator and cohesin. Published by Oxford University Press on behalf of Nucleic Acids Research 2017.

DELAY OF GERMINATION 1 mediates a conserved coat-dormancy mechanism for the temperature- and gibberellin-dependent control of seed germination

OpenAIRE

Graeber, K.; Linkies, A.; Steinbrecher, T.; Tarkowská, D. (Danuše); Turečková, V. (Veronika); Ignatz, M.; Voegele, A.; Urbanová, T. (Terezie); Strnad, M. (Miroslav); Leubner-Metzger, G. (Gerhard)

2014-01-01

Seed germination is an important life-cycle transition because it determines subsequent plant survival and reproductive success. To detect optimal spatiotemporal conditions for germination, seeds act as sophisticated environmental sensors integrating information such as ambient temperature. Here we show that the DELAY OF GERMINATION 1 (DOG1) gene, known for providing dormancy adaptation to distinct environments, determines the optimal temperature for seed germination. By reciprocal gene-swapp...

RISC-mediated control of selected chromatin regulators stabilizes ground state pluripotency of mouse embryonic stem cells.

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Pandolfini, Luca; Luzi, Ettore; Bressan, Dario; Ucciferri, Nadia; Bertacchi, Michele; Brandi, Rossella; Rocchiccioli, Silvia; D'Onofrio, Mara; Cremisi, Federico

2016-05-06

Embryonic stem cells are intrinsically unstable and differentiate spontaneously if they are not shielded from external stimuli. Although the nature of such instability is still controversial, growing evidence suggests that protein translation control may play a crucial role. We performed an integrated analysis of RNA and proteins at the transition between naïve embryonic stem cells and cells primed to differentiate. During this transition, mRNAs coding for chromatin regulators are specifically released from translational inhibition mediated by RNA-induced silencing complex (RISC). This suggests that, prior to differentiation, the propensity of embryonic stem cells to change their epigenetic status is hampered by RNA interference. The expression of these chromatin regulators is reinstated following acute inactivation of RISC and it correlates with loss of stemness markers and activation of early cell differentiation markers in treated embryonic stem cells. We propose that RISC-mediated inhibition of specific sets of chromatin regulators is a primary mechanism for preserving embryonic stem cell pluripotency while inhibiting the onset of embryonic developmental programs.

A genetically mediated bias in decision making driven by failure of amygdala control.

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Roiser, Jonathan P; de Martino, Benedetto; Tan, Geoffrey C Y; Kumaran, Dharshan; Seymour, Ben; Wood, Nicholas W; Dolan, Raymond J

2009-05-06

Genetic variation at the serotonin transporter-linked polymorphic region (5-HTTLPR) is associated with altered amygdala reactivity and lack of prefrontal regulatory control. Similar regions mediate decision-making biases driven by contextual cues and ambiguity, for example the "framing effect." We hypothesized that individuals hemozygous for the short (s) allele at the 5-HTTLPR would be more susceptible to framing. Participants, selected as homozygous for either the long (la) or s allele, performed a decision-making task where they made choices between receiving an amount of money for certain and taking a gamble. A strong bias was evident toward choosing the certain option when the option was phrased in terms of gains and toward gambling when the decision was phrased in terms of losses (the frame effect). Critically, this bias was significantly greater in the ss group compared with the lala group. In simultaneously acquired functional magnetic resonance imaging data, the ss group showed greater amygdala during choices made in accord, compared with those made counter to the frame, an effect not seen in the lala group. These differences were also mirrored by differences in anterior cingulate-amygdala coupling between the genotype groups during decision making. Specifically, lala participants showed increased coupling during choices made counter to, relative to those made in accord with, the frame, with no such effect evident in ss participants. These data suggest that genetically mediated differences in prefrontal-amygdala interactions underpin interindividual differences in economic decision making.

The Mediator complex and transcription regulation

Science.gov (United States)

Poss, Zachary C.; Ebmeier, Christopher C.

2013-01-01

The Mediator complex is a multi-subunit assembly that appears to be required for regulating expression of most RNA polymerase II (pol II) transcripts, which include protein-coding and most non-coding RNA genes. Mediator and pol II function within the pre-initiation complex (PIC), which consists of Mediator, pol II, TFIIA, TFIIB, TFIID, TFIIE, TFIIF and TFIIH and is approximately 4.0 MDa in size. Mediator serves as a central scaffold within the PIC and helps regulate pol II activity in ways that remain poorly understood. Mediator is also generally targeted by sequence-specific, DNA-binding transcription factors (TFs) that work to control gene expression programs in response to developmental or environmental cues. At a basic level, Mediator functions by relaying signals from TFs directly to the pol II enzyme, thereby facilitating TF-dependent regulation of gene expression. Thus, Mediator is essential for converting biological inputs (communicated by TFs) to physiological responses (via changes in gene expression). In this review, we summarize an expansive body of research on the Mediator complex, with an emphasis on yeast and mammalian complexes. We focus on the basics that underlie Mediator function, such as its structure and subunit composition, and describe its broad regulatory influence on gene expression, ranging from chromatin architecture to transcription initiation and elongation, to mRNA processing. We also describe factors that influence Mediator structure and activity, including TFs, non-coding RNAs and the CDK8 module. PMID:24088064

Mediation Analysis with Multiple Mediators

OpenAIRE

VanderWeele, T.J.; Vansteelandt, S.

2014-01-01

Recent advances in the causal inference literature on mediation have extended traditional approaches to direct and indirect effects to settings that allow for interactions and non-linearities. In this paper, these approaches from causal inference are further extended to settings in which multiple mediators may be of interest. Two analytic approaches, one based on regression and one based on weighting are proposed to estimate the effect mediated through multiple mediators and the effects throu...

PENGARUH ZPT TERHADAP KUALITAS BUAH MANGGIS

Directory of Open Access Journals (Sweden)

- Juanasri

2008-09-01

Full Text Available The objectives of this experiment was to examine the influence of polyamine, gibberelline and harvesting times to inhibit ripening process and to maintain postharvest quality on mangosteen. The method applied was randomized block design with two factors and three replications. First factor was harvesting time consisting of 14, 15 and 15 weeks after anthesis. Second factor is chemical concentration consisting of control (aquadest, GA3 (150, 200, 250 mg/l, polyamine (0,3; 1 and 3 mM. The result showed that spermidine application at 1 mM was more effective to maintain the postharvest quality of mangosteen, the fruit remained soft and the climacteric peak was longer than that of control. Gibberelline application showed unsightly result compared to control. Mangosteen fruits with harvesting time of 15 and 16 weeks after anthesis had better perfomance than those of harvesting at 14 weeks after anthesis, the fruit was remained soft and the weight lost was less.

Functional disability in patients with low back pain: the mediator role of suffering and beliefs about pain control in patients receiving physical and chiropractic treatment.

Science.gov (United States)

Pereira, M Graça; Roios, Edite; Pereira, Marta

Low back pain is the leading cause of disability worldwide. There is evidence that depression, anxiety, and external locus of control are negative predictors of functional disability in low back patients. This study focused on the mediator role of suffering and beliefs about pain control in the relationship between psychological morbidity and functional disability in patients receiving physical therapy and chiropractic treatment for chronic low back pain. The sample included 213 patients receiving chiropractic treatment and 125 receiving physical therapy, who answered the following instruments: Beliefs about Pain Control Questionnaire; Inventory of Subjective Experiences of Suffering in Illness; Oswestry Low Back Pain Disability Questionnaire; and the Hospital Anxiety and Depression Scales. Suffering was a mediator in the relationship between depression and functional disability in both treatment groups. Only beliefs related to external chance events mediated the relationship between depression and functional disability in the physical therapy group, but not in the chiropratic teratment group. Intervention should focus on suffering regardless of the type of treatment and target beliefs about pain control, in patients receiving physical therapy treatment since they seem to play a key role in functional disability in patients with low back pain. Copyright © 2017 Associação Brasileira de Pesquisa e Pós-Graduação em Fisioterapia. Publicado por Elsevier Editora Ltda. All rights reserved.

Endogenous gibberellins in Arabidopsis thaliana and possible steps blocked in the biosynthetic pathways of the semidwarf ga4 and ga5 mutants

International Nuclear Information System (INIS)

Talon, M.; Zeevaart, J.A.D.; Koornneef, M.

1990-01-01

Twenty gibberellins (GAs) have been identified in extracts from shoots of the Landsberg erecta line of Arabidopsis thaliana by full-scan gas chromatography-mass spectrometry and Kovats retention indices. Eight of them are members of the early-13-hydroxylation pathway (GA 53 , GA 44 , GA 19 , GA 17 , GA 20 , GA 1 , GA 29 , and GA 8 ), six are members of the early-3-hydroxylation pathway (GA 37 , GA 27 , GA 36 , GA 13 , GA 4 , and GA 34 ), and the remaining six are members of the non-3,13-hydroxylation pathway (GA 12 , GA 15 , GA 24 , GA 25 , GA 9 , and GFA 51 ). Seven of these GAs were quantified in the Landsberg erecta line of Arabidopsis and in the semidwarf ga4 and ga5 mutants by gas chromatography-selected ion monitoring (SIM) using internal standards. The relative levels of the remaining 13 GAs were compared by the use of ion intensities only. The growth-response data, as well as the accumulation of GA 9 in the ga4 mutant, indicate that GA 9 is not active in Arabidopsis, but it must be 3β-hydroxytlated to GA 4 to become bioactive. It is concluded that the reduced levels of the 3β-hydroxy-GAs, GA 1 and GA 4 , are the cause of the semidwarf growth habit of both mutants

Effect of hydromorphone hydrochloride combined with ropivacaine for PCEA after orthopedic surgery on the synthesis of pain mediators, inflammatory mediator and oxygen free radicals

Directory of Open Access Journals (Sweden)

Liang-Ying Luo

2017-08-01

Full Text Available Objective: To explore the effect of hydromorphone hydrochloride combined with ropivacaine for PCEA after orthopedic surgery on the synthesis of pain mediators, inflammatory mediator and oxygen free radicals. Methods: A total of 120 patients with fracture who underwent operation in the hospital between July 2014 and December 2016 were collected and divided into control group and observation group according to the random number table method, 60 cases in each group. Control group received morphine hydrochloride combined with ropivacaine for analgesia, observation group received hydromorphone hydrochloride combined with ropivacaine for analgesia, and the postoperative analgesia lasted for 48 h. The differences in serum levels of pain mediators, inflammatory mediators and oxidative stress indexes were compared between the two groups. Results: Immediately after operation, the differences in serum levels of pain mediators, inflammatory mediators and oxidative stress indexes were not statistically significant between the two groups. 48 h after operation, serum PGE2, SP, β-EP, IL-6, MCP-1, HMGB-1 and MDA levels of both groups of patients were significantly lower than those immediately after operation while Cu-Zn SOD and GSH-Px levels were significantly higher than those immediately after operation, and serum PGE2, SP, β-EP, IL-6, MCP-1, HMGB-1 and MDA levels of observation group were significantly lower than those of control group while Cu-Zn SOD and GSH-Px levels were significantly higher than those of control group. Conclusion: Hydromorphone hydrochloride combined with ropivacaine for PCEA after orthopedic surgery is effective in alleviating pain and inhibiting systemic inflammatory response.

Coordination of KSHV Latent and Lytic Gene Control by CTCF-Cohesin Mediated Chromosome Conformation

Science.gov (United States)

Kang, Hyojeung; Wiedmer, Andreas; Yuan, Yan; Robertson, Erle; Lieberman, Paul M.

2011-01-01

Herpesvirus persistence requires a dynamic balance between latent and lytic cycle gene expression, but how this balance is maintained remains enigmatic. We have previously shown that the Kaposi's Sarcoma-Associated Herpesvirus (KSHV) major latency transcripts encoding LANA, vCyclin, vFLIP, v-miRNAs, and Kaposin are regulated, in part, by a chromatin organizing element that binds CTCF and cohesins. Using viral genome-wide chromatin conformation capture (3C) methods, we now show that KSHV latency control region is physically linked to the promoter regulatory region for ORF50, which encodes the KSHV immediate early protein RTA. Other linkages were also observed, including an interaction between the 5′ and 3′ end of the latency transcription cluster. Mutation of the CTCF-cohesin binding site reduced or eliminated the chromatin conformation linkages, and deregulated viral transcription and genome copy number control. siRNA depletion of CTCF or cohesin subunits also disrupted chromosomal linkages and deregulated viral latent and lytic gene transcription. Furthermore, the linkage between the latent and lytic control region was subject to cell cycle fluctuation and disrupted during lytic cycle reactivation, suggesting that these interactions are dynamic and regulatory. Our findings indicate that KSHV genomes are organized into chromatin loops mediated by CTCF and cohesin interactions, and that these inter-chromosomal linkages coordinate latent and lytic gene control. PMID:21876668

The role of empowerment in youth development: a study of sociopolitical control as mediator of ecological systems' influence on developmental outcomes.

Science.gov (United States)

Christens, Brian D; Peterson, N Andrew

2012-05-01

Empowerment has become an influential concept and theoretical framework for social policy and practice. Still, relatively little is known about the roles that empowerment plays in the ecology of human development, particularly among young people. This article reports results of a study of psychological empowerment among young people, using data from 629 high school students (65.8% female; 96.5% non-white). Using a path analysis, we examined the role of perceived sociopolitical control--an indicator of the intrapersonal component of psychological empowerment--as a mediator between ecological support systems and developmental outcomes. Findings confirmed that social support in family, peer, and school settings, and family cohesion positively predict self-esteem and perceived school importance, which, in turn, have protective effects on psychological symptoms, violent behaviors and substance use. Sociopolitical control was found to mediate the relationships between ecological supports and risk factors and developmental outcomes, leading to the conclusion that perceived efficacy in the sociopolitical domain, and youth empowerment, more generally, should be considered as core elements of the ecology of human development. Policy and practice aimed at promoting positive developmental outcomes and preventing risk behaviors should take their relationship to sociopolitical control into account.

The Mediator Complex and Lipid Metabolism.

Science.gov (United States)

Zhang, Yi; Xiaoli; Zhao, Xiaoping; Yang, Fajun

2013-03-01

The precise control of gene expression is essential for all biological processes. In addition to DNA-binding transcription factors, numerous transcription cofactors contribute another layer of regulation of gene transcription in eukaryotic cells. One of such transcription cofactors is the highly conserved Mediator complex, which has multiple subunits and is involved in various biological processes through directly interacting with relevant transcription factors. Although the current understanding on the biological functions of Mediator remains incomplete, research in the past decade has revealed an important role of Mediator in regulating lipid metabolism. Such function of Mediator is dependent on specific transcription factors, including peroxisome proliferator-activated receptor-gamma (PPARγ) and sterol regulatory element-binding proteins (SREBPs), which represent the master regulators of lipid metabolism. The medical significance of these findings is apparent, as aberrant lipid metabolism is intimately linked to major human diseases, such as type 2 diabetes and cardiovascular disease. Here, we briefly review the functions and molecular mechanisms of Mediator in regulation of lipid metabolism.

Improved confidence in performing nutrition and physical activity behaviours mediates behavioural change in young adults: Mediation results of a randomised controlled mHealth intervention.

Science.gov (United States)

Partridge, Stephanie R; McGeechan, Kevin; Bauman, Adrian; Phongsavan, Philayrath; Allman-Farinelli, Margaret

2017-01-01

The burden of weight gain disproportionally affects young adults. Understanding the underlying behavioural mechanisms of change in mHealth nutrition and physical activity interventions designed for young adults is important for enhancing and translating effective interventions. First, we hypothesised that knowledge, self-efficacy and stage-of-change for nutrition and physical activity behaviours would improve, and second, that self-efficacy changes in nutrition and physical activity behaviours mediate the behaviour changes observed in an mHealth RCT for prevention of weight gain. Young adults, aged 18-35 years at risk of weight gain (n = 250) were randomly assigned to an mHealth-program, TXT2BFiT, consisting of a three-month intensive phase and six-month maintenance phase or to a control group. Self-reported online surveys at baseline, three- and nine-months assessed nutrition and physical activity behaviours, knowledge, self-efficacy and stage-of-change. The mediating effect of self-efficacy was assessed in multiple PROCESS macro-models for three- and nine-month nutrition and physical activity behaviour change. Young adults randomised to the intervention increased and maintained knowledge of fruit requirements (P = 0.029) compared to controls. Intervention participants' fruit and takeaway behaviours improved to meet recommendations at nine months, with a greater proportion progressing to action or maintenance stage-of-change (P behaviours did not meet recommendations, thereby halting progress to action or maintenance stage-of-change. Indirect effects of improved nutrition and physical activity behaviours at three- and nine-months in the intervention group were explained by changes in self-efficacy, accounting for 8%-37% of the total effect. This provides insights into how the mHealth intervention achieved part of its effects and the importance of improving self-efficacy to facilitate improved eating and physical activity behaviours in young adults

Social cognitive theory mediators of physical activity in a lifestyle program for cancer survivors and carers: findings from the ENRICH randomized controlled trial.

Science.gov (United States)

Stacey, F G; James, E L; Chapman, K; Lubans, D R

2016-04-14

Despite increasing numbers of cancer survivors and evidence that diet and physical activity improves the health of cancer survivors, most do not meet guidelines. Some social cognitive theory (SCT)-based interventions have increased physical activity behavior, however few have used objective physical activity measures. The Exercise and Nutrition Routine Improving Cancer Health (ENRICH) randomized controlled trial reported a significant intervention effect for the primary outcome of pedometer-assessed step counts at post-test (8-weeks) and follow-up (20-weeks). The aim of this study was to test whether the SCT constructs operationalized in the ENRICH intervention were mediators of physical activity behavior change. Randomized controlled trial with 174 cancer survivors and carers assessed at baseline, post-test (8-weeks), and follow-up (20-weeks). Participants were randomized to the ENRICH six session face-to-face healthy lifestyle program, or to a wait-list control. Hypothesized SCT mediators of physical activity behavior change (self-efficacy, behavioral goal, outcome expectations, impediments, and social expectations) were assessed using valid and reliable scales. Mediation was assessed using the Preacher and Hayes SPSS INDIRECT macro. At eight weeks, there was a significant intervention effect on behavioral goal (A = 9.12, p = 0.031) and outcome expectations (A = 0.25, p = 0.042). At 20 weeks, the intervention had a significant effect on self-efficacy (A = 0.31, p = 0.049) and behavioral goal (A = 13.15, p = 0.011). Only changes in social support were significantly associated with changes in step counts at eight weeks (B = 633.81, p = 0.023). Behavioral goal was the only SCT construct that had a significant mediating effect on step counts, and explained 22 % of the intervention effect at 20 weeks (AB = 397.9, 95 % CI 81.5-1025.5). SCT constructs had limited impact on objectively-assessed step counts in a multiple health

The Mediator complex: a central integrator of transcription

Science.gov (United States)

Allen, Benjamin L.; Taatjes, Dylan J.

2016-01-01

The RNA polymerase II (pol II) enzyme transcribes all protein-coding and most non-coding RNA genes and is globally regulated by Mediator, a large, conformationally flexible protein complex with variable subunit composition (for example, a four-subunit CDK8 module can reversibly associate). These biochemical characteristics are fundamentally important for Mediator's ability to control various processes important for transcription, including organization of chromatin architecture and regulation of pol II pre-initiation, initiation, re-initiation, pausing, and elongation. Although Mediator exists in all eukaryotes, a variety of Mediator functions appear to be specific to metazoans, indicative of more diverse regulatory requirements. PMID:25693131

Social cognitive mediators of parent-child sexual communication.

Science.gov (United States)

Evans, W Douglas; Blitstein, Jonathan L; Davis, Kevin C

2011-07-01

To test a social cognitive behavior change model and identify mediators of the effects of the Parents Speak Up National Campaign (PSUNC) on parent-child sexual communication. Investigators used 5 waves of data from an online randomized controlled trial. Latent variables were developed based on item response theory and confirmatory factor analysis. Structural equation modeling was used to test mediation. Outcome expectations mediated effects of social norms and self-efficacy on sexual communication. Other hypothesized mediators were not confirmed. Interventions to promote parent-child sexual communication should target outcome expectations. Future research should investigate parents' health information seeking.

Phosphorylation-mediated control of histone chaperone ASF1 levels by Tousled-like kinases.

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Maxim Pilyugin

Full Text Available Histone chaperones are at the hub of a diverse interaction networks integrating a plethora of chromatin modifying activities. Histone H3/H4 chaperone ASF1 is a target for cell-cycle regulated Tousled-like kinases (TLKs and both proteins cooperate during chromatin replication. However, the precise role of post-translational modification of ASF1 remained unclear. Here, we identify the TLK phosphorylation sites for both Drosophila and human ASF1 proteins. Loss of TLK-mediated phosphorylation triggers hASF1a and dASF1 degradation by proteasome-dependent and independent mechanisms respectively. Consistent with this notion, introduction of phosphorylation-mimicking mutants inhibits hASF1a and dASF1 degradation. Human hASF1b is also targeted for proteasome-dependent degradation, but its stability is not affected by phosphorylation indicating that other mechanisms are likely to be involved in control of hASF1b levels. Together, these results suggest that ASF1 cellular levels are tightly controlled by distinct pathways and provide a molecular mechanism for post-translational regulation of dASF1 and hASF1a by TLK kinases.

The coping with depression course: Short term outcomes and mediating effects of a randomized controlled trial in the treatment of subclinical depression

NARCIS (Netherlands)

Allart-van Dam, E.; Hosman, C.M.H.; Hoogduin, C.A.L.; Schaap, C.P.D.R.

2003-01-01

This article reports on a randomized controlled trial investigating the short-term effectiveness of the Coping With Depression course in a sample of adults seriously at risk of developing major depression. In addition, possible mediating properties of several proximal outcome variables were

The Coping with Depression course : Short-term outcomes and mediating effects of a randomized controlled trial in the treatment of subclinical depression

NARCIS (Netherlands)

Allart-van Dam, E; Hosman, CMH; Hoogduin, CAL; Schaap, CPDR

2003-01-01

This article reports on a randomized controlled trial investigating the short-term effectiveness of the Coping With Depression course in a sample of adults seriously at risk of developing major depression. In addition, possible mediating properties of several proximal outcome variables were

Mediator: A key regulator of plant development.