1,488 research outputs found

    FKF1 conveys timing information for CONSTANS stabilization in photoperiodic flowering

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    Plants use day-length information to coordinate flowering time with the appropriate season to maximize reproduction. In Arabidopsis, the long-day specific expression of CONSTANS (CO) protein is crucial for flowering induction. Although light signaling regulates CO protein stability, the mechanism by which CO is stabilized in the long-day afternoon has remained elusive. Here we demonstrate that FLAVIN-BINDING, KELCH REPEAT, F-BOX 1 (FKF1) protein stabilizes CO protein in the afternoon in long days. FKF1 interacts with CO through its LOV domain, and blue light enhances this interaction. In addition, FKF1 simultaneously removes CYCLING DOF FACTOR 1 (CDF1) that represses CO and FLOWERING LOCUS T (FT) transcription. Together with CO transcriptional regulation, FKF1 protein controls robust FT mRNA induction through multiple feedforward mechanisms that accurately control flowering timing

    Composição morfológica e bromatológica de pastagens de Pennisetum pirpureum submetidas a diferentes intervalos entre pastejos.

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    As composições bromatológica e morfológica são duas características qualitativas das plantas forrageiras de grande importância para o desempenho de bovinos em pastejo. Desse modo, o objetivo do ensaio experimental foi avaliar os efeitos de dois diferentes intervalos entre pastejos sobre a composição bromatológica e morfológica de pastagens de capim Elefante, pastejada por vacas lactantes. Os tratamentos testados foram: intervalo entre pastejos variável, determinado pela entrada dos animais na área a ser pastejada, quando o dossel atingisse 95% de interceptação de luz e intervalo entre pastejos fixo em 27 dias. O delineamento experimental foi o inteiramente casualizado com medidas repetidas no tempo (4 sub-periodos). Foram observados maiores (P<0,05) teores de extrato etéreo, fibra em detergente neutro e fibra em detergente ácido para o intervalo entre pastejos fixo em 27 dias. O intervalo entre pastejos variável proporcionou maior (P<0,05) teor de matéria mineral na forragem. Não foram observados efeitos dos tratamentos sobre os teores de matéria seca, proteína bruta e lignina. Houve maior massa de material senescido (P<0,05) e tendência (P~0,08) de maior massa de colmos para o intervalo entre pastejo fixo de 27 dias no pré e pós-pastejo. Houve também tendência (P=O,10) de maior massa de folhas para o intervalo entre pastejo variável no resíduo pós-pastejo. O intervalo entre pastejo variável melhorou os aspectos bromatológicos e morfológicos do capim Elefante

    Características produtivas e qualitativas de pastagens de Pennisetum purpureum submetidas a diferentes intervalos entre pastejos.

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    O intervalo entre pastejos pode exercer forte influência nos aspectos produtivos e qualitativos das plantas forrageiras tropicais, com reflexos na produção dos animais mantidos em pastagens. Assim, o objetivo do ensaio experimental foi comparar os efeitos de dois diferentes intervalos entre pastejos sobre algumas caracteristicas produtivas e qualitativas do dossel de capim Elefante pastejado por vacas em lactação. Os tratamentos foram: intervalo entre pastejos variável, determinado pela entrada dos animais na área a ser pastejada, quando o dossel atingisse 95% de interceptação de luz e intervalo entre pastejos fixados em 27 dias. O delineamento experimental foi o inteiramente casualizado com medidas repetidas no tempo. A frequência de desfolha, a altura do dossel no pré e pós-pastejo,. a interceptação de luz pelo dossel e o índice de área foliar, foram maiores (PO,O5) dos tratamentos sobre a massa de forragem em pré e pós-pastejo. O intervalo entre pastejos fixado em 27 dias, durante a época das águas, proporcionou forragem de pior qualidade

    Forest harvesting impacts on microclimate conditions and sediment transport activities in a humid periglacial environment

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    Sediment transport activities in periglacial environments are controlled by microclimate conditions (i.e., air and ground temperatures, throughfall), which are highly affected by vegetation cover. Thus, there is the possibility that forest harvesting, the most dramatic change to vegetation cover in mountain areas, may severely impact sediment transport activities in periglacial areas (i.e., soil creep, dry ravel). In this study, we investigated changes in sediment transport activities following forest harvesting in steep artificial forests located in a humid periglacial area of the southern Japanese Alps. In the southern Japanese Alps, rainfall is abundant in summer and autumn, and winter air temperatures frequently rise above and fall below 0∘. Our monitoring by time lapse cameras revealed that gravitational transport processes (e.g., frost creep and dry ravel) dominate during the freeze–thaw season, while rainfall-induced processes (surface erosion and soil creep) occur during heavy rainfall seasons. Canopy removal by forest harvesting increased the winter diurnal ground surface temperature range from 2.7 to 15.9&thinsp;∘C. Forest harvesting also increased the diurnal range of net radiation and ground temperature, and decreased the duration of snow cover. Such changes in the microclimate conditions altered the type of winter soil creep from frost creep to diurnal needle-ice creep. Winter creep velocity of ground surface sediment in the harvested site (&gt;&thinsp;2&thinsp;mm&thinsp;day−1 on the days with frost heave) was significantly higher than that in the non-harvested site (generally &lt;&thinsp;1&thinsp;mm&thinsp;day−1). Meanwhile, sediment flux on the hillslopes, as observed by sediment traps, decreased in the harvested site. Branches of harvested trees left on the hillslopes captured sediment moving downslope. In addition, the growth of understories after harvesting possibly reduced surface erosion. Consequently, removal of the forest canopy by forest harvesting directly impacts the microclimate conditions (i.e., diurnal range of ground temperature and net radiation, duration of snow cover) and increases frequency and velocity of periglacial soil creep, while sediment flux on hillslopes is decreased by branches left on the hillslopes and recovery of understories. The impact of forest harvesting on sediment transport activity is seasonally variable in humid periglacial areas, because microclimate conditions relevant to both freeze–thaw processes and precipitation-induced processes control sediment transport.</p

    The proapoptotic dp5 gene is a direct target of the MLK-JNK-c-Jun pathway in sympathetic neurons

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    The death of sympathetic neurons after nerve growth factor (NGF) withdrawal requires de novo gene expression. Dp5 was one of the first NGF withdrawal-induced genes to be identified and it encodes a proapoptotic BH3-only member of the Bcl-2 family. To study how dp5 transcription is regulated by NGF withdrawal we cloned the regulatory regions of the rat dp5 gene and constructed a series of dp5-luciferase reporter plasmids. In microinjection experiments with sympathetic neurons we found that three regions of dp5 contribute to its induction after NGF withdrawal: the promoter, a conserved region in the single intron, and sequences in the 3′ untranslated region of the dp5 mRNA. A construct containing all three regions is efficiently activated by NGF withdrawal and, like the endogenous dp5, its induction requires mixed-lineage kinase (MLK) and c-Jun N-terminal kinase (JNK) activity. JNKs phosphorylate the AP-1 transcription factor c-Jun, and thereby increase its activity. We identified a conserved ATF site in the dp5 promoter that binds c-Jun and ATF2, which is critical for dp5 promoter induction after NGF withdrawal. These results suggest that part of the mechanism by which the MLK-JNK-c-Jun pathway promotes neuronal apoptosis is by activating the transcription of the dp5 gene

    The nature of floral signals in Arabidopsis. II. Roles for FLOWERING LOCUS T (FT) and gibberellin

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    Signals produced in leaves are transported to the shoot apex where they cause flowering. Protein of the gene FLOWERING LOCUS T (FT) is probably a long day (LD) signal in Arabidopsis. In the companion paper, rapid LD increases in FT expression associated with flowering driven photosynthetically in red light were documented. In a far red (FR)-rich LD, along with FT there was a potential role for gibberellin (GA). Here, with the GA biosynthesis dwarf mutant ga1-3, GA4-treated plants flowered after 26 d in short days (SD) but untreated plants were still vegetative after 6 months. Not only was FT expression low in SD but applied GA bypassed some of the block to flowering in ft-1. On transfer to LD, ga1-3 only flowered when treated simultaneously with GA, and FT expression increased rapidly (<19.5 h) and dramatically (15-fold). In contrast, in the wild type in LD there was little requirement for GA for FT increase and flowering so its endogenous GA content was near to saturating. Despite this permissive role for endogenous GA in Columbia, RNA interference (RNAi) silencing of the GA biosynthesis gene, GA 20-OXIDASE2, revealed an additional, direct role for GA in LD. Flowering took twice as long after silencing the LD-regulated gene, GA 20-OXIDASE2. Such independent LD input by FT and GA reflects their non-sympatric expression (FT in the leaf blade and GA 20-OXIDASE2 in the petiole). Overall, FT acts as the main LD floral signal in Columbia and GA acts on flowering both via and independently of FT

    Monozygotic multiple gestation following in vitro fertilization: analysis of seven cases from Japan

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    We present a series of monozygous multiple gestations achieved following in vitro fertilization (IVF): one case of monochorionic triplet pregnancy and six cases of dizygotic triplet pregnancy. From September 2000 to December 2006, all patients achieving clinical pregnancy by ART were reviewed (n = 2433). A 37 year-old woman who delivered a healthy singleton after IVF returned two years later for FET, and a single blastocyst was transferred. This also resulted in pregnancy, but TV-USG revealed a single gestational sac with three distinct amniotic sacs, each containing a distinct fetal pole with cardiac activity. This pregnancy was electively terminated at nine weeks' gestation. An additional six cases of dizygotic triplets established after fresh embryo transfer (no ICSI or assisted hatching) are also described. Of these, one resulted in a miscarriage at eight weeks' gestation and five patients have an ongoing pregnancy. This case series suggests the incidence of dizygotic/monochorionic triplets following IVF is approximately 10 times higher than the expected rate in unassisted conceptions, and underscores the importance of a conservative approach to lower the number of embryos at transfer. The role of embryo transfer technique and in vitro culture media in the twinning process requires further study

    Deletion of CDKAL1 Affects Mitochondrial ATP Generation and First-Phase Insulin Exocytosis

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    A variant of the CDKAL1 gene was reported to be associated with type 2 diabetes and reduced insulin release in humans; however, the role of CDKAL1 in β cells is largely unknown. Therefore, to determine the role of CDKAL1 in insulin release from β cells, we studied insulin release profiles in CDKAL1 gene knockout (CDKAL1 KO) mice.Total internal reflection fluorescence imaging of CDKAL1 KO β cells showed that the number of fusion events during first-phase insulin release was reduced. However, there was no significant difference in the number of fusion events during second-phase release or high K(+)-induced release between WT and KO cells. CDKAL1 deletion resulted in a delayed and slow increase in cytosolic free Ca(2+) concentration during high glucose stimulation. Patch-clamp experiments revealed that the responsiveness of ATP-sensitive K(+) (K(ATP)) channels to glucose was blunted in KO cells. In addition, glucose-induced ATP generation was impaired. Although CDKAL1 is homologous to cyclin-dependent kinase 5 (CDK5) regulatory subunit-associated protein 1, there was no difference in the kinase activity of CDK5 between WT and CDKAL1 KO islets.We provide the first report describing the function of CDKAL1 in β cells. Our results indicate that CDKAL1 controls first-phase insulin exocytosis in β cells by facilitating ATP generation, K(ATP) channel responsiveness and the subsequent activity of Ca(2+) channels through pathways other than CDK5-mediated regulation

    Search for exotic neutrino-electron interactions using solar neutrinos in XMASS-I

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    We have searched for exotic neutrino-electron interactions that could be produced by a neutrino millicharge, by a neutrino magnetic moment, or by dark photons using solar neutrinos in the XMASS-I liquid xenon detector. We observed no significant signals in 711 days of data. We obtain an upper limit for neutrino millicharge of 5.4×\times1012e^{-12} e at 90\% confidence level assuming all three species of neutrino have common millicharge. We also set flavor dependent limits assuming the respective neutrino flavor is the only one carrying a millicharge, 7.3×1012e7.3 \times 10^{-12} e for νe\nu_e, 1.1×1011e1.1 \times 10^{-11} e for νμ\nu_{\mu}, and 1.1×1011e1.1 \times 10^{-11} e for ντ\nu_{\tau}. These limits are the most stringent yet obtained from direct measurements. We also obtain an upper limit for the neutrino magnetic moment of 1.8×\times1010^{-10} Bohr magnetons. In addition, we obtain upper limits for the coupling constant of dark photons in the U(1)BLU(1)_{B-L} model of 1.3×\times106^{-6} if the dark photon mass is 1×103\times 10^{-3} MeV/c2/c^{2}, and 8.8×\times105^{-5} if it is 10 MeV/c2/c^{2}

    Study on the criteria for assessing skull-face correspondence in craniofacial superimposition

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    Craniofacial superimposition has the potential to be used as an identification method when other traditional biological techniques are not applicable due to insufficient quality or absence of ante-mortem and post-mortem data. Despite having been used in many countries as a method of inclusion and exclusion for over a century it lacks standards. Thus, the purpose of this research is to provide forensic practitioners with standard criteria for analysing skull-face relationships. Thirty-seven experts from 16 different institutions participated in this study, which consisted of evaluating 65 criteria for assessing skull-face anatomical consistency on a sample of 24 different skull-face superimpositions. An unbiased statistical analysis established the most objective and discriminative criteria. Results did not show strong associations, however, important insights to address lack of standards were provided. In addition, a novel methodology for understanding and standardizing identification methods based on the observation of morphological patterns has been proposed
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