48 research outputs found

    Genetic dissection of photoperiod response based on GWAS of pre-anthesis phase duration in spring barley

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    Heading time is a complex trait, and natural variation in photoperiod responses is a major factor controlling time to heading, adaptation and grain yield. In barley, previous heading time studies have been mainly conducted under field conditions to measure total days to heading. We followed a novel approach and studied the natural variation of time to heading in a world-wide spring barley collection (218 accessions), comprising of 95 photoperiod-sensitive (Ppd-H1) and 123 accessions with reduced photoperiod sensitivity (ppd-H1) to long-day (LD) through dissecting pre-anthesis development into four major stages and sub-phases. The study was conducted under greenhouse (GH) conditions (LD; 16/8 h; ∼20/∼16°C day/night). Genotyping was performed using a genome-wide high density 9K single nucleotide polymorphisms (SNPs) chip which assayed 7842 SNPs. We used the barley physical map to identify candidate genes underlying genome-wide association scans (GWAS). GWAS for pre-anthesis stages/sub-phases in each photoperiod group provided great power for partitioning genetic effects on floral initiation and heading time. In addition to major genes known to regulate heading time under field conditions, several novel QTL with medium to high effects, including new QTL having major effects on developmental stages/sub-phases were found to be associated in this study. For example, highly associated SNPs tagged the physical regions around HvCO1 (barley CONSTANS1) and BFL (BARLEY FLORICAULA/LEAFY) genes. Based upon our GWAS analysis, we propose a new genetic network model for each photoperiod group, which includes several newly identified genes, such as several HvCO-like genes, belonging to different heading time pathways in barley

    The experience of educational research at doctoral level in the region of Cuyo, Argentina

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    [EN] In this paper are reported the results of an exploratory-analytical research of a qualitative nature, whose intention is to approach the comprehension of the experiences, their peculiarities and problems, of a sample of students and graduates from the three doctorates in Education existing in the region of Cuyo, Argentina, which –though they reach a certain maturity– also show in these years some specific difficulties, among which the most relevant is the low rate of completion (close to 20%). The administered questionnaire, elaborated ad hoc, by means of open-ended questions, inquires on three dimensions that can explain the experience of the PhD student: 1) educational research methodology training, 2) practice in scientific research and 3) doctoral research process. The results show that curricular paths of doctorate’s research methodology, in dependence of their approach, play an important role in the process of theses, in synergy with other factors: integration into a research team, a combination of intrinsic and extrinsic motives in the choice of the topic, a more elaborated conceptualization of educational research, conceptual changes of greater importance. Among the peculiarities, one warns the primacy of the experience and/or teacher workplace in decisions concerning doctoral research; among the difficulties, stand out the lack of time and the major frequency of intrinsic difficulties to the thesis in delayed students.[ES] En este trabajo se informan los resultados de una investigación exploratorio-analítica de carácter cualitativo, cuyo propósito es acercarnos a la comprensión de las experiencias, sus particularidades y problemáticas, de una muestra de alumnos y egresados de los tres doctorados en Educación existentes en la región de Cuyo, Argentina, los que –si bien alcanzan una cierta madurez– también muestran en estos años algunas dificultades específicas, entre las cuales la más relevante es la baja tasa de finalización (cercana al 20%). El cuestionario que se administra, elaborado ad hoc, mediante preguntas abiertas, indaga sobre tres dimensiones que pueden explicar la experiencia del doctorando: 1) formación en metodología de la investigación educativa, 2) práctica en investigación científica y 3) proceso de investigación doctoral. Los resultados muestran que los trayectos curriculares de metodología de la investigación del doctorado, en dependencia de su enfoque, desempeñan un papel relevante en el proceso de tesis, en sinergia con otros factores: la inserción en un equipo de investigación, una combinación de motivos intrínsecos y extrínsecos en la elección del tema, una conceptualización más elaborada de investigación educativa, cambios conceptuales de mayor envergadura. Entre las peculiaridades, se advierte la primacía de la experiencia y/o desempeño docente en decisiones relativas a la investigación doctoral; entre las dificultades, destaca la falta de tiempo y la mayor frecuencia de dificultades intrínsecas a la tesis en los estudiantes demorados.Difabio De Anglat, H.; Portela De Nieto, A.; Gelonch Villarino, S.; Muscará, F.; Boarini De Dutto, MG. (2018). La experiencia de investigación educativa de nivel doctoral en la región de Cuyo, Argentina. 11-32. doi:10.4995/redu.2018.5690SWORD113

    Genetic control of duration of pre-anthesis phases in wheat (Triticum aestivum L.) and relationships to leaf appearance, tillering, and dry matter accumulation

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    The duration of pre-anthesis developmental phases is of interest in breeding for improved adaptation and yield potential in temperate cereals. Yet despite numerous studies on the genetic control of anthesis (flowering) time and floral initiation, little is known about the genetic control of other pre-anthesis phases. Furthermore, little is known about the effect that changes in the duration of pre-anthesis phases could have on traits related to leaf appearance and tillering, or dry matter accumulation before terminal spikelet initiation (TS). The genetic control of the leaf and spikelet initiation phase (LS; from sowing to TS), the stem elongation phase (SE; from TS to anthesis), and, within the latter, from TS to flag leaf appearance and from then to anthesis, was studied in two doubled-haploid, mapping bread wheat populations, Cranbrook×Halberd and CD87×Katepwa, in two field experiments (ACT and NSW, Australia). The lengths of phases were estimated from measurements of both TS and the onset of stem elongation. Dry weight per plant before TS, rate of leaf appearance, tillering rate, maximum number of tillers and number of leaves, and dry weight per plant at TS were also estimated in the Cranbrook×Halberd population. More genomic regions were identified for the length of the different pre-anthesis phases than for total time to anthesis. Although overall genetic correlations between LS and SE were significant and positive, independent genetic variability between LS and SE, and several quantitative trait loci (QTLs) with different effects on both phases were found in the two populations. Several of these QTLs (which did not seem to coincide with reported major genes) could be of interest for breeding purposes since they were only significant for either LS or SE. There was no relationship between LS and the rate of leaf appearance. LS was strongly and positively correlated with dry weight at TS but only slightly negatively correlated with early vigour (dry weight before TS). Despite significant genetic correlations between LS and some tillering traits, shortening LS so as to lengthen SE without modifying total time to anthesis would not necessarily reduce tillering capacity, as QTLs for tillering traits did not coincide with those QTLs significant only for LS or SE. Therefore, the study of different pre-anthesis phases is relevant for a better understanding of genetic factors regulating developmental time and may offer new tools for fine-tuning it in breeding for both adaptability and yield potential

    Continuous-flow in-line solvent-swap crystallization of vitamin D(3)

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    A continuous tandem in-line evaporation–crystallization is presented. The process includes an in-line solvent-swap step, suitable to be coupled to a capillary based cooler. As a proof of concept, this setup is tested in a direct in-line acetonitrile mediated crystallization of Vitamin D₃. This configuration is suitable to be coupled to a new end-to-end continuous microflow synthesis of Vitamin D₃. By this procedure, vitamin particles can be crystallized in continuous flow and isolated using an in-line continuous filtration step. In one run in just 1 min of cooling time, ∼50% (w/w) crystals of Vitamin D₃ are directly obtained. Furthermore, the polymorphic form as well as crystals shape and size properties are described in this paper.Marc Escribà-Gelonch, Volker Hessel, Manuel C. Maier, Timothy Noël, Maria Fernanda Neira d’Angelo and Heidrun Gruber-Woelfle

    Exclusion of NFAT5 from Mitotic Chromatin Resets Its Nucleo-Cytoplasmic Distribution in Interphase

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    The transcription factor NFAT5 is a major inducer of osmoprotective genes and is required to maintain the proliferative capacity of cells exposed to hypertonic stress. In response to hypertonicity, NFAT5 translocates to the nucleus, binds to regulatory regions of osmoprotective genes and activates their transcription. Besides stimulus-specific regulatory mechanisms, the activity of transcription factors in cycling cells is also regulated by the passage through mitosis, when most transcriptional processes are downregulated. It was not known whether mitosis could be a point of control for NFAT5.Using confocal microscopy we observed that NFAT5 was excluded from chromatin during mitosis in both isotonic and hypertonic conditions. Analysis of NFAT5 deletions showed that exclusion was mediated by the carboxy-terminal domain (CTD). NFAT5 mutants lacking this domain showed constitutive binding to mitotic chromatin independent of tonicity, which caused them to localize in the nucleus and remain bound to chromatin in the subsequent interphase without hypertonic stimulation. We analyzed the contribution of the CTD, DNA binding, and nuclear import and export signals to the subcellular localization of this factor. Our results indicated that cytoplasmic localization of NFAT5 in isotonic conditions required both the exclusion from mitotic DNA and active nuclear export in interphase. Finally, we identified several regions within the CTD of NFAT5, some of them overlapping with transactivation domains, which were separately capable of causing its exclusion from mitotic chromatin.Our results reveal a multipart mechanism regulating the subcellular localization of NFAT5. The transactivating module of NFAT5 switches its function from an stimulus-specific activator of transcription in interphase to an stimulus-independent repressor of binding to DNA in mitosis. This mechanism, together with export signals acting in interphase, resets the cytoplasmic localization of NFAT5 and prevents its nuclear accumulation and association with DNA in the absence of hypertonic stress

    A Pilot Randomized Controlled Trial to Explore Cognitive and Emotional Effects of Probiotics in Fibromyalgia

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    It has recently been found that microbes in the gut may regulate brain processes through the gut microbiota–brain axis, which modulates affection, motivation and higher cognitive functions. According to this finding, the use of probiotics may be a potential treatment to improve physical, psychological and cognitive status in clinical populations with altered microbiota balance such as those with fibromyalgia (FMS). Thus, the aim of the present pilot study with a double-blind, placebo-controlled, randomised design was to test whether a multispecies probiotic may improve cognition, emotional symptoms and functional state in a sample of patients diagnosed with FMS. Pain, impact of FMS, quality of life, anxiety and depressive symptoms were measured during the pre- and post-intervention phases; participants also completed two computerised cognitive tasks to assess impulsive choice and decision-making. Finally, urinary cortisol concentration was determined. To our knowledge, this is the first study that explore the effect of a multispecies probiotic in FMS patients. Our results indicated that probiotics improved impulsivity and decision-making in these patients. However, more research is needed to further explore the potential effects of probiotics on other cognitive functions affected in FMS as well as in other clinical populations
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