1000 resultados para ddc: N3983


Relevância:

10.00% 10.00%

Publicador:

Resumo:

The function of the extracytoplasmic AUXIN-BINDING-PROTEIN1 (ABP1) is largely enigmatic. We complemented a homozygous T-DNA insertion null mutant of ABP1 in Arabidopsis thaliana Wassilewskia with three mutated and one wild-type (wt) ABP1 cDNA, all tagged C-terminally with a strepII-FLAG tag upstream the KDEL signal. Based on in silico modelling, the abp1 mutants were predicted to have altered geometries of the auxin binding pocket and calculated auxin binding energies lower than the wt. Phenotypes linked to auxin transport were compromised in these three complemented abp1 mutants. Red light effects, such as elongation of hypocotyls in constant red (R) and far-red (FR) light, in white light supplemented by FR light simulating shade, and inhibition of gravitropism by R or FR, were all compromised in the complemented lines. Using auxin-or light-induced expression of marker genes, we showed that auxininduced expression was delayed already after 10 min, and light-induced expression within 60 min, even though TIR1/AFB or phyB are thought to act as receptors relevant for gene expression regulation. The expression of marker genes in seedlings responding to both auxin and shade showed that for both stimuli regulation of marker gene expression was altered after 10-20 min in the wild type and phyB mutant. The rapidity of expression responses provides a framework for the mechanics of functional interaction of ABP1 and phyB to trigger interwoven signalling pathways.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

In diesem Beitrag wird ein neu entwickelter Schülerinnen- und Schülerfragebogen zur Erfassung aggressiver und nicht aggressiver Schülerstörungen, aggressiven Lehrerverhaltens, Störungen des methodisch-didaktischen Settings sowie Klassenführung und Beziehung vorgestellt und die testtheoretischen Kennwerte diskutiert. Die faktorielle Struktur wurde an einer Stichprobe von N=1341 Schülerinnen und Schüler der fünften und sechsten Klasse ermittelt. Eine explorative Faktorenanalyse mit Oblimin-Rotation ergab sieben eindeutige, gut interpretierbare Faktoren, welche den theoretisch postulierten Konstrukten entsprechen. Vier Faktoren erfassen Störungen und drei Faktoren umfassen störungspräventive Merkmale des Unterrichts. Die internen Konsistenzen der Skalen liegen zwischen .60 und .88. (DIPF/Orig.)

Relevância:

10.00% 10.00%

Publicador:

Resumo:

Cultivation of chilling-tolerant ornamental crops at lower temperature could reduce the energy demands of heated greenhouses. To provide a better understanding of how sub-optimal temperatures (12 degrees C vs. 16 degrees C) affect growth of the sensitive Petunia hybrida cultivar 'SweetSunshine Williams', the transcriptome, carbohydrate metabolism, and phytohormone homeostasis were monitored in aerial plant parts over 4 weeks by use of a microarray, enzymatic assays and GC-MS/MS. The data revealed three consecutive phases of chilling response. The first days were marked by a strong accumulation of sugars, particularly in source leaves, preferential up-regulation of genes in the same tissue and down-regulation of several genes in the shoot apex, especially those involved in the abiotic stress response. The midterm phase featured a partial normalization of carbohydrate levels and gene expression. After 3 weeks of chilling exposure, a new stabilized balance was established. Reduced hexose levels in the shoot apex, reduced ratios of sugar levels between the apex and source leaves and a higher apical sucrose/hexose ratio, associated with decreased activity and expression of cell wall invertase, indicate that prolonged chilling induced sugar accumulation in source leaves at the expense of reduced sugar transport to and reduced sucrose utilization in the shoot. This was associated with reduced levels of indole-3-acetic acid and abscisic acid in the apex and high numbers of differentially, particularly up-regulated genes, especially in the source leaves, including those regulating histones, ethylene action, transcription factors, and a jasmonate-ZIM-domain protein. Transcripts of one Jumonji C domain containing protein and one expansin accumulated in source leaves throughout the chilling period. The results reveal a dynamic and complex disturbance of plant function in response to mild chilling, opening new perspectives for the comparative analysis of differently tolerant cultivars.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

Es werden neue theoretische Überlegungen vorgetragen, die dazu beitragen können, die gesundheitspädagogische Forschung zu stimulieren und die Praxis der Gesundheitserziehung zu beeinflussen. Dabei werden Phasen des Selbstregulationsprozesses, der zu einem Risikoverhalten oder Gesundheitsverhalten führt, unterschieden. Die anfängliche Motivationsphase ist durch das Abwägen zwischen Alternativen gekennzeichnet und schließt mit einer Zielintention ab. In der nachfolgenden Volitionsphase geht es um die Umsetzung einer Absicht in einem Handlungsversuch sowie um die Aufrechterhaltung des Gesundheitsverhaltens gegen Widerstände. Auch hier erweist sich die Kompetenzerwartung als eine wichtige Einflußgröße. Abschließend werden Konsequenzen für die Gesundheitserziehung diskutiert. (DIPF/Orig.)

Relevância:

10.00% 10.00%

Publicador:

Resumo:

Ultra high pressure homogenization (UHPH) opens up new areas for dynamic high pressure assisted thermal sterilization of liquids. Bacillus amyloliquefaciens spores are resistant to high isostatic pressure and temperature and were suggested as potential surrogate for high pressure thermal sterilization validation. B. amyloliquefaciens spores suspended in PBS buffer (0.01 M, pH 7.0), low fat milk (1.5%, pH 6.7), and whole milk (3.5%, pH 6.7) at initial concentration of similar to 10(6) CFU/mL were subjected to UHPH treatments at 200, 300, and 350 MPa with an inlet temperature at similar to 80 degrees C. Thermal inactivation kinetics of B. amyloliquefaciens spores in PBS and milk were assessed with thin wall glass capillaries and modeled using first-order and Weibull models. The residence time during UHPH treatments was estimated to determine the contribution of temperature to spore inactivation by UHPH. No sublethal injury was detected after UHPH treatments using sodium chloride as selective component in the nutrient agar medium. The inactivation profiles of spores in PBS buffer and milk were compared and fat provided no clear protective effect for spores against treatments. Treatment at 200 MPa with valve temperatures lower than 125 degrees C caused no reduction of spores. A reduction of 3.5 log(10)CFU/mL of B. amyloliquefaciens spores was achieved by treatment at 350 MPa with a valve temperature higher than 150 degrees C. The modeled thermal inactivation and observed inactivation during UHPH treatments suggest that temperature could be the main lethal effect driving inactivation.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

Hans-Ulrich Grunder diskutiert am Beispiel von Andreas Flitners „Reform der Erziehung", ob eine pädagogische Aktualisierung ohne Rückgriff auf die Ergebnisse der bildungshistorischen Forschung möglich ist. Er versucht die These zu begründen, daß ohne Beachtung der Historiographie eine legitime Pädagogik nicht entwickelt werden kann. (DIPF/Orig.)

Relevância:

10.00% 10.00%

Publicador:

Resumo:

Attempting to achieve long-lasting and stable resistance using uniformly deployed rice varieties is not a sustainable approach. The real situation appears to be much more complex and dynamic, one in which pathogens quickly adapt to resistant varieties. To prevent disease epidemics, deployment should be customized and this decision will require interdisciplinary actions. This perspective article aims to highlight the current progress on disease resistance deployment to control bacterial blight in rice. Although the model system rice-Xanthomonas oryzae pv. oryzae has distinctive features that underpin the need for a case-by-case analysis, strategies to integrate those elements into a unique decision tool could be easily extended to other crops.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

Background: Interspecific hybridization is a useful tool in ornamental breeding to increase genetic variability and introduce new valuable traits into existing cultivars. The successful formation of interspecific hybrids is frequently limited by the presence of pre- and post-fertilization barriers. In the present study, we investigated the nature of hybridization barriers occurring in crosses between Kalanchoe species and evaluated possibilities of obtaining interspecific hybrids. Results: The qualitative and quantitative analyses of pollen tube growth in situ were performed following intra-and interspecific pollinations. They revealed occurrence of pre-fertilization barriers associated with inhibition of pollen germination on the stigma and abnormal growth of pollen tubes. Unilateral incongruity related to differences in pistil length was also observed. The pollen quality was identified as a strong factor influencing the number of pollen tubes germinating in the stigma. In relation to post-fertilization barriers, endosperm degeneration was a probable barrier hampering production of interspecific hybrids. Moreover, our results demonstrate the relation of genetic distance estimated by AFLP marker analysis of hybridization partners with cross-compatibility of Kalanchoe species. At the same time, differences in ploidy did not influence the success of interspecific crosses. Conclusions: Our study presents the first comprehensive analysis of hybridization barriers occurring within Kalanchoe genus. Reproductive barriers were detected on both, pre- and post-fertilization levels. This new knowledge will contribute to further understanding of reproductive isolation of Kalanchoe species and facilitate breeding of new cultivars. For the first time, interspecific hybrids between K. nyikae as maternal plant and K. blossfeldiana as well as K. blossfeldiana and K. marnieriana were generated.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

Immer wieder haben sich im Laufe der Geschichte Erzieher mit der Frage beschäftigt, wie der nachfolgenden Generation die einmal gewonnenen Einsichten und Wahrheiten abendländisch-gesellschaftlichen Lebens und Denkens zu vermitteln seien. Gelang ihnen eine Antwort, wurden sie zu Klassikern der Pädagogik. Auch Bertolt Brecht, der Lehrstückeschreiber, hat sich der Erziehungsproblematik angenommen und es droht ihm dasselbe Schicksal: Er, der einst als „Bürgerschreck“ galt, wird heute in die Schar der Klassiker eingereiht. Wie erklärt sich dieses Phänomen? Der vorliegende Text basiert auf der These, dass schon eine gründliche Analyse eines kleinen Abschnitts aus Brechts Werk eher über das Phänomen Aufschluss geben kann als die extensive Lektüre seiner „Gesammelten Schriften“.(DIPF/Orig.)

Relevância:

10.00% 10.00%

Publicador:

Resumo:

Cauliflower (Brassica oleracea var. botrytis) is a vernalization-responsive crop. High ambient temperatures delay harvest time. The elucidation of the genetic regulation of floral transition is highly interesting for a precise harvest scheduling and to ensure stable market supply. This study aims at genetic dissection of temperature-dependent curd induction in cauliflower by genome-wide association studies and gene expression analysis. To assess temperature dependent curd induction, two greenhouse trials under distinct temperature regimes were conducted on a diversity panel consisting of 111 cauliflower commercial parent lines, genotyped with 14,385 SNPs. Broad phenotypic variation and high heritability (0.93) were observed for temperature-related curd induction within the cauliflower population. GWA mapping identified a total of 18 QTL localized on chromosomes O1, O2, O3, O4, O6, O8, and O9 for curding time under two distinct temperature regimes. Among those, several QTL are localized within regions of promising candidate flowering genes. Inferring population structure and genetic relatedness among the diversity set assigned three main genetic clusters. Linkage disequilibrium (LD) patterns estimated global LD extent of r(2) = 0.06 and a maximum physical distance of 400 kb for genetic linkage. Transcriptional profiling of flowering genes FLOWERING LOCUS C (BoFLC) and VERNALIZATION 2 (BoVRN2) was performed, showing increased expression levels of BoVRN2 in genotypes with faster curding. However, functional relevance of BoVRN2 and BoFLC2 could not consistently be supported, which probably suggests to act facultative and/or might evidence for BoVRN2/BoFLC-independent mechanisms in temperature regulated floral transition in cauliflower. Genetic insights in temperature-regulated curd induction can underpin genetically informed phenology models and benefit molecular breeding strategies toward the development of thermo-tolerant cultivars.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

Quantum mechanics predicts that our physical reality is influenced by events that can potentially happen but factually do not occur. Interaction-free measurements (IFMs) exploit this counterintuitive influence to detect the presence of an object without requiring any interaction with it. Here we propose and realize an IFM concept based on an unstable many-particle system. In our experiments, we employ an ultracold gas in an unstable spin configuration, which can undergo a rapid decay. The object-realized by a laser beam-prevents this decay because of the indirect quantum Zeno effect and thus, its presence can be detected without interacting with a single atom. Contrary to existing proposals, our IFM does not require single-particle sources and is only weakly affected by losses and decoherence. We demonstrate confidence levels of 90%, well beyond previous optical experiments.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

Der vorliegende Wiederabdruck eines 1937 publizierten Textes rückt die Aktualität der damaligen bildungspolitischen Reformbemühungen zur Schulzeitverkürzung und Studiendauer in den Vordergrund. (DIPF/Bal)

Relevância:

10.00% 10.00%

Publicador:

Resumo:

Somatic embryogenesis has been shown to be an efficient in vitro plant regeneration system for many crops such as the important ornamental plant Cyclamen persicum, for which this regeneration pathway of somatic embryogenesis is of interest for the vegetative propagation of parental lines as well as elite plants. However, somatic embryogenesis is not commercially used in many crops due to several unsolved problems, such as malformations, asynchronous development, deficiencies in maturation and germination of somatic embryos. In contrast, zygotic embryos in seeds develop and germinate without abnormalities in most cases. Instead of time-consuming and labor-intensive experiments involving tests of different in vitro culture conditions and plant growth regulator supplements, we follow a more directed approach. Zygotic embryos served as a reference and were compared to somatic embryos in metabolomic analyses allowing the future optimization of the in vitro system. The aims of this study were to detect differences in the metabolite profiles of torpedo stage somatic and zygotic embryos of C. persicum. Moreover, major metabolites in endosperm and testa were identified and quantified. Two sets of extracts of two to four biological replicates each were analyzed. In total 52 metabolites were identified and quantified in the different tissues. One of the most significant differences between somatic and zygotic embryos was that the proline concentration in the zygotic embryos was about 40 times higher than that found in somatic embryos. Epicatechin, a scavenger for reactive oxygen species, was found in highest abundance in the testa. Sucrose, the most abundant metabolite was detected in significantly higher concentrations in zygotic embryos. Also, a yet unknown trisaccharide, was significantly enriched in zygotic embryos.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

Kultureller Wandel und Musikpädagogik stehen in einem dialektischen Verhältnis zueinander, weil zu den Schwerpunktfeldern musikpädagogischer Theoriebildung und schulischer wie außerschulischer Praxis das sich wandelnde kulturelle Handeln von (jungen) Menschen gehört, zugleich aber die Musikpädagogik in ihrem Selbstverständnis selbst einem Wandel unterliegt. Unter dem Thema der 99er Tagung des AMPF >Kultureller Wandel und Musikpädagogik< sind daher zahlreiche Beiträge zusammengekommen, die in ihrer thematischen Breite zentrale Aspekte dieses kulturpolitischen wie auch musikpädagogischen Wandels aufnehmen und so einen Beitrag zur theoretischen Reflexion bzw. Begründung des Kulturbegriffs und seine Bedeutung für das Handlungsfeld der schulischen und außerschulischen Sozialisation leisten. (DIPF/Orig.)