1,831 research outputs found
Over expression of Spcdc25 and of ATWEE1 in Arabidopsis alter the sensitivity of hypocotyl explants to auxin and cytokinin in culture
No full textThe cell cycle is regulated by plant growth regulators (PGRs), mainly auxins and cytokinins. In eukaryotes, two genes regulate entry into mitosis: cdc25 and wee1, although a confirmed homologue of cdc25 in plants has not yet been identified. Expressing the fission yeast cdc25 (Spcdc25) in tobacco BY2 cells allows them to bypass a cytokinin block at G2/M. In tobacco and Arabidopsis roots, Spcdc25 expression led to an increased frequency of lateral roots. Conversely, over-expression of AtWEE1 in Arabidopsis induces a slower rate of root elongation and a reduced frequency of lateral roots. Wild type Arabidopsis hypocotyl explants respond to increasing levels of cytokinin with rapid proliferation, greening and formation of shoots, but are unable to form shoots in the absence of auxin and cytokinin. We tested if hypocotyl explants from Arabidopsis lines over-expressing ATWEE1 and Spcdc25 respond like WT to auxin (NAA) and cytokinin (Kinetin). We used a system of two-way grids in which we increased concentration of NAA and kinetin in X- and Y-axes, respectively. There were clear differences in the response between the transgenic and WT. All concentrations of auxin and cytokinin suppressed growth of calli in the AtWEE1OE line compared to WT. Moreover, in the AtWEE1OE, both organogenesis and formation of root hair structures were suppressed. At higher PGR levels neither WT nor Spcdc25 lines produced shoots but both produced roots and hairs. A minimum level of NAA was required for callus induction in both WT and Spcdc25 lines. However at low NAA/Kinetin there was growth of calli and more roots in Spcdc25 lines compared with WT. In an inducible Spcdc25 line plus inducer, roots formed at concentrations which suppressed roots in the inducible Spcdc25 line without inducer These results are discussed in the context of plant growth regulators and regulatory genes of the plant cell cycle
Expression of Spcdc25 in Arabidopsis alters the response of hypocotyl explants to auxin & cytokinin in culture
No full textThe eukaryotic cell cycle comprises four distinct phases, mitosis (M), G1, DNA synthesis (S)-phase and G2 in which the key transitions are G1/S and G2/M. Progression of dividing cells through the cell cycle is controlled by key enzymes: cyclin-dependent kinases (CDKs), the products of cdc2-like genes. The regulation of CDK activity includes, amongst others, its activation by Cdc25 phosphatase at G2/M. This positive regulator is balanced by negative regulation by a protein kinase encoded by wee1. A plant homologue of the inactivating kinase, wee1, has already been cloned. However, a homologue of the activating phosphatase cdc25 has not been unequivocally identified in plants yet. The expression of cdc2-like genes can be influenced by many factors including plant growth regulators, mainly auxins and cytokinins. Expressing the fission yeast cdc25 (Spcdc25) in the tobacco BY2 cell line results in cells bypassing a cytokinin block, and in explants of tobacco expressing Spcdc25, shoot development is stimulated not only in a treatment that favours shoot formation (high cytokinin and low auxin) but also under root-stimulating conditions (high auxin and low cytokinin) and even without exogenous growth regulator treatment. Wild type Arabidopsis hypocotyls explants respond to increasing levels of cytokinin with rapid proliferation, greening and formation of shoots, but are unable to form shoots in the absence of auxin and cytokinin. We tested if hypocotyl explants from Arabidopsis transformed with constitutive and inducible lines Spcdc25 respond like wt to auxin (NAA) and cytokinin (Kinetin) in a system of grids in which we increase concentration of these exogenous plant growth regulators. We find that Wt and Spcdc25 hypocotiles segments are very sensible to higher liveles of ormons (1000 ngml-1 to 3000 ngml-1), calli grew with a lot of root hairs and the analysis of shots formation was impossible. Also is required a minimum level of NAA for calli induction in these strains: at 25 ngml-1 NAA/Kinetin we start to see grow of calli in Spcdc25 lines, plants in WT, not grow in not induced Spcdc25 line. Interesting results at 25, 50 ngml-1 NAA and 200ngml-1 Kinetin where in Spcdc25 there is grow of real roots, not visible in wt and not induced Spcdc25 line. At several concentrations of hormones Spcdc25 forms buds they will be show and discussed
PIDR(s): IDR(s) as a Projection Method
No full textThe Induced Dimension Reduction(s) method (or the IDR(s) method) is an example of an iterative method used for solving systems of linear equations. Projection methods are a special type of iterative method. They find an approximate solution in a subspace (the right subspace) by requiring that the residual is orthogonal to another subspace (the left subspace). In this thesis we investigate how we can implement IDR(s) as a projection method. We call this method IDR(s), which stands for Projected IDR(s).We present an implementation of PIDR(s) for solving systems of linear equations and for solving eigenvalue problems. These implementations are not meant to be optimal, but they are used to show that IDR(s) can indeed be seen as a projection method.Track: educationScience Education and CommunicationApplied Science
The allelochemical farnesene affects Arabidopsis thaliana root meristem altering auxin distribution
No full textFarnesene is a sesquiterpene with semiochemical activity involved in interspecies communication. This molecule, known for its phytotoxic potential and its effects on root morphology and anatomy, caused anisotropic growth, bold roots and a “left-handedness” phenotype. These clues suggested an alteration of auxin distribution, and for this reason, the aim of the present study was to evaluate its effects on: i) PIN-FORMED proteins (PIN) distribution, involved in polar auxin transport; ii) PIN genes expression iii) apical meristem anatomy of primary root, in 7 days old Arabidopsis thaliana seedlings treated with farnesene 250 μM. The following GFP constructs: pSCR::SCR-GFP, pDR5::GFP, pPIN1::PIN1-GFP, pPIN2::PIN2-GFP, pPIN3::PIN3-GFP, pPIN4::PIN4-GFP and pPIN7::PIN7-GFP were used to evaluate auxin distribution. Farnesene caused a reduction in meristematic zone size, an advancement in transition zone, suggesting a premature exit of cells from the meristematic zone, a reduction in cell division and an impairment between epidermal and cortex cells. The auxin-responsive reporter pDR5::GFP highlighted that auxin distribution was impaired in farnesene-treated roots, where auxin distribution appeared maximum in the quiescent center and columella initial cells, without extending to mature columella cells. This finding was further confirmed by the analysis on PIN transport proteins distribution, assessed on individual constructs, which showed an extreme alteration mainly dependent on the PIN 3, 4 and 7, involved in pattern specification during root development and auxin redistribution. Finally, farnesene treatment caused a down-regulation of all the auxin transport genes studied. We propose that farnesene affected auxin transport and distribution causing the alteration of root meristem, and consequently the left-handedness phenotype
Actie podium van de stad - De plek voor overlapping van publieke en private actie; onderzoeksrapport. Het grote huis en de kleine stad - de stad van ankers in plaats van wortels; essay, onderdeel van onderzoeksrapport.
No full textHet onderzoeksrapport is in samenwerking van bovengenoemde auteurs tot stand gekomen. Het essay is enkel geschreven door M.B. Dekker.At home in the city - BerlinDwellingArchitectur
Author Correction:A 41,500 year-old decorated ivory pendant from Stajnia Cave (Poland)
No full textCorrection to: Scientific Reports https://doi.org/10.1038/s41598-021-01221-6, published online 25 November 2021The original version of this Article contained errors in the author list where Marjolein D. Bosch was omitted from the author list, and Mikołaj Urbanowski was incorrectly listed as an author of the original Article, and has subsequently been removed.The Author contributions section now reads:“S.T. W.N. and A.N. conceived the project; S.T., W.N., A.P., M.B., S.C., M.D., H.F., A.M., M.D. B., D.P., M.P.R., C.M.R., V.S-M., G.M.S., P.S., M.S., K.S., A.V., F.W., H.W., A.W., M.Z., S.B., A.N., J-J. H., performed research; S.T., A.P., W.N., M.B., M.D.B., S.C., M.D., H.F., A.M., D.P., M.P.R., C.M.R., V.S-M., G.M.S., P.S., M.S., K.S., A.V., F.W., H.W., A.W., M.Z., S.B., A.N., J-J. H. analysed all archaeological data; S.T. and A.P. wrote the paper with the collaboration of all the co-authors.”The original Article and its accompanying Supplementary Information file have been corrected
Internet and e-health Care: an Interdigital Field of Study
No full textThe foreword focuses on a historical definition of the e-health field. The author contributed to shaping the e-health field in the international community being one of the pioneers' scholars since the 1990s. The chapter discusses current and challenging future scenarios based on the international evolution that brings about new challenges
Genetic, metabolic and antioxidant differences among three different Calabrian populations of Cynara cardunculus subsp. cardunculus
No full textCynara cardunculus subsp. cardunculus, belonging to Asteraceae family, and widely distributed in the Mediterranean area, exhibits high nutraceutical and nutritional potential, as compared to the cultivated varieties. This work reports, for the first time, on genetic and metabolic characteristics of three natural populations of C. cardunculus present in the Pollino National Park (Calabria, Italy), referred to as wild cardoons, collected in different areas (Castrovillari, Trebisacce and Sibari). One wild and one cultivated sardinian genotypes were also analysed as comparison. Six nuSSRs markers, were used to assess population structure and diversity. The obtained results showed that all three populations genetically diverge from the cultivated one and cluster with sardinian wild populations. Moreover, PCoA and Bayesian clustering analyses evidenced that Trebisacce and Sibari populations were closer to each other compared to Castrovillari one. HPLC analysis, also revealed a metabolic profile particularly rich in phenolic acids for Sibari population which also exhibited the highest capacity to protect linoleic acid from peroxidation. To long-term, these results could be useful to preserve biodiversity and promote ecotypes with major nutraceutical proprieties
LA PRIMA RICEZIONE DELLA FENOMENOLOGIA NEGLI STATI UNITI: UN'ANALISI STORICO-CRITICA
No full textMy research analyzes the characteristics of the first reception of husserlian phenomenology in the United States. The base of this work is a detailed historiographical reconstruction of this phase representing the point of departure of all those studies on phenomenological tradition that have been developed in the American academic world. Several institutions belong to the context in which this reception took place: the New School for Social Research as the original center for the teaching of phenomenology and a number of societies arisen since the sixties to diffuse Husserl’s philosophy in the United States (First Part: Chapter 2 and Chapter 3).
This first reception, promoted since the late thirties by Kaufmann, Schutz, Gurwitsch, Cairns and Farber, must be distinguished from an earlier phase, presenting only the general approach to Husserl’s thought of some American scholars (Second Part: Chapter 1). The origin of the studies of each author undoubtedly typifies their promotion of husserlian phenomenology: Gurwitsch, Schutz and Kaufmann belong to the European tradition, (First Part: Chapter 1) while the Americans Farber and Cairns mainly owe the growing interest in Husserl’s thought to their studies in Freiburg (Second Part: Chapter 2). Nevertheless, during this phase of reception of phenomenology, the original adherence to his lesson – useful to distinguish them from others Husserl’s students emigrated in United States – gradually disappears from their critiques. The aim of my research is to single out the salient features that characterize the different interpretations of Husserl’s thought elaborated by each author, whereas their originality can be indicated as decisive for following developments (Third Part). Gurwitsch builds an interesting critique of Husserl’s whole-part theory, focuses his analysis on the noema, and elaborates a non-egological conception of consciousness. Schutz’s critique of transcendental phenomenology mainly refers to his concept of mundane intersubjectivity. For what concerns Cairns, his few writings published until now don’t allow to deepen the exam on his interpretation. After the arrival in the United States, Kaufmann concentrates his discussion on the relationship between husserlian phenomenology and the logic. Farber proposes a critique which is far from being an original interpretation, although his analysis remains bound to the interest in phenomenology until the end.
With this work I want to explain how the interest about husserlian phenomenology began in the United States, who were its promoters, and also what kind of interpretations they developed in the American academic world. It must be considered that they hadn’t a decisive influence on further developments of phenomenological studies, but in any case helped bringing the attention on Husserl’s thought throughout their teaching
Fruit volatilome profiling through GC × GC-ToF-MS and gene expression analyses reveal differences amongst peach cultivars in their response to cold storage
No full textPeaches have a short shelf life and require chilling during storage and transport. Peach aroma is important for consumer preference and determined by underlying metabolic pathways and gene expression. Differences in aroma (profiles of volatile organic compounds, VOCs) have been widely reported across cultivars and in response to cold storage. However, few studies used intact peaches, or used equilibrium sampling methods subject to saturation. We analysed VOC profiles using TD-GC × GC-ToF-MS and expression of 12 key VOC pathway genes of intact fruit from six cultivars (three peaches, three nectarines) before and after storage at 1 °C for 7 days including 36 h shelf life storage at 20 °C. Two dimensional GC (GC × GC) significantly enhances discrimination of thermal desorption gas chromatography time-of-flight mass spectrometry (TD-GC-ToF-MS) and detected a total of 115 VOCs. A subset of 15 VOCs from analysis with Random Forest discriminated between cultivars. Another 16 VOCs correlated strongly with expression profiles of eleven key genes in the lipoxygenase pathway, and both expression profiles and VOCs discriminated amongst cultivars, peach versus nectarines and between treatments. The cultivar-specific response to cold storage underlines the need to understand more fully the genetic basis for VOC changes across cultivars
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