The evolution of seeds defines a remarkable landmark in the history of land plants. A developing seed contains three genetically distinct structures: the embryo, the nourishing tissue, and the seed ...coat. While fertilization is necessary to initiate seed development in most plant species, apomicts have evolved mechanisms allowing seed formation independently of fertilization. Despite their socio-economical relevance, the molecular mechanisms driving seed development have only recently begun to be understood. Here we review the current knowledge on the role of the hormone auxin for the initial development of the three seed structures and as a trigger of fertilization-independent seed development.
Introduction
Recovery is much broader than experiencing remission of symptoms. It is understood as the experience of a subjectively significant and satisfying life, even if some symptoms of mental ...illness persist. The recovery process from borderline personality disorder (BPD) is complex and includes recognizing the need for change and developing greater self-acceptance.
Objectives
Provide an overview of personal recovery from BPD.
Methods
The authors did a non-systematic review in pubmed with the words: “borderline personality disorder” and “Recovery”.
Results
BPD is a serious mental disorder characterized by a pattern of instability in interpersonal relationships, self-image and affections, marked by impulsiveness and (para) suicidal behaviors. Unemployment and difficulties in obtaining and maintaining employment are highly prevalent on BPD and add social exclusion and deterioration of physical and mental health. Recent long-term follow-up studies offer a optimistic scenario, indicating high rates of clinical remission (not equivalent to full recovery). Most psychotherapies, such as dialectical behavioral therapy (DBT) or mentalization-based therapy, have proven their effectiveness in treating emotional dysregulation, impulsivity and interpersonal difficulties. Teams working with people with BPD should develop comprehensive multidisciplinary care plans. The care plan should identify long-term goals that should be realistic, and linked to the short-term treatment aims and develop a crisis plan that identifies potential triggers that could lead to a crisis.
Conclusions
Cognitive rehabilitation and psychoeducational interventions can be effective in individuals with BPD. These interventions can be easily implemented in mental health settings and offer benefits for improving overall functioning, which often remains affected after clinical remission in long-term follow-up.
Introduction
Obsessive-compulsive disorder (OCD) is characterized by the presence of obsessive thoughts and recurring compulsive acts. The prevalence is 1-3% in the general population. The treatment ...consists of Cognitive Behavioral Therapy (CBT) alone, or in combination with antidepressants.
Objectives
Provide an overview of the elements of CBT in this disease and the techniques used.
Methods
The authors did a non-systematic review in Pubmed with the words: “Obsessive-Compulsive Disorder” and “Cognitive Behavioral Therapy”.
Results
According to the cognitive-behavioral model model, in this disease intrusive thoughts arise spontaneously, normally and universally, interrupting the normal flow of thought. They are usually neutral and form the basis for vulnerable people to develop obsessive problems. CBT uses techniques that aim to correct dysfunctional thoughts and beliefs, as well as behavioral techniques that aim to change compulsive behaviors. It aims to help people to come to the conclusion that the problem is not in the intrusive thoughts, but in the meaning they attribute to them, and in the various strategies they adopt to try to control them. It basically follows the following steps - patient assessment, through one or more semi-structured interviews; initial phase that includes the assessment of motivation for treatment and psychoeducation; intermediate phase, with the continuation of monitored exercises and reinforcement of cognitive and behavioral techniques; discharge, with discharge preparation working on relapse prevention and maintenance therapy.
Conclusions
Currently, CBT is considered the first-line therapy for the treatment of this disorder, however some patients are still refractory, and very little is known about its predictors of response.
We discuss here a purely hydrodynamical mechanism to invert the sign of the kinetic helicity, which plays a key role in determining the direction of propagation of cyclical magnetism in most models ...of dynamo action by rotating convection. Such propagation provides a prominent, and puzzling constraint on dynamo models. In the Sun, active regions emerge first at mid-latitudes, then appear nearer the equator over the course of a cycle, but most previous global-scale dynamo simulations have exhibited poleward propagation (if they were cyclical at all). Here, we highlight some simulations in which the direction of propagation of dynamo waves is altered primarily by an inversion of the kinetic helicity throughout much of the interior, rather than by changes in the differential rotation. This tends to occur in cases with a low Prandtl number and internal heating, in regions where the local density gradient is relatively small. We analyse how this inversion arises, and contrast it to the case of convection that is either highly columnar (i.e. rapidly rotating) or locally very stratified; in both of those situations, the typical profile of kinetic helicity (negative throughout most of the Northern hemisphere) instead prevails.
The endosperm is an ephemeral tissue that nourishes the developing embryo, similar to the placenta in mammals. In most angiosperms, endosperm development starts as a syncytium, in which nuclear ...divisions are not followed by cytokinesis. The timing of endosperm cellularization largely varies between species, and the event triggering this transition remains unknown. Here we show that increased auxin biosynthesis in the endosperm prevents its cellularization, leading to seed arrest. Auxin-overproducing seeds phenocopy paternal-excess triploid seeds derived from hybridizations of diploid maternal plants with tetraploid fathers. Concurrently, auxin-related genes are strongly overexpressed in triploid seeds, correlating with increased auxin activity. Reducing auxin biosynthesis and signaling reestablishes endosperm cellularization in triploid seeds and restores their viability, highlighting a causal role of increased auxin in preventing endosperm cellularization. We propose that auxin determines the time of endosperm cellularization, and thereby uncovered a central role of auxin in establishing hybridization barriers in plants.
The new data delivered by NASA’s Juno spacecraft significantly increase our understanding of the internal dynamics of Jupiter. The gravity data constrain the depth of the zonal flows observed at ...cloud level and suggest that they slow down considerably at a depth of about 0.96 rJ, where rJ is the mean radius at the one bar level. The magnetometer onboard Juno reveals the internal magnetic field of the planet. We combine the new zonal flow and magnetic field models with an updated electrical conductivity profile to assess the zonal-wind-induced dynamo action, concentrating on the outer part of the molecular hydrogen region of Jupiter where the conductivity increases very rapidly with depth. Dynamo action remains quasi-stationary and can therefore reasonably be estimated where the magnetic Reynolds number remains smaller than one, which is roughly the region above 0.96 rJ. We calculate that the locally induced radial magnetic field reaches rms values of about 10−6 T in this region and may just be detectable by the Juno mission. Very localized dynamo action and a distinct pattern that reflects the zonal wind system increases the chance to disentangle this locally induced field from the background field. The estimates of the locally induced currents also allow calculation of the zonal-flow-related Ohmic heating and associated entropy production. The respective quantities remain below new revised predictions for the total dissipative heating and total entropy production in Jupiter for any of the explored model combinations. Thus, neither Ohmic heating nor entropy production offer additional constraints on the depth of the zonal winds.
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FMFMET, NUK, UL, UM, UPUK
The evolution of seeds was a major reason for the rise of angiosperms to ecological dominance. Seeds of angiosperms are composed of three main structures: the embryo, which will give rise to the next ...generation; the endosperm, a nurturing tissue whose main function is to deliver nutrients from the mother plant to the embryo; and the seed coat (or testa), a tissue that is derived from the maternal integuments and which provides support and protection to the growing embryo. All three seed components need to exchange signals to ensure co-ordinated growth and development. The present review discusses the structure of the seed coat, its interaction with the endosperm, and bidirectional signalling events between endosperm and seed coat that co-ordinate growth of both tissues. Angiosperm seeds are not only of evolutionary significance, but also of major agronomic importance, demanding a thorough understanding of the events governing seed growth and development.
In flowering plants, seed development is initiated by the fusion of the maternal egg and central cells with two paternal sperm cells, leading to the formation of embryo and endosperm, respectively. ...The fertilization products are surrounded by the maternally derived seed coat, whose development prior to fertilization is blocked by epigenetic regulators belonging to the Polycomb Group (PcG) protein family. Here we show that fertilization of the central cell results in the production of auxin and most likely its export to the maternal tissues, which drives seed coat development by removing PcG function. We furthermore show that mutants for the MADS-box transcription factor AGL62 have an impaired transport of auxin from the endosperm to the integuments, which results in seed abortion. We propose that AGL62 regulates auxin transport from the endosperm to the integuments, leading to the removal of the PcG block on seed coat development.
Key message The DNA methylation status at an epigenetic quantitative trait locus in the Arabidopsis chromosome 2 is linked to the formation of apomictic-like endosperms. Abstract Seed development in ...most angiosperms is coupled to fertilization of the maternal gametes by two sperm cells. However, apomictic species can reproduce asexually via seeds. This trait is of great agricultural interest, as it would fix complex genotypes and allow for pollen-independent seed production. However, engineering full apomixis requires three independent processes: apomeiosis, parthenogenesis and autonomous endosperm development. While the first two have been successfully engineered in some crops, the formation of autonomous endosperms remains a challenge. Although it is known that this trait is under epigenetic control, such as of DNA methylation, the underlying mechanisms remain mostly undiscovered. Here, using epigenetic recombinant inbred lines, we identified an epigenetic quantitative trait locus in the Arabidopsis chromosome 2, which correlates with permissiveness for the formation of asexual seeds: hypomethylation at this genomic region allows the formation of larger autonomous endosperms. Importantly, the methylation at this locus only correlates with asexual seed size, and not to the size of sexual seeds or that of other organs. With this, we aim to show that screening for epialleles is a promising strategy to uncover loci underlying relevant traits and could pave the way to identifying genes necessary for the engineering of apomixis.
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EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, KILJ, KISLJ, MFDPS, NLZOH, NUK, OBVAL, OILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
MADS-box transcription factors (TFs) are ubiquitous in eukaryotic organisms and play major roles during plant development. Nevertheless, their function in seed development remains largely unknown. ...Here, we show that the imprinted
MADS-box TF PHERES1 (PHE1) is a master regulator of paternally expressed imprinted genes, as well as of non-imprinted key regulators of endosperm development. PHE1 binding sites show distinct epigenetic modifications on maternal and paternal alleles, correlating with parental-specific transcriptional activity. Importantly, we show that the CArG-box-like DNA-binding motifs that are bound by PHE1 have been distributed by RC/Helitron transposable elements. Our data provide an example of the molecular domestication of these elements which, by distributing PHE1 binding sites throughout the genome, have facilitated the recruitment of crucial endosperm regulators into a single transcriptional network.
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