Flowers and mycorrhizal roots – closer than we think?

Roots and flowers are formed at the extreme ends of plants and they differ in almost every aspect of their development and function; even so, they exhibit surprising molecular commonalities. For example, the calcium and calmodulin-dependent protein kinase (CCaMK) plays a central role in root symbioses with fungi and bacteria, but is also highly expressed in developing anthers. Moreover, independent evidence from transcriptomics, phylogenomics, and genetics reveals common developmental elements in root symbioses and reproductive development. We discuss the significance of these overlaps, and we argue that an integrated comparative view of the two phenomena will stimulate research and provide new insight, not only into shared components, but also into the specific aspects of anther development and root symbioses

Effect of Thomas Rotation on the Lorentz Transformation of Electromagnetic fields

A relativistic particle undergoing successive boosts which are non collinear will experience a rotation of its coordinate axes with respect to the boosted frame. This rotation of coordinate axes is caused by a relativistic phenomenon called Thomas Rotation. We assess the importance of Thomas rotation in the calculation of physical quantities like electromagnetic fields in the relativistic regime. We calculate the electromagnetic field tensor for general three dimensional successive boosts in the particle's rest frame as well as the laboratory frame. We then compare the electromagnetic field tensors obtained by a direct boost $\vec{\beta} + \delta \vec{\beta}$ and successive boosts $\vec{\beta}$ and $\Delta \vec{\beta}$ and check their consistency with Thomas rotation. This framework might be important to situations such as the calculation of frequency shifts for relativistic spin-1/2 particles undergoing Larmor precession in electromagnetic fields with small field non-uniformities.Comment: 18 pages, 4 figure

Diet of arbuscular mycorrhizal fungi: bread and butter ?

Most plants entertain mutualistic interactions known as arbuscular mycorrhiza (AM) with soil fungi (Glomeromycota) which provide them with mineral nutrients in exchange for reduced carbon from the plant. Mycorrhizal roots represent strong carbon sinks in which hexoses are transferred from the plant host to the fungus. However, most of the carbon in AM fungi is stored in the form of lipids. The absence of the type I fatty acid synthase (FAS-I) complex from the AM fungal model species Rhizophagus irregularis suggests that lipids may also have a role in nutrition of the fungal partner. This hypothesis is supported by the concerted induction of host genes involved in lipid metabolism. We explore the possible roles of lipids in the light of recent literature on AM symbiosis

Analytic treatment of complete and incomplete geodesics in Taub-NUT space-times

We present the complete set of analytical solutions of the geodesic equation in Taub-NUT space-times in terms of the Weierstrass elliptic function. We systematically study the underlying polynomials and characterize the motion of test particles by its zeros. Since the presence of the "Misner string" in the Taub-NUT metric has led to different interpretations, we consider these in terms of the geodesics of the space-time. In particular, we address the geodesic incompleteness at the horizons discussed by Misner and Taub, and the analytic extension of Miller, Kruskal and Godfrey, and compare with the Reissner-Nordstr\"om space-time.Comment: 22 pages, 14 figures, accepted for publication in PR

Reproductive outcome after hysteroscopic septoplasty in patients with septate uterus - a retrospective cohort study and systematic review of the literature

<p>Abstract</p> <p>Background</p> <p>Septate uterus, one of the most common forms of congenital uterine malformations, negatively affects female reproductive health.</p> <p>Methods</p> <p>In a retrospective cohort study, we evaluated the reproductive outcome after hysteroscopic septoplasty in 64 women with septate uterus and primary or secondary infertility. We performed a systematic review of studies evaluating the reproductive outcome after hysteroscopic septoplasty.</p> <p>Results</p> <p>Sixty-four women underwent hysteroscopic septoplasty. In 2/64 (3%) women, intraoperative uterine perforation occurred. Complete follow-up was available for 49/64 (76%) patients. Mean follow-up time was 68.6 +/- 5.2 months. The overall pregnancy rate after hysteroscopic septoplasty was 69% (34/49). The overall life birth rate (LBR) was 49% (24/49). The mean time interval between surgery and the first life birth was 35.8 +/- 22.5 months. Including our own data, we identified 18 studies investigating the effect of septoplasty on reproductive outcome in 1501 women. A pooled analysis demonstrated that hysteroscopic septoplasty resulted in an overall pregnancy rate of 60% (892/1501) and a LBR of 45% (686/1501). The overall rate of intra- and postoperative complications was 1.7% (23/1324) and the overall rate of re-hysteroscopy was 6% (79/1324).</p> <p>Conclusions</p> <p>In women with septate uterus and a history of infertility, hysteroscopic septoplasty is a safe and effective procedure resulting in a pregnancy rate of 60% and a LBR of 45%.</p

Beneficial services of arbuscular mycorrhizal fungi – from ecology to application

Arbuscular mycorrhiza (AM) is the most common symbiotic association of plants with microbes. AM fungi occur in the majority of natural habitats and they provide a range of important ecological services, in particular by improving plant nutrition, stress resistance and tolerance, as well as soil structure and fertility. AM fungi interact with most crop plants including cereals, vegetables, and fruit trees, therefore, they receive increasing attention for their potential use in sustainable agriculture. Basic research of the past decade has revealed the existence of a dedicated recognition and signaling pathway that is required for AM. Furthermore, recent evidence provided new insight into the exchange of nutritional benefits between the symbiotic partners. The great potential for application of AM has given rise to a thriving industry for AM-related products for agriculture, horticulture, and landscaping. Here, we discuss new developments in these fields, and we highlight future potential and limits towards the use of AM fungi for plant production

Comprehensive transcriptome analysis unravels the existence of crucial genes regulating primary metabolism during adventitious root formation in Petunia hybrida

To identify specific genes determining the initiation and formation of adventitious roots (AR), a microarray-based transcriptome analysis in the stem base of the cuttings of Petunia hybrida (line W115) was conducted. A microarray carrying 24,816 unique, non-redundant annotated sequences was hybridized to probes derived from different stages of AR formation. After exclusion of wound-responsive and root-regulated genes, 1,354 of them were identified which were significantly and specifically induced during various phases of AR formation. Based on a recent physiological model distinguishing three metabolic phases in AR formation, the present paper focuses on the response of genes related to particular metabolic pathways. Key genes involved in primary carbohydrate metabolism such as those mediating apoplastic sucrose unloading were induced at the early sink establishment phase of AR formation. Transcriptome changes also pointed to a possible role of trehalose metabolism and SnRK1 (sucrose non-fermenting 1- related protein kinase) in sugar sensing during this early step of AR formation. Symplastic sucrose unloading and nucleotide biosynthesis were the major processes induced during the later recovery and maintenance phases. Moreover, transcripts involved in peroxisomal beta-oxidation were up-regulated during different phases of AR formation. In addition to metabolic pathways, the analysis revealed the activation of cell division at the two later phases and in particular the induction of G1- specific genes in the maintenance phase. Furthermore, results point towards a specific demand for certain mineral nutrients starting in the recovery phase

Insight into the evolution of the Solanaceae from the parental genomes of Petunia hybrida

Petunia hybrida is a popular bedding plant that has a long history as a genetic model system. We report the whole-genome sequencing and assembly of inbred derivatives of its two wild parents, P. axillaris N and P. inflata S6. The current assemblies include 91.3% and 90.2% coverage of their diploid genomes (1.4 Gb; 2n=14) containing 32,928 and 36,697 protein-coding genes, respectively. The Petunia lineage has experienced at least two rounds of paleohexaploidization, the older gamma hexaploidy event, which is shared with other Eudicots, and the more recent Solanaceae paleohexaploidy event that is shared with tomato and other Solanaceae species. Transcription factors that were targets of selection during the shift from bee- to moth pollination reside in particularly dynamic regions of the genome, which may have been key to the remarkable diversity of floral color patterns and pollination systems. The high quality genome sequences will enhance the value of Petunia as a model system for basic and applied research on a variety of unique biological phenomena

Att främja datalogiskt tänkande i förskoleklassen

I MÅNGA LÄNDER världen runt har digitalisering och programmering införts i läroplaner för förskola och grundskola. Under senare tid har flera studier om undervisning i programmering i olika sammanhang genomförts. Dessa studier har oftast haft fokus på elever från 7 år och äldre och det finns få studier som rapporterar om införandet av programmering för barn i förskola och yngre elever i förskoleklass. Denna klyfta hanterar vi i denna studie som fokuserar på programmering och utveckling av elevers datalogiska tänkande i förskoleklass. Hösten 2017 startade Ifous (Innovation, forskning och utveckling i skola och förskola) ett forsknings- och utvecklingsprogram med fokus på utveckling av didaktiska modeller för programmering i utbildningen från förskola till och med grundskolan. Programmet avslutades våren 2020. I detta program deltog skolor från fem skolhuvudmän, Tyresö kommun, Åstorps kommun, Simrishamns kommun, Stockholms stad och Freinetskolan Hugin i Norrtälje. Programmet som sådant innebar viss kompetensutveckling och främjade forskning om programmeringsundervisning från förskoleklass till och med årskurs 9 i grundskolan. I denna artikel presenterar vi hur en lärare arbetade med programmering för att främja datalogiskt tänkande hos elever i förskoleklass under treårsperioden och den erfarenhet som hon förvärvat. I artikeln drar vi slutsatsen att förskoleklasselever med systematisk och tankeväckande didaktisk modellering fullt ut kan utveckla ett antal grundläggande datalogiska färdigheter.Programmering i ämnesundervisninge

Att främja datalogiskt tänkande i förskoleklassen

I MÅNGA LÄNDER världen runt har digitalisering och programmering införts i läroplaner för förskola och grundskola. Under senare tid har flera studier om undervisning i programmering i olika sammanhang genomförts. Dessa studier har oftast haft fokus på elever från 7 år och äldre och det finns få studier som rapporterar om införandet av programmering för barn i förskola och yngre elever i förskoleklass. Denna klyfta hanterar vi i denna studie som fokuserar på programmering och utveckling av elevers datalogiska tänkande i förskoleklass. Hösten 2017 startade Ifous (Innovation, forskning och utveckling i skola och förskola) ett forsknings- och utvecklingsprogram med fokus på utveckling av didaktiska modeller för programmering i utbildningen från förskola till och med grundskolan. Programmet avslutades våren 2020. I detta program deltog skolor från fem skolhuvudmän, Tyresö kommun, Åstorps kommun, Simrishamns kommun, Stockholms stad och Freinetskolan Hugin i Norrtälje. Programmet som sådant innebar viss kompetensutveckling och främjade forskning om programmeringsundervisning från förskoleklass till och med årskurs 9 i grundskolan. I denna artikel presenterar vi hur en lärare arbetade med programmering för att främja datalogiskt tänkande hos elever i förskoleklass under treårsperioden och den erfarenhet som hon förvärvat. I artikeln drar vi slutsatsen att förskoleklasselever med systematisk och tankeväckande didaktisk modellering fullt ut kan utveckla ett antal grundläggande datalogiska färdigheter.Programmering i ämnesundervisninge