TY - JOUR AB - We derive the Hasse principle and weak approximation for fibrations of certain varieties in the spirit of work by Colliot-Thélène–Sansuc and Harpaz–Skorobogatov–Wittenberg. Our varieties are defined through polynomials in many variables and part of our work is devoted to establishing Schinzel's hypothesis for polynomials of this kind. This last part is achieved by using arguments behind Birch's well-known result regarding the Hasse principle for complete intersections with the notable difference that we prove our result in 50% fewer variables than in the classical Birch setting. We also study the problem of square-free values of an integer polynomial with 66.6% fewer variables than in the Birch setting. AU - Destagnol, Kevin N AU - Sofos, Efthymios ID - 6835 IS - 11 JF - Bulletin des Sciences Mathematiques SN - 0007-4497 TI - Rational points and prime values of polynomials in moderately many variables VL - 156 ER - TY - JOUR AB - Migrasomes are a recently discovered type of extracellular vesicles that are characteristically generated along retraction fibers in migrating cells. Two studies now show how migrasomes are formed and how they function in the physiologically relevant context of the developing zebrafish embryo. AU - Tavano, Ste AU - Heisenberg, Carl-Philipp J ID - 6837 IS - 8 JF - Nature Cell Biology TI - Migrasomes take center stage VL - 21 ER - TY - JOUR AB - A novel magnetic scratch method achieves repeatability, reproducibility and geometric control greater than pipette scratch assays and closely approximating the precision of cell exclusion assays while inducing the cell injury inherently necessary for wound healing assays. The magnetic scratch is affordable, easily implemented and standardisable and thus may contribute toward better comparability of data generated in different studies and laboratories. AU - Fenu, M. AU - Bettermann, T. AU - Vogl, C. AU - Darwish-Miranda, Nasser AU - Schramel, J. AU - Jenner, F. AU - Ribitsch, I. ID - 6867 IS - 1 JF - Scientific Reports TI - A novel magnet-based scratch method for standardisation of wound-healing assays VL - 9 ER - TY - JOUR AB - V (vacuolar)/A (archaeal)-type adenosine triphosphatases (ATPases), found in archaeaand eubacteria, couple ATP hydrolysis or synthesis to proton translocation across theplasma membrane using the rotary-catalysis mechanism. They belong to the V-typeATPase family, which differs from the mitochondrial/chloroplast F-type ATP synthasesin overall architecture. We solved cryo–electron microscopy structures of the intactThermus thermophilusV/A-ATPase, reconstituted into lipid nanodiscs, in three rotationalstates and two substates. These structures indicate substantial flexibility betweenV1and Voin a working enzyme, which results from mechanical competition between centralshaft rotation and resistance from the peripheral stalks. We also describedetails of adenosine diphosphate inhibition release, V1-Votorque transmission, andproton translocation, which are relevant for the entire V-type ATPase family. AU - Zhou, Long AU - Sazanov, Leonid A ID - 6859 IS - 6455 JF - Science SN - 0036-8075 TI - Structure and conformational plasticity of the intact Thermus thermophilus V/A-type ATPase VL - 365 ER - TY - JOUR AU - Barton, Nicholas H ID - 6858 IS - 2 JF - National Science Review SN - 2095-5138 TI - Is speciation driven by cycles of mixing and isolation? VL - 6 ER - TY - JOUR AB - Hyperpolarization-activated cyclic-nucleotide-gated (HCN) channels control electrical rhythmicity and excitability in the heart and brain, but the function of HCN channels at the subcellular level in axons remains poorly understood. Here, we show that the action potential conduction velocity in both myelinated and unmyelinated central axons can be bidirectionally modulated by a HCN channel blocker, cyclic adenosine monophosphate (cAMP), and neuromodulators. Recordings from mouse cerebellar mossy fiber boutons show that HCN channels ensure reliable high-frequency firing and are strongly modulated by cAMP (EC50 40 mM; estimated endogenous cAMP concentration 13 mM). In addition, immunogold-electron microscopy revealed HCN2 as the dominating subunit in cerebellar mossy fibers. Computational modeling indicated that HCN2 channels control conduction velocity primarily by altering the resting membrane potential and are associated with significant metabolic costs. These results suggest that the cAMP-HCN pathway provides neuromodulators with an opportunity to finely tune energy consumption and temporal delays across axons in the brain. AU - Byczkowicz, Niklas AU - Eshra, Abdelmoneim AU - Montanaro-Punzengruber, Jacqueline-Claire AU - Trevisiol, Andrea AU - Hirrlinger, Johannes AU - Kole, Maarten Hp AU - Shigemoto, Ryuichi AU - Hallermann, Stefan ID - 6868 JF - eLife TI - HCN channel-mediated neuromodulation can control action potential velocity and fidelity in central axons VL - 8 ER - TY - JOUR AB - The apical hook is a transiently formed structure that plays a protective role when the germinating seedling penetrates through the soil towards the surface. Crucial for proper bending is the local auxin maxima, which defines the concave (inner) side of the hook curvature. As no sign of asymmetric auxin distribution has been reported in embryonic hypocotyls prior to hook formation, the question of how auxin asymmetry is established in the early phases of seedling germination remains largely unanswered. Here, we analyzed the auxin distribution and expression of PIN auxin efflux carriers from early phases of germination, and show that bending of the root in response to gravity is the crucial initial cue that governs the hypocotyl bending required for apical hook formation. Importantly, polar auxin transport machinery is established gradually after germination starts as a result of tight root-hypocotyl interaction and a proper balance between abscisic acid and gibberellins. AU - Zhu, Qiang AU - Gallemi, Marçal AU - Pospíšil, Jiří AU - Žádníková, Petra AU - Strnad, Miroslav AU - Benková, Eva ID - 6897 IS - 17 JF - Development TI - Root gravity response module guides differential growth determining both root bending and apical hook formation in Arabidopsis VL - 146 ER - TY - JOUR AB - Until recently, a great amount of brain studies have been conducted in human post mortem tissues, cell lines and model organisms. These researches provided useful insights regarding cell-cell interactions occurring in the brain. However, such approaches suffer from technical limitations and inaccurate modeling of the tissue 3D cytoarchitecture. Importantly, they might lack a human genetic background essential for disease modeling. With the development of protocols to generate human cerebral organoids, we are now closer to reproducing the early stages of human brain development in vitro. As a result, more relevant cell-cell interaction studies can be conducted. In this review, we discuss the advantages of 3D cultures over 2D in modulating brain cell-cell interactions during physiological and pathological development, as well as the progress made in developing organoids in which neurons, macroglia, microglia and vascularization are present. Finally, we debate the limitations of those models and possible future directions. AU - Oliveira, Bárbara AU - Yahya, Aysan Çerağ AU - Novarino, Gaia ID - 6896 JF - Brain Research SN - 00068993 TI - Modeling cell-cell interactions in the brain using cerebral organoids VL - 1724 ER - TY - GEN AB - OGs with putative pseudogenes by the number of affected genomes in different chlamydial species. Frameshift and nonsense mutations located less than 60 bp upstreamof the gene end or present in a single genome from the corresponding OG were excluded. (CSV 31 kb) AU - Sigalova, Olga AU - Chaplin, Andrei AU - Bochkareva, Olga AU - Shelyakin, Pavel AU - Filaretov, Vsevolod AU - Akkuratov, Evgeny AU - Burskaia, Valentina AU - Gelfand, Mikhail S. ID - 9731 TI - Additional file 11 of Chlamydia pan-genomic analysis reveals balance between host adaptation and selective pressure to genome reduction ER - TY - GEN AB - Predicted frameshift and nonsense mutations in Chlamydial pan-genome. For the analysis of putative pseudogenes, events located less than 60 bp. away from gene end or present in a single genome from the corresponding OG were excluded. (CSV 600 kb) AU - Sigalova, Olga M. AU - Chaplin, Andrei V. AU - Bochkareva, Olga AU - Shelyakin, Pavel V. AU - Filaretov, Vsevolod A. AU - Akkuratov, Evgeny E. AU - Burskaia, Valentina AU - Gelfand, Mikhail S. ID - 9783 TI - Additional file 10 of Chlamydia pan-genomic analysis reveals balance between host adaptation and selective pressure to genome reduction ER -