The receptor for Granulocyte-colony stimulating factor (G-CSF) is expressed in radial glia during development of the nervous system

<p>Abstract</p> <p>Background</p> <p>Granulocyte colony-stimulating (G-CSF) factor is a well-known hematopoietic growth factor stimulating the proliferation and differentiation of myeloid progenitors. Recently, we uncovered that G-CSF acts also as a neuronal growth factor in the brain, which promotes adult neural precursor differentiation and enhances regeneration of the brain after insults. In adults, the receptor for G-CSF is predominantly expressed in neurons in many brain areas. We also described expression in neurogenic regions of the adult brain, such as the subventricular zone and the subgranular layer of the dentate gyrus. In addition, we found close co-localization of the G-CSF receptor and its ligand G-CSF. Here we have conducted a systematic expression analysis of G-CSF receptor and its ligand in the developing embryo.</p> <p>Results</p> <p>Outside the central nervous system (CNS) we found G-CSF receptor expression in blood vessels, muscles and their respective precursors and neurons. The expression of the G-CSF receptor in the developing CNS was most prominent in radial glia cells.</p> <p>Conclusion</p> <p>Our data imply that in addition to the function of G-CSF and its receptor in adult neurogenesis, this system also has a role in embryonic neurogenesis and nervous system development.</p

Spin-dependent electronic hybridization in a rope of carbon nanotubes

We demonstrate single electron addition to different strands of a carbon nanotube rope. Anticrossings of anomalous conductance peaks occur in quantum transport measurements through the parallel quantum dots forming on the individual strands. We determine the magnitude and the sign of the hybridization as well as the Coulomb interaction between the carbon nanotube quantum dots, finding that the bonding states dominate the transport. In a magnetic field the hybridization is shown to be selectively suppressed due to spin effects.Comment: 4 pages, 4 figure

Impact of tunnel barrier strength on magnetoresistance in carbon nanotubes

We investigate magnetoresistance in spin valves involving CoPd-contacted carbon nanotubes. Both temperature and bias voltage dependence clearly indicate tunneling magnetoresistance as the origin. We show that this effect is significantly affected by the tunnel barrier strength, which appears to be one reason for the variation between devices previously detected in similar structures. Modeling the data by means of the scattering matrix approach, we find a non-trivial dependence of the magnetoresistance on the barrier strength. Furthermore, analysis of the spin precession observed in a nonlocal Hanle measurement yields a spin lifetime of $\tau_s = 1.1\,$ns, a value comparable with those found in silicon- or graphene-based spin valve devices.Comment: 10 pages, 5 figures, 1 tabl

The nasty neighbour in the striped mouse (Rhabdomys pumilio) steals paternity and elicits aggression

Background Territoriality functions to monopolize access to resources including mates, but is costly in terms of energy and time investment. Some species reduce these costs by being less aggressive towards their neighbours than towards unfamiliar strangers, the so called dear enemy phenomenon. However, in other species individuals are more, not less aggressive towards their neighbours. It has been hypothesised that this is due to the fact that neighbours can impose a greater threat than strangers, but this has not been tested previously. Results We tested aggression in wild group-living male striped mice in a neutral test arena and demonstrate that breeders are more aggressive than non-breeding philopatrics, and that more aggression occurs during the breeding than during the non-breeding season. Male breeders were significantly more aggressive towards their neighbours than towards strangers, leading to the prediction that neighbours are the most important competitors for paternity. Using a molecular parentage analysis we show that 28% of offspring are sired by neighbouring males and only 7% by strangers. Conclusions We conclude that in male striped mice the main function of male aggression is defending paternity against their territorial neighbours

Spastic paraplegia related loss of Kinesin-1 function causes developmental defects and synapse degeneration in a Drosophila model

Autosomal dominant mutations in the gene coding for the neuronal Kinesin-1 isoform KIF5A cause spastic paraplegia type 10 (SPG10). The mechanism behind Kinesin-1 mutation leading to slow progressing spasticity and weakness of the lower limbs of patients is not clear and there is no causative treatment. One of the point mutations in KIF5A is KhcN256S. In vitro studies show that KhcN256S acts dominant negative over wild type Khc [Ebbing et al. 2008]. Mouse and zebrafish animal models with loss of Khc function hint at predominantly neurodevelopmental defects [Hurd and Saxton 1996; Xia et al. 2003; Karle et al. 2012; Nakajima et al. 2012; Campbell et al. 2014]. In contrast human SPG10 is clinically classified as a neurodegenerative disorder. The fly model used in this study is characterized by low-level ectopic overexpression of the Drosophila melanogaster orthologue of KIF5A (kinesin heavy chain, khc) bearing the SPG10 point mutation (khcN262S). As KhcN262S acts in a dominant negative manner, overexpression of mutant Khc resembles more closely the situation in heterozygous SPG10 patients. Using this milder affected model the parallel occurrence of neurodevelopmental defects and neurodegeneration could be shown for the first time. Larvae expressing khcN262S build less new synapses in a given time window than controls. In addition to this neurodevelopmental defect, neuromuscular junctions (NMJs) of khcN262S expressing larvae show overgrowth including enhanced transport of active zone (AZ) precursor vesicles that also lead to increased Brp intensity, a marker for AZs, at the NMJ. But in parallel neurodegenerative signs such as accumulation of neuronal membranes inside boutons and disorganized microtubule (MT) cytoskeleton are detectable. In larvae expressing khcN262S, the impaired axonal transport of mitochondria leads to a reduced number of mitochondria at the NMJ. This could explain the behavioral defects, characteristic for fly models of axonal transport deficits [Hurd and Saxton 1996; Gindhart et al. 1998; Martin et al. 1999; Bowman et al. 2000]. These results show in greater detail the progression of paralysis in the posterior part of larvae because the chronology of emerging pathological characteristics of a Drosophila model of SPG10 could be described. To further study the way of degeneration in a model of loss of functional Khc, NMJs of khc-/- larvae were analyzed. They grow much slower than controls and die before pupation. NMJs are characterized by smaller size compared to controls and show frequent occurrence of accumulated neuronal membranes in NMJs as well as in axons. Cargos like Brp or synaptic vesicle marker VGlut accumulated in- and outside of axonal swellings and were diminished at the NMJ. The NMJ was especially marked by fragmentation of neuronal membranes and MTs. These did not retract from the terminal bouton as described for classical neuronal retraction [Eaton et al. 2002], but dispersed in central regions of the NMJ, separating parts of the NMJ from the innervating axon. Therefore, they show a disassembly of the NMJ, which is different from classical neuronal retraction and resembles more a Wallerian-like deconstruction of neuronmuscle innervation

Einfluss reduzierter Bodenbearbeitung auf Ertragsbildung, Unkrautdynamik und Regenwurmpopulationen im Ökologischen Landbau

Problemstellung und Ziele Reduzierte Bodenbearbeitung wirkt in vielfältiger Weise positiv auf Bodenstruktur, Humusgehalt und Bodenleben und bietet darüber hinaus Vorteile in ökonomischer und arbeitswirtschaftlicher Hinsicht. Im konventionellen Landbau wird seit mehreren Jahrzehnten reduzierte Bodenbearbeitung betrieben. Im Ökologischen Landbau stellt sich die Frage, inwiefern eine Reduktion der Bodenbearbeitungsintensität und –tiefe praktikabel ist. Arbeitshypothesen Ein Verzicht auf wendende Grundbodenbearbeitung ist im Ökologischen Landbau nicht durchgängig möglich, da es zu einer starken Zunahme von Unkräutern kommt, insbesondere mit perennierenden Unkräutern. Eine flache Pflugfuche oder der Zweischichtenpflug stellen günstige Verfahren dar, die sowohl die Vorteile der konventionellen Arbeitsweise als auch der reduzierten Bodenbearbeitung vereinen. Methoden Auf der Versuchsstation für Ökologischen Landbau Kleinhohenheim der Universität Hohenheim wurde 1999 ein Feldversuch angelegt, bei dem vier Verfahren der Grundbodenbearbeitung getestet werden: Pflug tief, Zweischichtenpflug, Pflug flach, Grubber. In diesem wurden in den Vegetationsperioden 1999/2000, 2000/2001 und 2001/2002 Erhebungen zu Ertragsbildung und Verunkrautung sowie im letzten Jahr zum Bodensamenvorrat und den Regenwurmpopulationen durchgeführt. Ergebnisse Die Daten zeigen, dass eine Unterlassung der wendenden Grundbodenbearbeitung gravierende Folgen für die Ertragsbildung und die Unkrautpopulationen besitzt. In der Variante mit nichtwendender Grundbodenbearbeitung (Grubber) waren deutlich mehr Unkräuter festzustellen als in den drei Varianten mit wendender Grundboden-bearbeitung. Allerdings zeigten sich auch in den Varianten ‚Pflug flach‘ und ‚Zweischichtenpflug‘ höhere Unkrautpopulationen und tendentiell niedrigere Erträge als in der Variante mit Pflugbearbeitung auf 25 cm Tiefe (Pflug tief). Die Regenwürmer wurden durch die Bodenbearbeitungsmassnahmen nicht eindeutig beeinflusst. Die vorliegenden Daten legen damit nahe, dass eine Reduktion von Bodenbearbeitungsintensität und –tiefe unter den Produktionsbedingungen des Ökologischen Landbaus pflanzenbauliche Nachteile mit sich bringt, die durch damit verbundene Vorteile vermutlich nicht ausgeglichen werden

The hematopoietic factor GM-CSF (Granulocyte-macrophage colony-stimulating factor) promotes neuronal differentiation of adult neural stem cells in vitro

BACKGROUND: Granulocyte-macrophage colony stimulating factor (GM-CSF) is a hematopoietic growth factor involved in the generation of granulocytes, macrophages, and dendritic cells from hematopoietic progenitor cells. We have recently demonstrated that GM-CSF has anti-apoptotic functions on neurons, and is neuroprotective in animal stroke models. RESULTS: The GM-CSF receptor α is expressed on adult neural stem cells in the rodent brain, and in culture. Addition of GM-CSF to NSCs in vitro increased neuronal differentiation in a dose-dependent manner as determined by quantitative PCR, reporter gene assays, and FACS analysis. CONCLUSION: Similar to the hematopoietic factor Granulocyte-colony stimulating factor (G-CSF), GM-CSF stimulates neuronal differentiation of adult NSCs. These data highlight the astonishingly similar functions of major hematopoietic factors in the brain, and raise the clinical attractiveness of GM-CSF as a novel drug for neurological disorders

Nanoscale X-ray investigation of magnetic metallofullerene peapods

Endohedral lanthanide ions packed inside carbon nanotubes (CNTs) in a one-dimensional assembly have been studied with a combination of high resolution transmission electron microscopy (HRTEM), scanning transmission X-ray microscopy (STXM), and X-ray magnetic circular dichroism (XMCD). By correlating HRTEM and STXM images we show that structures down to 30 nm are resolved with chemical contrast and record X-ray absorption spectra from endohedral lanthanide ions embedded in individual nanoscale CNT bundles. XMCD measurements of an Er$_3$N@C$_{80}$ bulk sample and a macroscopic assembly of filled CNTs indicates that the magnetic properties of the endohedral Er3+ ions are unchanged when encapsulated in CNTs. This study demonstrates the feasibility of local magnetic X-ray characterization of low concentrations of lanthanide ions embedded in molecular nanostructures

Intermittent bulk release of human cytomegalovirus

Human Cytomegalovirus (HCMV) can infect a variety of cell types by using virions of varying glycoprotein compositions. It is still unclear how this diversity is generated, but spatio-temporally separated envelopment and egress pathways might play a role. So far, one egress pathway has been described in which HCMV particles are individually enveloped into small vesicles and are subsequently exocytosed continuously. However, some studies have also found enveloped virus particles inside multivesicular structures but could not link them to productive egress or degradation pathways. We used a novel 3D-CLEM workflow allowing us to investigate these structures in HCMV morphogenesis and egress at high spatio-temporal resolution. We found that multiple envelopment events occurred at individual vesicles leading to multiviral bodies (MViBs), which subsequently traversed the cytoplasm to release virions as intermittent bulk pulses at the plasma membrane to form extracellular virus accumulations (EVAs). Our data support the existence of a novel bona fide HCMV egress pathway, which opens the gate to evaluate divergent egress pathways in generating virion diversity