25 research outputs found
Highly individual methylation patterns of alternative glucocorticoid receptor promoters suggest individualized epigenetic regulatory mechanisms
The transcription start sites (TSS) and promoters of many genes are located in upstream CpG islands. Methylation within such islands is known for both imprinted and oncogenes, although poorly studied for other genes, especially those with complex CpG islands containing multiple first exons and promoters. The glucocorticoid receptor (GR) CpG island contains seven alternative first exons and their promoters. Here we show for the five GR promoters activated in PBMCs that methylation patterns are highly variable between individuals. The majority of positions were methylated at levels >25% in at least one donor affecting each promoter and TSS. We also examined the evolutionarily conserved transcription factor binding sites (TFBS) using an improved in silico phylogenetic footprinting technique. The majority of these contain methylatable CpG sites, suggesting that methylation may orchestrates alternative first exon usage, silencing and controlling tissue-specific expression. The heterogeneity observed may reflect epigenetic mechanisms of GR fine tuning, programmed by early life environment and events. With 78% of evolutionarily conserved alternative first exons falling into such complex CpG islands, their internal structure and epigenetic modifications are bound to be biologically important, and may be a common transcriptional control mechanism used throughout many phyla
A short in-frame deletion in NTRK1 tyrosine kinase domain caused by a novel splice site mutation in a patient with congenital insensitivity to pain with anhidrosis
Background: Congenital insensitivity to pain with anhidrosis (CIPA) is a rare autosomal recessive genetic disease characterized by the lack of reaction to noxious stimuli and anhidrosis. It is caused by mutations in the NTRK1 gene, which encodes the high affinity tyrosine kinase receptor I for Neurotrophic Growth Factor (NGF). -- Case Presentation: We present the case of a female patient diagnosed with CIPA at the age of 8 months. The patient is currently 6 years old and her psychomotor development conforms to her age (RMN, SPECT and psychological study are in the range of normality). PCR amplification of DNA, followed by direct sequencing, was used to investigate the presence of NTRK1 gene mutations. Reverse transcriptase (RT)-PCR amplification of RNA, followed by cloning and sequencing of isolated RT-PCR products was used to characterize the effect of the mutations on NTRK1 mRNA splicing. The clinical diagnosis of CIPA was confirmed by the detection of two splice-site mutations in NTRK1, revealing that the patient was a compound heterozygote at this gene. One of these alterations, c.574+1G > A, is located at the splice donor site of intron 5. We also found a second mutation, c.2206-2 A > G, not previously reported in the literature, which is located at the splice acceptor site of intron 16. Each parent was confirmed to be a carrier for one of the mutations by DNA sequencing analysis. It has been proposed that the c.574+1G > A mutation would cause exon 5 skipping during NTRK1 mRNA splicing. We could confirm this prediction and, more importantly, we provide evidence that the novel c.2206-2A > G mutation also disrupts normal NTRK1 splicing, leading to the use of an alternative splice acceptor site within exon 17. As a consequence, this mutation would result in the production of a mutant NTRK1 protein with a seven aminoacid in-frame deletion in its tyrosine kinase domain. --Conclusions: We present the first description of a CIPA-associated NTRK1 mutation causing a short interstitial deletion in the tyrosine kinase domain of the receptor. The possible phenotypical implications of this mutation are discussed.This investigation was supported by the Instituto de Salud Carlos III and the Fundacion Vasca de Innovacion e Investigacion Sanitarias (funds to ES)
The dominant Anopheles vectors of human malaria in the Asia-Pacific region: occurrence data, distribution maps and bionomic précis
<p>Abstract</p> <p>Background</p> <p>The final article in a series of three publications examining the global distribution of 41 dominant vector species (DVS) of malaria is presented here. The first publication examined the DVS from the Americas, with the second covering those species present in Africa, Europe and the Middle East. Here we discuss the 19 DVS of the Asian-Pacific region. This region experiences a high diversity of vector species, many occurring sympatrically, which, combined with the occurrence of a high number of species complexes and suspected species complexes, and behavioural plasticity of many of these major vectors, adds a level of entomological complexity not comparable elsewhere globally. To try and untangle the intricacy of the vectors of this region and to increase the effectiveness of vector control interventions, an understanding of the contemporary distribution of each species, combined with a synthesis of the current knowledge of their behaviour and ecology is needed.</p> <p>Results</p> <p>Expert opinion (EO) range maps, created with the most up-to-date expert knowledge of each DVS distribution, were combined with a contemporary database of occurrence data and a suite of open access, environmental and climatic variables. Using the Boosted Regression Tree (BRT) modelling method, distribution maps of each DVS were produced. The occurrence data were abstracted from the formal, published literature, plus other relevant sources, resulting in the collation of DVS occurrence at 10116 locations across 31 countries, of which 8853 were successfully geo-referenced and 7430 were resolved to spatial areas that could be included in the BRT model. A detailed summary of the information on the bionomics of each species and species complex is also presented.</p> <p>Conclusions</p> <p>This article concludes a project aimed to establish the contemporary global distribution of the DVS of malaria. The three articles produced are intended as a detailed reference for scientists continuing research into the aspects of taxonomy, biology and ecology relevant to species-specific vector control. This research is particularly relevant to help unravel the complicated taxonomic status, ecology and epidemiology of the vectors of the Asia-Pacific region. All the occurrence data, predictive maps and EO-shape files generated during the production of these publications will be made available in the public domain. We hope that this will encourage data sharing to improve future iterations of the distribution maps.</p
Gelaendedaempfung durch Verdeckung der Fresnelzone zwischen den Hindernissen einer Uebertragungsstrecke
Available from TIB Hannover: RN 2978(143) / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekSIGLEDEGerman
Feldstaerkevorhersage im VHF-Bereich fuer verschiedene Zeitwahrscheinlichkeiten unter Beruecksichtigung von Gelaendedaten
9 figs., 1 tab.SIGLEAvailable from TIB Hannover: RN 2978(120) / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekDEGerman
An in-depth neurobehavioral characterization shows anxiety-like traits, impaired habituation behavior, and restlessness in male Cryptochrome-deficient mice
Many psychiatric disorders, for example, anxiety, are accompanied by disturbances of circadian rhythms, including disturbed sleep/wake cycles, changes in locomotor activity, and abnormal endocrine function. Conversely, alternations of circadian rhythms are a risk factor for the development of psychiatric disorders. This assumption is supported by animals with clock gene mutations which often display behaviors that resemble human psychiatric disorders. In this study, we performed an in-depth behavioral analysis with male mice lacking the central clock genes Cryptochrome 1 and 2 (Cry1/2( -/-)), which are thus unable to express endogenous circadian rhythms. With wild-type and Cry1/2( -/-) mice, we performed an extensive behavioral analysis to study their cognitive abilities, social behavior, and their expression of depression-like and anxiety-like behavior. While Cry1/2( -/-) mice showed only mild abnormalities at cognitive and social behavioral levels, they were consistently more anxious than wildtype mice. Anxiety-like behavior was particularly evident in reduced mobility in new environments, altered ability to habituate, compensatory behavior, and consistent restless behavior across many behavioral tests. In line with their anxiety-like behavioral phenotype, Cry1/2( -/-) mice have higher c-Fos activity in the amygdala after exposure to an anxiogenic stressor than wild-type mice. In our study, we identified Cry1/2( -/-) mice as animals that qualify as a translational mouse model for anxiety disorder in humans because of its consistent behavior of restlessness, increased immobility, and dysfunctional habituation in new environments
Chiral magnetoresistance in the Weyl semimetal NbP
NbP is a recently realized Weyl semimetal (WSM), hosting Weyl points through which conduction and valence bands cross linearly in the bulk and exotic Fermi arcs appear. The most intriguing transport phenomenon of a WSM is the chiral anomaly-induced negative magnetoresistance (NMR) in parallel electric and magnetic fields. In intrinsic NbP the Weyl points lie far from the Fermi energy, making chiral magneto-transport elusive. Here, we use Ga-doping to relocate the Fermi energy in NbP sufficiently close to the W2 Weyl points, for which the different Fermi surfaces are verified by resultant quantum oscillations. Consequently, we observe a NMR for parallel electric and magnetic fields, which is considered as a signature of the chiral anomaly in condensed-matter physics. The NMR survives up to room temperature, making NbP a versatile material platform for the development of Weyltronic applications
Cerebral involvement in axonal Charcot-Marie-Tooth neuropathy caused by mitofusin2 mutations.
Aqueous CSD approach for the growth of novel, lattice-tuned La x Ce 1Àx O d epitaxial layers †
Lanthanum-cerium oxide (LCO) films were deposited on Ni-5%W substrates by chemical solution deposition (CSD) from water-based precursors. LCO films containing different ratios of lanthanum and cerium ions (from CeO 2 to La 2 Ce 2 O 7 ) were prepared. The composition of the layers was optimized towards the formation of LCO buffer layers, lattice-matched with the superconducting YBa 2 Cu 3 O y layer, useful for the development of coated conductors. Single, crack-free LCO layers with a thickness of up to 140 nm could be obtained in a single deposition step. The crystallinity and microstructure of these lattice-matched LCO layers were studied by X-ray diffraction techniques, RHEED and SEM. We find that only layers with thickness below 100 nm show a crystalline top surface although both thick and thin layers show good biaxial texture in XRD. On the most promising layers, AFM and (S)TEM were performed to further evaluate their morphology. The overall surface roughness varies between 3.9 and 7.5 nm, while the layers appear much more dense than the frequently used La 2 Zr 2 O 7 (LZO) systems, showing much smaller nanovoids (1-2 nm) than the latter system. Their effective buffer layer action was studied using XPS. The thin LCO layers supported the growth of superconducting YBCO deposited using PLD methods. Introduction Among the current second generation of coated conductors, YBa 2 Cu 3 O 7Àx (YBCO) is of world-wide interest because of its excellent superconducting properties and its possibility to be deposited as thin film, overcoming the intrinsic brittle nature of this ceramic material. Recently, numerous efforts were undertaken for scaling up the fabrication of coated YBCO conductors to commercial lengths using various fabrication methods. 1,2 To obtain high quality, biaxially textured c-axis growth of YBCO on top of Ni-tapes, one or more intermediate buffer layers are always necessary. They prevent oxidation of the metal substrate during annealing of the YBCO at higher temperatures and diffusion of Ni-ions into the superconducting layer. Furthermore, the buffer layers need to assure well-textured growth of the YBCO top layer. Therefore, good texture alignment, both in-plane and out-ofplane, together with a close lattice match with YBCO thin film and substrate are principal requirements for good buffer layers. Moreover, the layers need to be dense, free of cracks and homogeneous. In practice, these high requirements translate into multiple buffer layer systems, 15-21 All these works report a possibility of growing single buffer layer on the given substrate with optimized properties. These single buffer layers showed good superconducting properties. shows that oxygen vacancies in LCO clearly prefer a Ce environment over a La one, resulting in a reduction of the Ce ions neighboring the oxygen vacancy. 26 Related to this, a similar work reported that the creation of vacancies and defects in the structure of CeO 2 , changing the oxidation state of the Ce ion, influences the stability and thus the reactivity of the layer. 27 Hence, La 1Àx Ce x O 2Àx/2 is a promising oxide material for use in solid oxide fuel cells as electrolyte layer or in catalysts 22-28 and could be envisaged as an alternative buffer layer for YBCO coated conductors, related to appropriate crystal structure and possible improved stability compared to CeO 2 . La 3+ is reported to be incorporated in the CeO 2 crystal lattice up to doping percentages of 55%. Since La 3+ has a larger radius than Ce 4+ (1.30 vs. 1.11 A), 29 it increases the cubic lattice parameter of ceria upon doping (from 5.6 A). 32-35 By varying the composition of the LCO material from pure CeO 2 to La 2 Ce 2 O 7 , the lattice mismatch with the Ni-5%W tape increases from 8 to 11%. At the same time, with increasing La content, an almost perfect lattice match with the YBCO 7Àx a-axis, YBCO 6+x or the YBCO 7Àx b-axis can be obtained. We studied the influence of the elemental composition of the material on its lattice parameter and the quality of the epitaxial growth of LCO layers directly on buffered tape. The research focused on the investigation of solid solution compositions with optimal lattice match toward YBCO, the growth of single buffer layers on Ni-5%W substrates exhibiting dense, crack-free, uniform and textured morphology and structure and the study of the buffer capacity of these coatings. Experimental Precursor solution synthesis Aqueous LCO precursor solutions (0.4 M) are prepared by dissolving cerium acetate (Ce(CH 3 COO) 3 xH 2 O, Sigma-Aldrich, ) was slowly added to the EDTA solution at room temperature and stirred for 10 minutes. The pH of the mixed solution was adjusted from 3 to 6 by addition of ammonia. After heating to 60 C, ethylene glycol (EG, Sigma-Aldrich, >99%) was added (molar ratio EDTA : EG ¼ 1 : 6). Finally, excess solvent was evaporated while stirring at 60 C, until the desired concentration of 0.4 mol L À1 was obtained. This precursor solution has a final pH of 6 and a viscosity of 5.60 mPa s. Preparation of powders A series of powders with varying compositions (La x Ce 1Àx O d with 0 # x # 1) were prepared from the precursor solutions discussed above. The powders were obtained by pouring 15 mL of the precursor solution into an Al 2 O 3 crucible that was placed inside a muffle furnace. The conversion into solid matter was carried out under air by reaching 1000 C from room temperature in 4 hours and let to stabilize for 2 hours. They were then cooled down to rt within 3 hours time. Solution deposition and heat treatment Ni-5%W tapes of 1 cm width and 80 mm thickness (manufactured by EVICO GmbH) were supplied by Zenergy Power GmbH. The tapes were cut into strips of 2.5 cm length for dip-coating. These substrates were dip-coated at a withdrawal speed ranging between 20 and 60 mm min À1 in a clean room (class 10 000) to prevent contamination with dust particles. The as-deposited layers were transformed into a gel by placing them in a drying furnace at 60 C for one hour. The amorphous gel layers were transformed into crystalline layers by applying a suitable heat treatment. The as-deposited layers were first heated from room temperature to 450 C (ramp rate of 1 C min À1 ) and let to dwell for 1 hour. Secondly, a heating rate of 3 C min À1 was applied from 450 C until 900 C (dwell time ¼ 1 h). Finally, the films were heated to 1050 C at a 10 C min À1 ramp with a dwell time of one hour. After the heat treatment, the furnace was switched off and the samples were left to cool inside the furnace. The entire heating and cooling process was carried out in an Ar-5%H 2 atmosphere (gas flow range: 0.1 L min À1 ). Characterization The thickness of the crystallized layers was analyzed by spec- View Online films on Ni-5%W substrates (l ¼ 638.3 nm, n ¼ 1.998). The crystallinity of the film was analyzed using a standard X-ray diffractometer for q-2q analysis (CuK a , Siemens D 5000). f-Scans were measured using a Bruker, AXS Discoverer diffractometer. To verify the crystallinity/texturation of the top surface (5 nm) we used Reflection High Energy Electron Diffraction (RHEED, Staib Instruments) at an energy of 30 keV under an incidence angle of 1-2 . The microstructure of the surface was analyzed with a scanning electron microscope (FEG-SEM, FEI). The buffer layer action was evaluated by monitoring the Ni penetration depth using X-ray photo-electron spectroscopy (S-Probe Monochromatized XPS spectrometer from Surface Science Instruments (VG) with an Al-source (monochromatized Al-radiation: 1486 eV)). The measured surface was 250 mm by 1000 mm. Experimental data were processed using the software package CasaXPS (Casa Software Ltd., UK), by including a Shirley background and Scofield sensitivity factors. Finally, a THEVA Cryoscan was used to measure the critical current density of the YBCO layers deposited on top of the LCO buffer layer. LCO specimens for (S)TEM investigations were prepared by conventional mechanical polishing and grinding followed by ion milling using a Res 100 Baltec ion milling machine operating at 4.5 kV and 3.5 mA for several hours. Plan-view specimens were ion milled from the substrate side only at an angle of 12 . A final polishing stage was done at 6 . High Angle Annular Dark Field (HAADF)-Scanning Transmission electron microscopy (STEM) imaging was carried out at EMAT on a double aberration-corrected FEI Titan 80-300 microscope operating in STEM mode. For HAADF-STEM imaging at 300 kV an inner collection semi-angle b of 50 mrad was used. Results and discussion Powders and cell parameters , these different precursor solutions were converted into solid matter by heating to 1000 C under air and studied by X-ray diffraction 26 They find that La 3+ addition in CeO 2 is more energetically favored when assuming such a structure. More specifically, it is shown that the introduced oxygen vacancies prefer a Ce tetrahedral surrounding. For a fluorite lattice with randomly distributed La and Ce cations, Vanpoucke et al. also calculate that the number of charge compensating oxygen vacancies will outnumber the number of Ce tetrahedra for a La concentration of about 43 at%, indicating the driving force of the pyrochlore transformation. In our case, all experimental XRD patterns obtained from powders are indicative of the typical pyrochlore-fluorite lattice for the full doping range, and no peaks related to the formation of secondary phases such as La 2 O 3 can be found. We can see a clear shift of the reflections towards lower 2q values as a function of La 3+ content. Using the (CeO 2 , fluorite) reflections indexed in 19,43 , we continued our research on thin films deposited on Ni-5%W tape. Again, a series of samples with varying La 3+ content, ranging from pure CeO 2 to La 2 Ce 2 O 7 , were prepared. The withdrawal speed during dip coating was set at 20 mm min À1 . In this way, layers with a thickness of 60 to 70 nm, as determined from ellipsometry, can be obtained. In line with the results for powder diffraction, no trace of any secondary phase can be found, and all layers exhibit the expected fluorite type structure. Also for the layers, the reflections shift to lower 2q values as a function of La 3+ content, related to its larger ionic radius compared to Ce 4+ . The lattice parameters extracted from these indexed XRD reflections, using Bragg's law, are plotted as a function of La 3+ content in A. Since LCO grows 45 rotated versus the Ni-5%W cubic lattice for lattice matching, this means that the substrate (sqrt(2a 2 ) ¼ 5.01 A) has a negative mismatch compared to the LCO layers and thus compressive strain will occur in the thin films. On the other hand, the LCO powders were synthesized under air while thin films on Ni-5%W tape have to be heat treated under reducing conditions (Ar-5%H 2 ). It is well known that LCO is very sensitive to the formation of oxygen vacancies and these can influence the lattice parameters. Vanpoucke et al. have published, based on DFT simulations, that in the case where no oxygen vacancies exist and thus similar to when processing under air, the lattice parameter changes 2.75% when moving from CeO 2 to La 2 Ce 2 O 8 . 26 From our experimental values for powders we find a value of 2.95%. In the case of LCO samples containing oxygen vacancies, the theoretical lattice expansion by La 3+ doping is expected to be smaller, somewhere between 2.7 and 1.7%, depending on the lattice site being occupied by the vacancies. These numbers are in line with a number of experimental reports. 38-41,43-45 Here, we find an experimental expansion of the lattice parameter of $2.4%, showing good agreement with the theoretical expectations. Fro