Using dissolved H₂O in rhyolitic glasses to estimate palaeo-ice thickness during a subglacial eruption at Bláhnúkur(Torfajökull, Iceland)

The last decade has seen the refinement of a technique for reconstructing palaeo-ice thicknesses based on using the retained H2O and CO2 content in glassy eruptive deposits to infer quenching pressures and therefore ice thicknesses. The method is here applied to Bláhnúkur, a subglacially erupted rhyolitic edifice in Iceland. A decrease in water content from ~0.7 wt.% at the base to ~0.3 wt.% at the top of the edifice suggests that the ice was 400 m thick at the time of the eruption. As Bláhnúkur rises 350 m above the surrounding terrain, this implies that the eruption occurred entirely within ice, which corroborates evidence obtained from earlier lithofacies studies. This paper presents the largest data set (40 samples) so far obtained for the retained volatile contents of deposits from a subglacial eruption. An important consequence is that it enables subtle but significant variations in water content to become evident. In particular, there are anomalous samples which are either water-rich (up to 1 wt.%) or water-poor (~0.2 wt.%), with the former being interpreted as forming intrusively within hyaloclastite and the latter representing batches of magma that were volatile-poor prior to eruption. The large data set also provides further insights into the strengths and weaknesses of using volatiles to infer palaeo-ice thicknesses and highlights many of the uncertainties involved. By using examples from Bláhnúkur, the quantitative use of this technique is evaluated. However, the relative pressure conditions which have shed light on Bláhnúkur’s eruption mechanisms and syn-eruptive glacier response show that, despite uncertainties in absolute values, the volatile approach can provide useful insight into the mechanisms of subglacial rhyolitic eruptions, which have never been observed

Cell-Surface Marker Signatures for the Isolation of Neural Stem Cells, Glia and Neurons Derived from Human Pluripotent Stem Cells

Neural induction of human pluripotent stem cells often yields heterogeneous cell populations that can hamper quantitative and comparative analyses. There is a need for improved differentiation and enrichment procedures that generate highly pure populations of neural stem cells (NSC), glia and neurons. One way to address this problem is to identify cell-surface signatures that enable the isolation of these cell types from heterogeneous cell populations by fluorescence activated cell sorting (FACS).We performed an unbiased FACS- and image-based immunophenotyping analysis using 190 antibodies to cell surface markers on naïve human embryonic stem cells (hESC) and cell derivatives from neural differentiation cultures. From this analysis we identified prospective cell surface signatures for the isolation of NSC, glia and neurons. We isolated a population of NSC that was CD184(+)/CD271(-)/CD44(-)/CD24(+) from neural induction cultures of hESC and human induced pluripotent stem cells (hiPSC). Sorted NSC could be propagated for many passages and could differentiate to mixed cultures of neurons and glia in vitro and in vivo. A population of neurons that was CD184(-)/CD44(-)/CD15(LOW)/CD24(+) and a population of glia that was CD184(+)/CD44(+) were subsequently purified from cultures of differentiating NSC. Purified neurons were viable, expressed mature and subtype-specific neuronal markers, and could fire action potentials. Purified glia were mitotic and could mature to GFAP-expressing astrocytes in vitro and in vivo.These findings illustrate the utility of immunophenotyping screens for the identification of cell surface signatures of neural cells derived from human pluripotent stem cells. These signatures can be used for isolating highly pure populations of viable NSC, glia and neurons by FACS. The methods described here will enable downstream studies that require consistent and defined neural cell populations

Interplay between phosphorylation and palmitoylation mediates plasma membrane targeting and sorting of GAP43.

Phosphorylation and lipidation provide posttranslational mechanisms that contribute to the distribution of cytosolic proteins in growing nerve cells. The growth-associated protein GAP43 is susceptible to both phosphorylation and S-palmitoylation and is enriched in the tips of extending neurites. However, how phosphorylation and lipidation interplay to mediate sorting of GAP43 is unclear. Using a combination of biochemical, genetic, and imaging approaches, we show that palmitoylation is required for membrane association and that phosphorylation at Ser-41 directs palmitoylated GAP43 to the plasma membrane. Plasma membrane association decreased the diffusion constant fourfold in neuritic shafts. Sorting to the neuritic tip required palmitoylation and active transport and was increased by phosphorylation-mediated plasma membrane interaction. Vesicle tracking revealed transient association of a fraction of GAP43 with exocytic vesicles and motion at a fast axonal transport rate. Simulations confirmed that a combination of diffusion, dynamic plasma membrane interaction and active transport of a small fraction of GAP43 suffices for efficient sorting to growth cones. Our data demonstrate a complex interplay between phosphorylation and lipidation in mediating the localization of GAP43 in neuronal cells. Palmitoylation tags GAP43 for global sorting by piggybacking on exocytic vesicles, whereas phosphorylation locally regulates protein mobility and plasma membrane targeting of palmitoylated GAP43

Untersuchungen der elektronischen Struktur des Volumens und der Oberflaeche von Kupfer, dem Adsorbatsystem Cu(001)-Schwefel und Nickelsulfid

Copy held by FIZ Karlsruhe; available from UB/TIB Hannover / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekSIGLEDEGerman

Am J Med Genet

Brachydactyly type C (BDC) is characterized by shortening of the middle phalanges of the index, middle, and little finger with hyperphalangy, usually of the index and middle finger. Heterozygous mutations of the cartilage derived morphogenetic protein-1 (CDMP1) resulting in a loss of function have been reported in BDC. We here describe a large kindred with a semi-dominant form of BDC and pronounced ulnar deviation of the second and third digits. In this family a novel homozygous missense mutation was identified (517A > G) changing methionine to valine at amino acid position 173. The mutation is located within a highly conserved seven amino acid region of the prodomain of CDMP1. Hand radiographs of heterozygous mutation carriers showed mild shortening of the metacarpals IV and V; a finding confirmed by the analysis of their metacarpophalangeal profiles (MCPPs). The mutation described here points toward an important function of the prodomain for the folding, secretion, and availability of biologically active CDMP1

Fischverzehr und Prävention ausgewählter ernährungsmitbedingter Krankheiten.

In addition to the DGE guideline “Fat intake and prevention of selected nutrition-related diseases” focussing on the nutrient fat (including long-chain n-3 fatty acids), this publication describes the data on the association between intake of fish as food and prevention of dyslipoproteinaemia, hypertension, coronary heart disease (CHD) and stroke. The data clearly show that regular intake of fish, particularly fatty fish, has a positive influence on the blood lipoprotein profile and reduces risk of CHD mortality and ischaemic stroke. The results confirm the recommendation of the DGE to eat fish once to twice a week

Association of the 867Asp variant of the human anion exchanger 3 gene with common subtypes of idiopathic generalized epilepsy

Genetic factors play a major role in the etiology of idiopathic generalized epilepsies (IGE). Our recent genome-wide search revealed suggestive evidence for a susceptibility locus for common IGE syndromes in the chromosomal region 2q36. The gene encoding the anion exchanger isoform 3 (AE3; gene symbol: SLC4A3) has been mapped to this candidate region. AE3 is prominently expressed in the brain and performs an electroneutral exchange of chloride and bicarbonate. To study the potential role of AE3 in the epileptogenesis of IGE, we performed a mutation analysis of the AE3 coding region, including the adjacent exon/intron boundaries, and the 5'-untranslated region in 16 IGE probands of families linked to chromosome 2q36 (cumulative two-point lod score: Z=5.32 at D2S371). Three exonic sequence variants were found: exon 17: 2600C/A, Ala867Asp; exon 21: 3391C/T, Leu1131Leu; exon 23: 3771G/A, 3'-UTR. Our subsequent population-based association study of the Ala867Asp substitution polymorphism revealed a significant increase of the 867Asp variant in 366 unrelated German IGE patients compared with 183 German control subjects (2=5.37, DF=1, P=0.021). Consistently, the transmission disequilibrium test (TDT) of 121 parent–child trios showed a significant preferential transmission of the 867Asp allele (McNemar 2=5.81, DF=1, P=0.016). Our results support the hypothesis that variation of the AE3 gene confers a common but small susceptibility effect to the etiology of a broad spectrum of IGE syndromes

A new spin effect in photoemission with unpolarized light: Experimental evidence of spin polarized electrons in normal emission from Pt(111) and Au(111)

Schmiedeskamp B, Irmer N, David R, Heinzmann U. A new spin effect in photoemission with unpolarized light: Experimental evidence of spin polarized electrons in normal emission from Pt(111) and Au(111). Applied Physics A: Materials Science and Processing. 1991;53(5):418-421