Recent developments in compact ultrafast lasers

Ultrafast lasers, which generate optical pulses in the picosecond and femtosecond range, have progressed over the past decade from complicated and specialized laboratory systems to compact, reliable instruments. Semiconductor lasers for optical pumping and fast optical saturable absorbers, based on either semiconductor devices or the optical nonlinear Kerr effect, have dramatically improved these lasers and opened up new frontiers for applications with extremely short temporal resolution (much smaller than 10 fs), extremely high peak optical intensities (greater than 10 TW/cm2) and extremely fast pulse repetition rates (greater than 100 GHz).     

Casein kinase 1 gamma couples Wnt receptor activation to cytoplasmic signal transduction

Signalling by Wnt proteins (Wingless in Drosophila) has diverse roles during embryonic development and in adults, and is implicated in human diseases, including cancer. LDL-receptor-related proteins 5 and 6 (LRP5 and LRP6; Arrow in Drosophila) are key receptors required for transmission of Wnt/beta-catenin signalling in metazoa. Although the role of these receptors in Wnt signalling is well established, their coupling with the cytoplasmic signalling apparatus remains poorly defined. Using a protein modification screen for regulators of LRP6, we describe the identification of Xenopus Casein kinase 1 gamma (CK1gamma), a membrane-bound member of the CK1 family. Gain-of-function and loss-of-function experiments show that CK1gamma is both necessary and sufficient to transduce LRP6 signalling in vertebrates and Drosophila cells. In Xenopus embryos, CK1gamma is required during anterio-posterior patterning to promote posteriorizing Wnt/beta-catenin signalling. CK1gamma is associated with LRP6, which has multiple, modular CK1 phosphorylation sites. Wnt treatment induces the rapid CK1gamma-mediated phosphorylation of these sites within LRP6, which, in turn, promotes the recruitment of the scaffold protein Axin. Our results reveal an evolutionarily conserved mechanism that couples Wnt receptor activation to the cytoplasmic signal transduction apparatus.     

Histochemische Untersuchungen zur Natur der Cytoplasma-Einschlüsse des Lungentumors der Maus

Résumé Dans une étude histochimique on a montré que les inclusions cytoplasmiques des tumeurs pulmonaires de la souris (Klärner etGieseking) contenaient une polysaccharide neutre jointe à l'acide ribonucléique. Les résultats ont été discutés au sens d'une hypothèse virale.     

Persistent near-tropical warmth on the Antarctic continent during the early Eocene epoch

The warmest global climates of the past 65 million years occurred during the early Eocene epoch (about 55 to 48 million years ago), when the Equator-to-pole temperature gradients were much smaller than today and atmospheric carbon dioxide levels were in excess of one thousand parts per million by volume. Recently the early Eocene has received considerable interest because it may provide insight into the response of Earth's climate and biosphere to the high atmospheric carbon dioxide levels that are expected in the near future as a consequence of unabated anthropogenic carbon emissions. Climatic conditions of the early Eocene 'greenhouse world', however, are poorly constrained in critical regions, particularly Antarctica. Here we present a well-dated record of early Eocene climate on Antarctica from an ocean sediment core recovered off the Wilkes Land coast of East Antarctica. The information from biotic climate proxies (pollen and spores) and independent organic geochemical climate proxies (indices based on branched tetraether lipids) yields quantitative, seasonal temperature reconstructions for the early Eocene greenhouse world on Antarctica. We show that the climate in lowland settings along the Wilkes Land coast (at a palaeolatitude of about 70° south) supported the growth of highly diverse, near-tropical forests characterized by mesothermal to megathermal floral elements including palms and Bombacoideae. Notably, winters were extremely mild (warmer than 10?°C) and essentially frost-free despite polar darkness, which provides a critical new constraint for the validation of climate models and for understanding the response of high-latitude terrestrial ecosystems to increased carbon dioxide forcing.     

Association scan of 14,500 nonsynonymous SNPs in four diseases identifies autoimmunity variants

We have genotyped 14,436 nonsynonymous SNPs (nsSNPs) and 897 major histocompatibility complex (MHC) tag SNPs from 1,000 independent cases of ankylosing spondylitis (AS), autoimmune thyroid disease (AITD), multiple sclerosis (MS) and breast cancer (BC). Comparing these data against a common control dataset derived from 1,500 randomly selected healthy British individuals, we report initial association and independent replication in a North American sample of two new loci related to ankylosing spondylitis, ARTS1 and IL23R, and confirmation of the previously reported association of AITD with TSHR and FCRL3. These findings, enabled in part by increased statistical power resulting from the expansion of the control reference group to include individuals from the other disease groups, highlight notable new possibilities for autoimmune regulation and suggest that IL23R may be a common susceptibility factor for the major 'seronegative' diseases.     

A new carnivorous dinosaur from the Late Jurassic Solnhofen archipelago

Small Late Jurassic theropod dinosaurs are rare worldwide. In Europe these carnivorous dinosaurs are represented primarily by only two skeletons of Compsognathus, neither of which is well preserved. Here we describe a small new theropod dinosaur from the Late Jurassic period of Schamhaupten in southern Germany. Being exquisitely preserved and complete from the snout to the distal third of the tail, the new fossil is the best-preserved predatory, non-avian dinosaur in Europe. It possesses a suite of characters that support its identification as a basal coelurosaur. A cladistic analysis indicates that the new taxon is closer to maniraptorans than to tyrannosauroids, grouping it with taxa often considered to be compsognathids. Large portions of integument are preserved along its tail. The absence of feathers or feather-like structures in a fossil phylogenetically nested within feathered theropods indicates that the evolution of these integumentary structures might be more complex than previously thought.     

DMP1 mutations in autosomal recessive hypophosphatemia implicate a bone matrix protein in the regulation of phosphate homeostasis

Hypophosphatemia is a genetically heterogeneous disease. Here, we mapped an autosomal recessive form (designated ARHP) to chromosome 4q21 and identified homozygous mutations in DMP1 (dentin matrix protein 1), which encodes a non-collagenous bone matrix protein expressed in osteoblasts and osteocytes. Intact plasma levels of the phosphaturic protein FGF23 were clearly elevated in two of four affected individuals, providing a possible explanation for the phosphaturia and inappropriately normal 1,25(OH)2D levels and suggesting that DMP1 may regulate FGF23 expression.