A new species of Friesea (Collembola: Neanuridae) from the Antarctic Continent

A new species of Friesea was found in East Antarctica and is described here as Friesea eureka sp. nov. This is the first new collembolan species to be described from the Antarctic continent in 30 years, even though ice-free areas have been intensively surveyed over that time. It brings to five the number of described species of the genus Friesea known from the Antarctic continent and Peninsula, so is the most speciose genus of Collembola in the region. However, one of these, F. grisea Schäffer, comprises a number of cryptic species of different molecular lineages. The new species is distinguished by having 4 + 4 ocelli plus 1 + 1 hardly visible, a very reduced furca, up to four or five faintly clavate tenent hairs, four anal spines and four spinose chaetae in adult. The restricted distribution of the species emphasises the importance of protecting ice-free areas on the continent as they often contain at least one locally endemic faunal species

www.zoobank.org/urn:lsid:zoobank.org:pub:865B9AE6-0428-4364-99A4-AF38A764D6D9     

DNA repair is limiting for haematopoietic stem cells during ageing

Accumulation of DNA damage leading to adult stem cell exhaustion has been proposed to be a principal mechanism of ageing. Here we address this question by taking advantage of the highly specific role of DNA ligase IV in the repair of DNA double-strand breaks by non-homologous end-joining, and by the discovery of a unique mouse strain with a hypomorphic Lig4(Y288C) mutation. The Lig4(Y288C) mouse, identified by means of a mutagenesis screening programme, is a mouse model for human LIG4 syndrome, showing immunodeficiency and growth retardation. Diminished DNA double-strand break repair in the Lig4(Y288C) strain causes a progressive loss of haematopoietic stem cells and bone marrow cellularity during ageing, and severely impairs stem cell function in tissue culture and transplantation. The sensitivity of haematopoietic stem cells to non-homologous end-joining deficiency is therefore a key determinant of their ability to maintain themselves against physiological stress over time and to withstand culture and transplantation.     

A redox switch in angiotensinogen modulates angiotensin release

Blood pressure is critically controlled by angiotensins, which are vasopressor peptides specifically released by the enzyme renin from the tail of angiotensinogen-a non-inhibitory member of the serpin family of protease inhibitors. Although angiotensinogen has long been regarded as a passive substrate, the crystal structures solved here to 2.1?? resolution show that the angiotensin cleavage site is inaccessibly buried in its amino-terminal tail. The conformational rearrangement that makes this site accessible for proteolysis is revealed in our 4.4?? structure of the complex of human angiotensinogen with renin. The co-ordinated changes involved are seen to be critically linked by a conserved but labile disulphide bridge. Here we show that the reduced unbridged form of angiotensinogen is present in the circulation in a near 40:60 ratio with the oxidized sulphydryl-bridged form, which preferentially interacts with receptor-bound renin. We propose that this redox-responsive transition of angiotensinogen to a form that will more effectively release angiotensin at a cellular level contributes to the modulation of blood pressure. Specifically, we demonstrate the oxidative switch of angiotensinogen to its more active sulphydryl-bridged form in the maternal circulation in pre-eclampsia-the hypertensive crisis of pregnancy that threatens the health and survival of both mother and child.     

The union of arts and sciences in the eighteenth century: Lorenz Spengler (1720–1807), artistic turner and natural scientist

The life and career of Lorenz Spengler (1720–1807) provides evidence to support the view that the eighteenth century was a period when there was a fruitful interrelationship between the arts, crafts, and sciences in the courts and capitals of Europe. Spengler was trained as a turner, and was appointed teacher of ornamental turning to the Danish royal family and turner of the court in 1745. Even in the early years of his artistic career Spengler was interested in electricity and its role in healing, and he became an avid collector of shells and naturalia. Over the years, Spengler's interests turned more to the natural sciences, and in 1771 he was appointed director of the King's Kunstkammer. Only by considering both aspects of Spengler's career can his scientific activities be placed in their proper historical context.     

SOL-1 is a CUB-domain protein required for GLR-1 glutamate receptor function in C. elegans

Ionotropic glutamate receptors (iGluRs) mediate most excitatory synaptic signalling between neurons. Binding of the neurotransmitter glutamate causes a conformational change in these receptors that gates open a transmembrane pore through which ions can pass. The gating of iGluRs is crucially dependent on a conserved amino acid that was first identified in the 'lurcher' ataxic mouse. Through a screen for modifiers of iGluR function in a transgenic strain of Caenorhabditis elegans expressing a GLR-1 subunit containing the lurcher mutation, we identify suppressor of lurcher (sol-1). This gene encodes a transmembrane protein that is predicted to contain four extracellular beta-barrel-forming domains known as CUB domains. SOL-1 and GLR-1 are colocalized at the cell surface and can be co-immunoprecipitated. By recording from neurons expressing GLR-1, we show that SOL-1 is an accessory protein that is selectively required for glutamate-gated currents. We propose that SOL-1 participates in the gating of non-NMDA (N-methyl-D-aspartate) iGluRs, thereby providing a previously unknown mechanism of regulation for this important class of neurotransmitter receptor.     

Meta-analysis of genome-wide association studies of asthma in ethnically diverse North American populations

Asthma is a common disease with a complex risk architecture including both genetic and environmental factors. We performed a meta-analysis of North American genome-wide association studies of asthma in 5,416 individuals with asthma (cases) including individuals of European American, African American or African Caribbean, and Latino ancestry, with replication in an additional 12,649 individuals from the same ethnic groups. We identified five susceptibility loci. Four were at previously reported loci on 17q21, near IL1RL1, TSLP and IL33, but we report for the first time, to our knowledge, that these loci are associated with asthma risk in three ethnic groups. In addition, we identified a new asthma susceptibility locus at PYHIN1, with the association being specific to individuals of African descent (P = 3.9 × 10(-9)). These results suggest that some asthma susceptibility loci are robust to differences in ancestry when sufficiently large samples sizes are investigated, and that ancestry-specific associations also contribute to the complex genetic architecture of asthma.     

C 3 and C 4 Species Changes Identified by δ 13 C values of soil organic matter in a Colorado prairie

We measured carbon isotope signatures (δ 13 C) from 0-10 cm and 10-20 cm soil depth intervals for grassland soils near Boulder, Colorado. These grasslands included tall-, short-, and mixed-grass prairies that were grazed, ungrazed, or hayed. Soils exhibited δ 13 C signatures consistent with observations that current sites are a mix of C 3 and C 4 species, with C 3 plants more abundant in mixed-grass than in native tall- or shortgrass prairies. The δ 13 C signatures were not significantly different for grassland types; however, management treatments (grazing, no grazing, haying) significantly influenced changes in soil δ 13 C signatures from the 0-10 cm to 10-20 cm soil depth intervals. We observed a correlation ( r = 0.63) between isotopic values of surface soils and percent native species in total vegetation cover. Overall, the community type with the lowest percentage of nonindigenous species cover had the most enriched δ 13 C signature. Sites currently grazed by prairie dogs, cattle, or both herbivores had stronger C 3 signatures, indicating that grazing may have increased C 3 plant productivity in these communities at the expense of C 4 grasses. This finding differs from studies of native shortgrass steppe where grazing has the opposite effect on the relative abundance of these 2 functional groups of plants. This result, along with the correlation between C 3 isotopic values and nonnative vegetation abundance, provides evidence that management practices that maintain dominance of C 4 grasses should be encouraged.     

Evaluating potential for whole-genome studies in Kosrae, an isolated population in Micronesia

Whole-genome association studies are predicted to be especially powerful in isolated populations owing to increased linkage disequilibrium (LD) and decreased allelic diversity, but this possibility has not been empirically tested. We compared genome-wide data on 113,240 SNPs typed on 30 trios from the Pacific island of Kosrae to the same markers typed in the 270 samples from the International HapMap Project. The extent of LD is longer and haplotype diversity is lower in Kosrae than in the HapMap populations. More than 98% of Kosraen haplotypes are present in HapMap populations, indicating that HapMap will be useful for genetic studies on Kosrae. The long-range LD around common alleles and limited diversity result in improved efficiency in genetic studies in this population and augments the power to detect association of 'hidden SNPs'.     

Genome-wide association study identifies a common variant associated with risk of endometrial cancer

Endometrial cancer is the most common malignancy of the female genital tract in developed countries. To identify genetic variants associated with endometrial cancer risk, we performed a genome-wide association study involving 1,265 individuals with endometrial cancer (cases) from Australia and the UK and 5,190 controls from the Wellcome Trust Case Control Consortium. We compared genotype frequencies in cases and controls for 519,655 SNPs. Forty seven SNPs that showed evidence of association with endometrial cancer in stage 1 were genotyped in 3,957 additional cases and 6,886 controls. We identified an endometrial cancer susceptibility locus close to HNF1B at 17q12 (rs4430796, P = 7.1 × 10(-10)) that is also associated with risk of prostate cancer and is inversely associated with risk of type 2 diabetes.