Chemical preservation of tail feathers from Anchiornis huxleyi,a theropod dinosaur from the Tiaojishan Formation (Upper Jurassic,China)

A panel of geochemical techniques is used here to investigate the taphonomy of fossil feathers preserved in association with the skeleton of the Jurassic theropod Anchiornis huxleyi. Extant feathers were analysed in parallel to test whether the soft tissues morphologically preserved in the fossil also exhibit a high degree of chemical preservation. Scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDS) indicate that clays and iron oxide pseudomorphs occur in the surrounding sediment and also reveal the preservation of melanosome-like microbodies in the fossil. Carbon gradient along a depth profile and co-occurrence of carbon and sulphur are shown in the fossil by elastic backscattering (EBS) and particle-induced x-ray emission (PIXE), which are promising techniques for the elemental analysis of fossil soft tissues. The molecular composition of modern and fossil soft tissues was assessed from micro-attenuated total reflectance fourier transform infrared spectroscopy (micro-ATR FTIR), solid-state ¹³C nuclear magnetic resonance (CP-MAS ¹³C NMR) and pyrolysis gas chromatography mass spectrometry in the presence of TMAH (TMAH-Py-GC-MS). Results indicate that the proteinaceous material that comprises the modern feathers is not present in the fossil feathers. The fossil feathers and the embedding sediment exhibit a highly aliphatic character. However, substantial differences exist between these samples, revealing that the organic matter of the fossil feathers is, at least partially, derived from original constituents of the feathers. Our results suggest that, despite the morphological preservation of Anchiornis feathers, original proteins, that is keratin, were probably not preserved in the 160-myr-old feathers.     

PAX3 Confers Functional Heterogeneity in Skeletal Muscle Stem Cell Responses to Environmental Stress

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Binding of Lassa virus perturbs extracellular matrix-induced signal transduction via dystroglycan

The arenavirus Lassa virus (LASV) causes a severe haemorrhagic fever with high mortality in man. The cellular receptor for LASV is dystroglycan (DG). DG is a ubiquitous receptor for extracellular matrix (ECM) proteins, which cooperates with β1 integrins to control cell-matrix interactions. Here, we investigated whether LASV binding to DG triggers signal transduction, mimicking the natural ligands. Engagement of DG by LASV resulted in the recruitment of the adaptor protein Grb2 and the protein kinase MEK1 by the cytoplasmic domain of DG without activating the MEK/ERK pathway, indicating assembly of an inactive signalling complex. LASV binding to cells however affected the activation of the MEK/ERK pathway via α6β1 integrins. The virus-induced perturbation of α6β1 integrin signalling critically depended on high-affinity LASV binding to DG and DG's cytoplasmic domain, indicating that LASV-receptor binding perturbed signalling cross-talk between DG and β1 integrins.     

A caterpillar (Callopistria floridensis G. (Lepidoptera: Noctuidae)) accumulates arsenic from an arsenic‐hyperaccumulating fern (Pteris vittata L.).

1. The consumption of arsenic is toxic to most biota. However, a noctuid caterpillar was recently reported feeding on a plant known to hyperaccumulate arsenic. 2. The aim of this study was to investigate the effects of arsenic‐rich Pteris vittata L. consumption by Callopistria floridensis G., and measure differences in arsenic concentrations at various stages of development (larval and adult), and associated with exuviae and frass. 3. Callopistria floridensis accumulated extraordinary concentrations of arsenic. The relative accumulation of arsenic was highest in exuviae and larvae. Larvae invariably preferred P. vittata grown on low arsenic soil to P. vittata grown on higher soil arsenic concentrations, and appeared able to selectively forage on lower arsenic concentrations within each treatment. 4. These findings show that C. floridensis is tolerant of arsenic, and successfully develops to adulthood containing elevated concentrations of arsenic. Callopistria floridensis represents the only known terrestrial animal capable of accumulating arsenic, and may have developed novel physiological and behavioural adaptations to regulate the negative effects of arsenic.     

A novel nucleotide receptor in Xenopus activates the cAMP second messenger pathway

We describe a Xenopus P2Y receptor that shares only weak homology with members of the mammalian P2Y family, being most similar to human P2Y(11). When activated by nucleotide analogs, it stimulates both calcium and cAMP mobilization pathways, a feature unique, among mammalian P2Y receptors, to P2Y(11). Activity can be blocked by compounds known to act as antagonists of mammalian P2Y(11). Genomic synteny between Xenopus and mammals suggests that the novel gene is a true ortholog of P2Y(11). Xenopus P2Y(11) is transcribed during embryonic development, beginning at gastrulation, and is enriched in the developing nervous system.