Taphonomic Bias of Selective Silicification Revealed by Paired Petrographic and Insoluble Residue Analysis

Silicification is an important mode of fossil preservation but the extent to which silicified material represents an unbiased sampling of the total fossil assemblage within a given rock sample remains poorly quantified. Here, we use paired analyses of thin sections and acid-extracted silicified specimens from the same samples to examine the biases introduced during silicification of Lower Triassic Virgin Limestone carbonates preserved in the Muddy Mountains of southern Nevada. Bivalves dominate most thin sections in the point count data, but rarely silicify completely enough to be recognized in residue. Echinoderms and gastropods are less abundant in thin section but dominate the residues. The abundances of these groups in thin section and residue are only weakly correlated. These findings suggest that although silicification generally captures relative trends in proportional abundance of higher taxa among samples, the silicification process can be taxonomically biased. Given the biases that can occur during silicification, it should not be assumed that silicified collections present a pristine picture of taxonomic or paleoecologic composition. Petrographic analysis has the potential to illuminate the reliability of paleontological data based on silicified collections

Complement C3 and C3aR mediate different aspects of emotional behaviours; relevance to risk for psychiatric disorder

Complement is a key component of the immune system with roles in inflammation and host-defence. Here we reveal novel functions of complement pathways impacting on emotional reactivity of potential relevance to the emerging links between complement and risk for psychiatric disorder. We used mouse models to assess the effects of manipulating components of the complement system on emotionality. Mice lacking the complement C3a Receptor (C3aR−/−) demonstrated a selective increase in unconditioned (innate) anxiety whilst mice deficient in the central complement component C3 (C3−/−) showed a selective increase in conditioned (learned) fear. The dissociable behavioural phenotypes were linked to different signalling mechanisms. Effects on innate anxiety were independent of C3a, the canonical ligand for C3aR, consistent with the existence of an alternative ligand mediating innate anxiety, whereas effects on learned fear were due to loss of iC3b/CR3 signalling. Our findings show that specific elements of the complement system and associated signalling pathways contribute differentially to heightened states of anxiety and fear commonly seen in psychopathology

Paleoecology of post-extinction fossil assemblages of the lower Triassic virgin limestone member in the Muddy Mountains, Southern Nevada : new insights into silicification of recovery faunas

The Virgin Limestone of the Moenkopi Formation in the southwestern United States has proven key in understanding the marine invertebrate recovery during the latest Early Triassic (e.g., Schubert and Bottjer, 1995; Pruss and Bottjer, 2004; Marenco et al., 2012), but to date no studies have focused on its silicified fossils. A major goal of this work is to analyze the paleoecology of these silicified faunas through samples from Virgin Limestone exposures at two localities in Muddy Mountains, Nevada. A second goal is to gain insight into preservation biases associated with silicification by comparing the silicified fossil assemblages with results of point-count analyses of thin sections of the same samples, which show both silicified and non-silicified fossils. A third part of the study compares !13Ccarb isotope profiles from Muddy Mountains with !13Ccarb profiles of dated Lower Triassic carbonates from the Great Bank of Guizhou, China, from Payne et al. (2004), and estimates the age of the Virgin Limestone at Ute and Overton exposures to be around ~247.95 Ma to ~246.11 Ma

Plasma proteome of growing tumors

Abstract Early detection of cancer is vital for the best chance of successful treatment, but half of all cancers are diagnosed at an advanced stage. A simple and reliable blood screening test applied routinely would therefore address a major unmet medical need. To gain insight into the value of protein biomarkers in early detection and stratification of cancer we determined the time course of changes in the plasma proteome of mice carrying transplanted human lung, breast, colon, or ovarian tumors. For protein measurements we used an aptamer-based assay which simultaneously measures ~ 5000 proteins. Along with tumor lineage-specific biomarkers, we also found 15 markers shared among all cancer types that included the energy metabolism enzymes glyceraldehyde-3-phosphate dehydrogenase, glucose-6-phophate isomerase and dihydrolipoyl dehydrogenase as well as several important biomarkers for maintaining protein, lipid, nucleotide, or carbohydrate balance such as tryptophanyl t-RNA synthetase and nucleoside diphosphate kinase. Using significantly altered proteins in the tumor bearing mice, we developed models to stratify tumor types and to estimate the minimum detectable tumor volume. Finally, we identified significantly enriched common and unique biological pathways among the eight tumor cell lines tested