53 research outputs found
Farewell to the ‘childhood of man’: ritual, seasonality, and the origins of inequality
Evidence of grand burials and monumental construction is a striking feature in the archaeological record of the Upper Palaeolithic period, between 40 and 10 kya (thousand years ago). Archaeologists often interpret such finds as indicators of rank and hierarchy among Pleistocene hunter-gatherers. Interpretations of this kind are difficult to reconcile with the view, still common in sociobiology, that pre-agricultural societies were typically egalitarian in orientation. Here we develop an alternative model of ‘Palaeolithic politics’, which emphasizes the ability of hunter-gatherers to alternate – consciously and deliberately – between contrasting modes of political organization, including a variety of hierarchical and egalitarian possibilities. We propose that alternations of this sort were an emergent property of human societies in the highly seasonal environments of the last Ice Age. We further consider some implications of the model for received concepts of social evolution, with particular attention to the distinction between ‘simple’ and ‘complex’ hunter-gatherers
A Flow Cytometry-Based FRET Assay to Identify and Analyse Protein-Protein Interactions in Living Cells
Försters resonance energy transfer (FRET) microscopy is widely used for the analysis of protein interactions in intact cells. However, FRET microscopy is technically challenging and does not allow assessing interactions in large cell numbers. To overcome these limitations we developed a flow cytometry-based FRET assay and analysed interactions of human and simian immunodeficiency virus (HIV and SIV) Nef and Vpu proteins with cellular factors, as well as HIV Rev multimer-formation.Amongst others, we characterize the interaction of Vpu with CD317 (also termed Bst-2 or tetherin), a host restriction factor that inhibits HIV release from infected cells and demonstrate that the direct binding of both is mediated by the Vpu membrane-spanning region. Furthermore, we adapted our assay to allow the identification of novel protein interaction partners in a high-throughput format.The presented combination of FRET and FACS offers the precious possibility to discover and define protein interactions in living cells and is expected to contribute to the identification of novel therapeutic targets for treatment of human diseases
Antimicrobial Activity and Genetic Profile of Enteroccoci Isolated from Hoopoes Uropygial Gland
Symbiotic microorganisms may be directly transferred from parents to offspring or acquired from a particular environment that animals may be able to select. If benefits for hosts vary among microbial strains, natural selection may favour hosts holding the most beneficial one. Enterococci symbionts living in the hoopoe (Upupa epops) uropygial gland are able to synthesise bacteriocins (antimicrobial peptides that inhibit the growth of competitor bacteria). We explored variability in genetic profile (through RAPD-PCR analyses) and antimicrobial properties (by performing antagonistic tests against ten bacterial indicator strains) of the different isolates obtained from the uropygial glands of hoopoe females and nestlings. We found that the genetic profile of bacterial isolates was related to antimicrobial activity, as well as to individual host identity and the nest from which samples were obtained. This association suggest that variation in the inhibitory capacity of Enterococci symbionts should be under selection.This work was financed by Ministerio de Ciencia e Innovación (Spanish National Government) and FEDER founds (projects CGL2010-19233-C03-01, and CGL2010-19233-C03-03), and Junta de Andalucía (P09-RNM-4557)
Polarity Changes in the Transmembrane Domain Core of HIV-1 Vpu Inhibits Its Anti-Tetherin Activity
Tetherin (BST-2/CD317) is an interferon-inducible antiviral protein that restricts the release of enveloped viruses from infected cells. The HIV-1 accessory protein Vpu can efficiently antagonize this restriction. In this study, we analyzed mutations of the transmembrane (TM) domain of Vpu, including deletions and substitutions, to delineate amino acids important for HIV-1 viral particle release and in interactions with tetherin. The mutants had similar subcellular localization patterns with that of wild-type Vpu and were functional with respect to CD4 downregulation. We showed that the hydrophobic binding surface for tetherin lies in the core of the Vpu TM domain. Three consecutive hydrophobic isoleucine residues in the middle region of the Vpu TM domain, I15, I16 and I17, were important for stabilizing the tetherin binding interface and determining its sensitivity to tetherin. Changing the polarity of the amino acids at these positions resulted in severe impairment of Vpu-induced tetherin targeting and antagonism. Taken together, these data reveal a model of specific hydrophobic interactions between Vpu and tetherin, which can be potentially targeted in the development of novel anti-HIV-1 drugs
Uranium mobility in organic matter-rich sediments: A review of geological and geochemical processes
Uranium (U) is of enormous global importance because of its use in energy generation, albeit with potential environmental legacies. While naturally occurring U is widespread in the Earth's crust at concentrations of ~1 to 3 ppm, higher concentrations can be found, includingwithin organicmatter (OM)-rich sediments, leading to economic extraction opportunities. The primary determinants of U behaviour in ore systems are pH, Eh, U oxidation state (U(IV), U(VI)) and the abundance of CO3 2– ions. The concentration/availability and interrelationships among such determinants vary, and the solubility and mobility of ions (e.g. OH-, CO3 2–, PO4 3-, SiO4 4-, SO4 2-) that compete for U (primarily as U(VI)) will also influence the mobility of U. In addition, the presence of OM can influence U mobility and fate by the degree of OMsorption to mineral surfaces (e.g. Fe- and Si- oxides and hydroxides). Within solid-phase OM, microbes can influence U oxidation state and U stability through direct enzymatic reduction, biosorption, biomineralisation and bioaccumulation. The biogenic UO2 product is, however, reported to be readily susceptible to reoxidation and therefore more likely remobilised over longer time periods. Thus several areas of uncertainty remain with respect to factors contributing to U accumulation, stability and/or (re)mobilisation. To address these uncertainties, this paper reviews U dynamics at both geological and molecular scales. Here we identify U-OMbond values that are in agreement, relatively strong, independent from ionic strength and which may facilitate either U mobilisation or immobilisation, depending on environmental conditions. We also examine knowledge gaps in the literature, with U-OM solubility data generally lacking in comparison to data for U sorption and dissolution, and little information available on multi-component relationships, such as UOM-V (V as vanadate). Furthermore, the capability ofOMto influence the oxidation state of U at near surface conditions remains unclear, as it can be postulated that electron shuttling by OM may contribute to changes in U redox state otherwise mediated by bacteria. Geochemical modelling of the environmental mobility of U will require incorporation of data from multi-corporation studies, as well as from studies of U-OM microbial interactions, all of which are considered in this review
Farewell to the ‘childhood of man’: ritual, seasonality, and the origins of inequality
2012 ACCF/AHA/ACP/AATS/PCNA/SCAI/STS guideline for the diagnosis and management of patients with stable ischemic heart disease
The recommendations listed in this document are, whenever possible, evidence based. An extensive evidence review was conducted as the document was compiled through December 2008. Repeated literature searches were performed by the guideline development staff and writing committee members as new issues were considered. New clinical trials published in peer-reviewed journals and articles through December 2011 were also reviewed and incorporated when relevant. Furthermore, because of the extended development time period for this guideline, peer review comments indicated that the sections focused on imaging technologies required additional updating, which occurred during 2011. Therefore, the evidence review for the imaging sections includes published literature through December 2011
An investigation into the use of alginates as bioadhesive delivery systems
Sodium alginates are naturally occurring polymers consisting of two monomers, mannuronate and guluronate. Their gel-forming properties and their potential use as bioadhesives have attracted particular attention within the pharmaceutical industry. The aim of this study is to characterise the gelling behaviour of several batches of sodium alginates of differing chemical characteristics and to relate this behaviour to their bioadhesive properties.
Three methods based on the internal bulking gelation were used to assess factors that may affect the basic characteristics of alginate gels, particularly gel strength. Isothermal oscillatory rheology and thermorheology, as well as texture analysis were used to assess the behaviour of these gels. It was possible from these analyses to demonstrate that the level of calcium, the method of preparing these gels, the fraction of guluronate, and the amount of sodium alginate all affect the gel behaviour.
In order to relate these findings to bioadhesion, two formulations, solid compacts and solutions and their interactions with various mucin types were examined. It was found that sodium alginate interaction with all types of mucin was more pronounced when the alginate consisted of predominantly mannuronate monomer. Further examinations revealed that there was also a temperature-dependent thermogelation process when alginate/mucin mixes were subjected to heat/cool cycles.
Finally, the bioadhesive potential of solutions of sodium alginate to porcine oesophageal tissues was assessed using a purpose-designed bioadhesion test system within a humidity chamber, based on flow channel technique. Fluorescently labelled sodium alginate solutions were applied to oesophageal tissues, continuously perfused with de-ionised water, phosphate buffer pH 7.4, or artificial saliva over 30 minutes. The total amount left after 30 minutes was calculated and expressed as a bioadhesive index. Mannuronate-rich alginates were found to exhibit better bioadhesive properties than their guluronate-rich alginates
Fresh Approach for High-Throughput Studies of Ion-Selective Materials Using Reusable ChemFET Platform
Aqueous anions play an important role in our world, and the ability to continuously measure them provides both environmental and health benefits. Chemically-sensitive field effect transistors (ChemFETs) are becoming increasingly popular in the field of aqueous measurement due to their relatively low-cost capability for real-time, continuous sensing. Receptor molecules or mixtures displaying affinity for a particular ion can also be utilized in a ChemFET gate membrane. Receptors can be incorporated into the gate oxide membrane and the entire ChemFET can utilized in an aqueous environment, thus utilizing hydrophobic receptors in an aqueous anion-sensing application.
Demonstrating the ability to reuse the sensors validates an important characteristic for ChemFET-based research. Additionally, numerous other receptor molecules are evaluated against an array of common anions. Selectivity coefficients are compared to the Hofmeister Series. Additional membranes are evaluated for suitability for incorporation of receptors on the ChemFET gate oxide surface. This thesis includes previously unpublished co-authored material.2021-04-3
Choosing Preferences by Constructing Institutions: A Cultural Theory of Preference Formation
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