109 research outputs found

    A Five-coordinate Metal Center in Co(II)-substituted VanX

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    In an effort to structurally probe the metal binding site in VanX, electronic absorption, EPR, and extended x-ray absorption fine structure (EXAFS) spectroscopic studies were conducted on Co(II)-substituted VanX. Electronic spectroscopy revealed the presence of Co(II) ligand field transitions that had molar absorptivities of ∌100 m–1 cm–1, which suggests that Co(II) is five-coordinate in Co(II)-substituted VanX. Low temperature EPR spectra of Co(II)-substituted VanX were simulated using spin Hamiltonian parameters of M = |Â±Âœă€‰, E/D = 0.14, greal(x,y) = 2.37, and grealS(z) = 2.03. These parameters lead to the prediction that Co(II) in the enzyme is five-coordinate and that there may be at least one solvent-derived ligand. Single scattering fits of EXAFS data indicate that the metal ions in both native Zn(II)-containing and Co(II)-substituted VanX have the same coordination number and that the metal ions are coordinated by 5 nitrogen/oxygen ligands at ∌ 2.0 Å. These data demonstrate that Co(II) (and Zn(II) from EXAFS studies) is five-coordinate in VanX in contrast to previous crystallographic studies (Bussiere, D. E., Pratt, S. D., Katz, L., Severin, J. M., Holzman, T., and Park, C. H. (1998) Mol. Cell 2, 75–84). These spectroscopic studies also demonstrate that the metal ion in Co(II)-substituted VanX when complexed with a phosphinate analog of substrate d-Ala-d-Ala is also five-coordinate

    Differential Binding of Co(II) and Zn(II) to Metallo-ÎČ-Lactamase Bla2 from \u3cem\u3eBacillus anthracis\u3c/em\u3e

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    In an effort to probe the structure, mechanism, and biochemical properties of metallo-ÎČ-lactamase Bla2 from Bacillus anthracis, the enzyme was overexpressed, purified, and characterized. Metal analyses demonstrated that recombinant Bla2 tightly binds 1 equiv of Zn(II). Steady-state kinetic studies showed that mono-Zn(II) Bla2 (1Zn-Bla2) is active, while di-Zn(II) Bla2 (ZnZn-Bla2) was unstable. Catalytically, 1Zn-Bla2 behaves like the related enzymes CcrA and L1. In contrast, di-Co(II) Bla2 (CoCo-Bla2) is substantially more active than the mono-Co(II) analogue. Rapid kinetics and UV−vis, 1H NMR, EPR, and EXAFS spectroscopic studies show that Co(II) binding to Bla2 is distributed, while EXAFS shows that Zn(II) binding is sequential. To our knowledge, this is the first documented example of a Zn enzyme that binds Co(II) and Zn(II) via distinct mechanisms, underscoring the need to demonstrate transferability when extrapolating results on Co(II)-substituted proteins to the native Zn(II)-containing forms

    Habitat use and spatial fidelity of male South American sea lions during the nonbreeding period

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    Conditions experienced during the nonbreeding period have profound long-term effects on individual fitness and survival. Therefore, knowledge of habitat use during the nonbreeding period can provide insights into processes that regulate populations. At the Falkland Islands, the habitat use of South American sea lions (Otaria flavescens) during the nonbreeding period is of particular interest because the population is yet to recover from a catastrophic decline between the mid-1930s and 1965, and nonbreeding movements are poorly understood. Here, we assessed the habitat use of adult male (n = 13) and juvenile male (n = 6) South American sea lions at the Falkland Islands using satellite tags and stable isotope analysis of vibrissae. Male South American sea lions behaved like central place foragers. Foraging trips were restricted to the Patagonian Shelf and were typically short in distance and duration (127 ± 66 km and 4.1 ± 2.0 days, respectively). Individual male foraging trips were also typically characterized by a high degree of foraging site fidelity. However, the isotopic niche of adult males was smaller than juvenile males, which suggested that adult males were more consistent in their use of foraging habitats and prey over time. Our findings differ from male South American sea lions in Chile and Argentina, which undertake extended movements during the nonbreeding period. Hence, throughout their breeding range, male South American sea lions have diverse movement patterns during the nonbreeding period that intuitively reflects differences in the predictability or accessibility of preferred prey. Our findings challenge the long-standing notion that South American sea lions undertake a winter migration away from the Falkland Islands. Therefore, impediments to South American sea lion population recovery likely originate locally and conservation measures at a national level are likely to be effective in addressing the decline and the failure of the population to recover

    Hematopoietic Fingerprints: An Expression Database of Stem Cells and Their Progeny

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    SummaryHematopoietic stem cells (HSCs) continuously regenerate the hematologic system, yet few genes regulating this process have been defined. To identify candidate factors involved in differentiation and self-renewal, we have generated an expression database of hematopoietic stem cells and their differentiated progeny, including erythrocytes, granulocytes, monocytes, NK cells, activated and naive T cells, and B cells. Bioinformatic analysis revealed HSCs were more transcriptionally active than their progeny and shared a common activation mechanism with T cells. Each cell type also displayed unique biases in the regulation of particular genetic pathways, with Wnt signaling particularly enhanced in HSCs. We identified ∌100–400 genes uniquely expressed in each cell type, termed lineage “fingerprints.” In overexpression studies, two of these genes, Zfp105 from the NK cell lineage, and Ets2 from the monocyte lineage, were able to significantly influence differentiation toward their respective lineages, demonstrating the utility of the fingerprints for identifying genes that regulate differentiation

    Developing ecosystem service indicators: experiences and lessons learned from sub-global assessments and other initiatives

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    People depend upon ecosystems to supply a range of services necessary for their survival and well-being. Ecosystem service indicators are critical for knowing whether or not these essential services are being maintained and used in a sustainable manner, thus enabling policy makers to identify the policies and other interventions needed to better manage them. As a result, ecosystem service indicators are of increasing interest and importance to governmental and inter-governmental processes, including amongst others the Convention on Biological Diversity (CBD) and the Aichi Targets contained within its strategic plan for 2011-2020, as well as the emerging Intergovernmental Platform on Biodiversity and Ecosystem Services (IPBES). Despite this growing demand, assessing ecosystem service status and trends and developing robust indicators is o!en hindered by a lack of information and data, resulting in few available indicators. In response, the United Nations Environment Programme World Conservation Monitoring Centre (UNEP-WCMC), together with a wide range of international partners and supported by the Swedish International Biodiversity Programme (SwedBio)*, undertook a project to take stock of the key lessons that have been learnt in developing and using ecosystem service indicators in a range of assessment contexts. The project examined the methodologies, metrics and data sources employed in delivering ecosystem service indicators, so as to inform future indicator development. This report presents the principal results of this project

    Global Developments in Social Prescribing

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    Social prescribing is an approach that aims to improve health and well-being. It connects individuals to non-clinical services and supports that address social needs, such as those related to loneliness, housing instability and mental health. At the person level, social prescribing can give individuals the knowledge, skills, motivation and confidence to manage their own health and well-being. At the society level, it can facilitate greater collaboration across health, social, and community sectors to promote integrated care and move beyond the traditional biomedical model of health. While the term social prescribing was first popularised in the UK, this practice has become more prevalent and widely publicised internationally over the last decade. This paper aims to illuminate the ways social prescribing has been conceptualised and implemented across 17 countries in Europe, Asia, Australia and North America. We draw from the ‘Beyond the Building Blocks’ framework to describe the essential inputs for adopting social prescribing into policy and practice, related to service delivery; social determinants and household production of health; workforce; leadership and governance; financing, community organisations and societal partnerships; health technology; and information, learning and accountability. Cross-cutting lessons can inform country and regional efforts to tailor social prescribing models to best support local needs

    Phase 1/2a Study of the Malaria Vaccine Candidate Apical Membrane Antigen-1 (AMA-1) Administered in Adjuvant System AS01B or AS02A

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    Contains fulltext : 79496.pdf (publisher's version ) (Open Access)BACKGROUND: This Phase 1/2a study evaluated the safety, immunogenicity, and efficacy of an experimental malaria vaccine comprised of the recombinant Plasmodium falciparum protein apical membrane antigen-1 (AMA-1) representing the 3D7 allele formulated with either the AS01B or AS02A Adjuvant Systems. METHODOLOGY/PRINCIPAL FINDINGS: After a preliminary safety evaluation of low dose AMA-1/AS01B (10 microg/0.5 mL) in 5 adults, 30 malaria-naive adults were randomly allocated to receive full dose (50 microg/0.5 mL) of AMA-1/AS01B (n = 15) or AMA-1/AS02A (n = 15), followed by a malaria challenge. All vaccinations were administered intramuscularly on a 0-, 1-, 2-month schedule. All volunteers experienced transient injection site erythema, swelling and pain. Two weeks post-third vaccination, anti-AMA-1 Geometric Mean Antibody Concentrations (GMCs) with 95% Confidence Intervals (CIs) were high: low dose AMA-1/AS01B 196 microg/mL (103-371 microg/mL), full dose AMA-1/AS01B 279 microg/mL (210-369 microg/mL) and full dose AMA-1/AS02A 216 microg/mL (169-276 microg/mL) with no significant difference among the 3 groups. The three vaccine formulations elicited equivalent functional antibody responses, as measured by growth inhibition assay (GIA), against homologous but not against heterologous (FVO) parasites as well as demonstrable interferon-gamma (IFN-gamma) responses. To assess efficacy, volunteers were challenged with P. falciparum-infected mosquitoes, and all became parasitemic, with no significant difference in the prepatent period by either light microscopy or quantitative polymerase chain reaction (qPCR). However, a small but significant reduction of parasitemia in the AMA-1/AS02A group was seen with a statistical model employing qPCR measurements. SIGNIFICANCE: All three vaccine formulations were found to be safe and highly immunogenic. These immune responses did not translate into significant vaccine efficacy in malaria-naive adults employing a primary sporozoite challenge model, but encouragingly, estimation of parasite growth rates from qPCR data may suggest a partial biological effect of the vaccine. Further evaluation of the immunogenicity and efficacy of the AMA-1/AS02A formulation is ongoing in a malaria-experienced pediatric population in Mali. TRIAL REGISTRATION: www.clinicaltrials.gov NCT00385047

    Crop Updates 2003 - Cereals

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    This session covers twenty one papers from different authors: PLENARY 1. Recognising and responding to new market opportunities in the grains industry, Graham Crosbie, Manager, Grain Products Research, Crop Breeding, Plant Industries, Department of Agriculture 2. Stripe rust – where to now for the WA wheat industry? Robert Loughman1, Colin Wellings2 and Greg Shea11Department of Agriculture, 2University of Sydney Plant Breeding Institute, Cobbitty (on secondment from NSW Agriculture) 3. Benefits of a Grains Biosecurity Plan, Dr Simon McKirdy, Plant Health Australia, Mr Greg Shea, Department of Agriculture 4. Can we improve the drought tolerance of our crops? Neil C. Turner, CSIRO Plant Industry, Wembley 5. The silence of the lambing, Ross Kingwell, Department of Agriculture AGRONOMY AND VARIETIES 6. Maximising performance of wheat varieties, Brenda Shackley, Wal Anderson, Darshan Sharma, Mohammad Amjad, Steve Penny Jr, Melanie Kupsch, Anne Smith, Veronika Reck, Pam Burgess, Glenda Smith and Elizabeth Tierney, Department of Agriculture 7. Wheat variety performance in wet and dry, Peter Burgess 8. e-VarietyGuide for stripe rust – an updated version (1.02 – 2003), Moin Salam, Megan Collins, Art Diggle and Robert Loughman, Department of Agriculture 9. Baudin and Hamelin – new generation of malting barley developed in Western Australia, Blakely Paynter, Roslyn Jettner and Kevin Young, Department of Agriculture 10. Oaten hay production, Jocelyn Ball, Natasha Littlewood and Lucy Anderton, Department of Agriculture 11. Improving waterlogging tolerance in wheat and barley, Irene Waters and Tim Setter, Department of Agriculture 12. Broadscale variety comparisons featuring new wheat varieties, Jeff Russell, Department of Agriculture, Centre for Cropping Systems BIOTECHNOLOGY 13. Barley improvement in the Western Region – the intergration of biotechnologies, Reg Lance, Chengdao Li and Sue Broughton, Department of Agriculture 14. The Western Australian State Agricultural Biotechnology Centre – what we are and what we do, Michael Jones, WA State Agricultural Biotechnology Centre, Murdoch University 15. Protein and DNA methods for variety identification, Dr Grace Zawko, Saturn Biotech Limited 16. The Centre for High-throughput Agricultural Genetic Analysis (CHAGA), Keith Gregg, CHAGA, Murdoch University NUTRITION 17. Potassium – topdressed, drilled or banded? Stephen Loss, Patrick Gethin, Ryan Guthrie, Daniel Bell, Wesfarmers CSBP 18. Liquid phosphorus fertilisers in WA, Stephen Loss, Frank Ripper, Ryan Guthrie, Daniel Bell and Patrick Gethin, Wesfarmers CSBP 19. Wheat nutrition in the high rainfall cropping zone, Narelle Hill1and Laurence Carslake2, 1Department of Agriculture, 2Wesfarmers Landmark PESTS AND DISEASES 20. Managenent options for root lesion nematode in West Australian cropping systems, Vivien Vanstone, Sean Kelly and Helen Hunter, Department of Agriculture STORAGE 21. Aeration can profit your grain enterprise, Christopher R. Newman, Department of Agricultur
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