Polyphosphates as a source of enhanced P fluxes in marine sediments overlain by anoxic waters: Evidence from (31)P NMR

Sedimentary phosphorus (P) composition was investigated in Effingham Inlet, a fjord located on the west coast of Vancouver Island in Barkley Sound. Solid-state (31)P nuclear magnetic resonance (NMR) spectroscopy was applied to demineralized sediment samples from sites overlain by oxic and anoxic bottom waters. The two sites were similar in terms of key diagenetic parameters, including the mass accumulation rate, integrated sulfate reduction rate, and bulk sediment organic carbon content. In contrast, P benthic fluxes were much higher at the anoxic site. (31)P NMR results show that P esters and phosphonates are the major organic P species present at the surface and at depth in sediments at both sites. Polyphosphates were only found in the surface sediment of the site overlain by oxic waters. The varying stability of polyphosphates in microorganisms under different redox conditions may, in part, explain their distribution as well as differences in P flux between the two sites

Educação interprofissional e prática colaborativa na Atenção Primária à Saúde*

RESUMO Objetivo Compreender as percepções de docentes, trabalhadores e estudantes sobre a articulação da educação interprofissional com as práticas na Atenção Primária à Saúde. Método Qualitativo compreensivo e interpretativo, cuja coleta de dados foi realizada de 2012 a 2013, por meio de 18 entrevistas semiestruturadas com docentes e quatro sessões de grupos focais homogêneos com estudantes, docentes e trabalhadores da Atenção Primária. Resultados A triangulação dos resultados possibilitou a construção de duas categorias: prática colaborativa centrada no usuário e barreiras para educação interprofissional. A primeira indicou a necessidade de mudança do modelo de atenção e de formação dos profissionais de saúde, e a segunda apontou dificuldades percebidas pelos diferentes atores sociais no que se refere à implementação da educação interprofissional. Conclusão A educação interprofissional é incipiente no Brasil e sinaliza possibilidades de mudança em direção à prática colaborativa, mas requer maiores investimentos na articulação ensino-serviço

HIV-1 assembly in macrophages

The molecular mechanisms involved in the assembly of newly synthesized Human Immunodeficiency Virus (HIV) particles are poorly understood. Most of the work on HIV-1 assembly has been performed in T cells in which viral particle budding and assembly take place at the plasma membrane. In contrast, few studies have been performed on macrophages, the other major target of HIV-1. Infected macrophages represent a viral reservoir and probably play a key role in HIV-1 physiopathology. Indeed macrophages retain infectious particles for long periods of time, keeping them protected from anti-viral immune response or drug treatments. Here, we present an overview of what is known about HIV-1 assembly in macrophages as compared to T lymphocytes or cell lines

Protein S is a cofactor for platelet and endothelial tissue factor pathway inhibitor-a but not for cell surface-associated tissue factor pathway inhibitor

OBJECTIVE - Tissue factor pathway inhibitor (TFPI) is produced in 2 isoforms: TFPIa, a soluble protein in plasma, platelets, and endothelial cells, and TFPIß, a glycosylphosphatidylinositol-anchored protein on endothelium. Protein S (PS) functions as a cofactor for TFPIa, enhancing the inhibition of factor Xa. However, PS does not alter the inhibition of prothrombinase by TFPIa, and PS interactions with TFPIß are undescribed. Thus, the physiological role and scope of the PS-TFPI system remain unclear. APPROACH AND RESULTS - Here, the cofactor activity of PS toward platelet and endothelial TFPIa and endothelial TFPIß was quantified. PS enhanced the inhibition of factor Xa by TFPIa from platelets and endothelial cells and stabilized the TFPIa/factor Xa inhibitory complex, delaying thrombin generation by prothrombinase. By contrast, PS did not enhance the inhibitory activity of TFPIß or a membrane-anchored form of TFPI containing the PS-binding third Kunitz domain (K1K2K3) although PS did function as a cofactor for K1K2K3 enzymatically released from the cell surface. CONCLUSIONS - The PS-TFPI anticoagulant system is limited to plasma TFPIa and TFPIa released from platelets and endothelial cells. PS likely functions to localize solution-phase TFPIa to the cell surface, where factor Xa is bound. PS does not alter the activity of membrane-associated TFPI. Because activated platelets release TFPIa and PS, the PS-TFPIa anticoagulant system may act physiologically to dampen thrombin generation at the platelet surface. © 2013 American Heart Association, Inc