46 research outputs found

    How does the general public view posthumous organ donation? A meta-synthesis of the qualitative literature

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    <p>Abstract</p> <p>Background</p> <p>Many individuals are unwilling to become posthumous organ donors, resulting in a disparity between the supply and demand for organ transplants. A meta-synthesis of the qualitative literature was therefore conducted to determine how the general public views posthumous organ donation.</p> <p>Methods</p> <p>Three online databases (PubMed, PsycINFO, Scopus) were searched for articles published between January 1990 and May 2008 using the following search terms: organ donation, qualitative, interview. Eligibility criteria were: examination of beliefs about posthumous organ donation; utilization of a qualitative research design; and publication in an English peer-reviewed journal. Exclusion criteria were examining how health professionals or family members of organ donors viewed posthumous organ donation. Grounded theory was used to identify the beliefs emerging from this literature. Thematically-related beliefs were then grouped to form themes.</p> <p>Results</p> <p>27 articles from 24 studies met the inclusion criteria and were reviewed. The major themes identified were: religion, death, altruism, personal relevance, the body, the family, medical professionals, and transplant recipients. An altruistic motivation to help others emerged as the most commonly identified motivator for becoming an organ donor, although feeling a sense of solidarity with the broader community and believing that donated organs are put to good use may be important preconditions for the emergence of this motivation. The two most commonly identified barriers were the need to maintain bodily integrity to safeguard progression into the afterlife and the unethical recovery of organs by medical professionals. The influence of stakeholder groups on willingness to become an organ donor was also found to vary by the level of control that each stakeholder group exerted over the donation recovery process and their perceived conflict of interest in wanting organ donation to proceed.</p> <p>Conclusions</p> <p>These findings afford insights into how individuals perceive posthumous organ donation.</p

    Direct observation of DNA threading in flap endonuclease complexes

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    Maintenance of genome integrity requires that branched nucleic acid molecules are accurately processed to produce double-helical DNA. Flap endonucleases are essential enzymes that trim such branched molecules generated by Okazaki fragment synthesis during replication. Here, we report crystal structures of bacteriophage T5 flap endonuclease in complexes with intact DNA substrates, and products, at resolutions of 1.9–2.2 Å. They reveal single-stranded DNA threading through a hole in the enzyme enclosed by an inverted Vshaped helical arch straddling the active site. Residues lining the hole induce an unusual barb-like conformation in the DNA substrate juxtaposing the scissile phosphate and essential catalytic metal ions. A series of complexes and biochemical analyses show how the substrate’s single-stranded branch approaches, threads through, and finally emerges on the far side of the enzyme. Our studies suggest that substrate recognition involves an unusual “flycasting, thread, bend and barb” mechanis

    Single gene locus changes perturb complex microbial communities as much as apex predator loss

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    Many bacterial species are highly social, adaptively shaping their local environment through the production of secreted molecules. This can, in turn, alter interaction strengths among species and modify community composition. However, the relative importance of such behaviours in determining the structure of complex communities is unknown. Here we show that single-locus changes affecting biofilm formation phenotypes in Bacillus subtilis modify community structure to the same extent as loss of an apex predator and even to a greater extent than loss of B. subtilis itself. These results, from experimentally manipulated multitrophic microcosm assemblages, demonstrate that bacterial social traits are key modulators of the structure of their communities. Moreover, they show that intraspecific genetic variability can be as important as strong trophic interactions in determining community dynamics. Microevolution may therefore be as important as species extinctions in shaping the response of microbial communities to environmental change

    Export of malaria proteins requires co-translational processing of the PEXEL motif independent of phosphatidylinositol-3-phosphate binding

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    Plasmodium falciparum exports proteins into erythrocytes using the Plasmodium export element (PEXEL) motif, which is cleaved in the endoplasmic reticulum (ER) by plasmepsin V (PMV). A recent study reported that phosphatidylinositol-3-phosphate (PI(3)P) concentrated in the ER binds to PEXEL motifs and is required for export independent of PMV, and that PEXEL motifs are functionally interchangeable with RxLR motifs of oomycete effectors. Here we show that the PEXEL does not bind PI(3)P, and that this lipid is not concentrated in the ER. We find that RxLR motifs cannot mediate export in P. falciparum. Parasites expressing a mutated version of KAHRP, with the PEXEL motif repositioned near the signal sequence, prevented PMV cleavage. This mutant possessed the putative PI(3)P-binding residues but is not exported. Reinstatement of PEXEL to its original location restores processing by PMV and export. These results challenge the PI(3)P hypothesis and provide evidence that PEXEL position is conserved for co-translational processing and export
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