68 research outputs found

    Geographic distribution at subspecies resolution level: closely related Rhodopirellula species in European coastal sediments.

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    Members of the marine genus Rhodopirellula are attached living bacteria and studies based on cultured Rhodopirellula strains suggested that three closely related species R. baltica, 'R. europaea' and 'R. islandica' have a limited geographic distribution in Europe. To address this hypothesis, we developed a nested PCR for a single gene copy detection of a partial acetyl CoA synthetase (acsA) from intertidal sediments collected all around Europe. Furthermore, we performed growth experiments in a range of temperature, salinity and light conditions. A combination of Basic Local Alignment Search Tool (BLAST) and Minimum Entropy Decomposition (MED) was used to analyze the sequences with the aim to explore the geographical distribution of the species and subspecies. MED has been mainly used for the analysis of the 16S rRNA gene and here we propose a protocol for the analysis of protein-coding genes taking into account the degeneracy of the codons and a possible overestimation of functional diversity. The high-resolution analysis revealed differences in the intraspecies community structure in different geographic regions. However, we found all three species present in all regions sampled and in agreement with growth experiments we demonstrated that Rhodopirellula species do not have a limited geographic distribution in Europe

    Possible Brucellosis in an Early Hominin Skeleton from Sterkfontein, South Africa

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    We report on the paleopathological analysis of the partial skeleton of the late Pliocene hominin species Australopithecus africanus Stw 431 from Sterkfontein, South Africa. A previous study noted the presence of lesions on vertebral bodies diagnosed as spondylosis deformans due to trauma. Instead, we suggest that these lesions are pathological changes due to the initial phases of an infectious disease, brucellosis. The macroscopic, microscopic and radiological appearance of the lytic lesions of the lumbar vertebrae is consistent with brucellosis. The hypothesis of brucellosis (most often associated with the consumption of animal proteins) in a 2.4 to 2.8 million year old hominid has a host of important implications for human evolution. The consumption of meat has been regarded an important factor in supporting, directing or altering human evolution. Perhaps the earliest (up to 2.5 million years ago) paleontological evidence for meat eating consists of cut marks on animal remains and stone tools that could have made these marks. Now with the hypothesis of brucellosis in A. africanus, we may have evidence of occasional meat eating directly linked to a fossil hominin

    Dual mechanism of daunorubicin-induced cell death in both sensitive and MDR-resistant HL-60 cells

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    Exposure of some acute myeloid leukaemia (AML) cells to daunorubicin leads to rapid cell death, whereas other AML cells show natural drug resistance. This has been attributed to expression of functional P-glycoprotein resulting in reduced drug accumulation. However, it has also been proposed that P-glycoprotein-expressing multidrug-resistant (MDR) cells are inherently defective for apoptosis. To distinguish between these different possibilities, we have compared the cell death process in a human AML cell line (HL-60) with a MDR subline (HL-60/Vinc) at doses that yield either similar intracellular daunorubicin concentrations or comparable cytotoxicity. Adjustment of the dose to obtain the same intracellular drug accumulation in the two cell lines did not result in equal cytotoxicity, suggesting the presence of additional resistance mechanisms in the P-glycoprotein-expressing HL-60/Vinc cells. However, at equitoxic doses, similar cell death pathways were observed. In HL-60 cells, daunorubicin induced rapid apoptosis at 0.5–1 ÎŒM and delayed mitotic cell death at 0.1 ÎŒM. These concentrations are within the clinical dose range. Similarly, HL-60/Vinc cells underwent apoptosis at 50–100 ÎŒM daunorubicin and mitotic cell death at 10 ÎŒM. These results show, for the first time, that anthracyclines can induce cell death by a dual mechanism in both sensitive and MDR cells. Our results also show that not only the cytotoxicity, but also the kinetics and mechanism of cell death, are dose dependent. Interestingly, regrowth was observed only in association with delayed cell death and the formation of enlarged, often polyploid, cells with micronucleation, suggesting that morphological criteria may be useful to evaluate treatment efficacy in patients with myeloid leukaemias. © 1999 Cancer Research Campaig

    Approaches to study in higher education portuguese students: a portuguese version of the Approaches and Study Skills Inventory for Students (ASSIST)

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    This paper examines the validity of the Approaches and Study Skills Inventory for Students—short version (ASSIST; Tait et al. in Improving student learning: Improving students as learners, 1998), to be used with Portuguese undergraduate students. The ASSIST was administrated to 566 students, in order to analyse a Portuguese version of this inventory. Exploratory factor analysis (principal axis factor analysis followed by direct oblimin rotation) reproduced the three main factors that correspond to the original dimensions of the inventory (deep, surface apathetic and strategic approaches to learning). The results are consistent with the background theory on approaches to learning. Additionally, the reliability analysis revealed acceptable internal consistency indexes for the main scales and subscales. This inventory might represent a valuable research tool for the assessment of approaches to learning among Portuguese higher education students

    Host hindrance to HIV-1 replication in monocytes and macrophages

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    Monocytes and macrophages are targets of HIV-1 infection and play critical roles in multiple aspects of viral pathogenesis. HIV-1 can replicate in blood monocytes, although only a minor proportion of circulating monocytes harbor viral DNA. Resident macrophages in tissues can be infected and function as viral reservoirs. However, their susceptibility to infection, and their capacity to actively replicate the virus, varies greatly depending on the tissue localization and cytokine environment. The susceptibility of monocytes to HIV-1 infection in vitro depends on their differentiation status. Monocytes are refractory to infection and become permissive upon differentiation into macrophages. In addition, the capacity of monocyte-derived macrophages to sustain viral replication varies between individuals. Host determinants regulate HIV-1 replication in monocytes and macrophages, limiting several steps of the viral life-cycle, from viral entry to virus release. Some host factors responsible for HIV-1 restriction are shared with T lymphocytes, but several anti-viral mechanisms are specific to either monocytes or macrophages. Whilst a number of these mechanisms have been identified in monocytes or in monocyte-derived macrophages in vitro, some of them have also been implicated in the regulation of HIV-1 infection in vivo, in particular in the brain and the lung where macrophages are the main cell type infected by HIV-1. This review focuses on cellular factors that have been reported to interfere with HIV-1 infection in monocytes and macrophages, and examines the evidences supporting their role in vivo, highlighting unique aspects of HIV-1 restriction in these two cell types

    On the Role of Faith in Sustainability Management: A Conceptual Model and Research Agenda

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    International audienceThe objective of this article is to develop a faith development perspective on corporate sustainability. A firm’s management of sustainability is arguably determined by the way decision-makers relate to the other and the natural environment, and this relationship is fundamentally shaped by faith. This study advances theoretical understanding of the approach managers take on sustainability issues by explaining how four distinct phases of faith development—improvidence, obedience, irreverence and providence—determine a manager’s disposition towards sustainability. Combining insights from intentional and relational faith development theories, the analysis reveals that a manager’s faith disposition can be measured according to four interrelated process criteria: (1) connectivity as a measure of a manager’s actual engagement and activities aimed at relating to sustainability; (2) inclusivity as a measure of who and what is included or excluded in a manager’s moral consideration; (3) emotional affinity as a measure of a manager’s sensitivity and affection towards the well-being of others and ecological welfare; and (4) reciprocity as a measure of the degree to which a manager is rewarded for responding to the needs and concerns of ‘Others’, mainly in the form of a positive emotional (and relational) stimulus. The conceptual model consolidates earlier scholarly works on the psychological drivers of sustainability management by illuminating our search for a process of faith development that connects with an increasingly complex understanding of the role of business in society

    International Consensus Statement on Rhinology and Allergy: Rhinosinusitis

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    Background: The 5 years since the publication of the first International Consensus Statement on Allergy and Rhinology: Rhinosinusitis (ICAR‐RS) has witnessed foundational progress in our understanding and treatment of rhinologic disease. These advances are reflected within the more than 40 new topics covered within the ICAR‐RS‐2021 as well as updates to the original 140 topics. This executive summary consolidates the evidence‐based findings of the document. Methods: ICAR‐RS presents over 180 topics in the forms of evidence‐based reviews with recommendations (EBRRs), evidence‐based reviews, and literature reviews. The highest grade structured recommendations of the EBRR sections are summarized in this executive summary. Results: ICAR‐RS‐2021 covers 22 topics regarding the medical management of RS, which are grade A/B and are presented in the executive summary. Additionally, 4 topics regarding the surgical management of RS are grade A/B and are presented in the executive summary. Finally, a comprehensive evidence‐based management algorithm is provided. Conclusion: This ICAR‐RS‐2021 executive summary provides a compilation of the evidence‐based recommendations for medical and surgical treatment of the most common forms of RS

    Positive and Negative Structures and Processes Underlying Academic Performance: A Chained Mediation Model

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    This study proposed and tested a comprehensive, chained mediation model of university students’ academic performance. The hypothesized model included adaptive-positive and maladaptive-negative submodels. The structures and processes in the adaptive-positive submodel were hypothesized to facilitate students’ academic performance, whereas the structures and processes in the maladaptive-negative submodel were hypothesized to undermine it. A sample of 373 university students completed a set of questionnaires measuring their approaches to studying, positive and negative affect, evaluation anxiety, use of creative cognition, motivational orientations, and adaptive and maladaptive metacognitions. Participants’ end-of-semester and prior semester academic performance was retrieved from the university registry. A structural equation model explained 90 % of the variance in students’ future academic performance, supported all but one hypothesized intermediate paths, and revealed that only positive affect in studying and prior academic performance predict directly future academic performance. The theoretical and practical implications of these findings are outlined
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