102 research outputs found

    Cells Assemble Invadopodia-Like Structures and Invade into Matrigel in a Matrix Metalloprotease Dependent Manner in the Circular Invasion Assay

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    The ability of tumor cells to invade is one of the hallmarks of the metastatic phenotype. To elucidate the mechanisms by which tumor cells acquire an invasive phenotype, in vitro assays have been developed that mimic the process of cancer cell invasion through basement membrane or in the stroma. We have extended the characterization of the circular invasion assay and found that it provides a simple and amenable system to study cell invasion in matrix in an environment that closely mimics 3D invasion. Furthermore, it allows detailed microscopic analysis of both live and fixed cells during the invasion process. We find that cells invade in a protease dependent manner in this assay and that they assemble focal adhesions and invadopodia that resemble structures visualized in 3D embedded cells. We propose that this is a useful assay for routine and medium throughput analysis of invasion of cancer cells in vitro and the study of cells migrating in a 3D environment

    Achieving Education for Sustainable Development (ESD) in Early Childhood Education Through Critical Reflection in Transformative Learning

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    The central role of education in creating a more sustainable future has been already recognized by educators and policy-makers alike. This chapter argues that this can only be truly achieved through the efforts of teachers in implementing an “education of a different kind,” a general educational shift that seeks to encompass a converging transformation of the priorities and mindsets of education professionals. In this regard, the professional preparation of teachers, as the leading actors in shaping children’s learning processes, and their continuous professional development are vital considerations for Education for Sustainable Development (ESD) to be successfully achieved. Linking transformative learning and ESD has emerged as a distinct and useful pedagogy because they both support the process of critically examining habits of mind, then revising these habits and acting upon the revised point of view. This study aims to describe and evaluate the potential of transformative learning in innovating mainstream education toward sustainability by focusing on the role of critical reflection in a capacity building research project realized in Turkey. The data was gathered from 24 early childhood educators using a mixed-method research design involving learning diaries, a learning activities survey, and follow-up interviews. This chapter identified content, context, and application method of the in-service training as factors that have contributed to the reflective practices of the participants. In addition, presenting the implications regarding the individual differences in how learners engage in critical reflection practices, this research offers a framework for a content- and process-based approach derived from Mezirow’s conception of critical reflection

    Molecular phylogeny and timing of diversification in Alpine Rhithrogena (Ephemeroptera: Heptageniidae).

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    BACKGROUND: Larvae of the Holarctic mayfly genus Rhithrogena Eaton, 1881 (Ephemeroptera, Heptageniidae) are a diverse and abundant member of stream and river communities and are routinely used as bio-indicators of water quality. Rhithrogena is well diversified in the European Alps, with a number of locally endemic species, and several cryptic species have been recently detected. While several informal species groups are morphologically well defined, a lack of reliable characters for species identification considerably hampers their study. Their relationships, origin, timing of speciation and mechanisms promoting their diversification in the Alps are unknown. RESULTS: Here we present a species-level phylogeny of Rhithrogena in Europe using two mitochondrial and three nuclear gene regions. To improve sampling in a genus with many cryptic species, individuals were selected for analysis according to a recent DNA-based taxonomy rather than traditional nomenclature. A coalescent-based species tree and a reconstruction based on a supermatrix approach supported five of the species groups as monophyletic. A molecular clock, mapped on the most resolved phylogeny and calibrated using published mitochondrial evolution rates for insects, suggested an origin of Alpine Rhithrogena in the Oligocene/Miocene boundary. A diversification analysis that included simulation of missing species indicated a constant speciation rate over time, rather than any pronounced periods of rapid speciation. Ancestral state reconstructions provided evidence for downstream diversification in at least two species groups. CONCLUSIONS: Our species-level analyses of five gene regions provide clearer definitions of species groups within European Rhithrogena. A constant speciation rate over time suggests that the paleoclimatic fluctuations, including the Pleistocene glaciations, did not significantly influence the tempo of diversification of Alpine species. A downstream diversification trend in the hybrida and alpestris species groups supports a previously proposed headwater origin hypothesis for aquatic insects

    Plasma and cellular fibronectin: distinct and independent functions during tissue repair

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    Fibronectin (FN) is a ubiquitous extracellular matrix (ECM) glycoprotein that plays vital roles during tissue repair. The plasma form of FN circulates in the blood, and upon tissue injury, is incorporated into fibrin clots to exert effects on platelet function and to mediate hemostasis. Cellular FN is then synthesized and assembled by cells as they migrate into the clot to reconstitute damaged tissue. The assembly of FN into a complex three-dimensional matrix during physiological repair plays a key role not only as a structural scaffold, but also as a regulator of cell function during this stage of tissue repair. FN fibrillogenesis is a complex, stepwise process that is strictly regulated by a multitude of factors. During fibrosis, there is excessive deposition of ECM, of which FN is one of the major components. Aberrant FN-matrix assembly is a major contributing factor to the switch from normal tissue repair to misregulated fibrosis. Understanding the mechanisms involved in FN assembly and how these interplay with cellular, fibrotic and immune responses may reveal targets for the future development of therapies to regulate aberrant tissue-repair processes

    Fibroblast Migration in 3D is Controlled by Haptotaxis in a Non-muscle Myosin II-Dependent Manner

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    Cell migration in 3D is a key process in many physiological and pathological processes. Although valuable knowledge has been accumulated through analysis of various 2D models, some of these insights are not directly applicable to migration in 3D. In this study, we have confined biomimetic hydrogels within microfluidic platforms in the presence of a chemoattractant (platelet-derived growth factor-BB). We have characterized the migratory responses of human fibroblasts within them, particularly focusing on the role of non-muscle myosin II. Our results indicate a prominent role for myosin II in the integration of chemotactic and haptotactic migratory responses of fibroblasts in 3D confined environments.Grants: EUR/7FP/ERC-2012-StG 306751 ES/MINECO - DPI2012-38090-C03-01 ES/MINECO - SAF2011- 2495

    Antioxidant and antihypertensive properties of phenolic-protein complexes in extracted protein fractions from Nigella damascena and Nigella arvensis

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    The study involved the investigation of the antioxidant and antihypertensive properties of the phenolic eprotein complexes obtained from isolated protein fractions from Nigella damascena and Nigella arvensis. Protein fractions from flours made from the seeds of Nigella species were isolated and included albumin, globulin, glutelin-1, glutelin-2 and prolamin. Albumin and glutelin-1 fractions were the predominant proteins in the two Nigella species studied in terms of protein content and percent protein yield. Free phenolics were extracted from the isolated protein fractions by methanol treatment at either 25 C or 60 C followed by acid and base hydrolysis to obtain bound phenolics. The free and bound phenolic composition was assessed by RP-HPLC. The highest phenolic content was observed in the free phenolic extract at 25 C (FP-25 C) in glutelin-2 of both Nigella species. The free and bound phenolics of the protein fractions were tested for angiotensin converting enzyme (ACE) inhibitory and antioxidant activities. The greatest ACE inhibitory activities were seen for the free and bound phenolic extracts obtained from glutelin-2 and globulin fractions of both Nigella species. The highest antioxidant activities were observed in the extracted phenolics from glutelin-1 and globulin from N. damascena and albumin from N. arvensis. Only a weak correlation was seen between the phenolic content of the isolated protein fractions and the ACE inhibitory and antioxidant activities. The present study indicates that phenolic eprotein complexes in the Nigella species have significant antioxidant and ACE inhibitory properties although the bioactivities of the protein fractions are not closely related to their total phenolic content
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