127 research outputs found

    Construçao do masculino na Curitiba das décadas de 1940 e 1950 tornar-se homem

    Get PDF
    Orientadora : Maria Luiza AndreazzaAutor não autorizou a divulgação do arquivo digitalDissertaçao (mestrado) - Universidade Federal do Paraná, Setor de Ciencias Humanas, Letras e ArtesInclui referência

    Organometallic Pillarplexes That Bind DNA 4-Way Holliday Junctions and Forks

    Full text link
    Holliday 4-way junctions are key to important biological DNA processes (insertion, recombination, and repair) and are dynamic structures that adopt either open or closed conformations, the open conformation being the biologically active form. Tetracationic metallo-supramolecular pillarplexes display aryl faces about a cylindrical core, an ideal structure to interact with open DNA junction cavities. Combining experimental studies and MD simulations, we show that an Au pillarplex can bind DNA 4-way (Holliday) junctions in their open form, a binding mode not accessed by synthetic agents before. Pillarplexes can bind 3-way junctions too, but their large size leads them to open up and expand that junction, disrupting the base pairing, which manifests in an increased hydrodynamic size and lower junction thermal stability. At high loading, they rearrange both 4-way and 3-way junctions into Y-shaped forks to increase the available junction-like binding sites. Isostructural Ag pillarplexes show similar DNA junction binding behavior but lower solution stability. This pillarplex binding contrasts with (but complements) that of metallo-supramolecular cylinders, which prefer 3-way junctions and can rearrange 4-way junctions into 3-way junction structures. The pillarplexes’ ability to bind open 4-way junctions creates exciting possibilities to modulate and switch such structures in biology, as well as in synthetic nucleic acid nanostructures. In human cells, the pillarplexes do reach the nucleus, with antiproliferative activity at levels similar to those of cisplatin. The findings provide a new roadmap for targeting higher-order junction structures using a metallo-supramolecular approach, as well as expanding the toolbox available to design bioactive junction binders into organometallic chemistry

    Selective autophagy maintains centrosome integrity and accurate mitosis by turnover of centriolar satellites

    Get PDF
    The centrosome is the master orchestrator of mitotic spindle formation and chromosome segregation in animal cells. Centrosome abnormalities are frequently observed in cancer, but little is known of their origin and about pathways affecting centrosome homeostasis. Here we show that autophagy preserves centrosome organization and stability through selective turnover of centriolar satellite components, a process we termed doryphagy. Autophagy targets the satellite organizer PCM1 by interacting with GABARAPs via a C-terminal LIR motif. Accordingly, autophagy deficiency results in accumulation of large abnormal centriolar satellites and a resultant dysregulation of centrosome composition. These alterations have critical impact on centrosome stability and lead to mitotic centrosome fragmentation and unbalanced chromosome segregation. Our findings identify doryphagy as an important centrosome-regulating pathway and bring mechanistic insights to the link between autophagy dysfunction and chromosomal instability. In addition, we highlight the vital role of centriolar satellites in maintaining centrosome integrity

    Insights into the mechanisms of aquaporin-3 inhibition by gold(III) complexes: the importance of non-coordinative adduct formation

    Get PDF
    A series of six new Au(III) coordination compounds with phenanthroline ligands have been synthesized and studied for the inhibition of the water and glycerol channel aquaporin-3 (AQP3). From a combination of different experimental and computational approaches, further insights into the mechanisms of AQP3 inhibition by gold compounds at a molecular level have been gained. The results evidence the importance of noncoordinative adduct formation, prior to “covalent” protein binding, to achieve selective AQP3 inhibition

    Clathrin- and Dynamin-Independent Endocytosis of FGFR3 – Implications for Signalling

    Get PDF
    Endocytosis of tyrosine kinase receptors can influence both the duration and the specificity of the signal emitted. We have investigated the mechanisms of internalization of fibroblast growth factor receptor 3 (FGFR3) and compared it to that of FGFR1 which is internalized predominantly through clathrin-mediated endocytosis. Interestingly, we observed that FGFR3 was internalized at a slower rate than FGFR1 indicating that it may use a different endocytic mechanism than FGFR1. Indeed, after depletion of cells for clathrin, internalization of FGFR3 was only partly inhibited while endocytosis of FGFR1 was almost completely abolished. Similarly, expression of dominant negative mutants of dynamin resulted in partial inhibition of the endocytosis of FGFR3 whereas internalization of FGFR1 was blocked. Interfering with proposed regulators of clathrin-independent endocytosis such as Arf6, flotillin 1 and 2 and Cdc42 did not affect the endocytosis of FGFR1 or FGFR3. Furthermore, depletion of clathrin decreased the degradation of FGFR1 resulting in sustained signalling. In the case of FGFR3, both the degradation and the signalling were only slightly affected by clathrin depletion. The data indicate that clathrin-mediated endocytosis is required for efficient internalization and downregulation of FGFR1 while FGFR3, however, is internalized by both clathrin-dependent and clathrin-independent mechanisms

    Organometallic Pillarplexes that bind DNA 4-way Holliday Junctions and Forks.

    Get PDF
    Holliday 4-way junctions are key to important biological DNA processes (insertion, recombination and repair) and are dynamic structures which adopt either open or closed conformations, with the open conformation being the biologically active form. Tetracationic metallo-supramolecular pillarplexes display aryl faces about a cylindrical core giving them an ideal structure to interact with the central cavities of open DNA junctions. Combining experimental studies and MD simulations we show that an Au pillarplex can bind DNA 4-way junctions (Holliday junctions) in their open form, a binding mode not accessed by synthetic agents before. The Au pillarplexes can bind designed 3-way junctions too but their large size leads them to open up and expand that junction, disrupting the base pairing which manifests in an increase in hydrodynamic size and a lower junction thermal stability. At high loading they re-arrange both 4-way and 3-way junctions into Y-shaped DNA forks to increase the available junction-like binding sites. The structurally related Ag pillarplexes show similar DNA junction binding behaviour, but a lower solution stability. This pillarplex binding contrasts with (but complements) that of the metallo-supramolecular cylinders, which prefer 3-way junctions and we show can rearrange 4-way junctions into 3-way junction structures. The ability of pillarplexes to bind open 4-way junctions creates exciting possibilities to modulate and switch such structures in biology, as well as in synthetic nucleic acid nanostructures where they are key interconnecting components. Studies in human cells, confirm that the pillarplexes do reach the nucleus, with antiproliferative activity at levels similar to those of cisplatin. The findings provide a new roadmap for targeting higher order junction structures using a metallo-supramolecular approach, as well as expanding the toolbox available to design bioactive junction-binders into organometallic chemistry

    Reconciling views of project success : a multiple stakeholder model

    Get PDF
    This paper presents a new model encompassing all the important critical attributes to measure project success across different stakeholder groups. The study investigates the possibility that project failure is a result of the interpretations of the criteria and factors used for success by multiple stakeholder groups. Unique projects must have their outcome parameters monitored and controlled to minimize the chances of failure and the likely major financial and managerial ramifications for the organization. Early testing of the model supports its use to increase the shared, multiple stakeholder perception of project success leading to more informed decision making and motivation of employees

    Integration in primary community care networks (PCCNs): examination of governance, clinical, marketing, financial, and information infrastructures in a national demonstration project in Taiwan

    Get PDF
    Background. Taiwan's primary community care network (PCCN) demonstration project, funded by the Bureau of National Health Insurance on March 2003, was established to discourage hospital shopping behavior of people and drive the traditional fragmented health care providers into cooperate care models. Between 2003 and 2005, 268 PCCNs were established. This study profiled the individual members in the PCCNs to study the nature and extent to which their network infrastructures have been integrated among the members (clinics and hospitals) within individual PCCNs. Methods. The thorough questionnaire items, covering the network working infrastructures - governance, clinical, marketing, financial, and information integration in PCCNs, were developed with validity and reliability confirmed. One thousand five hundred and fifty-seven clinics that had belonged to PCCNs for more than one year, based on the 2003-2005 Taiwan Primary Community Care Network List, were surveyed by mail. Nine hundred and twenty-eight clinic members responded to the surveys giving a 59.6 % response rate. Results. Overall, the PCCNs' members had higher involvement in the governance infrastructure, which was usually viewed as the most important for establishment of core values in PCCNs' organization design and management at the early integration stage. In addition, it found that there existed a higher extent of integration of clinical, marketing, and information infrastructures among the hospital-clinic member relationship than those among clinic members within individual PCCNs. The financial infrastructure was shown the least integrated relative to other functional infrastructures at the early stage of PCCN formation. Conclusion. There was still room for better integrated partnerships, as evidenced by the great variety of relationships and differences in extent of integration in this study. In addition to provide how the network members have done for their initial work at the early stage of network forming in this study, the detailed surveyed items, the concepts proposed by the managerial and theoretical professionals, could be a guide for those health care providers who have willingness to turn their business into multi-organizations. © 2007 Lin; licensee BioMed Central Ltd.published_or_final_versio

    One-Dimensional Fermi liquids

    Full text link
    I attempt to give a pedagogical overview of the progress which has occurred during the past decade in the description of one-dimensional correlated fermions. Fermi liquid theory based on a quasi-particle picture, breaks down in one dimension because of the Peierls divergence and because of charge-spin separation. It is replaced by a Luttinger liquid whose elementary excitations are collective charge and spin modes, based on the exactly solvable Luttinger model. I review this model and various solutions with emphasis on bosonization (and its equivalence to conformal field theory), and its physical properties. The notion of a Luttinger liquid implies that all gapless 1D systems share these properties at low energies. Chapters 1 and 2 of the article contain an introduction and a discussion of the breakdown of Fermi liquid theory. Chapter 3 describes in detail the solution of the Luttinger model both by bosonization and by Green's functions methods and summarizes the properties of the model, expressed thorugh correlation functions. The relation to conformal field theory is discussed. Chapter 4 of the article introduces the notion of a Luttinger liquid. It describes in much detail the various mappings applied to realistic models of 1D correlated fermions, onto the Luttinger model, as well as important corrections to the Luttinger model properties discussed in Ch.3. Chapter 5 describes situations where the Luttinger liquid is not a stable fixed point, and where spin or charge gaps open in at least one channel. Chapter 6 discusses multi-band and multichain problems, in particular the stability of a Luttinger liquid with respect to interchain hopping. Ch. 7 gives a brief summary of experimental efforts to uncover Luttinger liquid correlations in quasi-1D materials.Comment: uuencoded Latex files and postscript figures, one Readme-file approx 160 pages + 13 figures; to be published by Reports on Progress in Physic
    corecore