Aspectos éticos na organização do conhecimento na prática profissional arquivística: um estudo dos princípios de ética da AAB, CIA e SAA

An axiological discussion is drawn from the analysis of the three codes of ethics in archives developed by the Association of Brazilian Archivists (AAB), the International Council on Archives (ICA) and the Socie-ty of American Archivists (SAA), presenting a frame-work of ethical values for the activities related to the organization and representation of knowledge, thus contributing to the theoretical framework underlying the social issues in Archival science.Se propone un debate axiológico a partir del análisis de los tres códigos de ética profesional archivística desarrollados por la Asociación de Archiveros de Brasil (AAB), el Consejo Internacional de Archivos (CIA) y la Sociedad de Archiveros Americanos (SAA), presentando un cuadro de valores éticos en los que el profesional de la información debe basar sus acti-vidades relacionadas con la organización y represen-tación del conocimiento, contribuyendo al avance en el marco teórico para el tratamiento de las cuestiones sociales dentro de la archivística.Actualmente, la tecnología se ha convertido en una poderosa herramienta utilizada por los profesionales de la información para organizar la misma, incluyendo a los archivos y los archiveros. Gracias a esto, las actividades realizadas por estos profesionales son cada vez más exigentes, generando cada vez más, estudios sobre su conducta y actuación. Con el objetivo de contribuir a estos estudios, en el presente artículo, se propone un debate axiológico a partir del análisis de tres principios de ética profesional archivística desarrollados por la Asociación de Archiveros de Brasil (AAB), el Consejo Internacional de Archivos (CIA) y la Sociedad de Archiveros Americanos (SAA), presentando un cuadro de valores éticos en los que el profesional de la información debe basar sus actividades relacionadas con la organización y representación del conocimiento, y así contribuir al universo teórico que sustenta las cuestiones sociales de la Archivística

Modulation of cancer cell invasion by extracellular vesicles

The cancer microenvironment is a receptacle of stimuli necessary to promote tumour growth. The role of extracellular vesicles (EVs) in orchestrating a crosstalk between cancer cells and other cell types in the surroundings is integral part of the tumour network. Extracellular vesicles are subcellular structures that emanate virtually from any cell type and carry information both within the primary tumour site and to distant sites. Here I show that two oncogenic stimuli control the release of EVs to render cancer and untransformed cells more aggressive. Firstly, I show that loss of the tumour suppressor RASSF1A in breast cancer cells allows the alternative transcript and oncogene RASSF1C to exploit its tumourigenic activity through enhanced secretion of EVs. I characterise RASSF1C EVs as able to drive migration and invasion in recipient breast cancer cells and I show that RASSF1C elicits exocytosis through activation of the small GTPase RhoA. Secondly, I explore the role of the TGF β cytokine in altering extracellular vesicle secretion. Here, I report the selective enrichment of the tetraspanin CD9 on TGF β driven EVs. I show that CD9 is a positive mediator of TGF β pathway and conclude that TGF β employs exocytosis as a route to secrete CD9 from pathway activated cells, as a negative feedback on the signalling cascade. Finally, I describe a novel role of CD9 positive EVs in propagating TGF-β signalling in recipient breast cancer cells and in mediating TGF-β driven invasion in untransformed breast epithelium. This work highlights the importance of tumourigenic stimuli, both intracellular (RASSF1C) and environmental (TGF-β), in fostering a pro invasive cancer environment and the pivotal role that extracellular vesicles play in mediating oncogenic signalling.</p

MST2 kinase suppresses rDNA transcription in response to DNA damage by phosphorylating nucleolar histone H2B

The heavily transcribed rDNA repeats that give rise to the ribosomal RNA are clustered in a unique chromatin structure, the nucleolus. Due to its highly repetitive nature and transcriptional activity, the nucleolus is considered a hotspot of genomic instability. Breaks in rDNA induce a transient transcriptional shut down to conserve energy and promote rDNA repair; however, how nucleolar chromatin is modified and impacts on rDNA repair is unknown. Here, we uncover that phosphorylation of serine 14 on histone H2B marks transcriptionally inactive nucleolar chromatin in response to DNA damage. We identified that the MST2 kinase localises at the nucleoli and targets phosphorylation of H2BS14p in an ATM-dependent manner. We show that establishment of H2BS14p is necessary for damage-induced rDNA transcriptional shut down and maintenance of genomic integrity. Ablation of MST2 kinase, or upstream activators, results in defective establishment of nucleolar H2BS14p, perturbed DNA damage repair, sensitisation to rDNA damage and increased cell lethality. We highlight the impact of chromatin regulation in the rDNA damage response and targeting of the nucleolus as an emerging cancer therapeutic approach

Beads for Cell Immobilization: Comparison of Alternative Additive Manufacturing Techniques

The attachment or entrapment of microbial cells and enzymes are promising solutions for various industrial applications. When the traps are beads, they are dispersed in a fluidized bed in a vessel where a pump guarantees fresh liquid inflow and waste outflow without washing out the cells. Scientific papers report numerous types of cell entrapment, but most of their applications remain at the laboratory level. In the present research, rigid polymer beads were manufactured by two different additive manufacturing (AM) techniques in order to verify the economy, reusability, and stability of the traps, with a view toward a straightforward industrial application. The proposed solutions allowed for overcoming some of the drawbacks of traditional manufacturing solutions, such as the limited mechanical stability of gel traps, and they guaranteed the possibility of producing parts of constant quality with purposely designed exchange surfaces, which are unfeasible when using conventional processes. AM proved to be a viable manufacturing solution for beads with complex shapes of two different size ranges. A deep insight into the production and characteristics of beads manufactured by AM is provided. The paper provides biotechnologists with a manufacturing perspective, and the results can be directly applied to transit from the laboratory to the industrial scale

Influence of Trabecular Geometry on Scaffold Mechanical Behavior and MG-63 Cell Viability

In a scaffold-based approach for bone tissue regeneration, the control over morphometry allows for balancing scaffold biomechanical performances. In this experimental work, trabecular geometry was obtained by a generative design process, and scaffolds were manufactured by vat photopolymerization with 60% (P60), 70% (P70) and 80% (P80) total porosity. The mechanical and biological performances of the produced scaffolds were investigated, and the results were correlated with morphometric parameters, aiming to investigate the influence of trabecular geometry on the elastic modulus, the ultimate compressive strength of scaffolds and MG-63 human osteosarcoma cell viability. The results showed that P60 trabecular geometry allows for matching the mechanical requirements of human mandibular trabecular bone. From the statistical analysis, a general trend can be inferred, suggesting strut thickness, the degree of anisotropy, connectivity density and specific surface as the main morphometric parameters influencing the biomechanical behavior of trabecular scaffolds, in the perspective of tissue engineering applications

Lack of involvement of CD63 and CD9 tetraspanins in the extracellular vesicle content delivery process

International audienceExtracellular vesicles (EVs) are thought to mediate intercellular communication by transferring cargoes from donor to acceptor cells. The EV content-delivery process within acceptor cells is still poorly characterized and debated. CD63 and CD9, members of the tetraspanin family, are highly enriched within EV membranes and are respectively enriched within multivesicular bodies/endosomes and at the plasma membrane of the cells. CD63 and CD9 have been suspected to regulate the EV uptake and delivery process. Here we used two independent assays and different cell models (HeLa, MDA-MB-231 and HEK293T cells) to assess the putative role of CD63 and CD9 in the EV delivery process that includes uptake and cargo delivery. Our results suggest that neither CD63, nor CD9 are required for this function