Sobre a escrita etnográfica

Este texto propõe uma reflexão sobre a escrita etnográfica, suas marcas discursivas, seus objetivos e seu modus faciendi no âmbito de uma antropologia pós-moderna. Tendo como corpus artigos assinados por James Clifford e Stephen Tyler, publicados em Writing culture: the poetics and politics of ethnography, de 1986 – obra coletiva que sublinha a centralidade da escrita ao mesmo tempo em que questiona o relato etnográfico enquanto testemunho da verdade – , buscaremos mapear, num primeiro momento, o discurso científico classicamente considerado; em seguida, apresentaremos as contribuições das teorias da linguagem que ecoam na prática etnográfica; finalmente, caracterizaremos a emergência do paradigma pós-moderno e os efeitos por ele deflagrados na escrita etnográfica

De cidade e de “cavalos”: notas sobre a São Paulo de Luiz Ruffato

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In and out of the Replication Factory

In this issue of Cell, Kitamura et al. (2006) use live-fluorescence microscopy to monitor individual genomic loci as they replicate in budding yeast. They confirm that DNA is recruited to replication factories and show that sister replication forks initiated from the same origin are held together within a single replication factory

Temporal separation of replication and recombination requires the intra-S checkpoint

In response to DNA damage and replication pausing, eukaryotes activate checkpoint pathways that prevent genomic instability by coordinating cell cycle progression with DNA repair. The intra-S-phase checkpoint has been proposed to protect stalled replication forks from pathological rearrangements that could result from unscheduled recombination. On the other hand, recombination may be needed to cope with either stalled forks or double-strand breaks resulting from hydroxyurea treatment. We have exploited fission yeast to elucidate the relationship between replication fork stalling, loading of replication and recombination proteins onto DNA, and the intra-S checkpoint. Here, we show that a functional recombination machinery is not essential for recovery from replication fork arrest and instead can lead to nonfunctional fork structures. We find that Rad22-containing foci are rare in S-phase cells, but peak in G2 phase cells after a perturbed S phase. Importantly, we find that the intra-S checkpoint is necessary to avoid aberrant strand-exchange events during a hydroxyurea block

Proteomics Characterization of Outer Membrane Vesicles from the Extraintestinal Pathogenic Escherichia coli ΔtolR IHE3034 Mutant

Extraintestinal pathogenic Escherichia coli are the cause of a diverse spectrum of invasive infections in humans and animals, leading to urinary tract infections, meningitis, or septicemia. In this study, we focused our attention on the identification of the outer membrane proteins of the pathogen in consideration of their important biological role and of their use as potential targets for prophylactic and therapeutic interventions. To this aim, we generated a DeltatolR mutant of the pathogenic IHE3034 strain that spontaneously released a large quantity of outer membrane vesicles in the culture supernatant. The vesicles were analyzed by two-dimensional electrophoresis coupled to mass spectrometry. The analysis led to the identification of 100 proteins, most of which are localized to the outer membrane and periplasmic compartments. Interestingly based on the genome sequences available in the current public database, seven of the identified proteins appear to be specific for pathogenic E. coli and enteric bacteria and therefore are potential targets for vaccine and drug development. Finally we demonstrated that the cytolethal distending toxin, a toxin exclusively produced by pathogenic bacteria, is released in association with the vesicles, supporting the recently proposed role of bacterial vesicles in toxin delivery to host cells. Overall, our data demonstrated that outer membrane vesicles represent an ideal tool to study Gram-negative periplasm and outer membrane compartments and to shed light on new mechanisms of bacterial pathogenesis

Multisignal control of expression of the LHCX protein family in the marine diatom Phaeodactylum tricornutum

Diatoms are phytoplanktonic organisms that grow successfully in the ocean where light conditions are highly variable. Studies of the molecular mechanisms of light acclimation in the marine diatom Phaeodactylum tricornutum show that carotenoid de-epoxidation enzymes and LHCX1, a member of the light-harvesting protein family, both contribute to dissipate excess light energy through non-photochemical quenching (NPQ). In this study, we investigate the role of the other members of the LHCX family in diatom stress responses. Our analysis of available genomic data shows that the presence of multiple LHCX genes is a conserved feature of diatom species living in different ecological niches. Moreover, an analysis of the levels of four P. tricornutum LHCX transcripts in relation to protein expression and photosynthetic activity indicates that LHCXs are differentially regulated under different light intensities and nutrient starvation, mostly modulating NPQ capacity. We conclude that multiple abiotic stress signals converge to regulate the LHCX content of cells, providing a way to fine-tune light harvesting and photoprotection. Moreover, our data indicate that the expansion of the LHCX gene family reflects functional diversification of its members which could benefit cells responding to highly variable ocean environments

Interpretare e costruire mondi: pratiche inclusive a varie latitudini

Il contributo delle discipline umanistiche si rivela oggi più che mai essenziale per poter leggere e interpretare la complessità del mondo contemporaneo. Le molteplici crisi che hanno segnato la storia moderna e contemporanea hanno fatto (ri)emergere pericolose narrative di esclusione che intellettuali ed artisti si sono sentiti chiamati a decostruire. A fronte di diverse forme di marginalizzazione, pratiche di censura e di disuguaglianza sociale, la produzione culturale e artistica ha tentato di (ri)costruire nuove forme di solidarietà e di offrire nuove prospettive di miglioramento comune. Il numero 2/2022 della rivista DIVE-IN – An International Journal on Diversity and Inclusion contiene otto contributi, uniti dal fil rouge dell’inclusione, che offrono una interessante panoramica dei tentativi di (ri)costruzione che si articolano in diversi campi espressivi a varie latitudini geografiche e tematico-disciplinari