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Abstract Srs2 is an Sf1a helicase that helps maintain genome stability in Saccharomyces cerevisiae through its ability to regulate homologous recombination. Srs2 downregulates HR by stripping Rad51 from single–stranded DNA, and Srs2 is also thought to promote synthesis–dependent strand annealing by unwinding D–loops. However, it has not been possible to evaluate the relative contributions of these two distinct activities to any aspect of recombination. Here, we used a structure–based approach to design an Srs2 separation–of–function mutant that can dismantle Rad51–ssDNA filaments but is incapable of disrupting D–loops, allowing us to assess the relative contributions of these pro– and anti–recombinogenic functions. We show that this separation–of–function mutant phenocopies wild–type SRS2 in vivo, suggesting that the ability of Srs2 to remove Rad51 from ssDNA is its primary role during HR.

Denne artikkelen er en del av et doktorgradsprosjekt som undersøker den politiske dimensjonen av bærekraftig utvikling og dens betydning for utdanningen og pedagogens rolle. Prosjektet ser på perspektiver til norske barnehagelærere og medlemmer av den meksikanske Zapatist-bevegelsen med det mål å åpne for refleksjoner og debatt om hva en utdanning for bærekraft bør innebære. Tittelen «We are peasants» («Vi er bønder») er hentet fra en norsk barnehagelærer i Sørvest-Norge og refererer til en felles bondeidentitet blant denne lærerens personalgruppe. I denne artikkelen ser jeg på bondekulturens rolle i en utdanning for bærekraft, pedagogens politiske engasjement i bærekraftspørsmål og forståelsen pedagogen har av seg selv som politisk aktør. Paolo Freires kritiske pedagogikk og syn på lærere som politiske aktører blir brukt for å utforske lærerens politiske og transformerende rolle gjennom deres profesjon og som medlem av lokale fellesskap (Freire, 2005; Freire, 2017). Jeg bruker en metode inspirert av Deleuze og Guattaris (1987) «rhizomatiske» tenkning som gjør det mulig å koble og flette disse norske barnehagelærernes perspektiver sammen med perspektiver til medlemmer av den meksikanske Zapatist-bevegelsen, som også er en bondebevegelse. Datamaterialet er samlet under feltarbeid over en toårsperiode i Chiapas, sørøst i Mexico, og i en barnehage i Sørvest-Norge. En tematisk analyse av datamaterialet viser til koblinger mellom disse to kontekster. Disse kan samles i tre områder, som påvirker og bygger på hverandre: Bøndenes identitetsfølelse og verdier, deres rolle som pedagoger, og som politiske aktører. Resultater viser at tilhørigheten som bonde fører til økologiske, sosiale og politiske verdier som kan hjelpe lærere å forstå hvilken rolle de har som medlemmer av lokale og globale fellesskap, samt å utvikle bærekraftige, transformerende og frigjørende praksiser.

Replication stress and abundant repetitive sequences have emerged as primary conditions underlying genomic instability in eukaryotes. Here the authors use a prokaryotic Tus/Ter barrier designed to induce transient replication fork stalling near inverted repeats in the budding yeast genome to support a model for recombination of closely linked repeats at stalled replication forks.

Understanding the plasticity of genomes has been greatly aided by assays for recombination, repair and mutagenesis. These assays have been developed in microbial systems that provide the advantages of genetic and molecular reporters that can readily be manipulated. Cellular assays comprise genetic, molecular, and cytological reporters. The assays are powerful tools but each comes with its particular advantages and limitations. Here the most commonly used assays are reviewed, discussed, and presented as the guidelines for future studies.

Bacterial homologous recombination involves the actions of RadA and RecA to promote single-stranded DNA integration. Here the authors report the structure of RadA fromStreptococcus pneumoniaeand demonstrate that it acts as a hexameric DnaB-type helicase.

Le pyoderma gangrenosum (PG) est une dermatose neutrophilique non infectieuse rare souvent méconnue. Il se présente généralement par des ulcérations cutanées inflammatoires, très douloureuses et d'évolution rapide. Il est fréquemment retrouvé dans un contexte de néoplasie, de pathologies inflammatoires digestives, rhumatologiques et/ou hématologiques. Son diagnostic est très souvent tardif après de multiples échecs thérapeutiques. Nous rapportons un cas de pyoderma gangrenosum dont le diagnostic n'a pas été criant. Un patient a été admis dans notre service pour une lésion dermatologique persistante et d'évolution défavorable malgré les débridements et l'administration d'antibiotiques. Il était suivi pour un cancer de la prostate, une hypertension artérielle et un asthme. Du fait des anomalies biologiques observées telles qu'une hyperleucocytose à polynucléaires neutrophiles avec myélémie à myélocytes et métamyélocytes, sans blastose sanguine et une anémie normochrome normocytaire, une leucémie myéloïde chronique a été évoquée chez ce patient. Elle a par la suite été infirmée devant les différents examens complémentaires non concluants. C'est ainsi que le diagnostic de PG a été évoqué et confirmé à l'examen anatomopathologique montrant un aspect histopathologique d'un tissu de granulation concordant avec un pyoderma gangrenosum et une absence de signe histologique de malignité. L'institution d'un traitement à base de corticothérapie a abouti à la guérison.

Sustainability involves a temporal dimension connecting the past, the present and the future. This article explores the significance of time for sustainability education. It discusses how the understanding of this temporal dimension shapes humans' relationship with the world and affects the political engagement of the educator with sustainability and the view of herself as a political agent of change. To do so, the article uses an assemblage methodology inspired by Deleuze and Guattari's (1987) rhizome to connect the experiences of Norwegian early childhood educators and members of the Zapatista organization. Using a critical theory lens and Paulo Freire's views of educators as cultural workers (Freire 2005, 2017), the article explores two aspects of the temporal dimension that educators relate to across contexts. First, time as a resource, conditioning the relation to the present, the day-to day rhythm and work from a Marxist perspective. Secondly, sustainability's future orientation, with its connections to the political role of the educator as the creator of social reality. The encounters between Zapatista and Norwegian perspectives show how educators' positions and roles in reflecting upon, engaging with, and reappropriating the notion of time, are central for sustainability education.

This article discusses the contributions of different worldviews to the debates on what a transformative sustainability education could be. It focuses on mainstream and alternative strands of thought present in the West, as well as Indigenous worldviews, taking the Zapatistas as an example. The Zapatista social movement of Mexico fights for the autonomy of Mayan communities and the preservation of their culture, social organization and relationship to nature, all of which centers on traditional Mayan cosmovision. To secure the survival of the culture and of the movement itself, these ecological values are included in the education system. The Zapatistas remind us that it is possible to rethink the world and the ideologies underlying the discourses on sustainability and suggest that taking a stand and organize politically should be at the center of an education for sustainability that aims at being transformative.

Sustainability involves a temporal dimension connecting the past, the present and the future. This article explores the significance of time for sustainability education. It discusses how the understanding of this temporal dimension shapes humans' relationship with the world and affects the political engagement of the educator with sustainability and the view of herself as a political agent of change. To do so, the article uses an assemblage methodology inspired by Deleuze and Guattari's (1987) rhizome to connect the experiences of Norwegian early childhood educators and members of the Zapatista organization. Using a critical theory lens and Paulo Freire's views of educators as cultural workers (Freire 2005, 2017), the article explores two aspects of the temporal dimension that educators relate to across contexts. First, time as a resource, conditioning the relation to the present, the day-to day rhythm and work from a Marxist perspective. Secondly, sustainability's future orientation, with its connections to the political role of the educator as the creator of social reality. The encounters between Zapatista and Norwegian perspectives show how educators' positions and roles in reflecting upon, engaging with, and reappropriating the notion of time, are central for sustainability education. [ABSTRACT FROM AUTHOR]

This article explores the significance of peasant culture for sustainability education, the political engagement of the educator with sustainability and the understanding of herself as a political agent of change. Paolo Freire’s critical pedagogy and understanding of educators as political actors is used to explore the political and transformative role of the educator through both their profession and as members of local communities. This study is part of a doctoral project seeking to connect perspectives of Norwegian early childhood educators and members of the Mexican Zapatista social movement, who in both contexts identify as peasants. The critical use of a bricolage methodology allows us to expand on the critical lens chosen here and foster productive encounters between these disparate views (Kincheloe et al., 2011; Rogers, 2012). Results show that being a peasant fosters ecological, social, and political values which could help educators understand their role as members of local and global communities and develop education practices for sustainability that are transformative and empowering. [ABSTRACT FROM AUTHOR]

Pancreatic ductal adenocarcinoma (PDAC) poses a significant threat due to its tendency to evade early detection, frequent metastasis, and the subsequent challenges in devising effective treatments. Processes that govern epithelial-mesenchymal transition (EMT) in PDAC hold promise for advancing novel therapeutic strategies. SAMD1 (SAM domain-containing protein 1) is a CpG island-binding protein that plays a pivotal role in the repression of its target genes. Here, we revealed that SAMD1 acts as a repressor of genes associated with EMT. Upon deletion of SAMD1 in PDAC cells, we observed significantly increased migration rates. SAMD1 exerts its effects by binding to specific genomic targets, including CDH2, encoding N-cadherin, which emerged as a driver of enhanced migration upon SAMD1 knockout. Furthermore, we discovered the FBXO11-containing E3 ubiquitin ligase complex as an interactor and negative regulator of SAMD1, which inhibits SAMD1 chromatin-binding genome-wide. High FBXO11 expression in PDAC is associated with poor prognosis and increased expression of EMT-related genes, underlining an antagonistic relationship between SAMD1 and FBXO11. In summary, our findings provide insights into the regulation of EMT-related genes in PDAC, shedding light on the intricate role of SAMD1 and its interplay with FBXO11 in this cancer type.