De-romanticising dialogue in collaborative health care research:A critical, reflexive approach to tensions in an action research project’s initial phase

In the current socio-political conjuncture, collaborative, dialogic forms of knowledge production abound and are idealised as democratic and inclusive. The aim of the article is to contribute to the body of critical, reflexive analyses of collaborative research by analysing how complex dynamics of exclusion as well as inclusion create tensions in researchers’ attempts to establish collaborative relations in the initial phase of an action research project. The analysis applies a framework combining Bakhtinian dialogic communication theory and Foucauldian theory to explore inclusion and exclusion in the tensional interplay of multiple voices whereby certain voices dominate. Finally, the article offers a typology of ideal types of collaborative research relations that can be used in the initial research phase as a platform for reflexive discussion between researchers and potential collaborative partners about their respective understandings of collaboration and dialogue and corresponding expectations about the research process and results

Oxidative DNA damage is instrumental in hyperreplication stress-induced inviability of Escherichia coli

En Escherichia coli, un aumento en la forma unida de ATP del iniciador de proteína DnaA da resultados en hiperiniciación e inviabilidad. Aquí, mostramos que dicha replicación de estrés es tolerada en el crecimiento anaeróbico. En las células de hiperiniciación, un cambio de la anaeróbica para crecimiento aeróbico dio como resultado la fragmentación aparente de cromosomas y una disminución en su concentración terminal, lo que conduce a un aumento dramático de la ratio ori/ter y el cese del crecimiento celular. La viabilidad aeróbica fue restaurada por reducir el nivel de especies reactivas del oxígeno (ROS) o por eliminación mutM (Fpg glicosilasa). Las roturas de la doble hélice observadas en las células de hiperiniciación resultan, por lo tanto, del encuentro entre los tenedores de replicación y las lesiones de ADN de una sola hélice generadas mientras se quitan bases oxidadas, principalmente 8-oxoG, a partir del ADN. Llegamos a la conclusión de que existe un delicado equilibrio entre la replicación cromosómica y el daño del ADN infligido a ROS por lo que el número de horquillas de replicación sólo puede aumentar cuando la formación de ROS se reduce o si la reparación pertinente se ve comprometida.In Escherichia coli, an increase in the ATP bound form of the DnaA initiator protein results in hyperinitiation and inviability. Here, we show that such replication stress is tolerated during anaerobic growth. In hyperinitiating cells, a shift from anaerobic to aerobic growth resulted in appearance of fragmented chromosomes and a decrease in terminus concentration, leading to a dramatic increase in ori/ter ratio and cessation of cell growth. Aerobic viability was restored by reducing the level of reactive oxygen species (ROS) or by deleting mut M (Fpg glycosylase). The double-strand breaks observed in hyperinitiating cells therefore results from replication forks encountering single-stranded DNA lesions generated while removing oxidized bases, primarily 8-oxoG, from the DNA. We conclude that there is a delicate balance between chromosome replication and ROS inflicted DNA damage so the number of replication forks can only increase when ROS formation is reduced or when the pertinent repair is compromised.-- Unión Europea (PIRG05-GA-2009-247241) -- Danish Research Concil for Natural Sciences (09-064250/FNU) -- Lundbeck Foundation -- Novo Nordist Foundation -- University of Copenhagen para presenter por open accesspeerReviewe

Effects of depth and overgrowth of ephemeral macroalgae on a remote subtidal NE Atlantic eelgrass (Zostera marina) community

We conducted a short-term field sampling complemented with time integrating stable isotope analysis to holistically investigate status and ecological interactions in a remote NE Atlantic Zostera marina meadow. We found high nutrient water concentrations, large biomass of fast-growing, ephemeral macroalgae, low abundance, and biodiversity of epifauna and a food web with thornback ray (Raja clavata) as intermediate and cod (Gadus morhua) as top predator. We observed no variation with increasing depth (3.5-11 m) except for decreasing shoot density and biomass of Zostera and macroalgae. Our results indicate that the Finnoya Zostera ecosystem is eutrophicated. During the past three to four decades, nutrients from aquaculture have steadily increased to reach 75% of anthmpogenic input while the coastal top predator cod has decreased by 50%. We conclude that bottom-up regulation is a predominant driver of change since top-down regulation is generally weak in low density and exposed Zostera ecosystems such as Finnoya.Peer reviewe

Re-wiring of energy metabolism promotes viability during hyperreplication stress in E. coli

Chromosome replication in Escherichia coli is initiated by DnaA. DnaA binds ATP which is essential for formation of a DnaA-oriC nucleoprotein complex that promotes strand opening, helicase loading and replisome assembly. Following initiation, DnaAATP is converted to DnaAADP primarily by the Regulatory Inactivation of DnaA process (RIDA). In RIDA deficient cells, DnaAATP accumulates leading to uncontrolled initiation of replication and cell death by accumulation of DNA strand breaks. Mutations that suppress RIDA deficiency either dampen overinitiation or permit growth despite overinitiation. We characterize mutations of the last group that have in common that distinct metabolic routes are rewired resulting in the redirection of electron flow towards the cytochrome bd-1. We propose a model where cytochrome bd-1 lowers the formation of reactive oxygen species and hence oxidative damage to the DNA in general. This increases the processivity of replication forks generated by overinitiation to a level that sustains viability