Deletion of sigma54 (rpoN) alters the rate of autolysis and biofilm formation in Enterococcus faecalis

Transcription initiation is a critical step in bacterial gene regulation and is often controlled by transcription regulators. The alternate sigma factor (sigma54) is one such regulator that facilitates activator-dependent transcription initiation and thus modulates the expression of a variety of genes involved in metabolism and pathogenesis in bacteria. This study describes the role of sigma54 in the nosocomial pathogen Enterococcus faecalis. Biofilm formation is one of the important pathogenic mechanisms of E. faecalis, as it elevates the organism’s potential to cause surgical site and urinary tract infections. Lysis of bacterial cells within the population contributes to biofilm formation by providing extracellular DNA (eDNA) as a key component of the biofilm matrix. Deletion of rpoN rendered E. faecalis resistant to autolysis, which in turn impaired eDNA release. Despite the significant reduction in eDNA levels compared to the parental strain, the rpoN mutant formed more robust biofilms as observed using laser scanning confocal microscopy and Comstat analysis, indicating and emphasizing the presence of other matrix components. Initial adherence to a polystyrene surface was also enhanced in the mutant. Proteinase K treatment at early stages of biofilm development significantly reduced the accumulation of biofilm by the rpoN mutant. In conclusion, our data indicate that other factors in addition to eDNA might contribute to the overall composition of the enterococcal biofilm and that the regulatory role of sigma54 governs the nature and composition of the biofilm matrix

Impact of COVID-19 in nutritional and functional status of survivors admitted in intensive care units during the first outbreak. Preliminary results of the NUTRICOVID study

Depto. de MedicinaFac. de MedicinaTRUEpu

A Contemporary Archaeology of Cultural Change in Rural North-Western Spain: From Traditional Domesticity to Postmodern Individualisation

This paper explores the built environment in two rural areas of Northwest Spain that were historically inhabited by two of the so-called “cursed peoples.” Combining contemporary archaeology and material culture studies, we analyze the role played by the house in processes of socio-economic and cultural change, and in the reproduction of internal hegemony within villages. To do so, we study the tensions and connections existing between the transformations undergone by the built environment during the last century and different socio-economic processes, including the depopulation of the rural areas, their conversion into tourist attractions, and the current process of individualisation of subjectivity in line with the transformations taking place in the postmodern era.Peer reviewe