DUGi

Análisis del gen cyran_114 presente en el profago Cyrano de Escherichia coli LF82 y su posible implicación en la motilidad

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Crohn’s disease (CD) is a chronic inflammatory bowel disease caused by multiple factors. Intestinal dysbiosis plays a key role in the development of the disease. They found an increased presence of adherent-invasive Escherichia coli (AIEC) strains in the microbiota of CD patients. These strains have the ability to infect intestinal epithelial cells, survive within macrophages, and even replicate within them. However, the molecular mechanisms involved in pathogenicity and the regulatory mechanisms of expression at the molecular level are not fully clear. In this study, the E. coli LF82 strain, being AIEC the reference strain, was used in order to observe the expression of cyran_114, which is a gene that is present in a bacteriophage of LF82 (Cyrano) found in an episomal manner. The assumption of this study is that cyran_114 would have an effect on the regulation of bacterial motility genes, specifically, that cyran_114 represses fliC under conditions of cellular stress or macrophage infection. The expression of cyran_114 was studied under very diverse conditions: growth in LB medium (stationary and exponential phase), in nutrient-poor acidic medium that attempts to simulate an intracellular environment, and also in the infection of J774A.1 macrophages. In addition, the interference of the alarmone ppGpp in the expression of cyran_114 was evaluated, and a ∆cyran_114 mutant was designed in order to study the role of this gene. With this modified strain, a motility test was performed to check whether deletion of the gene had an effect on the motility of the bacterium. The results show that cyran_114 is differentially expressed under stress conditions and intracellular infection and that its expression is modulated by ppGpp. It could also be seen that cyran_114 is a repressor for the stationary phase expression of the flagellar gene fliC, since, in the absence of the cyran_114 gene, this repression disappears. In comparison, when the ppGpp molecule is not present, fliC expression increases, so fliC is repressed by ppGpp when stress is present. This reveals that both ppGpp and Cyrano participate in the regulation of bacterial motility. These results provide new insights into the different regulatory processes involved in AIEC bacteria, providing a new point of view to develop different therapies against CD Santano Moreno, Jordi Efecte de l’ozonització en la formació de trihalometans durant el tractament d’aigua potable