Examinando por Autor "Le, Casin"
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Ítem Acceso Abierto Histone-like nucleoid-structuring protein (H-NS) regulatory role in antibiotic resistance in Acinetobacter baumannii(Nature Research, 2021) Rodgers, Deja; Le, Casin; Pimentel, Camila; Tuttobene, Marisel Romina; Subils, Tomás; Escalante, Jenny; Nishimura, Brent; García Véscovi, Eleonora; Sieira, Rodrigo; Bonomo, Robert A.; Tolmasky, Marcelo E.; Ramírez, María SoledadÍtem Acceso Abierto Human Serum Proteins and Susceptibility of Acinetobacter baumannii to Cefiderocol: Role of Iron Transport(MDPI, 2022-03-03) Le, Casin; Pimentel, Camila; Pasteran, Fernando; Tuttobene, Marisel Romina; Subils, Tomás; Escalante, Jenny; Nishimura, Brent; Arriaga, Susana; Carranza, Aimee; Mezcord, Vyanka; Vila, Alejandro J.; Corso, Alejandra; Actis, Luis A.; Tolmasky, Marcelo E.; Bonomo, Robert A.; Ramírez, María SoledadÍtem Acceso Abierto Interaction of Acinetobacter baumannii with Human Serum Albumin: Does the host hetermine the outcome?(MDPI, 2021-07-08) Pimentel, Camila; Le, Casin; Tuttobene, Marisel Romina; Subils, Tomás; Bonomo, Robert A.; Tolmasky, Marcelo E.; Ramírez, María SoledadÍtem Acceso Abierto Involvement of the histone-like nucleoid structuring protein (H-NS) in Acinetobacter baumannii’s natural transformation(MDPI, 2021-08-26) Le, Casin; Pimentel, Camila; Tuttobene, Marisel Romina; Subils, Tomás; Escalante, Jenny; Nishimura, Brent; Arriaga, Susana; Rodgers, Deja; Bonomo, Robert A.; Sieira, Rodrigo; Tolmasky, Marcelo E.; Ramírez, María Soledad; https://orcid.org/0000-0003-0234-4643; https://orcid.org/0000-0002-4495-563X; https://orcid.org/0000-0002-6298-7811; https://orcid.org/0000-0002-9904-7890Most Acinetobacter baumannii strains are naturally competent. Although some information is available about factors that enhance or reduce the frequency of the transformation of this bacterium, the regulatory elements and mechanisms are barely understood. In this article, we describe studies on the role of the histone-like nucleoid structuring protein, H-NS, in the regulation of the expression of genes related to natural competency and the ability to uptake foreign DNA. The expression levels of the natural transformation-related genes pilA, pilT, pilQ, comEA, comEC, comF, and drpA significantly increased in a ∆hns derivative of A. baumannii A118. The complementation of the mutant with a recombinant plasmid harboring hns restored the expression levels of six of these genes (pilT remained expressed at high levels) to those of the wild-type strain. The transformation frequency of the A. baumannii A118 ∆hns strain was significantly higher than that of the wild-type. Similar, albeit not identical, there were consequences when hns was deleted from the hypervirulent A. baumannii AB5075 strain. In the AB5075 complemented strain, the reduction in gene expression in a few cases was not so pronounced that it reached wild-type levels, and the expression of comEA was enhanced further. In conclusion, the expression of all seven transformation-related genes was enhanced after deleting hns in A. baumannii A118 and AB5075, and these modifications were accompanied by an increase in the cells’ transformability. The results highlight a role of H-NS in A. baumannii’s natural competence.Ítem Acceso Abierto The H-NS regulator plays a role in the stress induced by carbapenemase expression in acinetobacter baumannii(American Society for Microbiology, 2020-08-26) Huang, Fanny; Fitchett, Noelle; Razo Gutiérrez, Chelsea; Le, Casin; Martínez, Jasmine; Ra, Grace; López, Carolina; González, Lisandro Javier; Sieira, Rodrigo; Vila, Alejandro J.; Bonomo, Robert A.; Ramírez, María Soledad; https://orcid.org/0000-0002-9904-7890Disruption of the histone-like nucleoid structuring protein (H-NS) was shown to affect the ability of Gram-negative bacteria to regulate genes associated with virulence, persistence, stress response, quorum sensing, biosynthesis pathways, and cell adhesion. Here, we used the expression of metallo--lactamases (MBLs), known to elicit envelope stress by the accumulation of toxic precursors in the periplasm, to interrogate the role of H-NS in Acinetobacter baumannii, together with other stressors. Using a multidrug-resistant A. baumannii strain, we observed that H-NS plays a role in alleviating the stress triggered by MBL toxic precursors and counteracts the effect of DNA-damaging agents, supporting its role in stress response.