Browsing by Author "Cabezas, Carolina"
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Item Arsenic Response of Three Altiplanic Exiguobacterium Strains With Different Tolerance Levels Against the Metalloid Species: A Proteomics Study(Frontiers Media S.A., 2019-09) Castro Severyn, Juan; Pardo Esté, Coral; Sulbaran, Yoelvis; Cabezas, Carolina; Gariazzo, Valentina; Briones, Alan; Morales, Naiyulin; Séveno, Martial; Decourcelle, Mathilde; Salvetat, Nicolas; Remonsellez, Francisco; Castro Nallar, Eduardo; Molina, Franck; Molina, Laurence; Saavedra, Claudia P.Exiguobacterium is a polyextremophile bacterial genus with a physiology that allows it to develop in different adverse environments. The Salar de Huasco is one of these environments due to its altitude, atmospheric pressure, solar radiation, temperature variations, pH, salinity, and the presence of toxic compounds such as arsenic. However, the physiological and/or molecular mechanisms that enable them to prosper in these environments have not yet been described. Our research group has isolated several strains of Exiguobacterium genus from different sites of Salar de Huasco, which show different resistance levels to As(III) and As(V). In this work, we compare the protein expression patterns of the three strains in response to arsenic by a proteomic approach; strains were grown in absence of the metalloid and in presence of As(III) and As(V) sublethal concentrations and the protein separation was carried out in 2D electrophoresis gels (2D-GE). In total, 999 spots were detected, between 77 and 173 of which showed significant changes for As(III) among the three strains, and between 90 and 143 for As(V), respectively, compared to the corresponding control condition. Twenty-seven of those were identified by mass spectrometry (MS). Among these identified proteins, the ArsA [ATPase from the As(III) efflux pump] was found to be up-regulated in response to both arsenic conditions in the three strains, as well as the Co-enzyme A disulfide reductase (Cdr) in the two more resistant strains. Interestingly, in this genus the gene that codifies for Cdr is found within the genic context of the ars operon. We suggest that this protein could be restoring antioxidants molecules, necessary for the As(V) reduction. Additionally, among the proteins that change their expression against As, we found several with functions relevant to stress response, e.g., Hpf, LuxS, GLpX, GlnE, and Fur. This study allowed us to shed light into the physiology necessary for these bacteria to be able to tolerate the toxicity and stress generated by the presence of arsenic in their niche. © Copyright © 2019 Castro-Severyn, Pardo-Esté, Sulbaran, Cabezas, Gariazzo, Briones, Morales, Séveno, Decourcelle, Salvetat, Remonsellez, Castro-Nallar, Molina, Molina and Saavedra.Item Biochemical, genomic and structural characteristics of the Acr3 pump in Exiguobacterium strains isolated from arsenic-rich Salar de Huasco sediments(Frontiers Media S.A., 2022-11) Castro-Severyn, Juan; Pardo-Esté, Coral; Araya-Durán, Ingrid; Gariazzo, Valentina; Cabezas, Carolina; Valdés, Jorge; Remonsellez, Francisco; Saavedra, Claudia P.Arsenic is a highly toxic metalloid of major concern for public safety. However, microorganisms have several resistance mechanisms, particularly the expression of arsenic pumps is a critical component for bacterial ability to expel it and decrease intracellular toxicity. In this study, we aimed to characterize the biochemical, structural, and genomic characteristics of the Acr3 pump among a group of Exiguobacterium strains isolated from different sites of the arsenic-rich Salar de Huasco (SH) ecosystem. We also determined whether the differences in As(III) resistance levels presented by the strains could be attributed to changes in the sequence or structure of this protein. In this context, we found that based on acr3 sequences the strains isolated from the SH grouped together phylogenetically, even though clustering based on gene sequence identity did not reflect the strain’s geographical origin. Furthermore, we determined the genetic context of the acr3 sequences and found that there are two versions of the organization of acr3 gene clusters, that do not reflect the strain’s origin nor arsenic resistance level. We also contribute to the knowledge regarding structure of the Acr3 protein and its possible implications on the functionality of the pump, finding that although important and conserved components of this family of proteins are present, there are several changes in the amino acidic sequences that may affect the interactions among amino acids in the 3D model, which in fact are evidenced as changes in the structure and residues contacts. Finally, we demonstrated through heterologous expression that the Exiguobacterium Acr3 pump does indeed improve the organisms As resistance level, as evidenced in the complemented E. coli strains. The understanding of arsenic detoxification processes in prokaryotes has vast biotechnological potential and it can also provide a lot of information to understand the processes of evolutionary adaptation. Copyright © 2022 Castro-Severyn, Pardo-Esté, Araya-Durán, Gariazzo, Cabezas, Valdés, Remonsellez and Saavedra.Item The ArcB kinase sensor participates in the phagocyte-mediated stress response in Salmonella Typhimurium(Frontiers Media SA, 2025) Pardo-Esté, Coral; Urbina, Francisca; Aviles, Nicolas; Pacheco, Nicolas; Briones, Alan; Cabezas, Carolina; Rojas, Vicente; Pavez, Valentina; Sulbaran-Bracho, Yoelvis; Hidalgo, Alejandro A.; Castro-Severyn, Juan; Saavedra, Claudia P.The ArcAB two-component system includes a histidine kinase sensor (ArcB) and a regulator (ArcA) that respond to changes in cell oxygen availability. The ArcA transcription factor activates genes related to metabolism, membrane permeability, and virulence, and its presence is required for pathogenicity in Salmonella Typhimurium, which can be phosphorylated independently of its cognate sensor, ArcB. In this study, we aimed to characterize the transcriptional response to hypochlorous acid (HOCl) mediated by the presence of the ArcB sensor. HOCl is a powerful microbicide widely used for sanitization in industrial settings. We used wild-type S. Typhimurium and the mutant lacking the arcB gene exposed to NaOCl to describe the global transcriptional response. We also infected murine neutrophils to evaluate the expression levels of relevant genes related to the resistance and infection process while facing ROS-related stress. Our results indicate that the absence of the arcB gene significantly affects the ability of S. Typhimurium to grow under HOCl stress. Overall, 6.6% of Salmonella genes varied their expression in the mutant strains, while 8.6% changed in response to NaOCl. The transcriptional response associated with the presence of ArcB is associated with metabolism and virulence, suggesting a critical role in pathogenicity and fitness, especially under ROS-related stress. Our results show that ArcB influences the expression of genes associated with fatty acid degradation, protein secretion, cysteine and H2S biosynthesis, and translation, both in vitro and under conditions found within neutrophils. We found that protein carbonylation is significantly higher in the mutant strain than in the wild type, suggesting a critical function for ArcB in the response and repair processes. This study contributes to the understanding of the pathogenicity and adaptation mechanisms that Salmonella employs to establish a successful infection in its host.Item Weighted gene co-expression network analysis reveals immune evasion related genes in Echinococcus granulosus sensu stricto(Frontiers Media SA, 2023) Pereira, Ismael; Prado Paludo, Gabriela; Hidalgo, Christian; Stoore, Caroll; Baquedano, María Soledad; Cabezas, Carolina; Cancela, Martín; Ferreira, Henrique Bunselmeyer; Bastías, Macarena; Riveros, Aníbal; Meneses, Claudio; Sáenz, Leonardo; Paredes, RodolfoCystic echinococcosis (CE) is a zoonotic disease caused by the tapeworm Echinococcus granulosus sensu lato (s.l). In the intermediate host, this disease is characterized by the growth of cysts in viscera such as liver and lungs, inside of which the parasite develops to the next infective stage known as protoscoleces. There are records that the infected viscera affect the development and morphology of E. granulosus s.l. protoscolex in hosts such as buffalo or humans. However, the molecular mechanisms that drive these differences remains unknown. Weighted gene co-expression network analysis (WGCNA) using a set of RNAseq data obtained from E. granulosus sensu stricto (s.s.) protoscoleces found in liver and lung cysts reveals 34 modules in protoscoleces of liver origin, of which 12 have differential co-expression from protoscoleces of lung origin. Three of these twelve modules contain hub genes related to immune evasion: tegument antigen, tegumental protein, ubiquitin hydrolase isozyme L3, COP9 signalosome complex subunit 3, tetraspanin CD9 antigen, and the methyl-CpG-binding protein Mbd2. Also, two of the twelve modules contain only hypothetical proteins with unknown orthology, which means that there are a group of unknown function proteins co-expressed inside the protoscolex of liver CE cyst origin. This is the first evidence of gene expression differences in protoscoleces from CE cysts found in different viscera, with co-expression networks that are exclusive to protoscoleces from liver CE cyst samples. This should be considered in the control strategies of CE, as intermediate hosts can harbor CE cysts in liver, lungs, or both organs simultaneously. Copyright © 2024 Pereira, Paludo, Hidalgo, Stoore, Baquedano, Cabezas, Cancela, Ferreira, Bastías, Riveros, Meneses, Sáenz and Paredes.