Examinando por Autor "Castillo-Ruiz, Mario"
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Ítem Characterization of MgtC, a virulence factor of Salmonella enterica serovar typhi(Public Library of Science, 2009-04-14) Retamal, Patricio; Castillo-Ruiz, Mario; Mora, Guido C.The MgtC is a virulence factor in Salmonella Typhimurium that is required for growth at low-Mg2+ concentrations and intramacrophage survival. This gene is codified in a conserved region of the Salmonella pathogenicity island 3 (SPI-3), and is also present in the chromosome of other Salmonella serovars. In this study we characterized the MgtC factor in S. Typhi, a human specific pathogen, by using mgtC and SPI-3 mutant strains. We found that MgtC is the most important factor codified in the SPI-3 of S. Typhi for growth in low-Mg2+ media and survival within human cells. In addition, by using reporter genes we determined that the low-Mg2+ concentration, acidic media and PhoP regulator induce mgtC expression in S. Typhi. We suggest that MgtC is the most important virulence factor codified in the SPI-3 of S. Typhi. © 2009 Retamal et al.Ítem Evaluation of the antioxidant capacity of vegetable waste from a wholesale market in Chile(Pontificia Universidad Catolica de Chile, Facultad de Agronomia e Ingenieria Forestal, 2023) Rodríguez Palleres, Ximena; Castillo-Ruiz, Mario; Correa Alfaro, Sebastián; Rojas González, FancyConsumption of vegetables is associated with lower risks of cancer, diabetes, coronary diseases and obesity, but parts of vegetables such as the peels, stems and leaves are not valued, which increases waste and impacts the environment. The aim of the present study was to determine the antioxidant capacity of the leaves and stems of celery, broccoli and beet discarded from the patios of the Lo Valledor Wholesale Market, the main fruit and vegetable distribution center in Santiago, Chile. The leaves and stems were separated to analyze total polyphenol content and antioxidant capacity (ORAC). The total polyphenol contents in celery, broccoli and beet leaves were 155.5, 144.7 and 117.1 mg EAG 100 g-1 mta, respectively, while in the stems, they were between 22.7, 41.4 and 69.3 mg EAG 100 g-1 mta, respectively. Similarly, the leaves showed higher antioxidant capacity than the stems. The ORAC for celery, broccoli and beet stems was 2,325.2, 2,098.1 and 1,756.5 μmol TE 100 g-1 mta, respectively, while for stems, it was 317.8, 625.1 and 970.2 μmol TE 100 g-1 mta, respectively. The antioxidant capacity of the leaves and stems of celery, beets and broccoli suggest that they are healthy eating options and that their valorization should be considered. © 2023, Pontificia Universidad Catolica de Chile, Facultad de Agronomia e Ingenieria Forestal. All rights reserved.Ítem In Vivo Efficacy of Purified Quillaja Saponin Extracts in Protecting against Piscirickettsia salmonis Infections in Atlantic Salmon (Salmo salar)(Multidisciplinary Digital Publishing Institute (MDPI), 2023-09) Cortés, Hernán; Castillo-Ruiz, Mario; Cañon-Jones, Hernán; Schlotterbeck, Trinidad; San Martín, Ricardo; Padilla, LeandroPiscirickettsiosis, the main infectious disease affecting salmon farming in Chile, still has no efficient control measures. Piscirickettsia salmonis is a facultative intracellular bacterium that can survive and replicate within the host macrophages, evading the immune response. Triterpenic saponins obtained from the Quillaja saponaria tree have been widely studied, and have been shown to be immunomodulatory agents, suitable for feed and vaccine applications for veterinary and human uses. The impact of the oral administration of two extracts of Quillaja saponins on the infection of P. salmonis in Salmo salar and the corresponding gene expressions of immunomarkers were studied under three in vivo models. In the intraperitoneal challenge model, the group fed with Quillaja extracts showed lower mortality (29.1% treated vs. 37.5% control). Similar results were obtained in the cohabitation model trial (36.3% vs. 60.0%). In the commercial pilot trial, the results showed a significant reduction of 71.3% in mortality caused by P. salmonis (0.51% vs. 1.78%) and antibiotic use (reduction of 66.6% compared to untreated control). Also, Quillaja extracts significantly modulated the expression of IFN-II and CD8. These results represent evidence supporting the future use of purified Quillaja extracts as a natural non-pharmacological strategy for the prevention and control of P. salmonis infections in salmon. © 2023 by the authors.Ítem Modified intracellular-associated phenotypes in a recombinant Salmonella typhi expressing S. typhimurium SPI-3 sequences(Public Library of Science, 2010-02-24) Retamal, Patricio; Castillo-Ruiz, Mario; Villagra, Nicolás A.; Morgado, Juan; Mora, Guido C.A bioinformatics comparison of Salmonella Pathogenicity Island 3 sequences from S. Typhi and S. Typhimurium serovars showed that ten genes are highly conserved. However three of them are pseudogenes in S. Typhi. Our aim was to understand what functions are lost in S. Typhi due to pseudogenes by constructing a S. Typhi genetic hybrid carrying the SPI-3 region of S. Typhimurium instead of its own SPI-3. We observed that under stressful conditions the hybrid strain showed a clear impairment in resistance to hydrogen peroxide and decreased survival within U937 culture monocytes. We hypothesized that the marT-fidL operon, encoded in SPI-3, was responsible for the new phenotypes because marT is a pseudogen in S. Typhi and has a demonstrated role as a transcriptional regulator in S. Typhimurium. Therefore we cloned and transferred the S. Typhimurium marT-fidL operon into S. Typhi and confirmed that invasion of monocytes was dramatically decreased. Finally, our findings suggest that the genomic and functional differences between SPI-3 sequences have implications in the host specificity of Typhi and Typhimurium serovars. Copyright: © 2010 Retamal et al.Ítem Quillaja saponaria (Molina) Extracts Inhibits In Vitro Piscirickettsia salmonis Infections(MDPI AG, 2020-12) Cañon-Jones, Hernán; Cortes, Hernán; Castillo-Ruiz, Mario; Schlotterbeck, Trinidad; San Martín, RicardoP. salmonis infections are the cause of major bacterial disease in salmonids in Chile, and the reason for using more antibiotics compared to other salmon-producing countries. Vaccination and antibiotics have not been efficient and new approaches are needed. The safety of Quillaja saponaria extracts was measured by cytotoxicity using flow cytometry of cytopathic and death of fish cell cultures and efficacy was assessed using in vitro infection models with pathogenic P. salmonis. Cytotoxicity was low and control of in vitro infections was achieved with all products, with protection of over 90%. Minimum inhibitory concentrations were much higher than those in the infection using cell cultures. These results suggest a dual mechanism of action where less purified extracts with a combination of saponin and non-saponin components simultaneously decrease P. salmonis infection while protecting cell lines, rather than exerting a direct antimicrobial effect. Quillaja saponins controlled in vitro infections with P. salmonis and could be considered good candidates for a new, safe and sustainable method of controlling fish bacterial infectious diseases. © 2020 by the authors. Licensee MDPI, Basel, Switzerland.Ítem Salmonella enterica: una revisión de la trilogía agente, hospedero y ambiente, y su trascendencia en Chile(Sociedad Chilena de Infectología, 2016-10) Barreto, Marlen; Castillo-Ruiz, Mario; Retamal Merino, PatricioSalmonella enterica is a major foodborne pathogen worldwide, being the main cause of outbreaks by food consumption in Chile. Despite all efforts deployed for control and prevention, the high incidence in people still persists, with several factors that could be influencing the epidemiological behavior of this infection. The objective of this review is to identify these factors belonging to the biological agent, the human host and the environment, which probably have a greater importance in Chile. Thus, priority areas for research of S. enterica are inferred, which hopefully will help to understand its spread in nature and its success as a wide host range pathogen. In the future, increased understanding of these determinants will facilitate the implementation of biosecurity and surveillance strategies for the prevention of disease in people and animals.Ítem Skeletal Muscle Atrophy Induced by Diabetes Is Mediated by Non-Selective Channels and Prevented by Boldine(MDPI, 2023-04) Cea, Luis A.; Vásquez, Walter; Hernández-Salinas, Romina; Vielma, Alejandra Z.; Castillo-Ruiz, Mario; Velarde, Victoria; Salgado, Magdiel; Sáez, Juan C.Individuals with diabetes mellitus present a skeletal muscle myopathy characterized by atrophy. However, the mechanism underlying this muscular alteration remains elusive, which makes it difficult to design a rational treatment that could avoid the negative consequences in muscles due to diabetes. In the present work, the atrophy of skeletal myofibers from streptozotocin-induced diabetic rats was prevented with boldine, suggesting that non-selective channels inhibited by this alkaloid are involved in this process, as has previously shown for other muscular pathologies. Accordingly, we found a relevant increase in sarcolemma permeability of skeletal myofibers of diabetic animals in vivo and in vitro due to de novo expression of functional connexin hemichannels (Cx HCs) containing connexins (Cxs) 39, 43, and 45. These cells also expressed P2X7 receptors, and their inhibition in vitro drastically reduced sarcolemma permeability, suggesting their participation in the activation of Cx HCs. Notably, sarcolemma permeability of skeletal myofibers was prevented by boldine treatment that blocks Cx43 and Cx45 HCs, and now we demonstrated that it also blocks P2X7 receptors. In addition, the skeletal muscle alterations described above were not observed in diabetic mice with myofibers deficient in Cx43/Cx45 expression. Moreover, murine myofibers cultured for 24 h in high glucose presented a drastic increase in sarcolemma permeability and levels of NLRP3, a molecular member of the inflammasome, a response that was also prevented by boldine, suggesting that, in addition to the systemic inflammatory response found in diabetes, high glucose can promote the expression of functional Cx HCs and activation of the inflammasome in skeletal myofibers. Therefore, Cx43 and Cx45 HCs play a critical role in myofiber degeneration, and boldine could be considered a potential therapeutic agent to treat muscular complications due to diabetes. © 2023 by the authors.