Examinando por Autor "Sáenz, Leonardo"
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Ítem High prevalence of pathogenic Leptospira in alien American mink (Neovison vison) in Patagonia(Sociedad de Biología de Chile, 2014) Barros, Macarena; Sáenz, Leonardo; LapierreII, Lisette; Nuñez, Camila; Medina-Vogel, GonzaloBACKGROUND: Leptospirosis is an important zoonosis with worldwide distribution caused by pathogenic bacteria of the genus Leptospira. The North American mink (Neovison vison) has an important role in the environmental contamination with Leptospira, as minks live in aquatic environments and are the predators of rodents. FINDINGS: Blood and kidney samples were obtained from 57 minks in Southern Chile 39° S to 45° S. Pathogenic species of Leptospira were detected by PCR on 31/57 minks. To determine the species, we sequenced the 16S ribosomal RNA (rRNA) gene on nine of the positive samples. We predicted two pathogenic species: Leptospira interrogans (five samples) and Leptospira borgpetersenii (four samples). CONCLUSIONS: This study showed that the American mink presents pathogenic species of Leptospira and confirm important environmental contamination of Patagonian rivers and lakes with pathogenic Leptospira.Ítem Novel Proteoliposome-Based Vaccine against E. coli: A Potential New Tool for the Control of Bovine Mastitis(MDPI, 2022-09) Quiroga, John; Vidal, Sonia; Siel, Daniela; Caruffo, Mario; Valdés, Andrea; Cabrera, Gonzalo; Lapierre, Lissette; Sáenz, LeonardoEscherichia coli is an important causative agent of clinical mastitis in cattle. Current available vaccines have shown limited protection. We evaluated the efficacy of a novel vaccine based on bacterial proteoliposomes derived from an E. coli field strain. Female BALB/c mice were immunized subcutaneously with two doses of the vaccine, 3 weeks apart. Between days 5 and 8 after the first inoculation, the females were mated. At 5–8 days postpartum, the mice were intramammary challenged with the same E. coli strain. Two days after bacterial infection, mice were euthanized, and the mammary glands were examined and removed to evaluate the efficacy and safety of the vaccine as well as the immune response generated by the new formulation. The vaccinated mice showed mild clinical symptoms and a lower mammary bacterial load as compared to non-vaccinated animals. The vaccination induced an increase in levels of IgG, IgG1 and IgG2a against E. coli in blood and mammary glands that showed less inflammatory infiltration and tissue damage, as compared to the control group. In summary, the vaccine based on bacterial proteoliposomes is safe, immunogenic, and effective against E. coli, constituting a new potential tool for mastitis control. © 2022 by the authors.Ítem Reproductive and Behavioral Evaluation of a New Immunocastration Dog Vaccine(MDPI AG, 2020-02) Siel, Daniela; Ubilla, María José; Vidal, Sonia; Loaiza, Alexandra; Quiroga, John; Cifuentes, Federico; Hardman, Timothy; Lapierre, Lisette; Paredes, Rodolfo; Sáenz, LeonardoCanine immunocastration development has been of interest for many years as a complementary strategy to surgical castration. The purpose of this paper was to verify the effect of a recombinant vaccine for dog immunocastration. Two tests were done, one under controlled conditions and a second under field conditions. Animals were injected with 1 mL of 500 µg GnRXG/Q recombinant protein; 500 µg of low molecular weight chitosan as adjuvant; 1 mL NaCl 0.9% q.s. In the first trial, eight Beagle male dogs between the ages of 1 and 3 comprised the sample, randomly divided into two groups: vaccinated group (n = 7) and control group (n = 2). The second trial had 32 dogs with owners. In the first controlled conditions trial, the vaccine produced specific antibodies that remained until the end of the trial (day 270), inducing reduced testosterone and spermiogram changes in the immunized animals. In a second trial, on the field, specific immunity was induced, which remained high up to day 150. The vaccine also reduced sexual agonistic and marking behaviors. This new vaccine proved to be safe, immunogenic, capable of reducing gonadal functionality, and had a positive effect on inducing reduced sexual, agonistic, and marking behavior of the animals. © 2020 by the authors. Licensee MDPI, Basel, Switzerland.Ítem 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.