Browsing by Author "Castaneda, Francisco"

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    Characterization of an Agarophyton chilense Oleoresin Containing PPARγ Natural Ligands with Insulin-Sensitizing Effects in a C57Bl/6J Mouse Model of Diet-Induced Obesity and Antioxidant Activity in Caenorhabditis elegans
    (2021) Pinto, Claudio; Raquel Ibanez, Maria; Loyola, Gloria; Leon, Luisa; Salvatore, Yasmin; Gonzalez, Carla; Barraza, Victor; Castaneda, Francisco; Aldunate, Rebeca; Contreras-Porcia, Loretto; Fuenzalida, Karen; Bronfman, Francisca C.
    The biomedical potential of the edible red seaweed Agarophyton chilense (formerly Gracilaria chilensis) has not been explored. Red seaweeds are enriched in polyunsaturated fatty acids and eicosanoids, which are known natural ligands of the PPAR gamma nuclear receptor. PPAR gamma is the molecular target of thiazolidinediones (TZDs), drugs used as insulin sensitizers to treat type 2 diabetes mellitus. Medical use of TZDs is limited due to undesired side effects, a problem that has triggered the search for selective PPAR gamma modulators (SPPARMs) without the TZD side effects. We produced Agarophyton chilense oleoresin (Gracilex(R)), which induces PPAR gamma activation without inducing adipocyte differentiation, similar to SPPARMs. In a diet-induced obesity model of male mice, we showed that treatment with Gracilex(R) improves insulin sensitivity by normalizing altered glucose and insulin parameters. Gracilex(R) is enriched in palmitic acid, arachidonic acid, oleic acid, and lipophilic antioxidants such as tocopherols and beta-carotene. Accordingly, Gracilex(R) possesses antioxidant activity in vitro and increased antioxidant capacity in vivo in Caenorhabditis elegans. These findings support the idea that Gracilex(R) represents a good source of natural PPAR gamma ligands and antioxidants with the potential to mitigate metabolic disorders. Thus, its nutraceutical value in humans warrants further investigation.
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    Isolation of drug-resistant Salmonella enterica serovar enteritidis strains in gentoo penguins from Antarctica
    (2017) Retamal, Patricio; Llanos-Soto, Sebastian; Moreno Salas, Lucila; Lopez, Juana; Vianna, Juliana; Hernandez, Jorge; Medina-Vogel, Gonzalo; Castaneda, Francisco; Fresno, Marcela; Gonzalez-Acuna, Daniel
    Anthropogenic activity in Antarctica constitutes a continuous risk for the introduction of infectious diseases into indigenous wildlife populations. Penguin colonies living close to human settlements or inhabiting in areas considered for tourism could be facing a greater threat of infection. Fecal samples from Pygoscelis penguins (Pygoscelis spp.) were collected from different sites within Antarctic Peninsula and South Shetlands Islands in order to assess the presence of Salmonella enterica. Bacterial identification and characterization was performed applying biochemical and molecular techniques. Isolates were tested for antimicrobial resistance by the disk diffusion method, and PCR analyses were used for detection of resistance and virulence-associated genes. Four samples (1.74%) from P. papua were found to be positive to S. enterica serovar Enteritidis strains. All of them showed phenotypic antimicrobial resistance to at least three antimicrobials, and shared a similar gene profile through PCR. Results in this study urgently call for improvements in sanitary standards for waste disposal and sewage treatment in Antarctica. To our knowledge, this is the first study to report antimicrobial resistance in S. enterica isolated from Antarctic wild species.