Examinando por Autor "Ehrenfeld, Nicole"

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    Effect of microalgae on intestinal inflammation triggered by soybean meal and bacterial infection in zebrafish
    (PLoS ONE, 2017-11) Bravo-Tello, Karina; Ehrenfeld, Nicole; Solís, Camila J.; Ulloa, Pilar E.; Hedrera, Manuel; Pizarro-Guajardo, Marjorie; Paredes-Sabja, Daniel; Feijóo, Carmen G.
    Soybean meal has been used in many commercial diets for farm fish; despite this component inducing intestinal inflammation. On the other hand, microalgae have increasingly been used as dietary supplements in fish feed. Nevertheless, the vast quantity of microalgae species means that many remain under- or unstudied, thus limiting wide scale commercial application. In this work, we evaluated the effects to zebrafish (Danio rerio) of including Tetraselmis sp (Ts); Phaeodactylum tricornutum (Pt); Chlorella sp (Ch); Nannochloropsis oculata (No); or Nannochloropsis gaditana (Ng) as additives in a soybean meal-based diet on intestinal inflammation and survival after Edwardsiella tarda infection. In larvae fed a soybean meal diet supplemented with Ts, Pt, Ch, or Ng, the quantity of neutrophils present in the intestine drastically decreased as compared to larvae fed only the soybean meal diet. Likewise, Ts or Ch supplements in soybean meal or fishmeal increased zebrafish survival by more than 20% after being challenged. In the case of Ts, the observed effect correlated with an increased number of neutrophils present at the infection site. These results suggest that the inclusion of Ts or Ch in fish diets could allow the use of SBM and at the same time improve performance against pathogen. © 2017 Bravo-Tello et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
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    Florfenicol Binding to Molecularly Imprinted Polymer Nanoparticles in Model and Real Samples
    (MDPI AG, 2020-02) Caro, Nelson; Bruna, Tamara; Guerreiro, Antonio; Alvarez-Tejos, Paola; Garretón, Virginia; Piletsky, Sergey; González-Casanova, Jorge; Rojas-Gómez, Diana; Ehrenfeld, Nicole
    A simple and straightforward technique for coating microplate wells with molecularly imprinted polymer nanoparticles (nanoMIPs) to develop assays similar to the enzyme-linked immunosorbent (ELISA) assay to determine and quantify florfenicol (FF) in real food samples such as liquid milk and salmon muscle is presented here. The nanoMIPs were synthesized by a solid-phase approach with an immobilized FF (template) and characterized using dynamic light scattering, a SPR-2 biosensor system and transmission electron microscopy. Immobilization of nanoMIPs was conducted by preparing a homogenous solution of FF-nanoMIPs in water mixed with polyvinyl alcohol (PVA) 0.2% (w/v) in each well of a microplate. The detection of florfenicol was achieved in competitive binding experiments with a horseradish peroxidase−florfenicol (FF-HRP) conjugate. The assay made it possible to measure FF in buffer and in real samples (liquid milk and salmon muscle) within the range of 60−80 and 90–100 ng/mL, respectively. The immobilized nanoMIPs were stored for six weeks at room temperature and at 5 °C. The results indicate good signal recovery for all FF concentrations in spiked milk samples, without any detrimental effects to their binding properties. The high affinity of nanoMIPs and the lack of a requirement for cold chain logistics make them an attractive alternative to traditional antibodies used in ELISA. © 2020 by the authors. Licensee MDPI, Basel, Switzerland.
  • Miniatura
    Ítem
    Response to oxidative stress induced by high light and carbon dioxide (CO2) in the biodiesel producer model Nannochloropsis salina (Ochrophyta, Eustigmatales)
    (Universidad de Valparaíso. Facultad de Ciencias del Mar, 2015) Yangüez, Karen; Lovazzano, Carlos; Contreras-Porcia, Loretto; Ehrenfeld, Nicole
    Due to overconsumption of fossil fuels, microalgae have arrived as an alternative source of biofuel. Looking forward to generate a sustainable process, it is proposed to couple the cultures to CO2 emission sources, reaching in this way higher biomass performance and helping in the way with the capture of carbon released by the combustion processes. Nannochloropsis salina is a microalgae from the Monodopsidaceae family, which is easy to grow and produces high value compounds like essential pigments, polyunsaturated fatty acids and high amounts of lipids. Previous studies showed that adding CO2 to cultures (until 2%) generated an increment in biomass and in the production of fatty acids. However, these conditions also induce acidification of the media, a condition that may promote the generation of oxygen reactive species. In this work, the antioxidant performance of N. salina was studied under different culture conditions involving CO2 through 3 different approaches: analysis of antioxidant enzymatic activities (catalase, ascorbate peroxidase and peroxiredoxine), analysis of gene expression and the quantification of H2O2, phenolic compounds and lipoperoxides (e.g., cell damage marker). The results obtained suggest that an increase in the CO2 concentration in the cultures (15,000 ppm), together with high light (1,000 µmol m-1 s-1) induces an oxidative stress condition in N. salina cells. However, the antioxidant response observed in the microalgae manages to soften this stress, adapting themselves to these conditions without affecting their global performance.