Person:
Madrid Albarrán, María Yolanda

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First Name
María Yolanda
Last Name
Madrid Albarrán
URI
https://hdl.handle.net/20.500.14352/76072
Affiliation
Universidad Complutense de Madrid
Faculty / Institute
Ciencias Químicas
Department
Química Analítica
Area
Química Analítica
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Start date: 2017 × End date: 2017 ×

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Now showing 1 - 3 of 3
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    Determination of size and mass-and number-based concentration of biogenic SeNPs synthesized by lactic acid bacteria by using a multimethod approach
    (Analytica Chimica Acta, 2017) Moreno Martín, Gustavo; Pescuma, Micaela; Pérez Corona, María Teresa; Mozzi, Fernanda; Madrid Albarrán, María Yolanda
    Selenium nanoparticles (SeNPs) were synthesized by a green technology using lactic acid bacteria (LAB, Lactobacillus acidophilus, L. delbrueckii subsp. bulgaricus and L. reuteri). The exposure of aqueous sodium selenite to LAB led to the synthesis of SeNPs. Characterization of SeNPs by transmission electron microscopy with energy dispersive X-ray spectrum (EDXS) analysis revealed the presence of stable, predominantly monodispersed and spherical SeNPs of an average size of 146 ± 71 nm. Additionally, SeNPs hydrodynamic size was determined by dispersive light scattering (DLS) and nanoparticle tracking analysis (NTA). For this purpose, a methodology based on the use of surfactants in basic medium was developed for isolating SeNPs from the bacterial pellet. The hydrodynamic size values provided by DLS and NTA were 258 ± 4 and 187 ± 56 nm, respectively. NTA measurements of number-based concentration reported values of (4.67±0:30)x 109 SeNPs/mL with a relative standard deviation lower than 5% (n = 3). The quantitative results obtained by NTA were supported by theoretical calculations. Asymmetrical flow field flow fractionation (AF4) on line coupled to the inductively couple plasma mass spectrometry (ICP-MS) and off-line coupled to DLS was further employed to characterize biogenic SeNPs. The distribution of the particle size for the Se-containing peak provide an average size of (247 ± 14) nm. The data obtained by independent techniques were in good agreement and the developed methodology
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    Exploring the Behavior and Metabolic Transformations of SeNPs in Exposed Lactic Acid Bacteria. Effect of Nanoparticles Coating Agent
    (International Journal of Molecular Sciences, 2017) Palomo Siguero, María; Madrid Albarrán, María Yolanda
    The behavior and transformation of selenium nanoparticles (SeNPs) in living systems such as microorganisms is largely unknown. To address this knowledge gap, we examined the effect of three types of SeNP suspensions toward Lactobacillus delbrueckii subsp. bulgaricus LB-12 using a variety of techniques. SeNPs were synthesized using three types of coating agents (chitosan (CS-SeNPs), hydroxyethyl cellulose (HEC-SeNPs) and a non-ionic surfactant, surfynol (ethoxylated-SeNPs)). Morphologies of SeNPs were all spherical. Transmission electron microscopy (TEM) was used to locate SeNPs in the bacteria. High performance liquid chromatography (HPLC) on line coupled to inductively coupled plasma mass spectrometry (ICP-MS) was applied to evaluate SeNP transformation by bacteria. Finally, flow cytometry employing the live/dead test and optical density measurements at 600 nm (OD600) were used for evaluating the percentages of bacteria viability when supplementing with SeNPs. Negligible damage was detected by flow cytometry when bacteria were exposed to HEC-SeNPs or CS-SeNPs at a level of 10 μg Se mL−1. In contrast, ethoxylated-SeNPs were found to be the most harmful nanoparticles toward bacteria. CS-SeNPs passed through the membrane without causing damage. Once inside, SeNPs were metabolically transformed to organic selenium compounds. Results evidenced the importance of capping agents when establishing the true behavior of NPs.
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    Food prospects of selenium enriched-Lactobacillus acidophilus CRL 636 and Lactobacillus reuteri CRL 1101
    (Journal of Functional Foods, 2017) Pescuma, Micaela; Gómez Gómez, Beatriz; Pérez Corona, María Teresa; Font, Graciela; Madrid Albarrán, María Yolanda; Mozzi, Fernanda
    Selenium, which is present as SeCys in selenoproteins, is involved in cancer prevention, thyroid functioning, and pathogen inhibition. Lactobacilli can biotransform inorganic Se into seleno-amino acids. Growth, Se accumulation and seleno-amino acid formation by Lactobacillus acidophilus CRL636 and L. reuteri CRL1101 in a Se-supplemented medium were studied. Moreover, survival of Se-enriched strains to different pH values and bile salts was analyzed. L. acidophilus CRL636 showed low growth rate in the presence of Se while differences were less evident for L. reuteri CRL1101, which displayed higher amounts of intracellular SeCys and SeMet than the CRL636 strain. Interestingly, both lactobacilli could produce Se-nanoparticles. Se-enriched lactobacilli showed lower growth rates than non-Se exposed cells. The adverse effect of bile salts and the ability to survive at pH 4.0 diminished for the Se-enriched L. reuteri strain. The studied lactobacilli could be used as Se-enriched probiotics or as a vehicle for manufacturing Se-containing fermented foods.