Person:
Bravo Vázquez, Daniel Antonio

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First Name
Daniel Antonio
Last Name
Bravo Vázquez
URI
https://hdl.handle.net/20.500.14352/86409
Affiliation
Universidad Complutense de Madrid
Faculty / Institute
Ciencias Biológicas
Department
Genética, Fisiología y Microbiología
Area
Microbiología
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2017 - 20194
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Author: Peirotén, Ángela × End date: 2019 ×

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Now showing 1 - 4 of 4
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    Inactivation of Listeria monocytogenes during dry-cured ham processing.
    (International Journal of Food Microbiology, 2019) Montiel, Raquel; Peirotén, Ángela; Gaya, Pilar; Martinez-Suarez, Joaquín ; Tapiador, Julio; Núñez, Manuel; Medina, Margarita; Bravo Vázquez, Daniel Antonio; Ortiz, Sagrario
    The effect of Serrano and Iberian dry-cured ham processing and ripening on Listeria monocytogenes inactivation at the surface of whole hams was investigated. Salted hams were surface inoculated (6.5 log CFU) with a cocktail of 4 L. monocytogenes strains isolated from environment and products of a meat industry. Serrano and Iberian hams were ripened for 16 and 24 months, respectively. A decrease of at least 4.6 log units on the surface of Serrano ham was recorded after 4 months for L. monocytogenes counts, which remained under the detection limit thereafter. L. monocytogenes declined by >5 log units on the surface of Iberian ham during the first 9 months and was not detected afterwards. The higher nitrite content of Serrano ham might have accelerated the decrease of the pathogen. This study validates the inactivation of L. monocytogenes on the surface of whole dry-hams during extended ripening.
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    Bile-induced promoters for gene expression in Lactobacillus strains
    (Applied genetics and molecular biotechnology, 2019) Martínez Fernández, José Alberto ; Bravo Vázquez, Daniel Antonio; Peirotén, Ángela ; Arqués Orobón, Juan Luis; Landete , José María
    Bioengineering of probiotics allows the improvement of their beneficial characteristics. In this work, we develop a molecular tool that would allow the activation of desirable traits in probiotics once they reach the intestine. The activity of upstream regions of bile-inducible genes of Lactobacillus casei BL23 and Lactobacillus plantarum WCFS1 was analyzed using plasmids encoding an anaerobic fluorescent protein as reporter. The promoter P16090 from Lb. casei BL23 was selected and its bile induction confirmed in Lb. casei BL23, Lb. plantarum WCFS1, and in Lactobacillus rhamnosus and Lactobacillus reuteri strains. However, the induction did not occur in Lactococcus lactis MG1363 or Bifidobacterium strains. Studies with different bile compounds revealed the importance of cholic acid in the bile induction process. Induction of fluorescence was also confirmed for transformed Lb. casei BL23 under simulated colonic conditions and in the presence of intestinal microbiota. The developed vector, pNZ:16090-aFP, constitutes a promising tool suitable for the expression of genes of interest under intestinal conditions in probiotic strains of the species Lb. casei, Lb. plantarum, Lb. rhamnosus, and Lb. reuteri.
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    Phytoestrogen metabolism by lactic acid bacteria: Enterolignan production by Lactobacillus salivarius and Lactobacillus gasseri strains
    (Journal of Functional Foods, 2017) Peirotén, Ángela ; Álvarez, Inmaculada ; Landete, José ; Bravo Vázquez, Daniel Antonio
    Phytoestrogens are plant polyphenols similar to human estrogens. Isoflavones, ellagitanins, and lignans are metabolized by intestinal bacteria into equol, urolithins, and enterolignans, respectively, which are more bioavailable and bioactive, having beneficial effects on health. In this paper, we analysed the production of equol, 5-hydroxy-equol, enterodiol and enterolactone by 70 strains of Lactobacillus, Lactococcus and Enterococcus. Enterodiol and enterolactone production was found in Lactobacillus salivarius INIA P183, Lb. salivarius INIA P448 and Lactobacillus gasseri INIA P508, in levels around 46 mM and 6 mM respectively. However, we did not find neither equol nor 5-hydroxy-equol producing strains. Furthermore, analysis of the ellagic acid metabolism was extended to a total of 138 lactic acid bacteria strains, although none of them produced urolithins. This is the first time that simultaneous production of enterolactone and enterodiol is described in bacteria with probiotic potential, open their possible application in functional foods.
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    Bacterial metabolism as responsible of beneficial effects of phytoestrogens on human health
    (Critical Reviews in Food Science and Nutrition, 2019) Peirotén, Ángela; Bravo Vázquez, Daniel Antonio; Landete, José María
    Phytoestrogens (PE) are compounds found in plants such as soy (isoflavones), flax seeds and cereals (lignans) and pomegranates (ellagitannins). PE have shown estrogenic/antiestrogenic, antioxidant, anti-inflammatory, antineoplastic and apoptotic activities. The human studies are showing promising although inconsistent results about the beneficial effects of PE on ameliorating the menopausal symptoms or reducing the risk of certain cancers, cardiovascular disease or diabetes. The effects of PE on the organism are mediated by the intestinal microbiota, which transforms them into bioactive PE such as genistein, equol, enterolignans and certain urolithins. In this work, we review the most recent findings about the bacteria able to metabolize PE, together with the latest studies on the effects of PE on health. In addition, we describe the possible factors hindering the demonstration of the beneficial effect of PE on health, evincing the importance of measuring the actual circulating PE in order to encompass the variability of PE metabolism due to the intestinal microbiota. With this in mind, we also explore an approach to ensure the access to bioactive PE.