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Guglielmetti S.,University of Milan | Mayo B.,Institute Productos Lacteos Of Asturias | Alvarez-Martin P.,Nestle
Beneficial Microbes

Until recently, proper development of molecular studies in Bifidobacterium species has been hampered by growth difficulties, because of their exigent nutritive requirements, oxygen sensitivity and lack of efficient genetic tools. These studies, however, are critical to uncover the cross-talk between bifidobacteria and their hosts' cells and to prove unequivocally the supposed beneficial effects provided through the endogenous bifidobacterial populations or after ingestion as probiotics. The genome sequencing projects of different bifidobacterial strains have provided a wealth of genetic data that will be of much help in deciphering the molecular basis of the physiological properties of bifidobacteria. To this end, the purposeful development of stable cloning and expression vectors based on robust replicons - either from temperate phages or resident plasmids - is still needed. This review addresses the current knowledge on the mobile genetic elements of bifidobacteria (prophages, plasmids and transposons) and summarises the different types of vectors already available, together with the transformation procedures for introducing DNA into the cells. It also covers recent molecular studies performed with such vectors and incipient results on the genetic modification of these organisms, establishing the basis that would allow the use of bifidobacteria for future biotechnological applications. © 2013 Wageningen Academic Publishers. Source

Guinda A.,CSIC - Instituto de la Grasa | Rada M.,CSIC - Instituto de la Grasa | Delgado T.,Institute Productos Lacteos Of Asturias | Gutierrez-Adanez P.,CSIC - Instituto de la Grasa | Castellano J.M.,CSIC - Instituto de la Grasa
Journal of Agricultural and Food Chemistry

This work establishes a new procedure for the extraction and analysis of pentacyclic triterpenes, with which fruits and leaves from three Spanish olive cultivars ("Picual", "Hojiblanca", and "Arbequina" ) has been studied. The leaf contains important amounts of oleanolic acid (3.0-3.5% DW), followed by significant concentrations of maslinic acid and minor levels of ursolic acid, erythrodiol, and uvaol. The abundance and profile of triterpenoids change during the leaf ontogeny. In the fruit, triterpenes are exclusively located in the epicarp at concentrations 30-fold lower than that in the leaf. Maslinic acid is the main triterpenoid, only accompanied of oleanolic acid. Along the ripening the levels of these triterpenes decreased. All the analyzed leaves and fruits come from the same agricultural estate, with identical climate and culturing conditions. For this reason, the found differences could majorly be attributable to the genetic factors of the olive cultivars. © 2010 American Chemical Society. Source

Bernardo D.,Imperial College London | Sanchez B.,Institute Productos Lacteos Of Asturias | Al-Hassi H.O.,Imperial College London | Mann E.R.,Imperial College London | And 3 more authors.

The human gastrointestinal tract is exposed to a huge variety of microorganisms, either commensal or pathogenic; at this site, a balance between immunity and immune tolerance is required. Intestinal dendritic cells (DCs) control the mechanisms of immune response/tolerance in the gut. In this paper we have identified a peptide (STp) secreted by Lactobacillus plantarum, characterized by the abundance of serine and threonine residues within its sequence. STp is encoded in one of the main extracellular proteins produced by such species, which includes some probiotic strains, and lacks cleavage sites for the major intestinal proteases. When studied in vitro, STp expanded the ongoing production of regulatory IL-10 in human intestinal DCs from healthy controls. STp-primed DC induced an immunoregulatory cytokine profile and skin-homing profile on stimulated T-cells. Our data suggest that some of the molecular dialogue between intestinal bacteria and DCs may be mediated by immunomodulatory peptides, encoded in larger extracellular proteins, secreted by commensal bacteria. These peptides may be used for the development of nutraceutical products for patients with IBD. In addition, this kind of peptides seem to be absent in the gut of inflammatory bowel disease patients, suggesting a potential role as biomarker of gut homeostasis. © 2012 Bernardo et al. Source

Margolles A.,Institute Productos Lacteos Of Asturias | Sanchez B.,Institute Productos Lacteos Of Asturias
Applied and Environmental Microbiology

We have characterized a new strain, Bifidobacterium animalis subsp. lactis CECT 7953, obtained by random UV mutagenesis, which produces less acetic acid than the wild type (CECT 7954) in three different experimental settings: De Man-Rogosa-Sharpe broth without sodium acetate, resting cells, and skim milk. Genome sequencing revealed a single Phe-Ser substitution in the acetate kinase gene product that seems to be responsible for the strain's reduced acid production. Accordingly, acetate kinase specific activity was lower in the low acetate producer. Strain CECT 7953 produced less acetate, less ethanol, and more yoghourt-related volatile compounds in skim milk than the wild type did. Thus, CECT 7953 shows promising potential for the development of dairy products fermented exclusively by a bifidobacterial strain. © 2012, American Society for Microbiology. Source

Alvarez M.A.,Institute Productos Lacteos Of Asturias | Moreno-Arribas M.V.,Institute Investigacion En Ciencias Of La Alimentacion Cial
Trends in Food Science and Technology

Biogenic amines (BA) are low-molecular-weight nitrogenous organic bases, which can accumulate in high concentration in food due to microbial activity and cause toxic effects in consumers. In some fermented foods it is difficult to prevent the accumulation of BA since the microbiological/chemical/physical conditions of the fermentation can not be easily modified. An alternative in such cases is the use of food microorganisms that are able to degrade BA once they have been synthesized in the food matrix. In this review, we examine the microorganisms that have demonstrated the ability to degrade BA and their technological relevance in fermented foods. © 2014 . Source

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