title: Proteomic characterization of a selenium-metabolizing probiotic Lactobacillus reuteri Lb26 BM for nutraceutical applications.
abstract: Selenium (Se), Se-cysteines and selenoproteins have received growing interest in the nutritional field as redox-balance modulating agents. The aim of this study was to establish the Se-concentrating and Se-metabolizing capabilities of the probiotic Lactobacillus reuteri Lb26 BM, for nutraceutical applications. A comparative proteomic approach was employed to study the bacteria grown in a control condition (MRS modified medium) and in a stimulated condition (4.38 mg/L of sodium selenite). The total protein extract was separated into two pI ranges: 4-7 and 6-11; the 25 identified proteins were divided into five functional classes: (i) Se metabolism; (ii) energy metabolism; (iii) stress/adhesion; (iv) cell shape and transport; (v) proteins involved in other functions. All the experimental results indicate that L. reuteri Lb26 BM is able to metabolize Se(IV), incorporating it into selenoproteins, through the action of a selenocysteine lyase, thus enhancing organic Se bioavailability. This involves endo-ergonic reactions balanced by an increase of substrate-level phosphorylation, chiefly through lactic fermentation. Nevertheless, when L. reuteri was grown on Se a certain degree of stress was observed, and this has to be taken into account for future applicative purposes. The proteomic approach has proven to be a powerful tool for the metabolic characterization of potential Se-concentrating probiotics.
authors.affiliation: Dipartimento di Biologia Animale e dell'Uomo, University of Torino, Torino, Italy.
authors.forename: Cristina
authors.initials: C
authors.lastname: Lamberti
authors.forename: Erika
authors.initials: E
authors.lastname: Mangiapane
authors.forename: Alessandro
authors.initials: A
authors.lastname: Pessione
authors.forename: Roberto
authors.initials: R
authors.lastname: Mazzoli
authors.forename: Carlo
authors.initials: C
authors.lastname: Giunta
authors.forename: Enrica
authors.initials: E
authors.lastname: Pessione
mesh_terms: D000975:Antioxidants / Q000378:metabolism; D001426:Bacterial Proteins / Q000737:chemistry / Q000145:classification / Q000378:metabolism; D050260:Carbohydrate Metabolism; D002448:Cell Adhesion; D048430:Cell Shape; D015180:Electrophoresis, Gel, Two-Dimensional; D006863:Hydrogen-Ion Concentration; D007526:Isoelectric Point; D052200:Limosilactobacillus reuteri / Q000737:chemistry* / Q000166:cytology / Q000378:metabolism; D053858:Metabolic Networks and Pathways; D046529:Microscopy, Electron, Transmission; D019936:Probiotics; D040901:Proteomics / Q000379:methods*; D012643:Selenium / Q000378:metabolism*; D013312:Stress, Physiological
chemical_list: D000975:Antioxidants; D001426:Bacterial Proteins; D012643:Selenium