title: Bio-transformation of selenium in Se-enriched bacterial strains of Lactobacillus casei.
abstract: BACKGROUND
  Selenium is an element of very great importance for the proper functioning of the human body, mainly due to its antioxidant properties. Selenium exhibits a preventive effect in the case of cardiovascular disease, the immune system, male infertility and inhibits the toxic action of other agents. Selenium is important for Hashimoto's disease. Intake of selenium in the diet slows the aging process. The biological and toxicological effects of selenium strongly depend on its chemical form. Some organisms for example: plant, yeast, are capable of metabolizing low bioavailable selenium compounds (inorganic selenium) into its high bioavailable forms (organic selenium).
  
  
  OBJECTIVE
  The aim of this study was to investigate the bio-transformation of selenium by Lactobacillus bacteria towards the characterisation of selenium metabolites.
  
  
  METHODS
  The speciation of selenium was evaluated by high performance liquid chromatography with inductively coupled plasma mass spectrometry detector. The extraction of selenium species from lyophilized bacteria was executed with water, the mixture of lipase and protease, as well as lisozyme and sodium dodecyl sulphate.
  
  
  RESULTS
  All investigated bacteria strains cultivated in the presence of Na2SeO3 effectively uptake selenium. Surprisingly, none of the applied extraction media exhibited a strong power to release the majority of the uptaken selenium compounds. Thus a maximum of 10% of the selenium was extracted from bacteria exposed to the enzymes. However, it was found that Lactobacillus bacteria are able to metabolize inorganic ions of selenium (IV) into Se-methionine, Se-methyloselenocysteine and other unidentified forms.
  
  
  CONCLUSIONS
  The study confirmed the ability of probiotic bacteria to biotransform inorganic selenium into its organic derivatives. Therefore, Se-enriched bacteria can be considered as an addition to the functional food.
  
  
  BACKGROUND
  selenium speciation, extraction procedure, Lactobacillus casei bacteria, Lactic acid bacteria (LAB), HPLC ICP-MS, functional food.
authors.affiliation: University of Warsaw, Biological and Chemical Research Centre, Żwirki i Wigury 101 street, 02-089 Warsaw, Poland.
authors.forename: Eliza
authors.initials: E
authors.lastname: Kurek
authors.affiliation: University of Warsaw, Biological and Chemical Research Centre, Żwirki i Wigury 101 street, 02-089 Warsaw, Poland.|University of Warsaw, Faculty of Chemistry, Pasteura 1 street, 02-093 Warsaw, Poland.
authors.forename: Anna
authors.initials: A
authors.lastname: Ruszczyńska
authors.affiliation: University of Warsaw, Biological and Chemical Research Centre, Żwirki i Wigury 101 street, 02-089 Warsaw, Poland.|University of Warsaw, Faculty of Chemistry, Pasteura 1 street, 02-093 Warsaw, Poland.
authors.forename: Marcin
authors.initials: M
authors.lastname: Wojciechowski
authors.affiliation: University of Warsaw, Biological and Chemical Research Centre, Żwirki i Wigury 101 street, 02-089 Warsaw, Poland.
authors.forename: Anna
authors.initials: A
authors.lastname: Łuciuk
authors.affiliation: University of Warsaw, Biological and Chemical Research Centre, Żwirki i Wigury 101 street, 02-089 Warsaw, Poland.
authors.forename: Magdalena
authors.initials: M
authors.lastname: Michalska-Kacymirow
authors.affiliation: Lodz University of Technology, Faculty of Biotechnology and Food Sciences, Wolczanska 171/173 street, 90-924 Łodz, Poland.
authors.forename: Ilona
authors.initials: I
authors.lastname: Motyl
authors.affiliation: University of Warsaw, Biological and Chemical Research Centre, Żwirki i Wigury 101 street, 02-089 Warsaw, Poland.|University of Warsaw, Faculty of Chemistry, Pasteura 1 street, 02-093 Warsaw, Poland.
authors.forename: Ewa
authors.initials: E
authors.lastname: Bulska
mesh_terms: D002851:Chromatography, High Pressure Liquid; D043302:Cultured Milk Products / Q000382:microbiology; D003611:Dairy Products / Q000382:microbiology*; D006801:Humans; D007778:Lactobacillus / Q000378:metabolism*; D012441:Saccharomyces cerevisiae / Q000378:metabolism*; D012643:Selenium / Q000378:metabolism*
chemical_list: D012643:Selenium