title: In vivo imaging of Lactococcus lactis, Lactobacillus plantarum and Escherichia coli expressing infrared fluorescent protein in mice.
abstract: BACKGROUND
  In vivo imaging of orally administered lactic acid bacteria (LAB) and commensal bacteria in mice is shown to provide information on the spatial and temporal distribution of bacteria in the gastrointestinal tract. The bacteria can be detected and monitored using bioluminescence or near-infrared fluorescence.
  
  
  RESULTS
  Fluorescence imaging of bacteria was established by expressing the infrared fluorescent protein IRFP713 in Lactococcus lactis, Lactobacillus plantarum and Escherichia coli. All three bacterial species were monitored in live mice and no major differences in transit time were observed. Bacteria passed through the stomach and small intestine in 1 h and the majority were secreted from the large intestine after 6-8 h. Intestinal localization of bacteria was confirmed by imaging the isolated intestines and culturing the intestinal content. The use of fluorescence tomography for spatial localization of fluorescent bacteria has been established. The expression of an additional infrared fluorescent protein IRFP682 enabled concomitant detection of two bacterial populations in live mice.
  
  
  CONCLUSIONS
  The present work provides a methodological basis for future studies of probiotic and theranostic actions of LAB in mouse disease models.
authors.affiliation: Department of Biotechnology, Jožef Stefan Institute, Jamova 39, 1000, Ljubljana, Slovenia. ales.berlec@ijs.si.
authors.forename: Aleš
authors.initials: A
authors.lastname: Berlec
authors.affiliation: Department of Biochemistry and Molecular and Structural Biology, Jožef Stefan Institute, Jamova 39, 1000, Ljubljana, Slovenia. janja.zavrsnik@ijs.si.
authors.forename: Janja
authors.initials: J
authors.lastname: Završnik
authors.affiliation: Department of Biochemistry and Molecular and Structural Biology, Jožef Stefan Institute, Jamova 39, 1000, Ljubljana, Slovenia. miha.butinar@ijs.si.
authors.forename: Miha
authors.initials: M
authors.lastname: Butinar
authors.affiliation: Department of Biochemistry and Molecular and Structural Biology, Jožef Stefan Institute, Jamova 39, 1000, Ljubljana, Slovenia. boris.turk@ijs.si.|Centre of Excellence for Integrated Approaches in Chemistry and Biology of Proteins, Jamova 39, 1000, Ljubljana, Slovenia. boris.turk@ijs.si.|Faculty of Chemistry and Chemical Technology, University of Ljubljana, 1000, Ljubljana, Slovenia. boris.turk@ijs.si.
authors.forename: Boris
authors.initials: B
authors.lastname: Turk
authors.affiliation: Department of Biotechnology, Jožef Stefan Institute, Jamova 39, 1000, Ljubljana, Slovenia. borut.strukelj@ffa.uni-lj.si.|Faculty of Pharmacy, University of Ljubljana, Aškerčeva 7, 1000, Ljubljana, Slovenia. borut.strukelj@ffa.uni-lj.si.
authors.forename: Borut
authors.initials: B
authors.lastname: Štrukelj
mesh_terms: D000284:Administration, Oral; D000818:Animals; D004926:Escherichia coli / Q000378:metabolism*; D007422:Intestines / Q000382:microbiology / Q000473:pathology; D048191:Lactiplantibacillus plantarum / Q000378:metabolism*; D013294:Lactococcus lactis / Q000378:metabolism*; D008164:Luminescent Proteins / Q000235:genetics / Q000378:metabolism*; D051379:Mice; D061848:Optical Imaging; D059008:Time-Lapse Imaging
chemical_list: D008164:Luminescent Proteins