title: Differential analysis of protein expression of Bifidobacterium grown on different carbohydrates.
abstract: We observed recently that colonic fermentation of lactose might be a major factor in the pathophysiology of lactose intolerance. Proteomic techniques could be helpful in interpreting the metabolic pathways of lactose fermentation. The objective of this study was to explore proteomic methodologies for studying bacterial lactose metabolism that can be used to detect and identify proteins associated with the onset of intolerance symptoms. Differential expression of cytoplasmic proteins of Bifidobacterium animalis, Bifidobacterium breve and Bifidobacterium longum grown on different carbohydrates (lactose, glucose, galactose) was analyzed with surface-enhanced laser desorption ionization-time of flight (SELDI-TOF) MS and sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE). After fractionation by SDS-PAGE, differentially-expressed proteins were identified with LC-MS/MS. The three strains grown on the same carbohydrate or the same strain grown on glucose or lactose showed differences in SELDI-TOF MS protein profiles. Differences in protein expression were observed in B. breve grown on glucose, galactose or lactose as analyzed with SDS-PAGE. With LC-MS/MS, proteins from Bifidobacterium were identified, which included enzymes for metabolism of lactose, glucose and galactose. In conclusion, the applied techniques can discern differences in protein expression of bacteria metabolizing different carbohydrates. These techniques are promising in studying metabolism of lactose and other substrates in a complex bacterial ecosystem such as the colonic microbiota.
authors.affiliation: Center for Medical Biomics, Department of Medical Microbiology, University Medical Center Groningen, University of Groningen, Groningen, The Netherlands.
authors.forename: Tao
authors.initials: T
authors.lastname: He
authors.forename: Han
authors.initials: H
authors.lastname: Roelofsen
authors.forename: Gloria
authors.initials: G
authors.lastname: Alvarez-Llamas
authors.forename: Marcel
authors.initials: M
authors.lastname: de Vries
authors.forename: Koen
authors.initials: K
authors.lastname: Venema
authors.forename: Gjalt W
authors.initials: GW
authors.lastname: Welling
authors.forename: Roel J
authors.initials: RJ
authors.lastname: Vonk
mesh_terms: D001426:Bacterial Proteins / Q000096:biosynthesis* / Q000235:genetics; D001644:Bifidobacterium / Q000235:genetics / Q000378:metabolism*; D050260:Carbohydrate Metabolism / Q000502:physiology*; D002853:Chromatography, Liquid / Q000379:methods; D003470:Culture Media; D005690:Galactose / Q000378:metabolism; D005947:Glucose / Q000378:metabolism; D006801:Humans; D007785:Lactose / Q000378:metabolism; D007787:Lactose Intolerance / Q000378:metabolism / Q000382:microbiology; D040081:Protein Array Analysis / Q000379:methods; D040901:Proteomics / Q000379:methods*; D053719:Tandem Mass Spectrometry
chemical_list: D001426:Bacterial Proteins; D003470:Culture Media; D005947:Glucose; D007785:Lactose; D005690:Galactose