Detection and quantification of capsular exopolysaccharides from Streptococcus thermophilus using lectin probes.
The aim of this work was to use fluorescently labeled lectins to develop a convenient and reliable method to determine the relative abundance of capsular polysaccharides (CPS) at the surface of Streptococcus thermophilus MR-1C cells. Fluorescein isothiocyanate-labeled peanut agglutinin isolated from Arachis hypogaea was found to interact specifically with the CPS of Strep. thermophilus MR-1C. This labeled lectin was then used as an effective probe to detect and quantify CPS. A fluorescence-based lectin-binding assay was successfully applied to follow the accumulation of CPS during the growth of Strep. thermophilus MR-1C in milk and in M17 broth supplemented with lactose. Our results showed that in both media, CPS production by Strep. thermophilus MR-1C began during the exponential phase of growth and continued for several hours after the culture reached the stationary growth phase.
Robitaille
G
G
Food Research and Development Centre, Agriculture and Agri-Food Canada, Saint-Hyacinthe, Quebec, Canada, J2S 8E3. robitaillegi@agr.gc.ca
Moineau
S
S
St-Gelais
D
D
Vadeboncoeur
C
C
Britten
M
M
D000818:Animals; D010367:Arachis / Q000737:chemistry; D005452:Fluoresceins / Q000378:metabolism; D005456:Fluorescent Dyes / Q000032:analysis / Q000378:metabolism; D005690:Galactose; D006863:Hydrogen-Ion Concentration; D046529:Microscopy, Electron, Transmission / Q000379:methods; D008856:Microscopy, Fluorescence / Q000379:methods; D008892:Milk / Q000382:microbiology; D019887:Peanut Agglutinin / Q000378:metabolism; D011135:Polysaccharides, Bacterial / Q000032:analysis* / Q000378:metabolism; D048249:Streptococcus thermophilus / Q000254:growth & development / Q000502:physiology* / Q000648:ultrastructure; D013997:Time Factors; D014238:Trichloroacetic Acid
D005452:Fluoresceins; D005456:Fluorescent Dyes; D019887:Peanut Agglutinin; D011135:Polysaccharides, Bacterial; C098632:exopolysaccharide, Streptococcus; C468515:fluorescein isothiocyanate-peanut agglutinin; D014238:Trichloroacetic Acid; D005690:Galactose