Impact of luxS and suppressor mutations on the gastrointestinal transit of Lactobacillus rhamnosus GG.
It is generally believed that probiotic bacteria need to survive gastrointestinal transit to exert a health-promoting effect. In this study, a genuine luxS mutant and a luxS mutant containing unknown suppressor mutations of the probiotic strain Lactobacillus rhamnosus GG were compared to the wild type for survival and persistence in the murine gastrointestinal tract. The LuxS enzyme, catalyzing the production of the autoinducer-2 signaling molecule, also forms an integral part of the activated methyl cycle and the metabolism of methionine and cysteine. The genuine luxS mutant CMPG5412 showed drastically reduced persistence in mice, which was related to less survival in simulated gastric juice, indicating that LuxS metabolism is crucial for the gastric stress resistance of L. rhamnosus GG. The suppressor mutations in the other luxS mutant, CMPG5413, appear to compensate for the metabolic defects of the luxS mutation and to restore the resistance to gastric juice but cause a defect in adherence, biofilm formation, and exopolysaccharide production. The shorter residence time of this suppressor mutant in the murine gastrointestinal tract indicates a role for biofilm formation and exopolysaccharides in the persistence capacity of L. rhamnosus GG.
Lebeer
Sarah
S
Centre of Microbial and Plant Genetics, Katholieke Universiteit Leuven, Kasteelpark Arenberg 20, 3001 Leuven, Belgium.
Claes
Ingmar J J
IJ
Verhoeven
Tine L A
TL
Shen
Chong
C
Lambrichts
Ivo
I
Ceuppens
Jan L
JL
Vanderleyden
Jos
J
De Keersmaecker
Sigrid C J
SC
D000818:Animals; D001426:Bacterial Proteins / Q000235:genetics*; D018441:Biofilms; D013437:Carbon-Sulfur Lyases / Q000235:genetics*; D017931:DNA Primers; D005750:Gastric Juice / Q000382:microbiology; D041981:Gastrointestinal Tract / Q000382:microbiology*; D005772:Gastrointestinal Transit; D006801:Humans; D052201:Lacticaseibacillus rhamnosus / Q000235:genetics* / Q000302:isolation & purification; D051379:Mice; D008807:Mice, Inbred BALB C; D009154:Mutation; D010957:Plasmids; D016133:Polymerase Chain Reaction; D013489:Suppression, Genetic
D001426:Bacterial Proteins; D017931:DNA Primers; D013437:Carbon-Sulfur Lyases; C117753:LuxS protein, Bacteria