TABLE 5.

Genetic factors shown to contribute toward ecological performance of lactobacilli in the gut of mice

Loci	Protein encoded	Strain	Why studied?	Putative function in the GIT	Reference
lsp	Large surface protein	L. reuteri 100-23Ca	Dominant surface protein	Adherence	102
msrB	Methionine sulfoxide reductase B	L. reuteri 100-23C	Gene expression specifically induced in vivo	Reduction of oxidized methionine residues, resistance to nitric oxide produced by epithelial cells	102
luxS	LuxS	L. reuteri 100-23C	Importance of AI-2 on the formation of biofilms by gram-positive bacteria	Quorum sensing (AI-2) production/metabolic importance as part of activated methyl cycle	95
dltA	d-Alanine-d-alanyl carrier protein ligase (Dcl)	L. reuteri 100-23	Importance of the dlt operon for biofilm formation and adhesion of gram-positive bacteria	Resistance against low pH values and defensins	105
gtfA	Glycosyltransferase A	L. reuteri TMW1.106	Importance of EPS for bacterial biofilm formationb	Cell aggregation, biofilm formation	106
inu	Inulosucrase	L. reuteri TMW1.106	Importance of EPS for bacterial biofilm formationb	Cell aggregation, biofilm formation	106
LJ1680	IgA protease	L. johnsonii NCC533	In vivo expressed and associated with a long gut persistence phenotype	Degradation of IgA	19
LJ1654 to LJ1656	PTS transporter	L. johnsonii NCC533	In vivo expressed and associated with a long gut persistence phenotype	Sugar utilization	19

^aPlasmid-free variant of Lactobacillus reuteri 100-23.

^bEPS, extracellular polysaccharide.