CRB of agar-cultured AA L. crispatus strains were ≥ 50% than E. coli MC4 100 at 37 °C (Fig. 1a and f). CRB of lactobacilli was growth-temperature-dependent and significantly higher (P < 0.05) for strains grown at 37 °C than Trichostatin A at 30 °C (data not shown). CRB of L. crispatus 12005, L. rhamnosus GG, L. paracasei F8, L. plantarum F44, L. paracasei F19, and E. coli MC4 100 increased at a low pH and at a high ionic strength except for L. paracasei F8 at pH 3 and 4 (Fig. 2c). CRB of all five strains and E. coli MC4 100 was reduced significantly in the presence of 100 μg mL−1 of cholesterol
(Fig. 2). CRB was more than 95% for E. coli MC4 100 at high ionic strength combined with a low pH (3–4) and was completely inhibited in the presence of cholesterol at pH 3 and reduced to 10% at pH 8.0 (Fig. 2a–f). Pretreatment with proteolytic enzymes significantly reduced CRB of all five lactobacilli strains, including the S-layer-producing strain L. crispatus 12005 (Table 2). CRB by L. plantarum F44, L. paracasei F8, L. crispatus 12005 and L. paracasei F19 cells was significantly enhanced when these strains were grown in MRS with 0.5% TA (P < 0.05) Selleck JQ1 or 5% PB (P < 0.05) compared with cells grown in the MRS broth. The CRB of the L. paracasei F8 and L. paracasei F19 strains was significantly
enhanced with 0.25% mucin (P < 0.05), unlike L. rhamnosus 18243, which was unaltered when grown in MRS with bile or mucin. The SAT values of the less hydrophobic strains L. rhamnosus 18243, L. plantarum F44 and L. paracasei F19 dropped from 3.2 to 0.02 M, that is the cells were more hydrophobic when grown in MRS with 0.25% mucin, 0.5% TA or 5% PB, indicating an enhanced CSH in gut-simulated conditions (Fig. 3a–c). Three non-AA strains, L. rhamnosus 18243, L. plantarum F44 and L. paracasei F19, expressing
high CSH showed a dense biofilm formation when grown in MRS broth with either 5% PB or 0.5% TA compared Rucaparib in vitro with cells grown in MRS broth alone or in this broth with 0.25% mucin (Fig. 4a–c). The AA strains L. paracasei F8 and L. crispatus 12005 formed biofilm in MRS broth alone and MRS broth with 0.25% mucin (Fig. 4). Growth in MRS with 0.5% TA or 5% PB significantly reduced biofilm formation of the two AA strains (Fig. 4d and e). However, in the presence of 0.5% TA, the CRB ability of L. crispatus 12005 was significantly increased, and therefore the biofilm formation was increased (P < 0.05). Biofilm-forming lactobacilli strains, except L. paracasei F8, bound significantly (P < 0.05) more CR when cells were grown in MRS with 0.5% TA. Biofilm formation of five lactobacilli strains was studied after 24 and 72 h of growth (Fig. 5a). The AA strain L. crispatus 12005 showed higher biofilm formation with 0.5% TA and 5% PB stained with CR after 24 and 72 h of growth. The other four strains bound CR significantly more after 24 h in MRS with 0.5% TA compared with 72 h, and the CRB was similar for biofilm-forming cells after 24 and 72 h growth in MRS with 5% PB.