Abstract:

His-N2 protein, consisting of two domains at the N terminus of Lactobacillus plantarum KLDS 1.0320 adhesion
surface protein NP_785232, was selected as the candidate in this work. This protein was used to explore the exclusive
inhibition against E. coli DH5α adhesion to porcine intestinal mucus in vitro. First, porcine mucus was fixed on 96-well cell
plates and incubated at 37 ℃ for 1 h after adding His-N2 protein, and then the solution containing E. coli DH5α was added.
After co-incubation at 37 ℃ for 1 h, the mucus was washed and disrupted with 1% Triton X-100. Ten-fold dilutions of the
cell lysates were prepared and spread on LB agar plates for counting of E.coli DH5α. Results indicated that His-N2 protein
could inhibit the adhension of E. coli DH5α to porcine intestinal mucus by (50.37 ± 3.66)% compared with PBS and by
(38.33% ± 4.55)% compared with BSA protein at pH 6.6, while the inhibitory rates were (42.18 ± 3.44)% and
(34.48 ± 3.90)% at pH 7.5, respectively. Therefore, His-N2 protein is involved in the exclusive inhibition of E. coli DH5α
adhersion to porcine intestinal mucus in vitro.

Key words: Lactobacillus plantarum, His-N2 protein, E. coli DH5α, porcine mucus, exclusive inhibition