Inhibition of Shigella sonnei adherence to HT-29 cells by lactobacilli from Chinese fermented food and preliminary characterization of S-layer protein involvement

• Published in: Research in microbiology 2010-10, Vol.161 (8), p.667-672
• Main Authors: Zhang, Ying-Chun, Zhang, Lan-Wei, Tuo, Yan-Feng, Guo, Chun-Feng, Yi, Hua-Xi, Li, Jing-Yan, Han, Xue, Du, Ming
• Format: Article
• Language: English
• Subjects: Amino Acids - analysis; Antibiosis; Bacterial Adhesion; Bacterial Proteins - physiology; Bacteriology; Biological and medical sciences; China; Electrophoresis, Polyacrylamide Gel; Fermentation; Food Microbiology; Fundamental and applied biological sciences. Psychology; HT29 Cells; Humans; Inhibition adhesion; Intestinal Mucosa - microbiology; Lactobacilli; Lactobacillus - isolation & purification; Lactobacillus - physiology; Lactobacillus casei; Lactobacillus paracasei; Lactobacillus rhamnosus; Membrane Glycoproteins - physiology; Microbiology; Miscellaneous; S-layer proteins; Shigella sonnei; Shigella sonnei - physiology; Tibet
• ISSN: 0923-2508; 1769-7123
• DOI: 10.1016/j.resmic.2010.06.005

In this study, seven lactobacilli with a high degree of antagonistic activity against three pathogens and good adherence to HT-29 cells were selected. The ability of these seven lactobacilli to inhibit adhesion of Shigella sonnei to intestinal mucosa was studied on cultured HT-29 cells. Lactobacilli were added simultaneously with, before or after S. sonnei to test for their effectiveness in exclusion, competition and displacement assays, respectively. Lactobacillus paracasei subp . paracasei M5-L, Lactobacillus rhamnosus J10-L and Lactobacillus casei Q8-L all exhibited significant inhibitory activity. In order to elucidate the inhibitory functions of S-layer proteins, the S-layer proteins were removed with 5 M LiCl from the M5-L, J10-L and Q8-L strains. Under such conditions, inhibition activity was decreased in all three strains, as revealed in exclusion, competition and displacement assays. SDS-PAGE analysis confirmed the presence of S-layer proteins with dominant bands of approximately 45 kDa. Further analysis of S-layer proteins revealed that the hydrophobic amino acids accounted for 40.5%, 41.5% and 43.8% of the total amino acid for the M5-L, J10-L and Q8-L strains, respectively. These findings suggest that the M5-L, J10-L and Q8-L strains possess the ability to inhibit S. sonnei adherence to HT-29 cells, and S-layer proteins are involved in this adhesion inhibition.