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Characterization of adhesion property between Lactobacillus reuteri and milk phospholipids, and the gene expression of binding-promoting proteins.

L. Zhang

Abstract:

M9
Characterization of adhesion property between Lactobacillus reuteri and milk phospholipids, and the gene expression of binding-promoting proteins.
L. Zhang*, I. Garc�a-Cano, R. Jim�nez-Flores. Department of Food Science and Technology, The Ohio State University Columbus, OH.

Due to the beneficial effects of milk phospholipids (MPLs) and lactic acid bacteria (LAB), the application of using them as a combination is getting scientists' attention and has promoted research on analyzing their nutritional and functional properties. Recently, a strain-specific adhesion property between MPLs and LAB, especially Lactobacillus reuteri, was observed. This study aims to quantify such adhesion property and investigate its correlation to gene expression of 3 binding-promoting proteins: mucus adhesion-promoting protein (mapA), cell and mucus-binding protein A (cmbA) and collagen-binding protein (cnb). Out of 122 LAB cultivated in MPLs supplemented MRS medium, 27% demonstrated an adhesion property, 28% showed a “semi-adhesion” property, while the rest separated from the MPLs layer after incubation. It also indicated that the adhesion property was strain-specific −38% of LAB demonstrating the adhesion property with MPLs was L. reuteri. Six L. reuteri strains and 6 strains from other species were selected to quantify the adhesion property using a modified sucrose density gradient centrifugation method. Three binding-promoting proteins presented in L. reuteri were selected, and the gene expression of them in selected bacteria were analyzed using RT-qPCR in triplicates. The change of gene expression was calculated with the paired T-test. The criterion for significance was set at P < 0.05. Pearson correlation coefficient was used to evaluate the correlation between gene expression level and adhesion property. The result indicated that the gene expression level of all 3 proteins were not significantly changed by the addition of MPLs into MRS medium. However, in L. reuteri, the gene expression level of cmbA showed a significant correlation with the adhesion property. This study suggests that the addition of MPLs may not likely to affect the mucus adhesion property of LAB. Meanwhile, the combination of MPLs and L. reuteri with a high cmbA expression level might contribute to the delivery of MPLs into gut microbiota upon consumption.

Keywords: milk phospholipids, lactic acid bacteria, adhesion property.

Biography: Lin Zhang is a master student majoring in food science and technology in Dr. Rafael Jimenez-Flores′s lab at the Ohio State University. Her research is focusing on milk phospholipids and lactic acid bacteria.