The effect of saturated and unsaturated fatty acids on the production of outer membrane vesicles from Bacteroides fragilis and Bacteroides thetaiotaomicron

Abstract

Aim: The aim of present study is to investigate the effect of fatty acids on the outer membrane vesicles (OMVs) produced by Bacteroides spp.

Background: Bacteroides spp. is the important member of Gut microbiota that employ OMVs production for interact with host. Besides, dietary fatty acids could influence on determination of gut microbiota composition and immune response. In this regard, we evaluated the effect of fatty acids on the growth and OMVs production of Bacteroides fragilis and Bacteroides thetaiotaomicron.

Methods: B. fragilis and B. thetaiotaomicron were grown on BHI broth with and without palmitic and palmitoleic acids as saturated and unsaturated fatty acids, respectively. OMVs were extracted using multiple centrifugation and tris-ethylene diamine tetra acetic acid (EDTA)-Sodium deoxy cholate buffers. Physicochemical properties of OMVs were detected by electron microscopy (SEM), Bradford Coomassie brilliant blue assay and SDS-PAGE. Data were analyzed with One-way ANOVA using SPSS.

Results: The growths of both Bacteroides were significantly increased by palmitic acid. Nevertheless, palmitoleic acid had no significant effect on them. Palmitic acid significantly decreased and increased the production of B. fragilis OMVs at low and high concentration, respectively. However, the production of B. thetaiotaomicron OMVs was not significantly affected by palmitic acid. Although palmitoleic acid had a significant decreasing effect on the production of B. fragilis OMVs, it significantly increased the production of B. thetaiotaomicron OMVs at low concentration.

Conclusion: In conclusion we reported that palmitic acid had a stimulatory effect on the growth of B. fragilis and B. thetaiotaomicron and had a dose dependent effect on the production of B. fragilis OMVs. Also producing of B. thetaiotaomicron OMVs was affected by palmitoleic acid in a dose dependent manner.

Keywords: Bacteroides fragilis; Bacteroides thetaiotaomicron; Outer membrane vesicle; Palmitic acid; Palmitoleic acid.

Figure 1

Graph shows the OD values of B. fragilis ATCC23745 and B. taiotaomicron ATCC 10774 growths in BHI broth treated with palmitic acid. The horizontal and vertical axes show the concentration of Palmitoleic acid and the OD values of bacterial growth, respectively

Figure 2

Graph shows the OD values of B. fragilis ATCC23745 and B. thetaiotaomicron ATCC 10774 growths in BHI broth treated with Palmitoleic acid. The horizontal and vertical axes show the concentration of Palmitoleic acid and the OD values of bacterial growth, respectively

Figure 3

Graph shows the OD values of OMVs production by B. fragilis ATCC23745 and B. thetaiotaomicron ATCC 10774 in BHI broth supplemented with Palmitic acid. The horizontal and vertical axes show the concentration of Palmitoleic acid and the OD values of bacterial growth, respectively

Figure 4

Graph shows the OD values of OMVs production by B. fragilis ATCC23745 and B. thetaiotaomicron ATCC 10774 in BHI broth supplemented with Palmitoleic acid. The horizontal and vertical axes show the concentration of Palmitoleic acid and the OD values of bacterial growth, respectively

Figure 5

The protein profile of B. fragilis ATCC23745 and B. thetaiotaomicron ATCC 10774 derived OMVs which are produced in BHI broth supplemented with high and low concentration of palmitic acid. The protein profiles of OMVs from B. fragilis and B. thetaiotaomicron were compared using SDS-PAGE according to Claassen et al. (1996)

Figure 6

The protein profile of B. fragilis ATCC23745 and B. thetaiotaomicron ATCC 10774 derived OMVs which are produced in BHI broth supplemented with high and low concentration of palmitoleic acid. The protein profiles of OMVs from B. fragilis and B. thetaiotaomicron were compared using SDS-PAGE according to Claassen et al. (1996)