Identification and Immunological Activities of Exopolysaccharide Produced by Pediococcus pentosaceus Isolated from Thai Fermented Pork

• Main Authors: Nuttapoom Noomhorm, 許文俊
• Other Authors: Tzou-Chi Huang
• Format: Others
• Published: 2013
• Online Access: http://ndltd.ncl.edu.tw/handle/31623909759711299944

碩士 === 國立屏東科技大學 === 熱帶農業暨國際合作系 === 101 === Pediococcus pentosaceus, isolated from Thai fermented pork products, was identified and characterized for its exopolysaccharide and tested for its immunomodulatory ability. The exopolysaccharide (EPS) is the metabolite of lactic acid bacteria that has recently gained wide interest since they play key roles in therapeutic agents and possess a wide range of biological functions such as anti-tumor, immunomodulation, and antioxidation properties. In this study, EPS-producing P. pentosaceus strain was isolated from Thai fermented pork. Based on morphological, physiological characteristics and phylogenetic of 16S rDNA sequences the purified strain was characterized as P. pentosaceus. Then, a crude enzyme, prepared from purified P. pentosaceus, was incubated with sucrose solution for the enzymatic synthesis of the polysaccharide. The crude polysaccharide was isolated from the reacted broth and purified by ethanol precipitation and dialysis. Analysis showed that the EPS was homopolysaccharide with glucose as the major component. Its chemical structure was determined by FT-IR and nuclear magnetic resonance spectroscopy (1H NMR and 13C NMR), data indicated that the EPS contained D-glucose residues with a linear backbone of α-(1 4) having branched of α-(1 6) linkage. The immunomodulatory ability was tested with a murine macrophage cell line, RAW 264.7 cells. The results indicated that EPS was non-toxic and stimulated pseudopodia growth of macrophage cell. Also, EPS significantly increased the production of nitric oxide (NO) and TNF-α in a dose-dependent manner (50–200 μg/mL). Furthermore, EPS dose-dependently enhanced the expression of costimulatory molecules, CD80 and CD86, and major histocompatibility complex (MHC) molecules II. Additionally, confocal microscopic analysis demonstrated that EPS (100 μg/mL) induced the translocation of p65 molecules of nuclear factor-κB (NF-κB) from the cytosol into the nucleus after 60 min treatment. Taken together, the results confirmed that EPS produced by P. pentosaceus possess potent immunomodulatory activity on macrophage lineage cells though the NF- κB signaling pathways.