This study was performed to determine the effects of bacteriocin-producing and non-bacteriocin-producing Pediococcus acidilactici strains on the immune system and intestinal flora of normal mice.Two P.acidilactici str...This study was performed to determine the effects of bacteriocin-producing and non-bacteriocin-producing Pediococcus acidilactici strains on the immune system and intestinal flora of normal mice.Two P.acidilactici strains with antibacterial activity(P.acidilactici CCFM28 and CCFM18)were obtained based on the inhibition-zone assay.The produced components were identified as bacteriocins through protease treatment,pH adjustment and hydrogen peroxide treatment.Bacteriocin-producing and non-bacteriocin-producing P.acidilactici strains(P.acidilactici CCFM28,CCFM18 and NT17-3)caused significant changes in serum immune factors and intestinal flora of normal mice.After 14 days of intervention,the relative abundance of Firmicutes was significantly decreased,but that of Proteobacteria was significantly increased at the phylum level.At the genus level,the administration of three P.acidilactici strains resulted in the downregulation of Blautia and the upregulation of Ruminococcus and Lactobacillus.Furthermore,there were also different regulations on some probiotic strains,such as Bifidobacterium,Coprococcus and Akkermansia,which were closely related to the antibacterial ability of the bacteriocin and the type of strain.The results indicated that the intervention of different P.acidilactici strains could differently change the structure of intestinal flora in normal mice,which provided theoretical guidance for the selective use of bacteriocin-producing strains for health regulation in the future.展开更多
Two lactic acid bacteria strains (At1BEAE22 and At344E21) isolated during tchapalo production were identified on the basis of phenotypic analyses. Bacteriocins produced by these strains were tested for their antimicro...Two lactic acid bacteria strains (At1BEAE22 and At344E21) isolated during tchapalo production were identified on the basis of phenotypic analyses. Bacteriocins produced by these strains were tested for their antimicrobial activities using well diffusion agar method. Heat resistance, pH sensitivity and enzyme treatments were also analyzed. Results showed that both lactic acid bacteria strains were identified as Pediococcus acidilactici. Their bacteriocins inhibited growth of Lactobacillus delbrueckii F/31, Listeria innocua ATCC 33090, Enterococcus faecalis, Enterococcus faecalis ATCC 29212, Streptococcus sp, Enterococcus faecalis CIP 105042 and Enterococcus faecium ATCC 51558. These bacteriocins were heat stable at 60°C for 30 min for all indicator bacteria. However, they remained active only against Lactobacillus delbrueckii and Listeria innocua at 121°C for 60 min. Moreover, they were active in a wide range of pH (3 to 9) with a maximum activity observed at pH 5 and 6 on all indicator bacteria. But, bacteriocin from Pediococcus acidilactici At34E21 was more stable at acidic pH than basic one. The fact that the bacteriocin was inactivated by proteinase K and α-chymotrypsin indicated its proteinaceous nature, a general characteristics of bacteriocins.展开更多
基金supported by the National Natural Science Foundation of China Program(32021005)the Natural Science Foundation of Jiangsu Province(BK20200084)+2 种基金Projects of Innovation and Development Pillar Program for Key Industries in Southern Xinjiang of Xinjiang Production and Construction Corps(2018DB002)National First Class Discipline Program of Food Science and Technology(JUFSTR20180102)the Collaborative Innovation Center of Food Safety and Quality Control in Jiangsu Province。
文摘This study was performed to determine the effects of bacteriocin-producing and non-bacteriocin-producing Pediococcus acidilactici strains on the immune system and intestinal flora of normal mice.Two P.acidilactici strains with antibacterial activity(P.acidilactici CCFM28 and CCFM18)were obtained based on the inhibition-zone assay.The produced components were identified as bacteriocins through protease treatment,pH adjustment and hydrogen peroxide treatment.Bacteriocin-producing and non-bacteriocin-producing P.acidilactici strains(P.acidilactici CCFM28,CCFM18 and NT17-3)caused significant changes in serum immune factors and intestinal flora of normal mice.After 14 days of intervention,the relative abundance of Firmicutes was significantly decreased,but that of Proteobacteria was significantly increased at the phylum level.At the genus level,the administration of three P.acidilactici strains resulted in the downregulation of Blautia and the upregulation of Ruminococcus and Lactobacillus.Furthermore,there were also different regulations on some probiotic strains,such as Bifidobacterium,Coprococcus and Akkermansia,which were closely related to the antibacterial ability of the bacteriocin and the type of strain.The results indicated that the intervention of different P.acidilactici strains could differently change the structure of intestinal flora in normal mice,which provided theoretical guidance for the selective use of bacteriocin-producing strains for health regulation in the future.
文摘Two lactic acid bacteria strains (At1BEAE22 and At344E21) isolated during tchapalo production were identified on the basis of phenotypic analyses. Bacteriocins produced by these strains were tested for their antimicrobial activities using well diffusion agar method. Heat resistance, pH sensitivity and enzyme treatments were also analyzed. Results showed that both lactic acid bacteria strains were identified as Pediococcus acidilactici. Their bacteriocins inhibited growth of Lactobacillus delbrueckii F/31, Listeria innocua ATCC 33090, Enterococcus faecalis, Enterococcus faecalis ATCC 29212, Streptococcus sp, Enterococcus faecalis CIP 105042 and Enterococcus faecium ATCC 51558. These bacteriocins were heat stable at 60°C for 30 min for all indicator bacteria. However, they remained active only against Lactobacillus delbrueckii and Listeria innocua at 121°C for 60 min. Moreover, they were active in a wide range of pH (3 to 9) with a maximum activity observed at pH 5 and 6 on all indicator bacteria. But, bacteriocin from Pediococcus acidilactici At34E21 was more stable at acidic pH than basic one. The fact that the bacteriocin was inactivated by proteinase K and α-chymotrypsin indicated its proteinaceous nature, a general characteristics of bacteriocins.
基金Supported by the National Key Technology Research and Development Program of the Ministry of Science and Technology of China (2015BAD16B01)Tianjin Key Technology Research and Development Support Program (13ZCDNC01900)
