title: Investigation of Growth Phase-Dependent Acid Tolerance in Bifidobacteria longum BBMN68.
abstract: The underlying mechanisms imparting the growth phase-dependent acid tolerance have not been extensively investigated. In this study, we compared the acid resistance of the Bifidobacterium longum strain BBMN68 from different growth phases at lethal pH values (pH 2.5, 3.0, and 3.5), and analyzed the activity of H(+)-ATPase, the composition of fatty acids, and the mRNA abundance of ffh, uvrA, recA, lexA, groES, and dnaK in cells from different growth phases. The results indicated that the survival rates of cells from early stationary (ES) and late stationary (LS) growth phases at lethal pH values were significantly higher than those of exponential growth phase cells. Our findings indicated that by inducing a continuously auto-acidizing environment during cell growth, the acid resistance of ES and LS cells was strengthened. The higher activity of H(+)-ATPase, the decrease in unsaturated fatty acids, and the increased expression of genes involved in DNA repair and protein protection in the cells in stationary growth phase were all implicated in the significantly increased acid resistance of ES and LS cells compared with exponential growth phase cells of the B. longum strain BBMN68.
authors.affiliation: Food Science and Engineering College, Beijing University of Agriculture, Beijing Laboratory of Food Quality and Safety, Beijing Key Laboratory of Detection and Control of Spoilage Organisms and Pesticide Residues in Agricultural Products, Beijing Engineering Laboratory of Probiotics Key Technology Development, Beijing, 102206, China. jinjunhua002008@163.com.|The Innovation Centre of Food Nutrition and Human Health (Beijing), College of Food Science and Nutritional Engineering, China Agriculture University, Beijing, 100083, China. jinjunhua002008@163.com.
authors.forename: Junhua
authors.initials: J
authors.lastname: Jin
authors.affiliation: Food Science and Engineering College, Beijing University of Agriculture, Beijing Laboratory of Food Quality and Safety, Beijing Key Laboratory of Detection and Control of Spoilage Organisms and Pesticide Residues in Agricultural Products, Beijing Engineering Laboratory of Probiotics Key Technology Development, Beijing, 102206, China.
authors.forename: Jingyi
authors.initials: J
authors.lastname: Song
authors.affiliation: The Innovation Centre of Food Nutrition and Human Health (Beijing), College of Food Science and Nutritional Engineering, China Agriculture University, Beijing, 100083, China.|Beijing Higher Institution Engineering Research Center of Animal Product, Beijing, 100083, China.
authors.forename: Fazheng
authors.initials: F
authors.lastname: Ren
authors.affiliation: Food Science and Engineering College, Beijing University of Agriculture, Beijing Laboratory of Food Quality and Safety, Beijing Key Laboratory of Detection and Control of Spoilage Organisms and Pesticide Residues in Agricultural Products, Beijing Engineering Laboratory of Probiotics Key Technology Development, Beijing, 102206, China.
authors.forename: Hongxing
authors.initials: H
authors.lastname: Zhang
authors.affiliation: Food Science and Engineering College, Beijing University of Agriculture, Beijing Laboratory of Food Quality and Safety, Beijing Key Laboratory of Detection and Control of Spoilage Organisms and Pesticide Residues in Agricultural Products, Beijing Engineering Laboratory of Probiotics Key Technology Development, Beijing, 102206, China.
authors.forename: Yuanhong
authors.initials: Y
authors.lastname: Xie
authors.affiliation: Food Science and Engineering College, Beijing University of Agriculture, Beijing Laboratory of Food Quality and Safety, Beijing Key Laboratory of Detection and Control of Spoilage Organisms and Pesticide Residues in Agricultural Products, Beijing Engineering Laboratory of Probiotics Key Technology Development, Beijing, 102206, China.
authors.forename: Jingsheng
authors.initials: J
authors.lastname: Ma
authors.affiliation: Food Science and Engineering College, Beijing University of Agriculture, Beijing Laboratory of Food Quality and Safety, Beijing Key Laboratory of Detection and Control of Spoilage Organisms and Pesticide Residues in Agricultural Products, Beijing Engineering Laboratory of Probiotics Key Technology Development, Beijing, 102206, China.
authors.forename: Xue
authors.initials: X
authors.lastname: Li
mesh_terms: D000143:Acids / Q000378:metabolism*; D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism; D000069978:Bifidobacterium longum / Q000235:genetics / Q000254:growth & development* / Q000378:metabolism*; D015964:Gene Expression Regulation, Bacterial; D006863:Hydrogen-Ion Concentration; D050296:Microbial Viability
chemical_list: D000143:Acids; D001426:Bacterial Proteins