title: Proteomic analysis of responses of a new probiotic bacterium Lactobacillus casei Zhang to low acid stress.
abstract: Tolerance to acid is an important feature for probiotic bacteria during transition through the gastrointestinal tract. Proteomics analysis of a new probiotic bacterium, Lactobacillus casei Zhang, was performed upon 30-min exposure to low acid stress (pH 2.5 vs. pH 6.4) using two-dimensional electrophoresis. Out of 33 protein spots that showed changes of expression between the two pHs, 22 showed 1.5-fold higher expression at pH 2.5 than at pH 6.4, whereas five spots had expression decreased by 1.5-fold at pH 2.5. There were also six protein spots that were exclusively present on different pH maps. Further analysis showed that eight of the enhanced proteins, NagA, NagB, PGM, GlmM, LacC, TDP, GALM and PtsI, were involved in carbohydrate catabolism. Moreover, quantitative RT-PCR showed that the mRNA expression levels of dnaK, nagB, galm, estC, tuf and luxS were consistent with changes in protein expression. We postulate that there might be some relationship between differentially expressed proteins and acid tolerance in L. casei Zhang.
authors.affiliation: College of Food Science, Shenyang Agricultural University, Shenyang 110866, PR China.
authors.forename: Rina
authors.initials: R
authors.lastname: Wu
authors.forename: Wenyi
authors.initials: W
authors.lastname: Zhang
authors.forename: Tiansong
authors.initials: T
authors.lastname: Sun
authors.forename: Junrui
authors.initials: J
authors.lastname: Wu
authors.forename: Xiqing
authors.initials: X
authors.lastname: Yue
authors.forename: He
authors.initials: H
authors.lastname: Meng
authors.forename: Heping
authors.initials: H
authors.lastname: Zhang
mesh_terms: D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism*; D006863:Hydrogen-Ion Concentration; D007780:Lacticaseibacillus casei / Q000187:drug effects* / Q000235:genetics / Q000378:metabolism; D019936:Probiotics; D020543:Proteome / Q000378:metabolism*; D040901:Proteomics; D012333:RNA, Messenger / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction; D013312:Stress, Physiological
chemical_list: D001426:Bacterial Proteins; D020543:Proteome; D012333:RNA, Messenger