The anti-allergic activity of Lactobacillus plantarum L67 and its application to yogurt.

Recently, interest in the beneficial role of probiotics in the protection and management of allergic diseases caused by immune disorders has been increasing. This study investigated the inhibitory effect of Lactobacillus plantarum L67 on induced allergic inflammatory response in bisphenol A-treated rat basophilic leukemia 2H3 (RBL-2H3) cells and mouse splenocytes. We also evaluated the applicability of L. plantarum L67 as a yogurt starter culture. We measured the ability of Lactobacillus strains to induce the production of IL-12 and IFN- γ in cultured splenocytes by ELISA. Bisphenol A (50µM)-treated RBL-2H3 cells were cotreated with a glycoprotein (18kDa) isolated from L. plantarum L67 (5-100µg/mL) for 30min. We measured the expression of mitogen-activated protein kinase (ERK and p38), AP-1 (c-Fos and c-Jun), T-bet, and GATA-binding protein 3 (GATA-3) using Western blotting to examine the differentiation of T helper cells. Furthermore, we evaluated the gene expression of IL-1ß, IL-6, and IL-10 using real-time quantitative PCR. Finally, we evaluated the applicability of L. plantarum L67 as a yogurt starter by measuring pH, enumeration of bacteria, and sensory scores. Our results showed that L67 protein inhibited the phosphorylation of ERK and p38 mitogen-activated protein kinase through the transcriptional activation of AP-1 in bisphenol A-treated RBL-2H3 cells. During differentiation of T helper cells, the expression of transcription factor GATA-3 was significantly suppressed by L67 protein (100µg/mL) treatment, whereas expression of transcription factor T-bet was increased. In addition, the L67 protein significantly attenuated the expression of T helper 2-linked cytokines IL-1ß, IL-6, and IL-10. These results indicate that L. plantarum L67, made available as yogurt starters and dietary supplements, has the potential to prevent allergy-related immune disorders.

The proteins (12 and 15 kDa) isolated from heat-killed Lactobacillus plantarum L67 induces apoptosis in HT-29 cells.

A number of scientific studies have revealed that Lactobacillus strains have beneficial bioactivities in the gastrointestinal tract. In this study, the production of intracellular reactive oxygen species (ROS) and the amounts of intracellular calcium, protein kinase C activity, cytochrome c, Bid, Bcl-2, Bax and the apoptosis-mediated proteins [caspase-8, caspase-3 and poly ADP ribose polymerase (PARP)] were evaluated to understand the induction of programmed cell death in HT-29 cells by Lactobacillus plantarum L67. The results obtained from this study indicated that the relative intensities of the apoptotic-related factors (intracellular ROS and intracellular calcium) and of apoptotic signals (Bax and t-Bid) increased with increasing concentrations of the membrane proteins isolated from heat-killed L. plantarum L67, whereas the relative intensities of cytochrome c, Bcl-2, caspase-8, caspase-3 and PARP decreased. This study determines whether proteins (12 and 15 kDa) isolated from heat-killed L. plantarum L67 induce programmed cell death in HT-29 cells. Proteins isolated from L. plantarum L67 can stimulate the apoptotic signals and then consequently induce programmed cell death in HT-29 cells. The results in this study suggest that the proteins isolated from L. plantarum L67 could be used as an antitumoural agent in probiotics and as a component of supplements or health foods.

Bioactivity of proteins isolated from Lactobacillus plantarum L67 treated with Zanthoxylum piperitum DC glycoprotein.

Lactobacilli in the human gastrointestinal tract have beneficial effects on the health of their host. To enhance these effects, the bioactivity of lactobacilli can be fortified through exogenous dietary or pharmacological agents, such as glycoproteins. To elucidate the inductive effect of Zanthoxylum piperitum DC (ZPDC) glycoprotein on Lactobacillus plantarum L67, we evaluated the radical-scavenging activity, anti-oxidative enzymes (SOD, GPx and CAT), growth rate, ATPase activity and ß-galactosidase activity of this strain. When Lact. plantarum L67 was treated with ZPDC glycoprotein at different concentrations, the intensities of a few SDS-PAGE bands were slightly changed. The amount of a 23 kDa protein was increased upon treatment with increasing concentrations of ZPDC glycoprotein. The results of this study indicate that the radical-scavenging activity for O2(-) and OH¯, but not for the DPPH radical, increased in a concentration-dependent manner after treatment with ZPDC glycoprotein. The activation of anti-oxidative enzymes (SOD, GPx and CAT), growth rate and ß-galactosidase activity also increased in a concentration-dependent manner in response to ZPDC glycoprotein treatment, whereas ATPase activity was decreased. In summary, ZPDC glycoprotein stimulated an increase in the bioactivity of Lact. plantarum L67. Significance and impact of the study: This study demonstrated that Lactobacillus plantarum L67 possesses anti-oxidative activity. This strain of lactic bacteria has been known to have various probiotic uses, such as yogurt starters and dietary additional supplements. We found, through this experiment, that the protein has a strong anti-oxidative character, and the activity can be enhanced by treatment with Zanthoxylum piperitum DC (ZPDC) glycoprotein. This study may be application of Lact. plantarum L67 treated by ZPDC glycoprotein in yogurt fermentation. It could be one of the avenues of minimizing yogurt postacidification during storage. In addition, it can be manufactured and incorporated in food products without losing viability and functionality of Lact. plantarum L67.

Cold stress improves the ability of Lactobacillus plantarum L67 to survive freezing.

The stress resistance of bacteria is affected by the physiological status of the bacterial cell and environmental factors such as pH, salts and temperature. In this study, we report on the stress response of Lactobacillus plantarum L67 after four consecutive freeze-thaw cycles. The cold stress response of the cold-shock protein genes (cspC, cspL and cspP) and ATPase activities were then evaluated. The cold stress was adjusted to 5 °C when the bacteria were growing at the mid-exponential phase. A comparative proteomic analysis was performed with two-dimensional gel electrophoresis (2D SDS-PAGE) and a matrix assisted laser desorption/ionization-mass spectrometer. Only 56% of the L. plantarum L67 cells without prior exposure to cold stress survived after four consecutive freeze-thaw cycles. However, 78% of the L. plantarum L67 cells that were treated with cold stress at 5 °C for 6 h survived after freeze-thaw conditions. After applying cold stress to the culture for 6h, the cells were then stored for 60 days at 5 °C, 25 °C and 35 °C separately. The cold-stressed culture of L. plantarum L67 showed an 8% higher viability than the control culture. After applying cold stress for 6h, the transcript levels of two genes (cspP and cspL) were up-regulated 1.4 (cspP) and 1.2 (cspL) times compared to the control. However, cspC was not up-regulated. A proteomic analysis showed that the proteins increased after a reduction of the incubation temperature to 5 °C. The importance of the expression of 13 other relevant proteins was also determined through the study. The exposure of L. plantarum cells to low temperatures aids their ability to survive through subsequent freeze-thaw processes and lyophilization.