Enhancing Immunomodulatory Function of Red Ginseng Through Fermentation Using Bifidobacterium animalis Subsp. lactis LT 19-2.

Removal of sugar moieties from ginsenosides has been proposed to increase their biological effects in various disease models. In order to identify strains that can increase aglycone contents, we performed a screening using bacteria isolated from the feces of infants focusing on acid tolerance and ß-glucosidase activity. We isolated 565 bacteria and selected Bifidobacterium animalis subsp. lactis LT 19-2 (LT 19-2), which exhibited the highest ß-glucosidase activity with strong acid tolerance. As red ginseng (RG) has been known to exert immunomodulatory functions, we fermented RG using LT 19-2 (FRG) and investigated whether this could alter the aglycone profile of ginsenosides and improve its immunomodulatory effect. FRG increased macrophage activity more potently compared to RG, demonstrated by higher TNF-α and IL-6 production. More importantly, the FRG treatment stimulated the proliferation of mouse splenocytes and increased TNF-α levels in bone marrow-derived macrophages, confirming that the enhanced immunomodulatory function can be recapitulated in primary immune cells. Examination of the molecular mechanism revealed that F-RG could induce phosphorylations of ERK, p38, JNK, and NF-κB. Analysis of the ginsenoside composition showed a decrease in Rb1, Re, Rc, and Rb3, accompanied by an increase in Rd, Rh1, F2, and Rg3, the corresponding aglycone metabolites, in FRG compared to RG. Collectively, LT 19-2 maybe used as a probiotic strain to improve the bioactivity of functional foods through modifying the aglycone/glycoside profile.

Influence of gastrointestinal stress on autoinducer-2 activity of two Lactobacillus species.

Quorum sensing is a bacterial communication signalling system that regulates the expression of certain target genes with autoinducers in a cell density-dependent manner. The universal luxS-mediated quorum sensing using the autoinducer-2 (AI-2) signal is present in a wide variety of bacteria with only sparse information on probiotic lactobacilli. Effective probiotics should exhibit tolerance and adaptation to stress conditions typical of the GIT. Adhesion to human intestinal epithelial cells and competitive exclusion of pathogens are also considered important. The AI-2 signal system plays an important role in the response of probiotic lactobacilli to the surrounding environment. Intraspecies-related changes in quorum signalling in the GIT were determined by monitoring the AI-2 activity of two strains each of Lactobacillus rhamnosus and L. plantarum under various stress conditions. Modulation of the AI-2 activity of all the strains was induced by stress responses to pH, bile acid, temperature, osmotic pressure and starvation, and was both species- and strain-specific. AI-2 inhibition correlated with a reduction in the stress-related genes of L. rhamnosus. We therefore suggest that AI-2 quorum signalling of probiotic lactobacilli may represent one way of adapting to the host's ecosystem and of interacting within the intestinal environment.

Selection of functional lactic acid bacteria as starter cultures for the fermentation of Korean leek (Allium tuberosum Rottler ex Sprengel.).

The purpose of this research was to find safe and suitable starter cultures for the fermentation of Korean leek (Allium tuberosum Rottler), also known as garlic chives or Oriental garlic. This traditional herb has several functional properties and a strong flavour; its leaves are used as food material. Eighteen strains of lactic acid bacteria (LAB) were isolated from well-fermented leek kimchi. Controlled fermentation of the leek leaves was conducted with 2 strains (Weissella confusa LK4 and Lactobacillus plantarum LK8), selected as potential starter cultures on the basis of their safety properties, and on the pH, total titratable acidity (TTA), and viable cell numbers [colony forming units (CFUml(-1))] achieved during the fermentation. Microbial dynamics was also followed during fermentation by using PCR-DGGE (Denaturing Gradient Gel Electrophoresis) on DNA level. To analyse bioactive compounds such as thiols and allicin (diallyl thiosulfinates), the total flavonoid and polyphenolic contents were determined by colorimetric methods. Functional properties were assessed on the basis of anti-oxidative capacities by determining the 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical-scavenging effect, and ferric reducing antioxidant power (FRAP). W. confusa LK4 rapidly increased during the first stage of leek fermentation, and was mainly responsible for accelerated fermentation during the early period in contrast to L. plantarum LK8, a stronger acid producer during the later stages of fermentation. After 48 h fermentation, leeks fermented with W. confusa LK4 showed the highest radical scavenging effects and reducing ability. The detectable amount of allicin of fermented leeks decreased relative to the change in pH, whereas the concentration of thiols significantly increased. Total flavonoid and poly-phenolic contents changed during fermentation and showed correlation with anti-oxidant effects. We therefore suggest the suitability of W. confusa LK4 as a potential starter culture for fermentation of leeks.

Response of fetal rat calvarial cells to nanotubular titanium oxide surface.

This study examined the cell response to a TiO2 nanotubular surface (Ti-NT) for future biomedical applications. The level of cell attachment and spreading at 20 min and 60 min was evaluated by SEM. IL-6 and PGE2 secretion was evaluated by ELISA. In SEM analysis, the Ti-NT surface had more fully spread cells compared to the machined titanium surface (Ti-S). ELISA revealed that the level of IL-6 and PGE2 production was higher on the Ti-NT than on the Ti-S. These results suggest that a surface treatment with a nanotubular TiO2 surface enhances the early osteoblast responses, such as cell spreading and cytokine release, which are important for subsequent cell functions and bone healing in vivo.

[Genotypes of hepatitis B virus on Jeju island].

BACKGROUND/AIMS: Hepatitis B virus (HBV) was classified into 8 genotypes by a sequence divergence in the entire genome designated from A to H. HBV genotypes have distinct geographic distributions. Recently, HBV genotypes have been partially found as influencing the clinical manifestation of chronic liver disease in hosts. In Korea, the distribution of HBV genotypes remains unclear. The aim of this study was to evaluate the prevalence of the HBV genotype on Jeju Island. METHODS: Hepatitis B virus genotypes were evaluated among 107 hepatitis B carriers residing on Jeju Island. We used single PCR and multiplex-PCR assay with genotype-specific primer pairs for HBV genotypes A-F for the genotyping. RESULTS: 1. Fifty nine samples (55%) were positive for HBV DNA. The positivity was different according to the pattern of HBeAg/ anti-HBe expression, as -/-; 2/3 (66.7%), -/+; 30/73 (30%), +/-; 24/28 (85.7%) and +/+; 3/3 (100%). 2. In the single primer set of genotype-specific PCR, 59 samples (100%) were detected as genotype C and 2 (3%) were also detected as genotype A and B. 3. In multiplex-PCR, 58 samples (98%) were detected as genotype C and only one (2%) as a mixed pattern of genotype B and C. 4. When the PCR products were amplified with universal sense and genotype specific anti-sense from one genotype A, one B, and 2 C, all were included in genotype C. CONCLUSIONS: These results suggest that on Jeju Island, almost all HBV genotypes are C.