Lactobacillus plantarum CAU1055 ameliorates inflammation in lipopolysaccharide-induced RAW264.7 cells and a dextran sulfate sodium-induced colitis animal model.

This study aimed to screen lactic acid bacteria (LAB) for their anti-inflammatory activity by using RAW264.7 cells and dextran sulfate sodium (DSS)-induced colitis. In all, 192 LAB strains were isolated from healthy human feces, of which 8 strains showed excellent nitric oxide (NO) inhibitory activity. Peptidoglycan extracts of these 8 LAB strains were subjected to NO assay, Western blot, and ELISA. Among the 8 tested strains, extracts of 4 strains significantly inhibited the production of NO, related enzyme activities such as inducible nitric oxide synthase and cyclooxygenase 2, and key cytokines such as tumor necrosis factor-α and IL-6 in RAW264.7 cells. The 4 strains belonged to Lactobacillus (CAU1054, CAU1055, CAU1064, and CAU1301). Oral administration of the 4 strains inhibited DSS-induced body weight loss, colon shortening, and colon damage in ICR mice. The colon tissue of the mice treated with Lactobacillus plantarum strain CAU1055 had significantly reduced levels of inducible nitric oxide synthase, cyclooxygenase 2, tumor necrosis factor-α, and IL-6. We found that strain CAU1055 could be used as a candidate probiotic strain for the prevention and treatment of inflammatory bowel disease. Further studies are warranted to confirm the mechanisms of interaction between peptidoglycan of L. plantarum strain CAU1055 and upstream cellular signaling mediators.

Development of a Rapid Method for the Screening of Conjugated Linoleic Acid (CLA)-Producing Strains of Bifidobacterium breve.

This study was performed to isolate some strains of Bifidobacteriumbreve from fecal materials of neonates and to screen them for the biotransformation activity of converting linoleic acid into conjugated linoleic acid (CLA). Fecal samples were collected from twenty healthy neonates between 14 and 100 days old, and four hundred colonies were randomly selected from a Bifidobacterium selective transoligosaccharide medium. A duplex polymerase chain reaction technique was developed for the rapid and accurate molecular characterization of the B. breve strains that have been reported to show the species-specific characteristic of CLA production. They are identified by 16S ribosomal DNA, fructose-6-phosphate phosphoketolase encoding genes (xfp), and rapid pulsed field gel electrophoresis. Thirty-six isolates were identified as B. breve, and just two of the 12 neonates were harboring B. breve strains. Each isolate showed different CLA-producing ability in the spectrophotometric assay. All of the positive strains from the primary spectrophotometric assay were confirmed for their CLA-producing activities using gas-chromatographic analysis, and their conversion rates were different, depending on the strain isolated in this study. Some strains of B. breve were successfully isolated and characterized based on the CLA-producing activity, and further studies are necessary to characterize the enzyme and the gene responsible for the enzyme activity.

Screening and Characterization of Lactic Acid Bacteria Strains with Anti-inflammatory Activities through in vitro and Caenorhabditis elegans Model Testing.

The present study was conducted to screen candidate probiotic strains for anti-inflammatory activity. Initially, a nitric oxide (NO) assay was used to test selected candidate probiotic strains for anti-inflammatory activity in cultures of the murine macrophage cell line, RAW 264.7. Then, the in vitro probiotic properties of the strains, including bile tolerance, acid resistance, and growth in skim milk media, were investigated. We also performed an in vitro hydrophobicity test and an intestinal adhesion assay using Caenorhabditis elegans as a surrogate in vivo model. From our screening, we obtained 4 probiotic candidate lactic acid bacteria (LAB) strains based on their anti-inflammatory activity in lipopolysaccharide (LPS)-stimulated RAW 264.7 cell cultures and the results of the in vitro and in vivo probiotic property assessments. Molecular characterization using 16S rDNA sequencing analysis identified the 4 LAB strains as Lactobacillus plantarum. The selected L. plantarum strains (CAU1054, CAU1055, CAU1064, and CAU1106) were found to possess desirable in vitro and in vivo probiotic properties, and these strains are good candidates for further investigations in animal models and human clinical studies to elucidate the mechanisms underlying their anti-inflammatory activities.