Abstract.Objectives : To characterize mesenchymal stem cell-like cells isolated from human amniotic fluid for a new source of therapeutic cells. Materials : Fibroblastoidtype cells obtained from amniotic fluid at the time of birth. Methods : The ability of ex vivo expansion was investigated until senescence, and stem cell-like characteristics were analyzed by examining differentiation potential, messenger RNA expression and immunophenotypes. Results and Conclusions : A morphologically homogenous population of fibroblastoid-type (HAFFTs) cells, similar to mesenchymal stem cells from bone marrow (BM-MSCs), was obtained at the third passage. The cells became senescent after 27 passages over a period of 8 months while undergoing 66 population doublings. Under appropriate culture conditions, by the 8th passage they differentiated into adipocytes, osteocytes, chondrocytes and neuronal cells, as revealed by oil red O, von Kossa, Alcian blue and anti-NeuN antibody staining, respectively. Immunophenotype analyses at the 17th passage demonstrated the presence of TRA-1-60; SSEA-3 and-4; collagen types I, II, III, IV and XII; fibronectin; α -SMA; vimentin; desmin; CK18; CD44; CD54; CD106; FSP; vWF; CD31; and HLA ABC. Reverse transcriptasepolymerase chain reaction analysis of the HAFFTs from passages 6-20 showed consistent expression of Rex-1, SCF, GATA-4, vimentin, CK18, FGF-5 and HLA ABC genes. Oct-4 gene expression was observed up to the 19th passage but not at the 20th passage. HAFFTs showed telomerase activity at the 5th passage with a decreased level by the 21st passage. Interestingly, BMP-4, AFP, nestin and HNF-4 α genes showed differential gene expression during ex vivo expansion. Taken together, these observations suggest that HAFFTs are pluripotent stem cells that are less differentiated than BM-MSCs, and that their gene expression profiles vary with passage number during ex vivo expansion.

Aims:  To observe the antiobesity activity of trans‐10,cis‐12‐conjugated linoleic acid (CLA)‐producing lactobacillus in mice. Methods and Results:  Lactobacillus plantarum PL62, which can grow in the presence of linoleic acid, was selected and studied. The culture supernatant of Lact. plantarum PL62 contained trans‐10,cis‐12‐conjugated linoleic acid (6·4 μg ml−1), and the crude enzyme prepared from washed cells produced trans‐10,cis‐12 CLA (1395 μg mg−1 protein). Lact. plantarum PL62 reduced the weights of epididymal, inguinal, mesenteric, and perirenal white adipose tissues and significantly reduced the blood levels of total glucose and body weights of mice (P < 0·01). Conclusions:  trans‐10,cis‐12‐CLA‐producing Lact. plantarum PL62 can exert the same antiobesity activity as trans‐10,cis‐12‐CLA in mice. Significance and impact of the study:  trans‐10,cis‐12‐CLA‐producing Lactobacillus can be a replacement for CLA for obesity treatment via the continuous production of trans‐10,cis‐12‐CLA. The results provide a novel opportunity to develop foods with antiobesity activity.

Aims:  Modified deMan‐Rogosa Sharpe agar containing bromophenol blue (mMRS‐BPB) was tested as a medium for counting and differentiation of each lactic acid‐producing bacterium (LAB), especially in a mixed culture. Methods and Results:  Type strains of 10 LAB species (Lactobacillus acidophilus, L. brevis, L. bulgaricus, L. gasseri, L. paracasei, L. plantarum, L. reuteri, Weissella confusa, Bifidobacterium bifidum and B. infantis) and five commercial yogurts were inoculated on plate count agar with bromocresol purple, mMRS, and mMRS‐BPB. Each type strain showed more clearly formed colonies on the three media under anaerobic conditions than under aerobic conditions. Especially each type strain produced colonies with specific characteristics of each species on mMRS‐BPB. Commercial yogurts produced the largest number of colonies with various shapes and colours on mMRS‐BPB. Conclusions:  Modified deMan‐Rogosa Sharpe agar containing bromophenol blue under anaerobic conditions is appropriate for counting and differentiating each LAB in a mixed culture. Significance and Impact of the Study:  Modified deMan‐Rogosa Sharpe agar containing bromophenol blue will be useful in isolation and enumeration of each LAB from fermented foods as well as intestinal microflora.

Lactobacillus fermentum PL9988 was isolated from an elderly person over 80 years of age living in a Korean longevity village. Results from a previous study showed various characteristics of L. fermentum PL9988 as a probiotic, including resistance to acid and bile acid, immune-enhancing activity, adhesiveness to the intestinal cell line Caco-2, inhibition of various intestinal pathogens, antioxidation activity, and susceptibility to antimicrobials. In this study, the binding activity of L. fermentum PL9988 to the intestine was confirmed in another human intestinal cell line, HT-29, and mouse intestinal cells. The anti-inflammatory activity of L. fermentum PL9988 was examined via both in vitro and in vivo experiments. Lactobacillus fermentum PL9988 increased the amount of IL-10 and decreased the amount of TNF-α in HT-29 cells treated with LPS. Similar results were observed in an in vivo experiment with BALB/c mice fed L. fermentum PL9988. Thus, results from the previous study and this study demonstrate the beneficial characteristics of L. fermentum PL9988 as a good probiotic with anti-inflammatory, antioxidative, and immune-enhancing activities in addition to improving intestinal health.