The anti-diabetic activity of Bifidobacterium lactis HY8101 in vitro and in vivo.

AIMS: The aim of this study was to evaluate the effects of Bifidobacterium lactis HY8101 on insulin resistance induced using tumour necrosis factor-α (TNF-α) in rat L6 skeletal muscle cells and on the KK-A(Y) mouse noninsulin-dependent diabetes mellitus (NIDDM) model. METHODS AND RESULTS: The treatment using HY8101 improved the insulin-stimulated glucose uptake and translocation of GLUT4 via the insulin signalling pathways AKT and IRS-1(Tyr) in TNF-α-treated L6 cells. HY8101 increased the mRNA levels of GLUT4 and several insulin sensitivity-related genes (PPAR-γ) in TNF-α-treated L6 cells. In KK-A(Y) mice, HY8101 decreased fasting insulin and blood glucose and significantly improved insulin tolerance. HY8101 improved diabetes-induced plasma total cholesterol and triglyceride (TG) levels and increased the muscle glycogen content. We observed concurrent transcriptional changes in the skeletal muscle tissue and the liver. In the skeletal muscle tissue, the glycogen synthesis-related gene pp-1 and GLUT4 were up-regulated in mice receiving HY8101 treatment. In the liver, the hepatic gluconeogenesis-regulated genes (PCK1 and G6PC) were down-regulated in mice receiving HY8101 treatment. CONCLUSIONS: Bifidobacterium lactis HY8101 can be used to moderate glucose metabolism, lipid metabolism and insulin sensitivity in mice and in cells. SIGNIFICANCE AND IMPACT OF THE STUDY: Bifidobacterium lactis HY8101 might have potential as a probiotic candidate for alleviating metabolic syndromes such as diabetes.

Prophylactic effect of Korean mistletoe (Viscum album coloratum) extract on tumor metastasis is mediated by enhancement of NK cell activity.

We here demonstrated the prophylactic effect of an extract (KM-110) from Viscum album coloratum, a Korean mistletoe, on tumor metastasis produced by highly metastatic tumor cells, colon 26-M3.1 carcinoma, B16-BL6 melanoma and L5178Y-ML25 lymphoma cells, using experimental models in mice. Intravenous (i.v.) administration of KM-110 (100 microg/mouse) 2 days before tumor inoculation significantly inhibited lung metastasis of B16-BL6 and colon 26-M3.1 cells, and liver and spleen metastasis of L5178Y-ML25 cells. The prophylactic effect of KM-110 on tumor metastasis was evident with various administration routes, i.e. subcutaneous, oral, intranasal as well as i.v., and was dependent upon the dose of KM-110 administered. Furthermore, mice given KM-110 (100 microg) 2 days before tumor inoculation showed significantly prolonged survival rates compared with the untreated mice. In a time course analysis of NK activity, i.v. administration of KM-110 (100 microg) significantly augmented NK cytotoxicity to Yac-a tumor cells from 1 to 3 days after KM-110 treatment. Furthermore, depletion NK cells by injection of rabbit anti-asialo GM1 serum completely abolished the inhibitory effect of KM-110 on lung metastasis of colon 26-M3.1 cells. These results suggest that KM-110 possesses immunopotentiating activity which enhances the host defense system against tumors, and that its prophylactic effect on tumor metastasis is mediated by NK cell activation.

A selective enumeration medium for bifidobacteria in fermented dairy products.

A selective medium, blood-glucose-liver agar containing oxgall (.2 mg/ml) and gentamicin (30 micrograms/ml), was formulated for the selective enumeration of bifidobacteria in fermented dairy products containing both lactobacilli and streptococci. Recovery rates of bifidobacteria on this selective medium were around 90% of recovery on blood-glucose-liver agar. Strains of lactobacilli and streptococci were mostly inhibited with higher dilutions on this selective medium.

Antimicrobial susceptibility of bifidobacteria.

The antimicrobial susceptibility of 37 strains of bifidobacteria to 18 antimicrobial agents was determined by a macrodilution broth method. Most of the strains used were isolated from commercial yogurts and starters. Tested organisms were usually sensitive to Gram-positive spectrum antibiotics (bacitracin, erythromycin, lincomycin, and vancomycin), and most of the organisms were inhibited by a concentration < 1.56 micrograms/ml. Erythromycin was the most active agent; all strains were inhibited by < .19 microgram/ml. beta-Lactam antibiotics (penicillin G, ampicillin, methicillin, and cephalothin), showing a wide range of minimum inhibitory concentration, were less effective than Gram-positive spectrum antibiotics. Most strains were somewhat resistant to cephalothin, exhibiting inhibition at concentrations of 6.25 to 25.0 micrograms/ml. Test organisms were most resistant to kanamycin, neomycin, paromomycin sulfate, nalidixic acid, and polymyxin B sulfate; inhibition occurred only at > or = 50 micrograms/ml, and strains were somewhat less resistant to gentamicin and streptomycin. Susceptibility to nitrofurantoin and tetracycline was variable; minimum inhibitory concentrations ranged from 1.56 to 50.0 and .39 to 50.0 micrograms/ml, respectively, but chloramphenicol had a narrow range from 1.56 to 6.25 micrograms/ml.