ABSTRACT
Antarctic bacteria are a novel source of polysaccharides which might have potential applications as biological response modifiers (BRM). A heteropolysaccharide (PEP) was isolated from the liquid culture broth of the Antarctic bacterium Pseudoaltermonas sp.S-5. PEP contained Mannose, Glucose, and Galactose in a ratio of 4.8:50.9:44.3. High performance gel permeation chromatography of this polysaccharide showed a unimodal profile, and the molecular weight was 397 kDa. PEP was studied for its immunological effects on peritoneal macrophage cells. Morphological alterations were observed in macrophages treated with PEP. In vitro exposure to PEP increased the occurrence of activated macrophages and endocytic index in a dose-dependent pattern (2.5-50 µg/ml) after 24h of incubation, since increase of 136% and 133% was detected in the activated macrophage percentage and endocytic index respectively compared to untreated cells. At 200 µg/ml PEP caused a greatest increase (44.5%) in NO production when compared to the control group; however, this polysaccharide did not affect respiratory burst in the absence of PMA. Furthermore, it was demonstrated that PEP induces macrophages to secrete tumor necrosis factor (TNF)-α and interleukin (IL)-1ß. These results suggested that PEP from Pseudoaltermonas sp.S-5 can be classified as a BRM.
Subject(s)
Immunologic Factors/pharmacology , Macrophages, Peritoneal/drug effects , Polysaccharides, Bacterial/pharmacology , Pseudoalteromonas , Animals , Cell Survival/drug effects , Cells, Cultured , Interleukin-1beta/immunology , Macrophages, Peritoneal/immunology , Mice , Nitric Oxide/immunology , Phagocytosis/drug effects , Superoxides/immunology , Tumor Necrosis Factor-alpha/immunologyABSTRACT
In this study, a novel exopolysaccharide (EPS) was isolated from the fermentation broth of Trichoderma pseudokoningii and its anticancer activities on human leukemia K562 cells were studied. EPS could significantly inhibited K562 cells proliferation in a time- and concentration-dependent manner. Meanwhile, characteristic of apoptosis, including apoptotic morphological features and the apoptosis rate were obtained. Sequentially, the dissipation of mitochondrial membrane potential, increase production of Reactive oxygen species (ROS), enhancement of the concentration of intracellular, up-regulation of Bax and p53 mRNA, down-regulation of Bcl-2 mRNA were also detected. The results indicate that the EPS could induce of K562 cells apoptosis, primarily in involved the mitochondrial pathways. The present studies suggest that EPS could be a new potential adjuvant chemotherapeutic and chemo preventive agent against human leukemia.