摘要：We found that the genus Sphingobacterium spiritivorum (EY3101T) possessed significant amounts of 2-hydroxy isopentadecanoic acid-containing ceramide phospholipids. Through analysis before and after acidic or alkali hydrolysis of the isolated phospholipid and FAB/MS analysis of the intact molecule, the phospholipids were identified as ceramide phosphorylethanolamine-1 (cerPE-1) containing non-hydroxy fatty acid, ceramide phosphorylethanolamine-2 (cerPE-2) containing 2-hydroxy fatty acid, ceramide phosphorylinositol-1 (cerPI-1) containing non-hydroxy fatty acid and ceramide phosphorylinositol-2 (cerPI-2) containing 2-hydroxy fatty acid. The latter two compounds are demonstrated in bacteria for the first time. When HL-60 human leukemia cells were incubated with these bacterial ceramides for 2 to 4 hours at 37°C, marked apoptotic features were observed, such as DNA fragmentation, increase in cell permeability, shrinkage of the cells and cytoplasmic changes. The relative activities were compared with cerPE-1, cerPE-2, cerPI-1 and cerPI-2, and no difference was observed in potency among them. Analytical studies of chemical structure of isolated ceramide analogs demonstrated that fatty acid and sphinganine base did not possess potency as apoptotic inducers.
