| dc.description.abstract | Lipopolysaccharide (LPS), often referred as endotoxin, triggers the body’s innate immune response and is responsible for inflammation, sepsis and septic shock leading to fatalities in gram-negative bacteria. Research on the biological activity of LPS, lipid A, is therefore very important. Lipid A structures of gram-negative bacteria that do not induce sepsis-like syndrome in human are less understood. While several of these LPSs or lipid As have been shown to be non-toxic for mammalian, they are important antagonists of E. coli or other toxic LPS containing strains.
In this research, we used hot phenol extraction to obtain LPS and electrophoresis gel with silver stain to visualize LPS. Moreover, we used microwave, instead of conventional method, to hydrolyze the lipid A from LPS in order to accelerate the chemical reaction and to allow sufficient time to remove the sugars on LPS. We took the advantage of commercial available lipid A extract from E. coli (Sigma) as a model of our research to compare with the lipid A isolated by our isolation procedures. By these experiences of isolating and characterizing the lipid A from E. coli? we successfully obtained the lipid A from the non-pathogenic gram-negative bacteria, M. capsulatus, as well. Using NMR, ESI-MS, MALDI-TOF MS, we deduced the possible structure of lipid A from M. capsulatus. The structure consists of a glucose backbone with four acyl chains attached.
In conclusion, we have developed a more efficient method to isolate lipid A from gram-negative bacteria using microwave heating. Model structural tools have been used to determine the structure of isolated lipid A from M. capsulatus. | en_US |