Lipid A is considered to be the hydrophobic lipid moiety of the LPS molecule. Lipid A is essentially a phosphorylated glucosamine disaccharide with many fatty acids attached. This part of LPS is responsible for its endotoxic activity (Rietschel et al., 1982). Lipid A is the agent capable of inducing various endotoxic reactions such as fever, Shwartzman reaction, immune cell activation, fatal toxicity, etc. (Galanos et al 1985; Rietschel et al, 1987). Lipid A is integrated into the lipid bilayer of the outer membrane and is necessary for the functioning of the membrane barrier (Wyckoff et al., 1998). Lipid A generally consists of a bisphosphorylated β-(16)-linked glucosamine disaccharide substituted with a fatty acid ester linked at the 3 and 3' positions and an amide linked at the 2 and 2' positions (Zahringer et.al 199). Lipid A adopts an ordered hexagonal arrangement resulting in a more rigid structure compared to the rest of the molecule (Petsch and Anspach., 2000). Bacteria lacking lipid A are not known (Perola et al., 2007). LPS containing lipid A and Kdo, a unique sugar as well as ...