- Lipopolysaccharide (LPS) also known as Lipoglycon and Endotoxin.
- It consist of Lipid and Polyacrylamide composite, Lipid-A and core polyacrylamide of O-Antigen or O-side chain.
- As in peptidoglycan biosynthesis LPS molecules are assembled at the plasma or inner membrane.
- Outer core and inner core joined by covalent bond they are found in outer membrane of Gram negative bacteria.
- Lipid A contains endotoxin and sugars such as heptose.
- Lipopolysaccharide (LPS) is also Exogenous Pyrogen ( external fever inducing substances).
- Lipid A more than 99.9% of pyrogen activity.
- Lipid A composed of B-1, 6-glycosamine disaccharide units with aminohydrogens and fatty acids.
- Single Bacterial cell has been estimated to contain about 3.5 million Lipopolysaccharide (LPS) molecules.
- Lipopolysaccharide (LPS) is always toxic and pyrogenic and also causes endotoxic shock.
- Lipopolysaccharide (LPS) layer also called the outer membrane is the outer most layer present in the cell wall of gram negative bacteria. It is a characteristics feature of gram negative bacteria.
- Exception : some Gram positive bacteria, Ex : Listeria monocyotogenes has been found to contain an authentic lipopolysaccharide.Bacillus thuringenesis, Bacillus cereus and Bacillus anthrax are Gram positive bacteria, These bacteria are capable of produce crystal proteins ( proteinaceous inclusions) called delta endotoxins, that have insecticide action.
- Lipopolysaccharide (LPS) is extremely heat stable and pH stable, these are pass the 0.2 um membrane filter.
Related : peptidoglycan
