The bacterial outer membrane is found in Gram-negative bacteria. Its composition is distinct from that of the cytoplasmic membrane - among other things, the outer leaflet of the membrane includes a complex lipopolysaccharide whose lipid portion acts as an endotoxin - and it is linked to the cell's peptidoglycan by Braun's lipoprotein.
Porins can be found in this layer.[1]
If lipid A, part of the LPS, enters the circulatory system it causes a toxic reaction by activating TLR 4. Lipid A is very immunogenic and causes an aggressive response by the immune system. The sufferer will have a high temperature and respiration rate and a low blood pressure. This may lead to endotoxic shock, which may be fatal.
|