Lipid A

Definition

Lipid A is a component of the lipopolysaccharide (LPS) layer found in the outer membrane of Gram-negative bacteria. It acts as an endotoxin and plays a crucial role in triggering inflammatory responses in the host.

5 Must Know Facts For Your Next Test

1. Lipid A is responsible for the toxic effects associated with Gram-negative bacterial infections.
2. It triggers strong immune responses by activating Toll-like receptor 4 (TLR4) on host immune cells.
3. Excessive release of lipid A can lead to septic shock, characterized by fever, hypotension, and multi-organ failure.
4. The structure of lipid A consists of a disaccharide backbone with multiple fatty acid chains attached.
5. Antibiotics targeting LPS biosynthesis can potentially neutralize the pathogenic effects of lipid A.

Related terms

Lipopolysaccharide (LPS): A complex molecule consisting of lipid A, a core polysaccharide, and an O-antigen; found in the outer membrane of Gram-negative bacteria.

Endotoxin:

Toxins located within the cell wall of Gram-negative bacteria that are released when cells disintegrate.

Septic Shock:

A severe condition resulting from systemic infection leading to widespread inflammation and organ failure, often triggered by endotoxins like lipid A.