ABSTRACT

Endotoxins are formed by a certain group of bacteria, the gram-negative bacteria, which differ from other microorganisms by the unique architecture of their cell wall and thus their staining behavior as devised by Hans-Christian Gram (1). Endotoxins were originally described as heat-stable components of Vibrio cholerae by Richard Pfeiffer (2) and are known today to be generally present in the cell envelope of gram-negative bacteria. Here they are major and integral components of the outer membrane, being exclusively located in its outer leaflet facing the bacterial environment. Endotoxins participate in the physiological membrane functions and are therefore essential for bacterial growth and viability (3). At the same time, endotoxins represent a primary target for interaction with antibacterial drugs and components of the immune system of the host. They have therefore attracted the interest of microbiologists and bacterial geneticists, who initiated studies to understand the biosynthesis and the molecular basis of the vital function of endotoxins for bacteria.