<P> Lipopolysaccharides (LPS), also known as lipoglycans and endotoxins, are large molecules consisting of a lipid and a polysaccharide composed of O - antigen, outer core and inner core joined by a covalent bond; they are found in the outer membrane of Gram - negative bacteria . </P> <P> The term lipooligosaccharide ("LOS") is used to refer to a low - molecular - weight form of bacterial lipopolysaccharides . </P> <P> The toxic activity of LPS was first discovered and termed "endotoxin" by Richard Friedrich Johannes Pfeiffer, who distinguished between exotoxins, which he classified as a toxin that is released by bacteria into the surrounding environment, and endotoxins, which he considered to be a toxin kept "within" the bacterial cell and released only after destruction of the bacterial cell wall . Subsequent work showed that release of LPS from gram negative microbes does not necessarily require the destruction of the bacterial cell wall, but rather, LPS is secreted as part of the normal physiological activity of membrane vesicle trafficking in the form of bacterial outer membrane vesicles (OMVs), which may also contain other virulence factors and proteins . </P> <P> Today, the term' endotoxin' is mostly used synonymously with LPS, although there are a few endotoxins that are not related to LPS, such as the so - called delta endotoxin proteins secreted by Bacillus thuringiensis . </P>

When would endotoxins be released from a gram (-) bacterial cell