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What are endotoxins?

Endotoxins are a heat-stable toxins which are related with the outer membranes gram-negative bacteria.  They are also known by the names: lipopolysaccharides (LPS) and lipoglycans. The endotoxins comprise of a core polysaccharide chain, O-specific polysaccharide side chains (O-antigen) and a lipid component, Lipid A. Lipid A is responsible for the toxic effect of the endotoxins. The function of endotoxins in a gram negative bacteria is mainly protective and structural.


Endotoxins were discovered by Richard Friedrich Johannes Pfeiffer. He named them endotoxins, in opposition with exotoxins, which are toxins that are released by bacteria into the surrounding environment. In his opinion the endotoxins could release their toxins only after the cell wall of the bacteria was destroyed (which was proven later that is not necessarily true).

Endotoxins in the research field

The influence of the amount of endotoxins on the extract is not completely understood. Moreover, the minimum amount is not familiar and furthermore what is the effect of greater amount of LPS in the extracts is also unknown.  However, in our certificates of analysis you can always find the levels of endotoxin of our products. We can also deliver D. pteronyssinus extracts with a low level of endotoxins.