Thursday, June 4, 2009

Horseshoe Crabs and Endotoxins (I)

I had often told participants about horseshoe crab's blood and their importance in the medical industry through their detection of bacteria endotoxins. Here is some more indepth information and I will spit this topic into three separate postings for an easier read. However, this should still be a pretty dry posting for many but well, this is my blog and you can choose whether to read it or not so here goes:

Endotoxins are basically lipopolysaccrides (LPS); a sugar-lipid compound embedded on the outer cell walls of gram-negative bacteria. That is why they are termed as "endo", which means inside (in this case, on the cell). These bacteria are so called and classified due to differences in their cell wall based on gram staining.

These LPS serves as a shield to impede antibodies and phagocytes as well as controlling release of factors like interlukins and tumour necrosis factors (no idea what that means too, lol). But all the toxicity actually stemmed from the lipid component; known as lipid A. However, this toxin is only pronounced when released, since it is embedded within the cell wall. This happens when the cells are dividing, or that the bacteria burst due to various reasons, like for example, being killed by white blood cells.

Hence, it is important to scan drugs and other products that will come into contact with blood for these toxins. It doesn't help that these compounds cannot be denatured by heat either. Because of this, rabbits were used as test subjects last time. Obviously, it is not a very accurate procedure to go about yielding many false positive and negative results. Not to mention the guilt-ridden task to rear colonies of cute furry rabbits just to make them sick.

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Here is when the horseshoe crab's blood comes into play... check out my next posting, probably by tomorrow.

Check out my other postings in this series:
Part II: Horseshoe crabs and LAL
Part III: Horseshoe crabs and Factor C (to be updated)

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