It never ceases to amaze how quickly in any research endeavor one reaches the edge of human understanding. Research by search engine in any subject is like peeling back the skins of an onion. First comes the chaff, and then the facile answers as if we understand it completely, then the layers that make the complexity of the subject clear, and finally the edge.

All this came to mind because research into fluorouracil, a treatment mentioned in the prior post, yielded first that it was in a class of drugs called anti-metabolites. Now that name got me thinking it worked on mitochondria, but it does not. The next layer of the onion revealed that we understand its function completely and it interferes with the transcription of RNA. This is the facile layer. While some of its effect probably is copied to RNA, it definitely does not generally interfere with RNA transcription, and in fact may rely on RNA to perpetuate its action deep into tissues.

The next layer is  “thymineless death“, and the edge. It was discovered in the 1950’s that E. coli grown in a thymineless substrate would just up an’ die. This was noteworthy because substrates without adenine, guanine, and cytosine were limiting but not fatal.

There are theories but my own suspicion is that sticking that Fluorine on like a spike allows the uracil to function normally  in the pyrimidine pathway, binding on one side but preventing expression on the other.

Fluorine is bad stuff.