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Name: Fred
Status: student
Grade: other
Location: Outside U.S.
Country: Germany
Date: N/A 


Question:
RNA vs DNA which one is more abundant (in E.coli), RNA or DNA?



Replies:
Fred,

I am only speculating, but I would guess RNA (including rRNA) outweighs DNA because ribosomes are abundant, and copies of RNA are constantly being made for transcription and translation, whereas DNA is not being copied as frequently. The numbers depend on the stage of growth, but I'm not sure it would affect the overall answer.

I found a reference to this information (http://www.protocol-online.org/biology-forums/posts/26407.html) -- although I cannot confirm/verify its accuracy because I don't have access to the text:

Nucleic acid content of E. coli DNA per cell: 3-4% of dry weight
Total RNA per cell: 10-20% of dry weight (20 in exponential, mostly ribosomal RNA)
Protein per cell: 50% of dry weight
(Chapter by S.E. Luria, in The Bacteria; Gunsalus, I.C., Stanier, R.Y., Eds. Academic Press: New York, 1960, Vol. 1)

This is consistent with my speculation -- but that doesn't make it correct. ;)

Another publication found ~25% RNA mass, but this included protein, so it is an overestimate.
(Tissieres et al, Ribonucleoprotein Particles from Escherichia coli J. Mol. Biol. (1959) 1, 221-233.)

Hopefully another AAS volunteer will respond with more definitive information, but perhaps this will help in the interim,

Burr



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