Hi,

I would like to detect E.Coli after amplification of 16S rRNA (I am talking about part of the sequence, i.e. 230 nt). So I let cells to grow and then use Qiagen DNA/RNA extraction kit. Then I quantify what I get after extraction, it is 100 ng/µl... of what? I assume all nucleic acids, including 16S rRNA, add their "weight" to the obtained concentration of the sample. 

Now suppose that I repeat experiment (I mean grow another cell line of the same strain and extract the whole nucleic acid content from there) and get the new sample concenteration 100 ng/µl. Can I really compare them? Isn't it the case that one cell line contained different amount of ribosomes than another cell line?

I have read that number of ribosomes can vary significantly depending on something like "dividing time" or "doubling time" of cells, so does anyone have a nice idea how to treat my samples? Thank you.