Pellet Formation - pellet formation for different concentrations of e.coli (Jul/07/2010 )

Hi there,

Are there certain concentrations and volumes at which e.coli become visible as a pellet after centrifugation?

I am trying to stain e.coli with acridine orange and would like to remove the "fluorescent background" of the stained liquid I have the cells suspended in (which at the moment is PBS). I would like to replace the stained PBS and introduce fresh PBS so that only the cells are stained.

I am trying to do this for concentrations of about 10^6 and 10^7 bugs/mL. I can get a pellet when I spin the original amount (~3*10^8) in a 5mL volume.

Any suggestions?? Thanks!!

you could try spining harder but for a shorter period of time. Try 14000rpm for 30 sec