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How to wash pellet before RNA isolation - (May/01/2007 )


I am optimizing the RNA isolation for Rhizobium etli. When I centrifuge a culture in stationary phase, the pellet is not so clear. There is a cloud of polysaccharides above it. How can I get rid of it??
I stabilize the RNA by adding 1/5 volume 95/5 ethanol/phenol to the culture and dropping the falcon in liquid nitrogen. After thawing I centrifuge at 4750 rpm (maximum speed) for 30 min at 4 degrees. But the pellet is not clear.
I've tried washing it with TE-buffer (pH 8) to the pellet. But I'm not certain that the polysaccharides dissolve in the buffer. Will the RNA isolation remain intact? Anyone an idea?


-Maarten V-

if the cells are intact, wash them in PBS.
If not, after a first separation by acid phenol chloroform IAA, do an other PCI followed by chloroform only treatment.
Should allow the most part of polysacchatrides to get over.