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Microbiology questions...from an ungrad - (Nov/10/2006 )

I had a few questions. I am taking Micro right now...

What does the term '"'clonal population'"' mean? And what is the protocol in isolating a cloned isolate of a typical bacterial species?

Explain how Coliscan media is selective and differential for both total coliforms and E. coli.

opinions.. answers. comments appreciated.. thank you


clonal population i think is a term used to explain that one population was raised from single microorganism , so one expect that all individuals here are identical..


for second question, google is very helpful...
protocol is partiall given

For isolating single clones, you need to fix single bacterias. That's why you should use agar selective medium. (or unselective if you want all possible colonies.



The Coliscan Easygel medium is a patented formulation for water testing. It contains a sugar linked to a dye which, when acted on by the enzyme ß-galactosidase (produced by coliforms including E. coli), turns the colony a pink color. Similarly, there is a second sugar linked to a different dye which produces a blue-green color when acted on by the enzyme ß-glucuronidase. Because E. coli produces both ß-galactosidase and ß-glucuronidase, E. coli colonies grow with a purple color (pink + blue). The combination of these two dyes makes possible the unique ability to use one test to differentiate and quantify coliforms and E. coli. (Because E. coli is a member of the coliform group, add the number of purple colonies to the number of pink colonies when counting total coliforms.)