Coli B and K-12

George W. Chang changlab at nature.berkeley.edu
Fri Aug 19 20:37:26 EST 1994


In article <1994Aug18.134716.6730 at wisipc.weizmann.ac.il>,
comalin at dapsas1.weizmann.ac.il (Malin Gennady ) wrote:

> Does anybody know, what is the principal difference in
> two wild strains of Escherichia coli, B and K-12 from metabolic,
> genetical or physiologycal point of view.
> Any information will be appreciated.
................................................................

Malin,
        There are all the well-known differences... specificity of
restriction and modification machinery, ease of synchronizing on a
Helmstetter "Baby Machine", reverse transcripatse, etc.
        Then there is the interesting history.  The "B" in E.coli B came
from the fact that the physicist Delbruek (spelling?) called his bacterial
culture "B" for "bacterium, and his phage culture "P" for phage.  Later on
Hershey, who had originally given Max his E.coli B, found that his and
Max's E.coli had diverged, and they were actually carrying two different
lines of E.coli B.
        K-12 was a Stanford hospital isolate from the 1920s, I believe. 
It got really interesting when it was found to indulge in sex.  Then it
turned out to be carrying a prophage that got named "lambda".  Old-timers
at Stanford or who WERE at Stanford should be able to give you a more
accurate and complete picture.

Best regards,
George



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