Hi Mike,
I'll venture a guess at this question. In liquid media, bacteria are not
as crowded. There is less competition for space and nutrients (at least in
young, fresh cultures), so cells are more likely to assume a more natural
appearence and arrangement. Our strain of E. coli, for example, takes on
a more robust rod-shape when cultured in liquid medium, but when grown on
an agar slant or plate tends to appear more as a classic coccobacillus
with greater variations in individual appearence. This can also be true
for different species of Bacillus, etc. This is my current take on the
situation, and I am looking forward to other responses.
Karl J. Roberts, Ph.D.
PGCC
On Fri, 5 Mar 1999, Mike wrote:
> Unfortunately I've lost the old note, but someone suggested (to me, a
> beginner student) that it was advantageous to use liquid media instead of
> solid media when having difficulties differentiating between rods and cocci.
> Why is this?
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