« Our Counterintelligence Staph | Main | A Fastidious Bacteriophage »
by Stan Zahler
When you streak out Your Favorite Bacterium on an appropriate agar plate, the colonies reach an expected diameter and stop growing. Why?
Corollary: If you inoculate YFB in the center of an agar plate and incubate it, it would reach its expected diameter. What do you predict would happen if you touch the tip of a sterile hair to the edge of the colony, draw it out on the agar radially, and re-incubate the plate?
As a final step before posting your comment, enter the letters and numbers you see in the image below. This prevents automated programs from posting comments.
Having trouble reading this image? View an alternate.
Comments are moderated, and will not appear until the author has approved them.
Your Information
(Name is required. Email address will not be displayed with the comment.)
This is all a great thing to discuss. I have colleagues who used microprobes to demonstrate that the interior of colonies was essentially anoxic.
Fact is, colonies are strange things:
http://www3.interscience.wiley.com/journal/109913378/abstract?CRETRY=1&SRETRY=0
And:
http://www.ncbi.nlm.nih.gov/pubmed/9891813
And some interesting photos:
http://www.microbelibrary.org/asmonly/details.asp?id=1611&Lang=
I also think that not all microbes are created equal with regard to this phenotype. After all, agar plates and pure cultures and single colonies aren't all that common in nature?
Posted by: Mark O. Martin | June 24, 2010 at 05:24 PM