pathogen propagation: plates vs. broth?

James Graham graham at biodec.wustl.edu
Mon Jun 10 18:43:27 EST 1996


Evidently some researchers feel that it is best to restrict growth of 
pathogenic bacterial isolates to propagation on plates rather than 
broth in creating large "seed stocks" for subsequent experimental 
inocula. (Eg. intial colony isolate is restreaked or spread across
plates which are harvested for frozen stocks rather than subcultured in 

How wide-spread is this practice? I see the general theory that 
immobilizing individual cells might reduce competition between emerging
subpopulations for early growth, but how signficant would this be? 
One could imagine that any emerging subpopulations would still be greatly 
"over-represented" even during growth on solid media. Anyone know of any 
refernces adressing this point?

How about ideas on the mathematics of "attenuation" in serial broth 
subculture (eg. how many generations)?

Thanks much,

J. Graham PhD 
Biology Department 
Washington University of St. Louis 


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