This works for me. Streak the bacteria on agar in a Petri dish and add amoeba at one end. Then invert the plate and observe it through the bottom with the 10x objective on a compound scope.   You will have much better resolution than with a stereo scope. An inverted compound scope is good too. You can also use this technique for observation with amoebae in bacterial lawns or among scattered bacterial colonies. Fred Spiegel

Sent from my iPhone, Fred Spiegel

> On Apr 17, 2014, at 5:50 PM, "John D Reeve" <[log in to unmask]> wrote:
> 
> Hi All,
> 
> I'm interested in predator-prey dynamics, and would like to use D. discoideum-E. coli as a simple lab system.  For observations, I'm using a stereoscope at 50X with a combination of direct lighting and light reflected upward through the petri dish.  The growth medium is a thin layer of SM agar.  I'm not having any problems observing the amoebas on the agar surface, but they sure are hard to see on the bacterial colonies.  I can see little bumps crawling around the colony surface but they are pretty indistinct.  Any ideas on visualizing amoebas on bacterial colonies?  Would a GFP strain help?  Thanks for any help.
> 
> Cheers,
> John D. Reeve
> 
> 
> ************************************
> John D. Reeve
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> 
> William F. Buckley on Wordstar vs. modern 
> word processing programs:  
> 
> "I'm told there are better programs, but I'm 
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