Yes I agree with Richard. Be sure that the agar thickness and bacterial lawn density are the same for strains to be compared, because growth rate is sensitive to these variables. This is best achieved by putting them on opposite halves of the same plate. 
-Chris West


> On Mar 15, 2017, at 5:04 PM, Richard Gomer <[log in to unmask]> wrote:
> 
> We have done the colony expansion on agar lawns, its pretty simple....
> 
> Richard Gomer
> 
> ________________________________________
> From: DICTY [[log in to unmask]] on behalf of Kevin Swier [[log in to unmask]]
> Sent: Wednesday, March 15, 2017 3:24 PM
> To: [log in to unmask]
> Subject: Re: [DICTY] Bacterial streak Dicty growth assay
> 
> We were cloning some putative slow phagocytosers by diluting onto bacterial lawn...and noticed that the clearings of the mutants grew more slowly than those of wild type cells.  This observation did not repeat in subsequent assays, but that may be that our mutants were just no different than wild type cells.
> 
> Nonetheless, this seems to be another way to assay growth on bacteria as you could have many clones per plate and measure the change in diameter of the clearings over the first few days.  We have not gotten around to testing the assay on known mutants so would be happy to hear if anyone has thoughts about this or has tried this.
> 
> Kevin Swier
> Professor of Biology
> Chicago State University
> 9501 S King Drive
> Chicago, IL  60628
> 
> On Tue, Mar 14, 2017 at 2:39 PM, Knecht, David <[log in to unmask]<mailto:[log in to unmask]>> wrote:
> I have a vague recollection of a paper where someone used a streak assay to compare rates of consumption of different types of bacteria by Dictyosteleids.  My mental image is an agar plate with several linear streaks of bacteria.  The Dicty were inoculated at one end and the rate at which they moved up and cleared the line used as a measure of Dicty growth.  Perhaps it was a way to compare whether they consumed that type of bacteria at all.   Can anyone point me toward an assay like that?  It sounds simple, but I suspect there are tricks.  Thanks- Dave
> 
> Dr. David Knecht
> Professor , Department of Molecular and Cell Biology
> University of Connecticut
> 91 N. Eagleville Rd.
> U-3125
> Storrs, CT 06269-3125
> 860-486-2200<tel:860-486-2200>