Value 
3.3e+9
Cells/colony
Range: Table  link Cells/colony

Organism 
Bacteria Escherichia coli 
Reference 
Mashimo K, Nagata Y, Kawata M, Iwasaki H, Yamamoto K. Role of the RuvAB protein in avoiding spontaneous formation of deletion mutations in the Escherichia coli K12 endogenous tonB gene. Biochem Biophys Res Commun. 2004 Oct 8 323(1):197203 p.201 table 3PubMed ID15351721

Method 
Measurement of number of cells not explicitly given, however, to determine number of cells in colony method usually employed is: pick up single colonies (with maybe a bit of the agar to make sure one gets them all), suspend them in a known volume of sterile water, make a dilution series, and then one of two things: 1. Count total cells using a hemacytometer or similar counter. For motile organisms, kill them first. or 2. Plate suitable dilutions on agar medium and count colonies. Since not all the cells will necessarily be viable, this gives a count of viable cells. One can then calculate backwards to estimate the number of cells in the colony. If one just wants an average number of cells per colony, one could pick up about 100 colonies, suspend them all together, count cells, and divide the final number by 100. This is faster than doing counts on 100 individual colonies, but of course one will only get the mean (average) number of cells per colony with no estimator of variation among colonies such as the variance. [Method courtesy of Prof Bill Birky, Uni. of Arizona in Tuscon] 
Comments 
Abstract: "Value from 66 cell cultures. The endogenous tonB gene of Escherichia coli was used as a target for spontaneous deletion mutations which were isolated from ruvAB, recG, and ruvC cells." P.201 right column bottom paragraph: "[Investigators] first observed 23 tonB deletions among 49 tonB mutants from the ruvAB strain, giving a deletion rate of 2.08×10^8, which is 3.5fold different from the rate for ruv+, 0.59×10^8 (Table 1). Concerning the tonBtrp deletion rate, [they] calculated it to be 1.00×10^9 for ruvAB, which is 10fold higher than that of ruv+, 1.03×10^10 (Table 3)." Table gives deletion rates and number of cells in colony of RuvAB mutant strains 
Entered by 
Uri M 
ID 
104458 