{ "date" : "2013-06-27", "author" : "thomas", "title" : "Toxicity test on 5mM Arabinose induced EFE Cells", "content" : "In order to evalutate if the expression of EFE is toxic or not to our cells I created a growth curve. I started from an inoculum of AraCpBAD + EFE that I prepared yesterday. I diluited 50ul of the overnight culture in 5ml of LB and I incubated at 37C with shaker until the cultures reached approximately 0,6 O.D at 600nm. I took 2 samples for negative controls and 2 samples for the induced cells. After that I added 25ul of Arabinose 1M stock solution to the induced samples (5mM working solution) and I registered the O.D. of the samples one time per hour (for 4 hours). In the end I plotted the results.

As expected, the strong induction of our gene slightly influences on growth-rate (caused by stress) but still is not completely toxic.
To confirm this result I made a toxicity test by serial dilution. I diluited 50ul of overnight culture (one induced sample and one not induced) into 9,5ml of LB. After vortexed the samples, I further diluited them 1:10 for three times. In the end I plated 150ul of each dilution onto Chloramhenicol Plates.
As you can see from the images, there's not big differences in the colony forming ability of the induced and the not induced sample, even in a dilution of 1:1000. Maybe I should dilute them more!", "tags" : "EFE" }