How to Calculate Transformation Efficiency

hi everybody my name is Karen Martin I'm the marketing director at cold biotechnology and in this video I'm going to show you how to calculate transformation efficiency transformation efficiency is just a way of measuring how well or how efficiently your cells can take up DNA and it's expressed as the number of transform it's per microgram of your plasmid DNA so the general formula is going to look like this you have te or transformation efficiency equals the number of colonies that you count over the massive plated plasmid DNA and then you take that over the dilution that you end up using so let's look at an example in this example let's say that you have one microliter of 10 a picogram per microliter DNA and for conversion sake that's zero point zero zero zero zero one microgram per microliter DNA and then let's say you add that to a 25 micro liter equal isil suspension from there you add the suspension into 975 microliters of SOC recovery medium and then you do your first evolution so for that first dilution you take ten microliters of cell with SOC medium and you dilute that into 990 microliters of SOC medium and then from there you're ready to play so we'll say you played it 50 microliters and after incubation you commit 95 colonies so we know our colony count that's 95 colonies but what we don't know is the mass of native plasmid DNA and to get that we're gonna have to do a few easy steps the first thing I like to do though is break things down into two components I'd like to break things down into my nose and my so my knowns are the following I have one microliter of plasma DNA and then I had ten picograms per microliter of DNA and that converts to zero point zero zero zero zero one microgram per microliter of beginning that's my concentration ere the first dye Lucien that I did was where I took the ten microliters and put it into the nine hundred ninety microliters of SOC medium so we're gonna look at that in terms of the amount we pulled out and our total volume so that is ten microliters over one thousand then our total volume that we've been using is a thousand microliters and our plated volume is 50 microliters and at the end after incubation we counted ninety-five colonies okay so after solving my gnomes the next thing I want to look at are the things I need to solve for or my unknowns so the first thing I want to know is the total mass of plasmid DNA then I want to know the fraction of DNA that that was used from sample basically that's my second tech solution and then I'm going to look for the massive plated plasmid DNA which is this part right here so let's start with the first part here we'll look at our total mass of plasmid DNA and in this example it's really easy to solve but we're gonna map it out in anyway so you see how it works so we take our volume our plasmid volume times our concentration and that's one micro liter times zero point zero zero zero one microgram per microliter microliters cancel out and you know we're gonna be left with us basically so zero point zero zero zero zero one the next thing I'm gonna do is look at the fraction of DNA use from sample and what I'm doing is I'm looking at the amount plated over my kibble volume this is easy as that so 50 microliters over 1000 microliters and that's 0.05 and then the last part is the mass of plasmid or the mass of plated plasmid DNA that is so I'm gonna take the total DNA mass this part and I'm gonna multiply that by my second dilation this part I'll have my number so zero point zero zero zero zero one microgram times 0.05 and that keeps me my program so this is the amount that was actually plated so now I'm ready to use my formula here so I've got my 95 colonies and I'll take that over the massive DNA that I actually used or the plated massive plasmid DNA and then I also need to take that over my first solution here so that's 0.01 so my answer colony forming units per microgram of DNA so that's it ultimately when you're learning this you're gonna take what you know and use it to solve for what you don't know and then you just plug in the numbers but if you don't feel like doing all that math Gould bio does have a transformation efficiency calculator on our website all you have to do is check it out at Gould bio comm if you found this video helpful give us a thumbs up subscribe even add it to a playlist we hope you enjoyed thanks for watching you

Channel: Gold Biotechnology, Inc.

Views: 4,263

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Id: cmpMfhAA2Mw

Length: 6min 55sec (415 seconds)

Published: Wed Apr 08 2020