Re: [DIYbio] Storing competent cells without -80c freezer

Hi Dennis,

Thanks for the reminder!  I will let you know in a few days.  Already left the lab before I saw this email.  I actually forgot about this experiment so I will only be able to report the transformation efficiency at ~4 weeks.  I spent the money to buy these cells then did not do transformations.  I'll use the PUC19 vector purchased from NEB for the calculation.  I'll also make some aliquots of the tube I use and test again in a few days to see if a single freeze/thaw hurts the efficiency badly.

-Will

On Sunday, April 17, 2016 at 11:22:27 AM UTC-4, Dennis Oleksyuk wrote:

Will, it was 4+ weeks from your message. Any results of the storage experiment?

On Mon, Mar 14, 2016 at 12:19 AM Koeng <koen...@gmail.com> wrote:

Are these lucigen cells, in particular? I am interested to know how their storage goes. 

On Sunday, March 13, 2016 at 8:08:42 PM UTC-7, William Beeson wrote:

I want to echo Patrick's comments.  

Many people are limited in their time and their time has a definite and quantifiable value.  If it was possible to purchase and store competent cells for several weeks, rather than having to perform a protocol that requires multiple reagents and hands on time over a period of 24-48 hours -- that's a trade off many people will elect to make.  Many people routinely spend $10+ on coffee and breakfast, lunch, or a drink after work.  Even graduate students, which are probably near the lowest pay scale of anyone in the life sciences -- make approximately $15-20 per hour.  The "subcloning efficiency" cells I purchased were ~$70 for enough cells (six 400 uL tubes) to do about 50 transformations.  

I am storing the cells in my -20C freezer to see how they work 1, 2, 4 weeks out from the purchase date.  Will let you guys know what I find.

-Will

On Sunday, March 13, 2016 at 9:04:16 PM UTC-4, Patrik D'haeseleer wrote:

On Saturday, March 5, 2016 at 12:06:11 PM UTC-8, Sebastian wrote:

Pardon the rant but I really don't see a point in buying when there are so many good protocols for making them simply. 

I do think there is an important tradeoff to be made there. I agree that in an ideal world, every biohacker should be able to make their own competent cells at pennies on the dollar. In the real world, we have many people who are still very much beginners when it come to lab techniques, and paying ~$10 per transformation for commercial competent cells can allow them to bypass a significant amount of extra labwork and get on with the project they really wanted to work on that much faster.

One could definitely argue that those people should learn to walk before they can run. By that same argument, one could argue that everybody should be put through traditional factory-school undergrad courses to learn the basics of wetlab and molbio techniques before they are allowed to do any transformations on their own. We prefer to throw people in at the deep end, and get them involved in projects right off the bat, even if that means taking a few shortcuts while they get up to speed with lab techniques. 

Sometimes it's also just a matter of practicality: if we just paid a couple hundred dollars to get a new construct synthesized at IDT, why not pay an extra $10 to transform that precious limited resource of DNA it into a reliable commercial competent cell line? Once we have a plasmid prep, we'll have plenty of DNA to go around, and the reliability and efficiency of the competent cells is far less of an issue.

So yes, we should definitely teach everyone to make their own competent cells. But that doesn't necessarily mean that commercially bought competent cells don't have any place in a community lab.

Patrik

PS: We also don't let people pour their own PAGE gels. That one's more of a safety issue, but you could make the same argument that everyone should know how to make their own cheap, custom gradient gels...

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