Maintaining things RNase and DNase free - (Feb/08/2008 )
Hi - I was wondering when you guys are working with bigs of 500-1000 1.5ml eppendorf tubes that are RNase/DNase free, how do you keep it nuclease free? In my lab, we don't do PCR in a laminar flow hood because it does not need to be sterile, but the surfaces and things must be kept nuclease free. It takes a while before the bag full of tubes is empty. Each time the bag is open to air I feel it becomes contaminated, and each time I reach into the bag to take a tube it feels the same way. Do you just wipe your hands with something like RNase zap?
A few guidelines I've developed over time....
1) NEVER!, NEVER!, NEVER! reach into a bag of tubes (sorry to shout)- instead pour them out onto a 'clean' surface or container.
2) Whenever you open a new bag of tubes, 'aliquot' them out into several smaller containers that have been decontaminated w/ RNase away. Old pipette tip boxes work well for this.
3) Assuming that you may also wish not to contaminate your tubes with airborne DNA/RNA, you'd want to store and open the bags as far away from your cycler and gel tanks as possible.
4) You could assume anything that's not sterile is also not DNase/RNAse/Protease-free or DNA/RNA free - this is where laminar flow hood comes in handy.
5) Many arguments exist in favor of - or - opposed to autoclaving tips, tubes, etc for DNA/RNA manipulation. However since sterlilty does not guarantee that a surface,tube or container is also 'clean'(let alone whatever nasties are is vaporized and deposited during the process) I'd count myself in the latter camp.
Unless you have access to a perfect, airborne contaminant free atmosphere, the best you can do is minimize exposure of your reagents to anything exogenous, and be diligent about both positive AND negative controls in your experiments. Good Luck!
Thanks, JAH! These are really good tips you gave. Does any type of RNase away solution work (no difference between brands, etc)? Also, do these come in a spray bottle, or just wipes?