Silly question - screw lids on or not? (Sep/21/2009 )

Hi all, I'm new to growing bacterial cultures. When I put my tube in the incubator, should I screw the lid on tight or loose (in order to let air in)?? Thanks!!

Loose, but make sure they don't fall off!

besides you are working with anaerobic bacteria, then you must close it tight.

Its must not be tightened fully, just tight it so that it may not fall with shaking of the incubator........
When u start screwing it stop the turn of the lid where it is becoming harder or tighter to move.......I usually tight it full and then pierce the top of the lid with a BD needle so as to allow aeration in the incubator..........

Clearly overkill. For the great majority of bacterial cultures, it makes little difference if you tighten the caps or not. It's conventional to loosen them somewhat. For anaerobes - you'll need an anaerobic atmosphere - not tight caps.
The last thing you need is to stick needles in caps - it's unnecessary and a personal risk.

GeorgeWolff on Sep 24 2009, 12:01 AM said:

you can keep anaerobs in tubes tighly closed when you set them up in anaerobic conditons (like replacing air with N). But you have to close tubes tighly (and special tubes) so maybe it would be important to know which tubes we are talking about

Needles in caps

Well it depends on what strain u are using and under what conditions u r growing it.........i had this problem of lids, specially for overnite culture, if i tightened it completely then it would nt reach the OD i was needing and if i left the lids nt fully tight then in the morning it would have fallen from the tubes....and contaminated.....then i used to pierce the lid of falcon tube and tight it completely...........everything was ok and nothing happened to the culture.........it was perfect......

dc984 on Sep 21 2009, 05:44 PM said:

It kind of depends on what you're growing. If it likes oxygen (like E. coli) you should probably be growing it shaking, in which case you want the lid on tightly. Let us know what you're trying to grow and maybe you'll get more help.

Thank you very much everyone!!