Harvesting and Resuspension - (Jan/02/2010 )
Good day everyone!
I'm trying to culture a bacteria for my research study but I'm currently having a problem with the journal article I'm basing on. This is actually my first time, so please bear with me. It states:
"The cells from the flasks were harvested by centrifugation (7,000 X g for 10 min) and resuspended in 50 ml of the medium in 250-ml Erlenmeyer flasks."
The problem is, I don't exactly know how what 'harvest by centrifugation and resuspend' mean. I tried finding more articles about how to do it - harvesting and resuspension - but I'm still a bit confused. Can someone please help?? I would really appreciate it. Thank you!
This simply means that you put the liquid culture into a centrifuge tube (or grow it in a centrifuge tube to begin with) and centrifuge it at 7000 x g for 10 minutes to bring the cells to the bottom of the tube forming a pellet. The liquid is poured off (typically decontaminated with 10% bleach) and the pellet vortexed to resuspend it in the remaining liquid. Then you add 50 ml of new medium, vortex again to make sure the pellet is fully resuspended, then transfer to a 250 ml flask. Don't forget that you need to balance the centrifuge, so it may be easier to split the initial culture into two tubes and centrifuge the pair.
It is easier to resuspend the pellet by vortexing before adding the new culture medium, since the vortex action is more forceful on small volumes. Flat bottom centrifuge tubes in a swinging bucket rotor typically yield pellets that are easier to resuspend.
phage434 on Jan 2 2010, 10:35 PM said:
It is easier to resuspend the pellet by vortexing before adding the new culture medium, since the vortex action is more forceful on small volumes. Flat bottom centrifuge tubes in a swinging bucket rotor typically yield pellets that are easier to resuspend.
Thank you, sir phage434! This could really help us to better understand our study.