villen at CMGM.STANFORD.EDU (Anne Villeneuve) wrote:
>Regarding growing worms in liquid culture:
>>Good aeration is key to getting a high yield of healthy worms.
This is the probably the most important point to getting
good yields.
>Shake vigorously, using baffled flasks if possible, and larger
>volume flasks to maximize surface area/volume (e.g. 500 ml
>culture in a 2 liter flask).
I never got really good yields from shaker cultures. What I
did was to use aquarium bubblers, and had the flasks on
magnetic stirrers. I pumped as much air as I could though
the bubblers. If the compressed air source is very dry (as
its likely to be), you'll need to pass it through a flask
of water to pre-humidify the air using another bubbler or
you'll have problems with your S-basal getting too concentrated.
You'll want to get good bubblers that pass lots of air; some of
them seem to be more restrictive than others. For what its worth,
I was growing three liter cultures in six liter flasks this way.
Oh, and you'll probably need to use some Sigma anti-foam to keep
the foam from overflowing the culture flask.
>Also, using E coli strains that are healthier than OP50 is a good idea, >since you can get a better yield of food. Grow up several liters of >bugs in advance (store in the fridge as a concentrate) so that the worm >culture can be refed as the worm population expands.
This is good advice, too. If you feed them too much bacteria right
away, the bacteria can make the culture go anoxic. Several smaller
doses work much better than one large dose. I stored my bacteria
as pellets at -20 - it helps to keep the smell down.
later,
John Lye
