removing worms from an agarose pad - a poll
a.manning at ualberta.ca
Wed Mar 12 02:31:15 EST 1997
Dear fellow worm breeders,
There was a recent argument in our lab over the preferred method of
removing worms from an agarose pad following microinjection. I am asking
that people just email me directly with a response from the choices 'worm
pick,' 'glass pipette,' or 'pipetman' (with no need for an accompanying
explanation): maduro at odum.biology.ualberta.ca
I shall post the results and descriptions of any other methods suggested.
Method A: Removal by worm pick
A small drop of M9 (or 0.1 M NaCl) is added to the paraffin/halocarbon oil.
The worms float off after a minute or so and are removed one at a time by
passing a platinum pick under each one.
Typical time: varies, say 5-10 seconds per worm, or 1.5 to 3 minutes for 20
Typical recovery: depends on shape of worm pick and experience of user; can
approach 95% of animals that survived injection
Method B: Removal by pipette
I have been using a 10 ul Socorex pipetman to remove the worms. 10 ul of
M9 or 0.1 M NaCl are pipetted onto the oil; the liquid is pipetted up and
down to free the worms from the pad. After doing this two or three times,
all of the worms (10-20) are pipetted up into the tip all at once. The
worms are dispensed in one drop on the side of a seeded plate. Usually,
many worms stick to the inside of the pipette tip: This can be remedied by
just pipetting up and down, using the meniscus (and bits of paraffin oil)
to free them. As an alternative, silanized pipette tips or a glass
capillary and mouth pipet could be used (I haven't tried these).
Typical time: 30 seconds for 20 worms.
Typical recovery: routinely greater than 95% (of animals surviving
Morris Maduro (maduro at odum.biology.ualberta.ca)
Dept of Biological Sciences
University of Alberta
Edmonton, AB Canada
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