I've been doing injections of Drosophila embryos with P-elemnt based
constructs. After gaining some practice I used to have an efficiency of
the hatching about 30 - 50%. I haven't been using the technique for a
couple of months. When I started to inject embryoes again the hatching
rate dropped up to 0%. I started to test all possible reasons of my
problems. I found following things:
1. When I test undechorionated eggs I get 15-18 larvae out of 20 eggs.
2. I get the same rate of hatching when the same eggs are covered with a
layer of oil up to 4mm.
3. When the eggs are dechorionated (I dechorionate them with sticky tape)
and covered with oil only 0-5 larvae appear. Sometimes unhatched eggs
seem not to be developed at all, on other days they are quite
advanced in the development.
4. I use the same equipment, sticky tapes and oils. I checked influence
of following factors:
a) chemicals used for preparing agar plates on which I keep embryos after
injections (agar, sucrose, water) were used from different bottles;
b) 2 stockes were tried: w,+,TM6/Sb e delta2-3 and w,+,delta2-3/delta2-3;
they give the same results, previously I used the first one;
c) the width of the sticky tape on which eggs are positioned doesn't have
d) the light of the microscope under which I dechorionate embryoes seemed
to be very strong, but turning it off and tensing my eyes didn't help.
e) two different kinds of oil, either saturated with water or not give
5. Humidity in a room in which I used to work is now much higher then before,
but it could eventually make things more easy. When I test an influence
of any factors I simply dechorionate eggs and immediatelly cover them
Could anyone have any suggestions about these problems? Please send letters
to the newsgroup or immediatelly E-mail to me.
E-mail: bartoszewski at rsbs1.anu.edu.au