In response to the inquiries about using IBMX for activating gametes of C.
reinhardtii, folks should be aware that not all strains will activate with
dibutyryl cAMP and IBMX. For example, we are unable to activate strain 21gr
using this combination, and instead the cells resorb their flagella and
otherwise look funny. On the other hand gametes activate perfectly well if we
use 10 mM dibutyryl cAMP (50 mM stock is made in N-free medium and stored
frozen) and 0.15mM papaverine. We use 100% DMSO as the solvent
for the 15 mM papaverine stock solution. And we warm the DMSO to 60 degrees to
get the papaverine in solution. Also, we always make up fresh papaverine, and
we find it is important to use DMSO that is fresh. Thus we use DMSO sold in small
vials by Sigma. We find that cell concentration is not very important but
if money is an object, and one wants to use less dibutyryl cAMP, cells activate
just as well at 2 x 107 cells per ml as they do at 2 x 109 cells/ml.
UT-Southwestern Med. Ctr.
Dallas, TX 75235-9039