April 30, 1946+

Dear Dr. Wickerham,

Thank you for the reprint of your paper on Schizosaccharomyces

versatilis,

My brief study on the strains which you sent pe while I ws at
Columbia University indicates that it requires nicotinic acid and
inositol as growth factors, growth being quite adequate. I have not
tested the biotin requirament, largely because biotin is all over the
place here, being used for the Neurospora work. Other vitamins seem to be
slightly inhibitory if anything. I am afreid however that it has one or
two features that make it somewhat less satisfactory than I had hoped for
genetic work; the growth in broth seems to be considerably clumped with
aggregates of a dozen or more cells in many instances, so that I cannot
be confident of a single-cell isolation on plating out ; secondly it does
seem to grow quite slowly in pour plates, the anaerobic predilection being
somewhat embarrassing. Dr. Birkholder has suggested that other members of
this or related genera might be more satisfactory. Could you do me the kind~
ness of sending cultures of some other Schizosaccheromycetes, and possibly
Endomyces albicans? I am not able to define exactly whk& would handle the
most easily, but out of a sample of several species, the most appropriate
might be found.

Appreciatively,

Joshua Lederberg.