Madison, Wise
October 13, 1953

Dear Professor Rubbo:

I have your letter of the Sth. I had already heard of your vieit
in a letter from Ephrusai.

As we had previously agreed, the details of your program are best
left, open until we can all confer with you. However, some comment on
your note may be desirable.

The desirability of extending the analysie to bacteria of the
(shall we say) apo-plasmatic effects of euflavine has occurred to several
investigators, so far with no encouragement at all. E. coli and Salmo-
nella area 2g among the bacteria that have been most fully developed for
genetic analysis, but as their oxidative systems are not very prominent
at best, it 4s perhaps not surprising that no tangible results were
achieved. This 1a not to rule out the value of further attempts, but
the atmosphere ie already not very promising.

The aerobic bacilli would be likely to be more promising. I should he
quite surprised, however, if these had not been tested with eufliavine, most
likely by Plerre Schaeffer at the Pasteur Institute, Still, there would be
a large unexplored territory with such aerobes as Bacillus, Azotobacter, and
Paaudomonas, which I hope you will have an opportunity to investigate. On
the other hand, even supposing sane succese with the manipulation of the
plasmid system, there would still be the estimable problem of genetic analysis
which hes scareely been attempted with these organisms (except for my own
rather negative results in recombination assays with Pseudomonas fluorescens).
I do not think so large a problem should be entered on a casual basis.

A further consideration is the facilities of the Enzyme Institute, and
the research programs of your other sponsors, Professora Green and Wilson.
On the whole, I suggest that these would be most compatbhle with es program
xentuxeai tedhnically centered on the iselation of biologically or enzymatically
active particles from microbial cells. The Institute is not well set up for
much routine microbilological-genetic work, while it is admirably equipped
for particle fractionation and, of course, enzyme study. Therefore, I had
thought that your time at Wisconsin would be constructively focussed on the
4eolation of mitochondrial fractiogjs from yeast, and perhaps other microbes.
These fractions might then be exploited for a study of the influence of, Gefe,
euflavije, as a basis for the apo-plasmatic effect of this dye on yeast. They
would also provide an opportunity to test their re-incopporation into the
petite mutants, for which there may also be some other approaches we can
disouse later. The first topic would provide something less of a gamble
so that your time will not be misspent however the more speculative enterpriaes
some out. In any event, we can go over this after you get hers, end none of
your time now spent in reviewing the problem would be Wasted. Whatever /the
details of the problem, a modicum of samples of purified "euflavine" a
ite relatives would be handy to have.

Yours sincerely,

: . - : . / Joshua Lederberg