May 14, 1952

Dr. Bllis Englesberg
Hooner Foundation

U. Cal. Medical. Center
San Francisco 22, Cakif.

Dear Ellis:

Horton Zinder was describing the symposiuamat Boston on "prototroph”"
just the moment your letter came in.

Your usaze of prototroph is certainly correct. Remember that words
ara the tools of men, and not vica varsa. The context in which "nroto-—
trenk" deovalopad was that of the re-isclation of nmtritional wild types
from enyo-hsterctroohic mutants. In your context, Lt might be confusing
and 1 think it would be better to avoid "prototroph" altogether; other-
wise you will haves to define your terms very explicitly.

Yon might he intereated in the evolution of “auxotroph”, (T think it
better to accent, 14 as & bastard word then forse it into e menning It does
hot have, of greater erowth recuiramants., The wixo- means vrorth factor,
ae in auxin]. The expressions auxo-heterotrophic and auxo-autotrophic
ware already more or leas acceptable, the prefix specifying the context
of growth factors rather than ¢ or anergy nutrition. Auxotroph is alimply
an shbreviation cf auxe-heterotrork. These terms area ‘absolute’, lacking
the directicnal connotation of protctroph.

Prototroph is related to a protetype. This would ordinarily refer to
the wild time, as 4s. But it is theoretically sound to regard the auxo~
akieep autotrceph as the ancestral prototype of P. pestis, and you could
tranafer the terminology on this basis. However, I still think it would be
best of all not to use prototroph at all in this context. Except that no
one will be able to spell or pronounce it, Ischnotrepn vould have its uses.
1 would prefer "auxoautotrophic".

If you are gohng to coin 4 new term, why not go after the suffix end.
Auxotroph has the context that the organism feads (deveridentiy) on growth
factors. Why not dig up a termination in place of -troph tc imply that it
synthegiazs3 its own, or that 144 is sslf-offictient,

Zinder 1s working on the kinds of experiments you brought up. No
8. typhimurium is nonlysogenic, unfortunately. Streptomycin-resistance
may already serve for what you so-call a "negative" hereditary trait.

Sincerely,

Joshua Lederberg

hk