CHEMICAL MICROBICLOGY RESEARCH UNIT,
DEPARTMENT OF BIOCHEMISTRY,

UNIVERSITY OF CAMBRIDGE,

TENNIS COURT ROAD,

CAMBRIDGE,

TELEPHONE No.: CAMBRIDGE 56288

 

24 November 1956

Dear Dr Lederberg,

Many thanks for the reprints and the WS of your
paper on protoplasts of E. coli, I shall be happy to
exchange reprints as you Suggest,

I was greatly interested in the penicillin method
Since I have lone thought that it has something to do
with cell wall metabolism - C@.2. see enclosed reorint
on effect of penicillin on electrophoretic mobility.
It is indeed useful to have qnethod for making coli
protoplasts -—~ I suopose they are strictly protoplasts,
i.e. have lost their cell walk. I think it useful to
define protoplasts in terms of cell minus cell wall, ion't
you ? 4 definition in terms of a change to a spherical
form which is osmotically sensitive seems to be inadequate
and inconsistent with current botanicaa usage, I hope
you will agree with this. I mention this because a nuxwer
of papers are appearing in which the term 'protoplast& is
used in various senses, It might be useful to zet some
joint statemaat on a definition as happened with inducible
enzymes,

I enclose what reprints remain and will send future
ones.

“ours sincerely,

: Kenneth MeQuillen

Dr Joshua Lederberg,
Department of Genetics,
Univeristy of Wisconsin,
Madison,

Aisconsin,

U, 5. A,

PS. Yon rf SBA UP HOE rvifar Es SL.
by ‘SMe we, Drea ve SEPe S&S,