Department of Siochemistry,
University of Cambridge,
17 December 1957

Dear Dr “ederberg,

Your altogether charming and disarming letter has undone me
and I fe@l it was well worth waiting a year to hear from you .
Thank you for your kindness in replying at such length and with
such felicitous phrase to my enquiréés.

I respond in some haste because a final draft of the vcroposed
letter to Nature has been concocted and is girdling the globe and
I would feel the usefulness doubly secure were your name to appear
on it along with the others who have agreed to sign. You may
notige that I have slightly modified the orizinal wording in the light
of your remarks (and others) but do not feel able to crusade at this
time for the all-embracing term you desire (and I would favour).
Is it not perhaps best to establish first the correct usage for one
term and then go on to invent such new terms as are necessary and
agreeable ? The disease you mentioned can be chromic or acute
but also its effects may be malignant or benign. As you say usage takes
precedence over aesthetics but although the exisftng circumlocutions
are far from ideal (osmotically-sensitive spherical forms, etc.)
they are simply descriptive and are sufficiently variable (globular
for soherical and sog on) that they need not becomgridified into
forms which are later regretted because they imply too much, too little
, or something errant. Of all your alternatives I think I like best
MALAKOPLAST while HABROCYTE is least euphonious. Since it is a
aN Heraklean task to get two or three people to igree on a definition
3 and since there seems some chance of half a score putting signatures

¥ to this note of mine, would it not be well to cry @mirabile dictu"
vs and leave it at that for the time being ?
\ ;
~ To turn to your query concerning other lesions in Gram-negative
~ walls. It woudd seenfthat four components aré involved:
se Protein, lipid, polysaccharide (or lipopolysaccharide):
S ani mucopolysacchartde.
iy The lattte~ containd@ the D-smino acids, DAP, hesosamines ani so on,
¢ the polysaccharide, the mannoheptose and other sugars. Already I have

suggested to Toemhéesand Shockman that with their Strp. fagelis 9790
restriction of D-amino acids should lead to similar e&fects to lysine
4 deficiency and that it might be possible to derive protoplasts thus.
The exact experiments I had in mind have not be done but related ones
showed lysis when D-al@gng@ine became limiti»og as predicted bu: this was
A followed by a fresh wave of gpweth - cerhaos due to some synthesis of
B6. However, it seems to me that all these approaches - muramic acid,
 D-amino acids, glucoasmine, DEB etc. are all aimed at the same component
-~ tre mucopolysaccharide. “hat is needed is additwonal deprivation .
How about ethanolamine ? Or a double mutant DAP and e‘hanolamine ?
My thinking starts from 2 belief that it is likely that there is
lipoprotein in both cell wall and cytoplasmic menbrane and that therefore
chemical methods are Uf prdably not adequate to distinzuish the two.
But biochemical méhods might - it is p>ssibé@é that the lipid is

037

*s
ad
a
different in the two structures - for instance we have recently analysed
protoplast membrane of M. lysodeikticus after removal of the cell
wall with lysozyme. The wall contains four amino acids and 2'ucose
ani a lot of glucoasmine and muramic acid. The protoplast membrane
(cytoplasmic membrane ?) is 50% protein cantaining all the usual
amino acids, 28% lipid (more than 80% phosphlipid but not containing
any N - i.e. no ethanolamine, serine, choline etc.) and is probably
polyphosphataddtt acid) and 15 - 20% carbohydrate - largely mannose
probably weth next @@ no glucose and very little if any amino sugar.
Weibull has analysed the lipids of B. megaterium and avain finds most
of thetotal lipid is polyphosphatidic acid. Perhaps the lecithin
type phosphatides occur in Gram-negzatives walls and not membranes
so that ethanolamine deprivation would impair wall but not membrane.
This kind of approach I think might be fruitful.

I finished @ week or to ago my chapter on Bacterial Protoplasts
for Gunsalus an@ Stanier's book on "The sacteria" and wish I coudd
have seen your paper before writing it. However, I gambled on

the Gram negafives being "protoplasts" rather than protopiasts stricto
sensu and it seems that it came off.

 

I shall write again later if I may ani in the@meantime may I

ask that you consider whsher or not you feel able to sign this note
to Nature ?

Rll good wishes,

Yours sincerely,

f bee

 

_fkenté thvequillen. |

a

P, S. I shall send you under separate cover the Ms of a paper on the
chenistry of the protoplast membrane in ¥. lysod:ikticus, a note

I wrote for Lancet, the MS of a symposium contribution on Bacterial
Lysis resulting from metabo ic disturbance. I have also a copy of
my chapt=r on protoplasts wh'ch you are welcome to see if you would
so wish. It is bulky and has to go to one or two other peeple but
please let me know if it would be of any interest to you.

Professor J. Lederberg,
Dapartment of Genetics,
University of Wisconsin,
“adison, 6,

Visconsin,

U. “. A.