Che University of Melbourne
Bacteriology Department.
Carlton, N.3,.. 2ist October, = /9 59.

VICTORIA, AUSTRALIA

Dear Josh,

Many thanks for your letter of October 7th and the 1954 report which
arrived a few days later. Haven't really looked at the latter yet, but it
shouldn't be too hard to produce a much more extensive, if not beéter report,
which I hereby declare you will receive.

Have seen August J. Bact. but why mess about with snails guts when you can
do it all in tt's! And possibly even better with Streptomyces than with Aero-
bacillus. Haven't done any more on this for months now, but will get back to it
sometime. What I need right now ané several more pairs of hands. Have almost
completed the counting of a 10 clone, -5 cols from each at 3 times (40, 60 and
90 hours) experiment and am still recovering. This would not have been finished
but for the generosity of two friends who stayed back and spread plates with me
"til 2.30 and 3.30 a.m. respectively. Will not attempt this type of experiment
again without some assistance - which I have been promised in a couple of weeks,
when classes end. Probably won't do it again anyway with the present stocks.
Have asked Ephrussi for some guaranteed haploids with auxo-markers and preferably
of a non clumpy growth habit.

Haven't heard from him since he left France and am thankful for it in one
way because I have now worked out on my own a "Unified Peteteness Theory" based
on episomes and would have been disappointed if If had heard it from him first.

Your conments on the "fish gmess" of the frequency of segregational mutants
and the formation of "doubles" from these supplied the final jolt necessary to
get my mind working - even though I had misread it on first getting your letter.
Being rather preoccupied with suppressives I substituted this word for segregat—
ional and - heresy - thought to myse&f - "Josh is getting a bit sloppy in his
thinking, but one cant expect him to keep up with the details of everything".

Not much!
Morse -_ This is the story as I now see it. Douek /
<p NE > R- ~ Orne > A mer ec,
R* been TS _- _ > tg Ct nahin beet
Creme secccg ! - . 7 “se toned foodan,

s of neural fact Pp tek

Neetra! ~ (Ep xR7 R*)

ache . Ro

&
70} —8--- the. e # 5 a
; HE pet Se

eve

lowe s. iv “at b . .
trian a ty Sp lng f anki la (as toy

wei fruct new BS
2.

The cytogene is the Suppressive factor and inactivates or destroys
the normal factor. The product of the combination of the locus and chromogene
is some freely diffusible substance necessary for the activity of the mito-
chondrial enzymes, which are produced anyway because of presence of the normal
factor (Jamys green experiments with Hans Ris} when mitochondria of both cells
in mating pairs (R” x R+) were stained though migration of mitochondria not
observed. This would need to be repeated with more careful control over timing
and the introduction of mitochondrial counts. The hypothesis is fortunately
subject to a number of tests, some of which, based on the simplest and most
direct interpretation are:-

1. Difference in neutral petites depending on orig.

+ - + — —_
(a) R > RO (b) R “> By _s y09 "RR
Ro a) x Rt wy 0 tage. ~ — _BelddeR* > 212 cop Eph ngt alg 1955,
é. Should get some 2:2 asci from Reox R

I wonder how many such asci were tested by E., H. and R.

3. Segregational R. should show some suppressiveness pattern as vegetatives
i.e. low at birth and increasing with growth (as they approach "doubles" 3.

4, In cross Ro x Ro --> R” one should obtain segregations varying fram 2:2
(with "new bor" R=°) to O:4 as § factor multiplies.

5. R Segregants from cross of highly suppressive petite x R should show
segregation in further cross to R’. Such segregants could be obtained by
direct application of mating mixture to sporulation slant or by use of

"mentee" - still to be developed.
von muy

Have said most of this to Ephrussi and am now anxious to hear if his ideas
are different. I am working on a very interesting set of compounds (phenanthrene
derivatives) with a bloke from the Physiology Department (Albert Shulman). He
found a marked depression of respiration of brain tissue and Syd suggested that
yeast would be good material to use to get some idea of the basis of this effect.

I have found that some of the series ~ especially those which depress
respiration of brain tissue - produce a high yield of petites. So the point of
interference is not solely at the enzyme level but the heritable normal factor
is also affected. Some of these compounds have a ye potential in the region
of the terminal cytochromes so I am hopeful of being able to rig up an external
"cytochrome" system - ' safle" to enable R™ cells to produce spores. May run
into trouble if energy is the limiting factor in non sporulation of petites, but
worth a try. As I said — more hands needed,

Bruce has a reprint of your single-cell mating pair work (P.N.A.S.) which
I haven't seen. I thought the J. Bact. effort was the last published work on
this. Could I have one please? Have you examined the question of F infection
by micromanipulation? Would be darned tedious work but perhaps worth it? Bruce
came back with some such Story, but is not sure if the work had been done, was
being done, or just comtemplated.

Haven't heard from Canberra yet, but am becoming increasingly interested
in the Rhizobium problem. May have "discovered" transduction already in the
3.

literature ~ J. Kluzkowska J. Gen. Microbiol 4 298, 1950 and even earlier,
J. Bact 1945, I think. She found that phage resistant mutants often had
mutated in other respects. Haven't had time to look into this yet, but the
thought struck me that it could be a case of transduction.

att-fer thw. Will be very interested to hear what you think about the
petite story. Hope you are finding more time for lab. work or at least can
transmit your ideas to a capable pair of hands - which isn't half as much fun
but better than nothing.

Went down to do some boundry marking on Syd's new estate at Mt. Martha last
Sunday. He has a wonderful spot and we all had a most enjoyable time. Of course
he has plans for a tennis court, swimming pool, golf course, and house. Anyone
of the former wil involve a major earth moving job since the land, in most places,
slopes 10 to 30° - but if anyone can get it done he will. Was also very pleased
to see Ellen apparently quite well again.

Had another letter from Larry and have just written to him asking if he
can take, or knows anyone who can take, a grad. student. I am anxious to get
one of Bruce's students to the States. He is due to get his M.Sc. next March
and I think he would benefit tremendously by getting away for a while. He
hasn't got much of a reputation here as a researcher but strikes me as reasonably
bright and tremendously enthusiastic. I am sympathetic because he has many of
the faults which I had before I went overseas, e.g. tries to do the perfect
experiment the first time and hence doesn't get to do much except think about
details. He is also not very good at expressing himself and is not allowed
to forget it around here. Name Barry Egan. Now working on lysogeny and co-
operation in Pseudomonas phages and wants to go on in plage genetics. He has
done well in all of his course work and has had a good background in chemistry,
but is unfortunately ~ I think - not particularly interested in pushing the
chemical side.

I think he is good Ph.D. material particularly din view of his response to
my interest. Could you suggest anywhere he might get an assistantship? Larry
would be the ideal person to develop him, but I don't know if he can consider it.

I'll bet Stanford Med School is feeling pretty smug about it's two recent
Nobel laureates. Maggie Blackwood talked about Brink's stuff and during the
discussion John Paternan from Botany ~ (a heck of a good bloke to have around
since he is prepared to discuss and think about anything in the microbiol genetics
line) - suggested that the transallelic effect might be comparable to an adaptive
ema.effect. This is still an extremely vague notion in my mind, but is seems
worth thinking about. Any transfer mechanism seems out because of the 100%
nature of the change and diffusion of a utegenic substance seems out because
of the lack of reduction of the effect in trgnslocated stocks, where pairing
couldn't be so close. I am not conversant with the tests which Brink has done to
rule out cytoplasmic effects, but am going to talk the business over with Maggie
sometime. In fact, she and Nancy are coming to our place for dinner tonight when
the feature attraction will be her picture of your Nobel citation.

peaks more than enough for now, I am sure you will agree, so with best
regards to you and Esther, I'll sign off.
brafthy tort)