Leunnmrr
Dear Joshua!

Let me be permitted to give you a short report about some main
results from researck in starforming bacteria:

1.) strain Be, I did show you in Madison

mutants

red pigment formation poor pigment production
( carotenoid ) r leukos 1
rough colonie formation R ‘smooth Ss
Streptomycin resistance
different degree resistance
from 0,02 — 1,0% Sm™ Sm?
Aneurin auxotroph aneu” aneurin prototroph aneu*
Adenin " ad”  adenin " aa*
needs casein hydrolysate
polyauxotroph ;
high back mutation rate =107/

aux prot

cross experiments
a.) 1 R aneu~ Sm™ xX rR ad™ Sn™
gelective medium : minimal medium DO
recombination type :1R aneut ad’ Sm?
" rate : 5X 1076
be) 1 R aneu~ Sm™ X rR Sn®
selective medium : DO + Sm
recombination type : r R aneu* Sm*™
" rate : wii bitehy 4X 1o~6
ce) 1 Raneuw~ Sm’ xX fr S Smn§
selective medium : DO + Sm
recombination type : rs aneu’ Sm*
" rate : 3X 1076
The recombination with a smooth strain is an exception by this high-

starforming type.All other smooth strains are low star formers
and dotnt show any recombination.

 
~?.
2.) strain Agrobacterium stellulatum

mutants
R S
0,02 - 1% Sm™ Sm8

penicillium resistance
by means of penicillinase-

production, 3o0U/com, pen’ pen®
isoleucin auxotroph
ileu7 ileut

cross — experiments
R pen™ xX R Sm?

selective medium : nutrient agar + 0,5% Streptomycin
+ 30% U/eam Penicillin

recombination type : R pen’ Sm™

" rate : 3 X 1079
With S strains no recombination is observed.

3. ) strain By; Spirillum spec.?

mutants
yellow-grey pigment gr. ellow~red pigment r
0,04 - T of Smt y P en SmS
Chloramphenicol chlor? .- chlor’
10 y/com
Valin auxotr. val valin prototr. valt
Cystin "* 6y~ oy*
Threonin " thr7 thr
ValinyLeucin; +
Isoleucin auxotr. II7 II

not clear cut
cross experiments

gr cy~ chlor®r X fr thr7
selective medium : DO + chloramphenicol.
recombination types : gr cy, thr, chlor
rigey thr chlor*®
" rate 107
er 1/3
r 2/3

'In all cross experiments with the three strains samples of the
parental strains has been plated in the same mddia as samples of h
the crosses to prevent any misinterpretation caused by spontan
backmutations.

In B cross the phanotypic expression of the recombinants needs

5 - &aays.1 can't explain this lag period,

B,. seems to be more convenient for the genetical work tk as the
otter two strains,but more experience is necessary.

 
-3-

All orosses are performed in nutrient broth tubes puted in a tube-
roller.After 3 - 5 days the suspensions are washed twice and than
samples are plated in the selective media and distinct solutbons
in nutrient agar for cell count.If the cells are coherent in
» agglutinatione sessuale " (B, and A,stellulatum) the clusters
becomes disrupted by a high spgea mixer before washing.
I think these results are sufficient to give evidence for recombi-
nation in starforming bacteria but they give nog information
about the way of exchange.

Now I will prepare a publication of some of the results.
I have learned in your lab to work genetically with bacteria-
it was the happiest learning time I ever had.-I am thanksful every

time to Esther and you and I should like tofnow if you want to

participate in any way in the publication.Give me a short notice
about your wishes please. 1

Many thanks for the seas@ng greetings from Esther and you.-—
We have a very early springtime this year,the first flowesgs come h
in blossom now,crocus and eranthis hiemalis. .

Did you saw some of the olympio games in Squaw vallay?

All good wishes to =sther and you from Barbara

Sincerely yours