ISTITUTO Di PATOLOGIA GENERALE E BATTERIOLOGIA

DELLA UNIVERSITA DI GENOVA Genova, January T6,T95T

Direttore: Prof. LUIG! MICHELAZZI Viale Benedetto XV
Telef. 31.421

 

Prof. Joshua Lederberg
Department of Genetics
College of Agriculture
University of Wisconsin

Madison(Visconsin)
Dear Professor Lederberg,
many thanks for your letter of January 9 and for the kind advices which are
contained,
Your observations are essentially right.In effects,it cannot be excludedysa
priori,that the induction of new biochemical activities which I have obtain
ed in my strains is a consequence of an adaptive rather than of a mutative
phenomenon. In this case,however,it should be necessary to admit that desg
xyribonucleic acid has the ability to stimulate and to orient the adaptive
processes, because the untreated original stzzins,which were not able to
attack the sugars at the beginning of the experiment,maintained this prv=
perty at the end .I will however call your attention on the fact,which is
described &b page I65 of my italian work,that the strain of Proteus OX 19,
which did not produce ddaptive enzymes for the oxidation of xylose and
fructose even efter 45 passages on media added with the sugars,was able to
acquire the oxidative ability after a tre&ament with the NP pf Proteus 0X 2,
In this case it seems very difficult to think to an adaptive phenomenon.

It cannot be excluded also that NP provides the most favorable conditions
for the overgrowth of the variant cells.Nevertheless,it should be neces ary
to admit that not all the NP fractions have this ability:in effects,the ac
quisition of the new properties did not occur after treatment with NP from
all used bacteria(e.g. with NP from Coli IO).

In regards to the determinative technique which was employed,the manometric
technique was choosed because it offers the possibility to measure also the

little differences,which are not detected by cultural methods.In a second

atey of my research,¥¥uH the biochemical activities were tested also with
cultural methods,in media of agar-bromothymol-blue -sucrose(virage to

pH 6.0-7.6):it was observed that Coll 19 is a good fermenter(I agree
with you on this point),while the strains SG and I{@G-I6)are less good
fermentes and Coli I is a non-fermenter: these properties,in our media,
are now maintained et present. If you consider the values of attack which
are reported in the Tables I and 2 of my italian work,you can see that a
great correspondence exists among these data.

In regards to the acouisition of new enzymes,it results from the experim
ments of Avery and al. and of Boivin and al. that a rearrangement of the
enzymatic enuipment must teke place during the trensform.tive phenomana:in
effects,the production of a new capsular polysaccharide must be related to
a rearrangement of the enzymes which are responsible for therr synthesis.
Acquisition of M ptotein by mutation directed by DNA in pneumococci was re
cently described by Macleod and Austrian :it seems likelyjfrom these resear
ches,that elso the proteins can be acquired in consenuence of a directed
mutation :the enzymes atbo are presumably proteins/.

At present I am studying on the possibility of directed mutat*‘on in Staphy
lococci:I have found som differences,probably of mutative origin,in the
oxidative ettack of methionine and of cystine by tretment of a Staphylocoe
cus with the NP fractions from otherg Staphylococci. Anyhow, further resear
ches in the direction which you have suggested will be performed.Ifwill be
my duty to inform you on the eventual results,either positive or negative.

I shall look forward to Bearing from you agein.

Thanking you very much for your interest and for your very kind advices,I
am

Yours sincerely

Meee |X, Vy Ws } wel

Mario U.Dianzani glie De 9
Pharm.uv.