yey in thy Lets 7

FJB/NR
xxx JOU55

AIR MAIL 2uth October, 1957

Professor P.W. Wilson,
Department of Bacteriology,
University of Viscorsin,
MADISON. LVCOMSIN, Ue C.As

Dear Professor “ilson,

For the past four years I have been working
in Conberra with a group studyinr various aspects of the
Rhizobium-legume symbiosis. Two and a half years of this
period were spent under the direction of Dr. P.8. Nutman,
now head of the Soil Bacteriology Department at Rothamsted,
England. For the first 14-2 years my work was concerned with.
nodule and bacteroid structure in a range of host-bacterial
combinations. My early training was in the Microblolory
Department of the University of Otago, Dunedin, New “ealand,
and my interests in the root nodule work have always been
mainly concerned with the vacterial component of the s:mbiotic
system. Consc-vently for the p st two years I have been
studving the physiolory a-€ strveture of the so-celled
hacteroids" of root nodules in rel: tion to the host tissue
in which they lie. I have exnminec respiration, nucleic scid
and nitroren content of becteroids ‘*reurrout the functional
life of soy bean nodules, and 1m st present envnved in a study
of the terminal electron tronsport system of these forms. In
addition, electron microscony of thin sections of soy bean and
clover nodules, has revealed a sub=-microscopic membranous
structure which encloses individuals and groups of bacteria in
the host cytoplasm.

The results of these studies have raised the
possibility that nitrogen fixation occurs not in the bacteroids,
but at or near their surface, possibly in the abovementioned
membranes. In order to clinch this an isotopic study of the
incorporstion of fixed nitrocen into the host tissue and into
the bacteroids, is necessary: that is, does the fixed N appear
first in the bocteri:1 component of the nodules, or in the nodule
eytoplism.

Now aoecs the noint of this communication. At
present ve hove no fecilities for neavy isotope work, although
there is a mnss spectrorraph in the Australian National University
whieh is virtvally next door to us, but they are at present
engaged in work with lead isotopes and cannot conveniently help
us at present. The surgestion has been mode that I write to you
and encuire if it would be possible to come and work in your
department for one year, to gain exnerience with 15 N and perneps
even to carry out the experiments which we have in mind. If
the programme of your department would permit this, the
experience I would gain and the contacts I would m=ke with
people interested in symbiotic nitroven fixation would prove most
valuable for future work which I ray he cshle to do on this

subject.
~ 2 -

It is my intention to apply for a Commonwealth
Scientific and Industrial Research Organization Overseas
Postgraduate Studentship for 1958-59. However there is only
a limited number of these awarded each year for study in the
United States and my chances of winning one are therefore not
great. Should I be unsuccessful would there be any possibility
of a research assistantship or other similar appointment in
your departrent? If there is, I feel sure C.S.1I.R.0. would
provide additional finencial support for travel to and maintenance
in the United Stntes.

I will, of course, be pleased to supply in greater
detail my qualifications, exnecrience, publications and so on
should you recuire such information, but I think I have proviced
sufficient for this preliminary enquiry.

I am,

Yours sincerely,

(F... Bergersen)
RESEARCH OFFICER