UNITED STATES DEPARTMENT OF AGRICULTURE | ahtaws .

AGRICULTURAL RESEARCH ADMINISTRATION

BUREAU OF AGRICULTURAL AND INDUSTRIAL CHEMISTRY
PEORIA 5, ILLINOIS
Northern Regional Research Laboratory

February 21, 1946

Mr. Joshua Lederburg
% Mrs. E. Schrag
Columbia University
Department of Zoology
New York, New York

Dear Mr. Lederburg:

I shall be glad to send you cultures of the normal and agglutinative
forms of Schizosaccharomyces versatilis NRRL y-1026 as requested in your
letter of February 6, 1946. I cannot give you specific information on
the genetics or characteristics of strains derived from isolated spores
as we have not studied the species in this respect. However, I shall
give you what information I can on the points you discussed.

 

1. The spores will have to be isolated before the ascus ruptures if you
desire to know the source of all spores worked with. Since all asci with
a full complement of eight spores will break of its own accord, the intact
ascus may be isolated and allowed to rupture of its own accord. The spores
should be easily isolated since they are produced in large mumbers.

The vegetative cells of species of Schizosaccharomyces are much more resistant
to heat than the vegetative cells of yeasts in general, but I do not know
how much more resistant the spores are than the vegetative cells.

2. We have no information on the number of chromosomes or characteristics
of meiosis, ,

wa ae 5. Some factor in addition to the ordinary B vitamins is necessary to the

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4 yeast extract medium.

| best, development of this yeast, but we do not know what it is. However,

his yeast will grow well on potato-dextrose, wort, and to less extent on

4. The agglutinative form is the only mutation we have observed other than
a marked variation in growth rates of different colonies on some media. This
may reflect variations in the ability to synthesize needed growth factors.

Should you desire to study the nucleus of this species, I would suggest that
you use the coverglass type of culture described in the paper, for this way
you can observe the growing culture from time to time and use the cells when
the nuclei are most clearly visible in the surrounding vacuole. The coverglass
may be removed to give free access to the cells observed,

We shall send you a reprint when they are on hand. f f eobrbar?
Oo

Sincerely yours,

Lynferd J. Wickerham, Zymologist,
Fermentation Division