UNITED STATES DEPARTMENT OF AGRICULTURE

AGRICULTURAL RESEARCH SERVICE
NORTHERN UTILIZATION RESEARCH BRANCH
PEORIA, ILLINOIS

October 25, 195)

Dr. Joshua Lederberg
Department of Genetics

The University of Wisconsin
Madison 6, Wisconsin

Dear Dr, Lederberg:

I am glad to have your letter of October 18 and to know that you are
interested in studying some species of Hansenula and some of the
species of Saccharomyces which we intend to place in a separate
venus, to be designated as Dekkeromyces. JI hope they may serve the
particular purposes you have in mind.

We are sending you the following strains of Hansenula:

NRRL Y-1683, diploid H. subpelliculosa
tt Y-1822, nt W tt
"  -Y-1622-12 and Y-1683-11. These are mating types
of opposite sex.
"  -Y¥~366, a unisexual diploid of H. anomala
" Y¥-2153, a bisexual " a oF n
" Y4366-8 and Y-2153-l, mating types of opposite sex

I would suggest heating sporulated cultures of Hansemula at 57° C,
for isolation of mating types.

We are sending you a culture of Zygosaccharomyces ashbyi NRRL Y-1598,
It is a latent lactose fermenter, requiring about 8 days to ferment.
It hybridizes readily with other lactose and nonlactose fermenting
species which wil] be placed, with it, in Dekkeromyces,

 

None of the diploid species which will be placed in Dekkeromyces are
heterothallic, so I cannot send you mating types, but I am sending
you mating types of Saccharomyces lactis, a heterothallic haploid.
Strains NRRL Y-1140 and Y-1205 are typical of the species, including
ability to ferment lactose rapidly. They are of opposite sexes.

I am also sending you strains of Ss. lactis which do not ferment
lactose, Strain Y-113 assimilates neither lactose or galactose,
and mates with Y-11h0. Y-230 does not assimilate lactose but it
assimilates and ferments galactose; it mates with Y-11l0 and Y-113).
Strains Y-110 and Y-1205 are known to hybridize with Y-1598, and
probably the lactose-negative strains of 5, lactis would mate with
Y-1598. We have hybrids of S, lactis x Z. ashbyi which Dr. Rotman
is welcome to, ~ ~

 

 

THIS PAPER CONTAINS 49 PERCENT.
BLEACHED WHEAT-STRAW PULP MADE
BY OUR MECHANO-CHEMICAL PROCESS

 

 
2-Pr, Joshua Lederberg-~10/25/5h

I am sending you reprints on the occurrence of yeast matine types
in nature which deals briefly with 5, lactis, and one on the iso-
lation of mating types from diploid heterothallic species of Han-
senula,

We are sending a short mamiscript on hybridization of yeasts which
will be placed in a separate genus, Dekkeronyces, at a later date.
It has not been published yet, and I would appreciate it if you
would return it within the next month. J am now preparing two
rather lengthy papers on hybridization of 5S. lactis, 5. fragilis,

42. dobzhanskii and Z, ashbyi, If you are interested in seeing then,
they should be sufficiently advanced in a couple of months to send
copies to vou.

Sincerely yours,

lynferd J. Wickerham, 4yrologist
Fermentation Section

Enclosures 3