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June 1, 1951

TEPORT ON RESEARCH PROJECTS

 

 

for the
FISCAL YHAR 1950-51
501304
Name UEDERBERG, Joshua Dept. Genetics _ Proj. No.
m4 tle Bacterial Genetica
Personnel: Ethelya lively, Phyllis Fried Research Assistants
Norton Zinder” Res. Asst. (NIH)

E. Lederberg Project Associate (Chemical Corps)

. Statement cf other finencial sunvort, if any:

Rockefeller Foundation Spey "$000 (expared 5/1/51)
National Institutes of
indie eo tly related]

Chemical Corps Contract "moe. [0

Brief statement of specific “tooo (BY during

1. A new mechanism of genetic exchange was found in Salmonella typhimrium,
involving filter-passing entities produced by the bacteria under stimlus
from deleterious agents such as penicillin or phage. These entities may
be related to the L-forms described by other workers.

2. A mathod was developed and successfully applied to sereen fresh isolates

of Kecherichia coli for their ability to hybridize with strain K-12, previously
unique in this quality. From about 650 strains tested, 20 have been found

that can be crossed. They are of a variety of cultural and serological types:
the genetic basis of their natural differences is under study.

3. Genetic and cytological effects of radiations (ultra-violet light) were
correlated/ The effects of UV in causing nuclear aberrations persist in some
progeny after other descendants of a single cell have apparently recovered.
The basis of killing by radiations appears not ha to be hereditary lethal
mutations to any extent, but rater a damage to nuclear material from which
later recovery is possible, in eehascelis but not others.

. Publications that have appeared in print during the present fiscal yeer:

Lederberg, J., Isolation and characterization of biochemical stants of
bacteria, Methods of Medical Research, 3: 5 - 22, 1950

The beta~D-galactosidase of Eacheriahia coli, strain K-12.
Jour. Bacteriology, 60: 381-392, 1950 (October)

Streptomycin resistance: a genetically recessive amtation.
a icteriologs 614 549-550, 1951 (May)

MR. Lederberg, J. ‘Le-cell isola ng of diploid hetero us
Rachentahde solks Soon, Basterlobene ble 35a oss. (aber) a
ener accented for publication but not yet EBL

Lederberg,J., Gehetic studies with bacteria. IN Genetics in the 20th Century,
» New York, 1951 (June?)

Prevalence of F. coli strains exhibiting genetis recombination.
Selence, In Press

The pink cony should be returned to the Graduate School Office on or before

éviy 1, 1951. The biue copy is for vour file.

 

 

Lederberg,J., Lederberg,E., Zinder,N.D., and Lively,E.R., Recombination analysis
of bacterial gBeredity. Cold Spring Harbor Symposia on Quantitative Biology,
XVI, 1951, In Press.