THE ROCKEFELLER UNIVERSITY

pro bono humani generis
1230 YORK AVENUE - NEW YORK, NEW YORK 10021-6399

Joshua Lederberg
UNIVERSITY PROFESSOR

April 19, 1998

Ms Elaine Yaffe
1215 N Cascade Ave
Colorado Springs, CO 80903

Dear Ms. Yaffe
Harry Wassermann has referred your questions about Polly’s science to me.

I remember her well, with affection, as a woman who was laboring to get back into science
after many difficulties, and grievous personal loss. She was my lab mate at Yale, under
Tatum. Her recollections of me are colored by a few incidents of clumsiness with glassware;
I was also a very callow youth (20-21) at the time.

The system of red/white color variation in Serratia - the easiest marker to follow, just by
plating cells to form colonies on agar, was an intriguing one. Red strains would give white;
and vice versa. She made careful descriptive observations; but to this date I do not believe
the color variation has been closely enough studied, even with the DNA molecular technology
now available, to give any answers about mechanism. If I had to guess, I would look at it as
another possible example of phase variation (1). Work with Serratia has been hindered,
however, by the absence of a full blown system of conjugal recombination, as we know for E.
coli.

A few workers like RW Kaplan in Germany and Harshey in Texas have picked up on some
aspects of Serratia genetics. A 1978 review in Ann Rev Microbiol (see encl.) by Grimont and
Grimont barely mentions Bunting. But Serratia has come back into visibility as pathogenic,
drug-resistant variants intrude themselves, and we may see more about this "prodigiosus" bug
in future. I hope you will have had a chance to see the spectacular display of its scarlet
colonies on agar plates. On one occasion, at U/Wis I was plagued by many of them coming
in as contaminants on my plates. This coincided with the experience of my close friends, Dr
& Mrs William Stone, having a newborn who was excreting bright red feces - as it turned out
the baby girl was also colonized with the same strain of Serratia. This turned out to originate
from some aerosolization experiments being carried out nearby on campus: happily with no
pathological effect other than spoling my plates and scaring the Stones.

I hope this is helpful. Did you want the reprints back? If so, just whistle.

E MAIL: LEDERBERG @MAIL.ROCKEFELLER.EDU

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