JUL ~ 8 Jo02

Yale Universi ty Department of Biology Campus address:
Osborn Memorial Laboratories Osborn Memorial Laboratories
P.O. Box 6666 165 Prospect Street
New Haven, Connecticut 06511-8155 Telephone: 203 432-3850

Fax: 203 432-3854

June 28, 1993

Dr. Joshua Lederberg

The Rockefeller University
1230 York Avenue

New York, NY 10021

Dear Josh:

Many thanks for sending information on the early cultures of K-12 wildtype. This
was very helpful.

Bruce Stocker just called today to say that they have one old lyophil of K-12
remaining in the collection at Stanford. Lyophilization came along rather late in
the day. Nevertheless, I cautioned him not to let anyone open it for trivial reasons.
He is going to send me a transfer of their present vegetative stock.

Many persons now working in the field do not have any training in microbiology
and don't realize that vegetative cultivation of a bacterium on various media for 70
years in the laboratory could very well lead to an organism that differs significantly
from the original isolate. It would not be surprising if different tubes of K-12 carried
different mutations. At Stanford they now cultivate it on nutrient agar slants (not
even stabs, apparently) and have done so since anyone there now can remember. I
don't know when "nutrient agar" was first "invented" nor whether the formula for
this medium has changed over the years since it was first concocted.

Maybe someone who is really good will be willing to look into this carefully some
day. We have 4 lyophils of WG1, three of them dated 1951. I'm not going to open
them unless someone has a very good idea of what to do with them.

Thanks again for your help.

Sincerely,

“arborea

Barbara J. Bachmann
Curator, E. coli Genetic Stock Center

BJB/bac