5 i
G25. Genetic Exchanse in Selmonella, N. Db. “inder

end J. Lederberg, Denertment of Genetics,
University of Wisconsin, liedison, Wisconsin,

Salmonella typhimurium, when grown in the presence
of week nheges, produces @ filterable agent (Fa) cap-
able of trensferring hereditery traits from one strain
to enother, Individual filtrates may transduce many
éifferent treits, but no more then one to 2 sinzle
becteriua. The activities of e filtrete parallel the
cherecteristics of the donor cells. Nutritionel, fer-
mentetive, drug-resistence end antizenic cherecters
heve been trensduced. FA is resistant to such bec-
terial disinfectents as chloroform, toluene end
alcohol, end to severel enzymes including vencreetin,
trypsin, ribonuclease and desoxyribonucleese. Tho
size of the FA perticle, es determined by filtration
throush gradocol membrenes, is about 0.1 micron,
Adsorption of TA is rapid and, among verious sero-
types tested, is correlsted with the presence of
somatic entigen XII. Some inter-type transfers
heve been observed. Yor example, the i flageller
antigen from S. typhimurium hes been transduced
to.$. typhi to give a new serotype: IX, XII; i,--.
Genetic trensduction.in Salmonella is compared
and contrasted with "type transformetion"™ in
Eemophilus end the pneumococcus and with se-uel
° recombinetion in Escherichie coli.

Reprinted from Bacteriological Proceedings,
1952, p. 43.