for Anmeal Report, Kat. Inst. Genetics,
Misima. March 20, 1958

FRANSDUCTIONAL ANALYSIS OF MOMGPHASIC TYPRS OF SALMONELLA
(Report by Tetsuo Iino and Joshua Lederberg’ )

The specificity of flegeller{H)hntigen in. Selmonelle is
controlled by two distinct®¥e loci, phese~l by Ey and phase~2
by Ho. Which one is manifested in a given clone depends on the
phase determinant at the En) locus, fhat is, the slternation of
Ho state leads to the alternative expression, whieh hes been
known as phase variation of H~antigen (the Annual Report, 1956).
Some Selmonells» strains do not express two pheses but only
one. Those strains sre called monophasic-l1 or ~2 strains depending
on their fixed phase, either phase-1 or phase~2 respectively.
Three additional groups of the genes which are involved in the
production of H antigen were disclosed by treneductional anslysia
of the monophasic strains.
S. gbortus-equi CDC-26 i9 stable in phsse~2, enx-type.
A rere slternative phase can occasionelly be obtained by anti-
serum selection, resulting in S“equally steble phase-l (a).
franeductions were carried out from enx~phase of ODC-26 to i-phase
of a diphasic strain of S. typhimurium, @2 i:1.2 (such transduction
is designated CDC-26 (n)tenx ~ x TM2 1:1.2). Among 65 trenaductional
clones which had been selected on semisolid nutrient gelatine-agar
media (NGA), 4 expressed Atphasic g:1.2 type, 42 diphesic isenx and

19 monophasic-2 enx which cerry a hidden H,!, Thus, when e is
treneduced afreeticon_of the transductionel clones hechiia-meonephesi-es

* Department of Genetics, University of Wisconsin, Medison,

Wis., Uv. 8; As
the resulting trans@uctions remain diphasic, whereas when eax

is trensduced a fraction of the transductionel clones become
monophasic, By anti~enx selection, i-phase cultures were
obtained from the monophssic enx-transductionel clones. The
i~phase cultures obtained are also monophasic. The stabilization
of the H, stete in S. abortime-equf is therefore caused byga
factopr whieh is linked to Ho. The factoy will be given a symbol

Ya, +

S- typhimurium SW1061 is a monophasic-2 mtant of a diphasic
strain TM2 i:1.2. The culture reacts to anti-l.Q serum but not to
anti-i serum. However, the strain frequently produces nonmotile
H-negative (non-flagellar) subclones, which in turn revert
to motile cells with 1,2 antigen in successive cultures,

From the treneduction, diphasic S._abony CD0~103 b:enx —x
$W1061, monoptsic-2 enx, diphasic b:1.2 and = small number

of i:1.2 types were obtained. ‘The change from the monophasic
type to diphasic types was always coupled with the less of the
ability to oscillate between motile and nomnotile types.
Thekse results are consistent with the following explenstion,
In SW1061, H,* is inactive; on the other hent H,*” changes its

=~

state as in usual diphasic strains. Consequently, when Hp is

active, phase~Z antigen, 1.2, is produced, end when Ho changes
to inactive, that is both _H) and KH, are inective, the cell
Cannot
munkfents produce EH entigen end become non-motile. The production

of diphasic § 1:1.2 type suggests that the inactivation of A is
not caused by sn intrinsic change of a itself but by en inhibition
of its function by = gene linked to Hy. The Linkage and the
recombination between Ey ant H)~kxabtirttexactivity controller were
confirmed on Fis,” (linked to B,) traneductions from SW1061 —~x

S. heidelberg Fla, rtl.2, from which monophasio~2 -(i):1.2 and
diphasic i:1.2 as well as diphesic r:1.2 were obtained,

The Hy-activity controller is designeted abs Ab) was discoveréd
in two other monophesio-2 strains of S. typhimrtum _» SW629 ant
SU547. ALL of three Ab,~ ere nonfallelic snd linked to 2, ant Fis,
The paire2 type of gene, Abo which inhibites the function of

Hp, was disclosed on four monophasic-1 strsins of S, imurium .

WBERXMRYX SANS KARE All of them sre linked to EL. Both Ab, and

Ah, are phase specific but are aot concerned with the specificity

of antigen types, which ere determined exclusively by A, ami Ho.
(the detail will be reported in yp