I. THE THIRD STRAIN WHICH HAS NON-MOTILE PHASE-1.
II. MONOPHASIC NATURE OF SAL. ABORTUS-EQUI.
III. ARE Hp AND PHASE CONTROLLER SEPARABLE BY RECOMBINATION ?

EV. PHASE~1 MONOPHASIC VARIANTS OF SAL. TYPHIMURIUM AND SAL. PARATYPHI B.

V. RECURRENT ALTERNATION OF PHASE IN SAL. TYPHIMURIUM.

Report by Tetsuo Iino ‘Dec. 1, 1957)
THE THIRD STRAIN WHICH HAS NON-MOTILE PHASE#1,

SW547 is a phase-2 monophasic variant of Sal. typhimurium. A mass culture
of the strain segregates swarms (motile clones) and colonies (non=-motile clones)
on a NGA plate. The change from motile to non—-motile and the reverse occurres

as frequently as phase variation, suggesting the contribution of a similar factor as Ah,
in SW1061 and SW629.

Transduction was performed from SW547 to Sal. heidelberg SW1092 Fla7(r:1.2).
KMotile transductional clones were screened on NGA plates, and antigen type was
examined. The methods emploied are the same as thosé described in the Report
1956-i. The results were listed in table 1 together with the results on SW1061
and SW629. Among 11 Flaj-H, transductions , 8 are phase-2 monophasics, which produce
non=notile phase--in place of phase-1, whereas the remaining 3 are diphasics,.
Thereofore, it is inferred that the gene which inactivate the function of Hy
in SW547 is linked to H, as in SW1061 and SW629. The monophasic factors in SW1O6l1,
SW629 and SW547 will be given symbols Ahj,, Ahjp and Ahy, correspondingly.

To test allelism of Ahj,, Ahyp and Ah}, mutual transductions were made
between SW1O61, SW629 and SW547. Non-motile phase was used as both donor and
recipient, and i~type swarms were screened on NGA plates which were supplxemented
anti-1,2 serum. As a control, diphasic Sal. typhicurium 1.2 was used as a donor.
The results were summarized in table 2a. They are parallel with the results
previously obtained between SW1061 and SW629 (c.f. the Report 1956-3),
indicatiang that they are not allelic but closely linked each other and presumably

belong to a cistron.

When the number of swarms which occurred by spontaneous reversion arex
substracted frou the data in table 2a, and the numbers of transductions are
expressed by % of the yield in which 12 was used as a donor, the results are
represented as in table 2b. The data present a rule that the yield of the
recombinant is higher in between Ahi, and Ahy, than in between Ahjp and Ahi,
when the donor or the recipient is the same. Samely, the yield between Ahip and
Ahj, is higher than that between Ahj, and Ahj,. If the assumption that the number
of recombinant between two loci aide a function of AEnkage distance can be applied

to these results, the sequence of Ahy., Ahiy and Ahj, may be a-=c-=b. However,
genetic background of these three strains are considerably different, and the
possibility that some factors other than linkage distence affect the yield of
the recombinant type is not excluded. Consequently, the proposed sequence
must be examined by a more appropriate analysis in future (for example,

Hy? Ahya Ahyp Hols 2 — Hat Ahi a Ab Hols? anti-1,2 serum NGA screening
test whethe? mAjér type is i or r.).

 
Table 1

Transductions from Fla7(i):1,2 monophasic variants of

Sal. typhimurium to Sal. heidelberg Fla7(r:1,2).

 

Transductional
types

r: 1,2

ri: 1.2

i: 1,2

i: 1,2

(r): 1.2
(i): 1,2

Total

Donors
SW629

152 145

189 161

0 2

6 1
0

je

6 30

356 341

SW547

81
32

Oo Oo OD WwW

127

Transduced loci

Flay

Fla,

Flay, Hy

Flay, Hy?

Flay, Ah,~
Flay, H,+, Ahy~

 

* The cultures were lost before hidden antigen type is determined.

Table 2

Mutual transduction. between Ah)~ strains. Recombinants between

Ah, loci were scored by countingthe number of i-type swarms on

NGA plates.

phages were used.

In each combination, 5 x 10° cells and 8 x 108

T indicates trail production,

 

 

 

(a)
Recipient SW1061 SW629 SW547
Donor (Ahj,) (Ahy p) (Ah ¢)
T™M2 (+) 266 +7 32147 235+T
SW1061 (a) 0 230 50
SW629.— (b) 86 106 58
SW547 (c) 72 193 2
(b)
Recipient SW1061 SW629 SW547
Donor (Ahi) (Abip) (Ahj c)
TM2 (+) 100 100 100
SW1061 = (a) 0 58 21
SW629 (b) 32 0 24
sw547 (ec) 27 40 9