PHASE-1 MONOPHASIC VARIANTS OF SAL. TYPHIMURIUM AND SAL. PARATYPHT B A type of phase-l monophasic variant occurres by Sho”, Theoretically the pther types may occur by the suppressor of Ho, or by a factor which shifts phasel/phase-2 equilibrium extremehy to phase-1 side; in other words, by a factor which inhibits the change from inactive E> to active Hp but does not reverse. ‘The deficiency of Hp can also be tha cause of phase-1 monophasics. These monophasic factors colld be in Hp itself, in H], in other locus or in cytéplasm. When phase-2 culture of typical diphasic strain dj:do is used as a donor and a phase-1 monophasic strain rj:(r2) as a recipient of H-transduction, different types of recombinant are expected from the strains with different monophasic factors as shown in table 1. The report concerms with a survey of mono- phasic factors in phase-1 monophasic variants of Sal. typhimurium and Sal. paratyphi B. Materials and iethods. Fifteen i-monophasic variants of Sal. typhimurium and nine b-monophasic variants of Sal. paratyphi B are used for the experiment. They were originally isolated from nature and were identified serotype and monophasic character at Cc. D.C. By preliminary test of motility and the frequency of reversion in NGA deep tube, two very weak motile strain and six highly reversible strains were excluded from farther experiment. Phase-2 culture of SW925 a:e.n,x derived from Sal. abony b:re,n,x -—-x Sal. sendai a:1,5 was used as a donor. NGA plates supplemented 1/1000 dilution of anti-i serum (for Sal. typhimurium ) or anti-b serun (for Sal. paratyphi B) were used for the screening of transductional chones.” phase-1 culture of diphasic Sal. typhimurium THM2 was used also as a recipient to compare’H; and Hy transduction. the frequency of Experimental results. The results were summarized in table2, which indicates the followings. (1). Hp is transduced to all strains tested. Consequently, they have Ho locus. (2). In 12 out of 24 strains tested, original phase-2 antigen (1,2) are recovered either by reversion or by transduction. That is, at least 12 phase-1 monophasic variants have hidden Holr2, (3). Except one trensduction, ~-x SW1172, predominant type is ay: (r9), followed by ry:do. In 5 among 16 strains, rj:ro was obtained in small numbers. Therefore, the inhibition of Hor? activity occurred either by inactivation of Halse itself.or by a factor closely linked to H5. (4). The number of transductional clones obtained from --x SW1172 is only 2 (both r1:B>). Whether SW1172 belongs to the same category as (3) or not wili be decided after the more number is obtained by repeated experiment. (see also (6)}and the later description) (5). With one exception, number of ry:do is considerably smaller than dy:(ro). The difference can not be observed when diphasic strain TM2 is W22o 28.5 Reehaseis me pogaon de nok clear yet. ome peeribanty © that Meow’ oe (6). ‘the number of r1iro type obtained is very small. The experiment will be continued with SW1167, SW1169, SW1172 and SW1178, which may have Ho inhibitors, Aho“ » 4S M monophasic factors. The transduction From Sw925 will be repeated on these strains to confirm the constant recovery of ry:ro type. SW1167, SW1169 and SW1178 are not sensitive to PLT22, The screening off sensitive mutants is on the way. ‘Sa "Swi172, a lysate was prepared &md was used as a donor of transduction to SW725 a:e,n,x, SW1167 and SW1178. The results are shown in table 3e SW1172 can transduce both Hy> and Hols2 to@iphasic strain and produces only diphasic type. Consequently, Aho in SW1172 is neither linked to Hy nor identical with Ho. The linkage to Ho must be examined by farther transductim experiments with a diphasic strain as a donor. The transductions to SW1167 and to SW1178 produced “ti phasic i:1,2 types as well as nonophasic b type. This suggests that Aho” in SW1172 tsidéifferent from monophasic factora in SW1167 or in 1178. Table 1. Transductional types expected from dyj:do -——-x ry:(ro). Location of a Transductional types monophasic facvor Giilro) (ay):ro (rz) 240 (rj)iro g@y:re dire ride ryirs Ho deficiency + - - - 7 - - = on or linked to Ho + - - - - - - - on or linked to Hy - - - _ - tA - - other locus than Hy or Ho + - $5 - - - +K +A cytoplasmic + _ _ _ _ _ _ _ +: obtained regardless the nature of a monophasic factor. +5: a Ho-stabilizer causes monophasics. +K: obtained when a factor which shifts phase equilibrium causes monophasics. It gradually changes to ry: (do). +A: obtained when Ho inhibitor is Ho suppressor, and Ho in the recipient is in active state. Table 2 Transductional types obtained from SW925 a:e,n,x =--x Phase=1 monophasic variant of Sal. typhimurium or of Sal. paratyphi B. Serotype SW-number Antigen type in Reversion Transductional clones Swarm in phase~l1, phase-2 to diphase ay: (ro) ryido YTyiro control typhimurium 435 i (1,2) frequent / / / / " 965 " none weak motile " 1165 " none 29 8 8 0 " 1166 " none 23 4 0 0 " 1167 " (1,2) bone 22 11 1 0 ” 1168 " (1,2) frequent / / / / " 1169 " (1,2) rare 27 3 2 0 7 1170 " none weak motile " 1178 " (1,2) none 21 5 2 0 " 1179 " none 24 6 0 0 " 1180 . none 23 1 oO 0 n 1181 " none 20 4 0 0 " 1182 " (1,2) frequent / / / " 1183 " (1,2) rare 3 6 1 1 n 1184 " none 23 13 0 0 paratyphi B 705 ub none 59 17 0 0 " 997 " none 17 10 0 0 " 1164 " fvequent / / / / " 1171 " none 28 6 0 0 n 1172 " (1,2) none 0 0 2 0 " 1173 " (1,2) frequent / / / / " 1174 " (1,2) rare 17 5 0 0 " 1175 " (1,2) frequent / / / / " 1176 " (1,2) rare 41 3 0 0 typhimurium TH2 i 1,2 (diphasic control) gi:re el, ri:do 18. Table 3 tranduction from a phase-1 monophasic strain SW1172 b:(1,2) Donor Recipient Screened by SW1172 b:(1,2) SW725 a:e,n,x anti-a, & enx NGA i] uN 8W1167 i:(1,2) anti-i NGA sw1178 i:42,2)" tt u Transductional clone bie,n,x azl,2 12 24 b: (1,2) i:1,2 19 42 11 53