A phage, o , which attacks motile bacteria

SUMNARYIn 18 hr. incubation of broth inoculated with a majority of bacteria of Salmonella typhimurium LT2 coZ-, i.e. non-colicinogenic, and a minority of strain LT2 (coU), i.e. carrying colicine factor COZI, 30-70y0 of the colbacteria acquired COZI; this increased to 50-90 yo after 2 hr. of secondary incubation after tenfold dilution with broth. These cultures, containing a high proportion of bacteria newly infected by colI, transmitted COZI to about 50 yo of the bacteria of a col-strain in 1 hr. (whereas pure cultures of LT2 (coU) transmitted to only 0-01 yo); they are termed HFC (high-frequency colicinogeny-transferring). An inoculum containing 1-8 recently infected bacteria from an HFC preparation of a streptomycin-sensitive strain sufficed to transmit COZI to a resistant strain in streptomycin broth. We infer that 30-100 yo of bacteria newly infected by coZI are 'competent donors', able to transmit coll. By the same test the proportion of competent donors in LT2 (coZI) strains was only 0.02 yo. Inoculum size, ratio of inoculum components, motility, aeration and secondary incubation affected the HFC property of mixed cultures in a way explicable by the need for the epidemic spread of coZI in the col-component to reach a peak a t the time of testing. The rate of loss of the HFC property on further growth indicated that for 3-7 generations the progeny of newly infected bacteria are competent donors. Transmission was associated with clumping and pairing. Bacteria of an H F C preparation pair with 10% of an acceptor population within 2 min. of mixing; completion of transfer requires 2 k 3 0 min. Non-availability of nutrients and some growth inhibitors interfere with transfer.We conclude that COZI multiplies autonomously in newly infected bacteria and their immediate progeny and enables them to conjugate, but does not confer ability to conjugate in established colicinogenic strains ; perhaps it is then integrated into the host chromosome.

Section: Sl722mentioning

confidence: 99%

High Infectivity of Salmonella typhimurium newly infected by the colI factor

Stocker

Smith

Ozeki

1963

“…X-phage and/or semisolid medium were used for the selection of these mutants. With the exception of some specific serotypes, X-phage infects motile salmonellas ; both non-flagellate and paralysed organisms are resistant to this bacteriophage (Meynell, 1961). During the present investigation, an efficient selective method was invented by using X-phage and semisolid medium, so as to distinguish non-flagellate mutant clones from other non-motile mutants, namely paralysed, immediately on selective medium.…”

Section: Introductionmentioning

confidence: 99%

Genetical Studies of Non-flagellate Mutants of Salmonella

Iino¹,

Enomoto²

1966

SUMMARYTransductions were carried out with 22 non-flagellate mutants originating spontaneously from Salmonella typhimurium LT 2. Taking the productions of swarm and trail as the criteria of recombination and complementation respectively, the mutants were classified into seven groups, namely JlaA, JaB, $aC, $aD, JaP, $aJ and $aK. Each of them may correspond to a cistron. Among them, $aA, B, C , D and J were co-transduced with the structural gene of phase-1 flagellin, H I . Based on the frequency of recombination between two non-flagellate mutants, and that of H Ico-transduction when available, linearly arranged maps of mutant sites in $aA, JlaC and $aF were constructed. Co-linearity was demonstrated between the recombination map and complementation map in JlaA and $aC, but with some exceptions in JaF. Partial complementation was frequently observed in combination of two mutants in a cistron.Transductions from thirteen non-flagellate mutants investigated by Joys & Stocker to the above mutants indicated that, among the five complementation groups assigned by them on their mutants, four correspond to our JEaA, JaB, flaC and JlaD; the remaining one, jlaE, is missing in our mutants. Similarly, among eleven mutant sites of the non-flagellate strains of Salmonella abortusequi SL 23, ten are distributed in JlaA, $aF and $aC. The remaining one, assigned to a mutant of $aG, does not belong to any $a cistrons described above. The recovery of flagellation in the JlaG strain by transduction was unsuccessful even when a flagellate strain was used as a donor.Rabbits were immunized with each of the twenty-one stable non-flagellate mutant clones, and their ability to elicit antiserum specific to flagellar protein was examined by absorption-agglutination test. Among the clones examined, only one belonging to@aG was found to elicit antiserum specific in flagellar antigen of the parental flagellate strain. It was inferred that the JlaG mutant can synthesize flagellin but cannot construct flagellar fibres.The remaining $a mutants were presumed t o be unable to synthesize flagellin.

“…We here report the behaviour in complementation tests of eleven Jla-mutants isolated for this purpose, of four other L T~ $a-mutants isolated in this laboratory, and of one $astrain of s. paratyphi B. The L T~$ U -strains were obtained as spontaneous mutants by selection with phage x, which attacks various Salmonella species only when they are motile (Sertic & Boulgakov, 1936;Meynell, 1961 (Spicer & Datta, 1959). The non-flagellated strain of S. paratyphi B, sw543, was originally isolated as such; itsja-site is closely linked to H I ).…”

Section: Introductionmentioning

confidence: 99%

“…This procedure was necessary to get sufficient lysis since S . typhimurium strain L T~ is only moderately sensitive to this phage (Joys, 1961;Meynell, 1961). Discrete colonies which appeared in the area of lysis were picked.…”

Section: Introductionmentioning

confidence: 99%

Complementation of Non-flagellate Salmonella Mutants

Joys¹,

Stocker²

1965

SUMMARYSelection for resistance to phage x led to the isolation from SaZmoneZZa typhimurium strain LT 2 of fifteen non-flagellate ($a-) mutants due to spontaneous mutation at sites such that H 1 could be co-transduced with Jla+. Treatment with phage PZZ grown on L T~ Jla+ evoked swarms, i.e. motile ($a+) transductant clones, from all fifteen $a-mutants and from a $astrain of S. paratyphi B; and also evoked trails, i.e. Jla+ abortive transductants, from all these mutants except four. When the$a-strains were crossed with each other by transduction all pairs yielded $a+ clones, which indicated that none of the mutated sites was identical with, or overlapped, any other. In most pairs the appearance of trails showed that abortive transductants, of constitution Jla I-Jla 2+/$a I+Jla 2-, were flagellate, as a result of complementation. The mutants fell into five groups, such that mutants of any one group complemented mutants of all other groups; these groups perhaps correspond to five $a genes. Some pairs of the ten strains of group A complemented, perhaps through intragenic complementation.