Genetical Studies of Non-flagellate Mutants of Salmonella

Abstract

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.

A Mutant of Salmonella Possessing Straight Flagella

“…Differences in the tryptic peptide maps of flagellin between the flagellin of a curly flagellar mutant and that of the parental wild-type strain have been found (Enomoto & Iino, 1966). Although chemical analysis has not been done with the flagellin on the straight flagella, it is reasonable to infer that the straight flagellar characteristic is due to mutation of the structural gene of phase 2 flagellin, resulting in a change in the primary structure of the flagellin of the mutant.…”

“…Donor: 3 x 108 phage particles; recipient: I x log bacteria. Normal Straight 36 strain ~~6 8 8 , which produces normal flagella in both phase I (antigen-b) and phase 2 (antigen-e,n,x) (Iino & Enomoto, 1966). The use of phase I bacteria as recipient has two advantages: first, both phase I and phase 2 antigen type recombinants should be detectable, and secondly, even if genotypically normaf-i,a type clones appear by reversion, the 1,2 antigens will not be expressed unless phase variation from phase I to phase 2 occurs simultaneously (Lederberg & Iino, 1956).…”

Identification and characterization of the products of six region III flagellar genes (flaAII.3 through flaQII) of Salmonella typhimurium

“…S. typhimurium LT2 (11) was used for preparation of chromosomal DNA. E. coli strains used are listed in Table 2.…”

Temporary Expression of Flagellar Phase-1 in Phase-2 Clones of Diphasic Salmonella

“…Salmonella strains used in the present experiment are listed in Table I. The recombinants, ~~4 0 6 7 , SJ4142, S J~I 58 and S J~I 59, were obtained by phage Pas-mediated transduction following the procedure of Lederberg & Iino (1956).…”