Evaluation of the immune response directed against the Salmonella antigenic factors O4,5 and O9.

A pair of O4,5,12 and O9,12 his(+) sister transductants derived from a virulent Salmonella typhimurium parent were used as intraperitoneal and oral challenge strains to determine whether immunity directed against the O9 and O4,5 antigenic components could be detected after immunization with heat-killed vaccines containing one or the other of these antigenic components. Challenge with a mixture (ca. 1:1) of the two strains and culturing of livers and spleens at intervals indicated that the O4,5,12 strain multiplied to a greater extent than the O9,12 strain after both oral and intraperitoneal challenge of CF1 and C57BL/6J control mice.

Mutants defective in the 33K outer membrane protein of Salmonella typhimurium.

Salmonella typhimurium LT2 lines, if phenotypically rough, are fully sensitive to bacteriocin 4-59, produced by Salmonella canastel strain SL1712. Bacteriocin-resistant mutants fell into three classes. Those resistant to phage ES18 and to albomycin proved to be mutants of class chr (equivalent to tonB of Escherichia coli); these mutants still adsorb the bacteriocin and so are classified as tolerant.

Effect of host lex, recA, recF, and uvrD genotypes on the ultraviolet light-protecting and related properties of plasmid R46 in Escherichia coli.

The ability of plasmid R46 to reduce the lethal but enhance the mutagenic effect of ultraviolet (UV) irradiation was tested in sets of Escherichia coli K-12 derivatives, wild type or with different mutations affecting DNA repair capacity, but otherwise isogenic. UV protection and enhancement of UV mutagenic effect were obtained in uvrA6, uvrB5, uvrD3, and recF143 hosts, but not in a recA56 strain. The plasmid gave some UV protection in two lexA1 and two lexA101 strains and in one lexA102 host, but produced no such effect in another lexA102 host.

Segregation of the mutator property of plasmid R46 from its ultraviolet-protecting property.

Plasmid R46 (an R factor conferring resistance to ampicillin, sulfonamides, streptomycin and tetracycline) reduces the bactericidal effect of UV irradiation but increases its mutagenic effect (reversion of hisG46), and raises the frequency of spontaneous reversion (mutator effect). Putative deletion mutants of R46 were obtained by transduction of the plasmid, then two successive conjugal transfers. Plasmids of five of six deletion classes, each with a different combination of drug resistance traits, retained conjugative ability and the UV-protecting, mutagenesis-enhancing and mutator effects of R46.

Lipopolysaccharide core defects in Salmonella typhimurium mutants which are resistant to Felix O phage but retain smooth character.

FOR mutants of Salmonella typhimurium are resistant to Felix O phage, whose receptor includes the N-acetylglucosamine branch of the lipopolysaccharide (LPS) core, but smooth in cultural properties, antigenic character and phage sensitivity pattern (MacPhee et al., 1975). The rfa(FOR) genes determining the FOR character of nine mutants were transduced into a smooth cysE pyrE recipient: the nine FOR transductants (and a tenth FOR mutant) were then made rfb (i.

Genetics of sensitivity of Salmonella species to colicin M and bacteriophages T5, T1, and ES18.

Nearly all of 62 strains of Salmonella paratyphi B were sensitive to colicin M and phage T5 but resistant to phages T1 and ES18 and to colicin B. All tested S. typhimurium strains were resistant to colicin M and phage T5, and many were sensitive to phage ES18.

Comparison of the virulence of O:9,12 and O:4,5,12 Salmonella typhimurium his+ transductants for mice.

The purpose of these experiments was to determine whether qualitative differences in the O repeat unit of the lipopolysaccharide of pathogenic Salmonella species affected virulence for mice. O:4,5,12 and O:9,12 sister his+ transductants were derived from a virulent Salmonella typhimurium. Fermentation markers were introduced by transduction to differentiate these strains, and the strains were used as mixed challenge to CF1 and C57B1/6J mice.

Salmonella typhimurium mutants generally defective in chemotaxis.

The mutations of eight chemotaxis-deficient strains of Salmonella typhimurium, including five new mutants in strain LT2, were mapped by P22 transduction in relation to various fla mot deletions in S. abortus-equi. Seven recessive che mutations mapped between motB and flaC: three, all nontumbling, the che region I, adjacent to motB, and four, including one ever-tumbling, in che region II, adjacent to flaC.

Ultraviolet light protection, enhancement of ultraviolet light mutagenesis, and mutator effect of plasmid R46 in Salmonella typhimurium.

Plasmid R46 partially protected Salmonella typhimurium, wild type or uvrB or polA, against the lethal effect of ultraviolet (UV) irradiation, but did not protect recA mutants. The plasmid also increased frequency of UV-induced reversion to His+ in all tested his point mutants (wild type for UV sensitivity), including amber, ochre, UGA, missense, and frame-shift mutants. Plasmid R46 also increased UV-induced reversion to His+ in uvrB and polA strains, but no UV mutagenic effect was detected in R- or R46-carrying recA derivatives of a his (amber) mutant.

Integration, at hag or elsewhere, of H2 (phase-2 flagellin) genes transduced from Salmonella to Escherichia coli.

A fla mutant of E. coli K12 was given fla+ and H1-i by phage P1kc cotransduction from S. typhimurium, then made Fla- by transduction of ah1 from S.

Mutations in Salmonella typhimurium conferring resistance to Felix O phage without loss of smooth character.

Several mutants obtained from smooth Salmonella typhimurium strains by selection for resistance to Felix O (FO) phage [whose receptor site includes the N-acetylglucosamine branch of the lipopolysaccharide (LPS) core] were smooth in cultural properties, antigenic character and phage sensitivity pattern (except for their FO resistance). However, the affected genes of several such 'FOR' (FO-resistant) mutants were shown by transduction of map in the short cysE-pyrE segment, which includes nearly all known rfa genes responsible for synthesis of LPS core. All of seven FOR mutants differed from their parents, and resembled rfa mutants with defects in the deeper part of the LPS core, by increased sensitivity to various antibiotics.

Nonsense motility mutants in Salmonella typhimurium.

Of 313 motility-deficient mutants isolated from an LT2 his(amber) strain fixed in phase 1 by gene vh2(-), 25 regained motility when amber or ochre suppressors were introduced, in F' factors or by transduction. The fla mutants (23 amber, 1 ochre) fell in complementation groups A, B, C, F, K, a new group, M, and at least one further new group; the hypothesis of a fla gene which specifies only an RNA structural component of a flagellum-synthesizing basal apparatus is disproven for the corresponding genes. Hfr and transductional crosses confirmed gene assignments from complementation and indicated that flaM and another new fla locus map near H1.

Mapping of rfa Genes in Salmonella typhimurium by ES18 and P22 Transduction and by Conjugation.

Loci termed rfa, determining biosynthesis of somatic lipopolysaccharide core, have been mapped in Salmonella typhimurium LT2. The smooth-specific phage P22 co-transduced two leaky rfa alleles with cysE and with pyrE; one of the leaky alleles is perhaps rfaG, and the other is an unidentified gene concerned with synthesis of the heptose-containing part of the core. The lipopolysaccharide-indifferent phage ES18 (or its variant ES18.

Genetic transfer of Salmonella typhimurium and Escherichia coli lipopolysaccharide antigens to Escherichia coli K-12.

Escherichia coli K-12 varkappa971 was crossed with a smooth Salmonella typhimurium donor, HfrK6, which transfers early the ilv-linked rfa region determining lipopolysaccharide (LPS) core structure. Two ilv(+) hybrids differing in their response to the LPS-specific phages FO and C21 were then crossed with S. typhimurium HfrK9, which transfers early the rfb gene cluster determining O repeat unit structure.

A biochemical subdivision of one phage type of Salmonella typhimurium.

A total of 1537 strains of Salmonella typhimurium belonging to seven prevalent phage types were examined on solid media for their ability to ferment rhamnose, xylose and inositol, for colicine production and for nutritional requirements. Most of the strains in each phage type were almost completely homogeneous, especially in their sugar fermentation reactions. However, strains of phage type 1 a/2 were not homogeneous, but could be assigned to one of four subgroups on the basis of ability to ferment inositol, inhibition of growth by meso-tartrate and auxotrophy for nicotinic acid.

Properties of a Salmonella typhimurium mutant with an incomplete deficiency of uridinediphosphogalactose-4-epimerase.

A galactose-negative mutant, nonleaky in respect to fermentation and utilization, isolated from a smooth Salmonella typhimurium strain by phage selection and inferred deficient of uridine diphosphate (UDP)-galactose-epimerase, was used for experiments on relation of somatic lipopolysaccharide (LPS) character to virulence. Extracts of induced mutant cells retained ca. 1% of wild-type epimerase activity and had only ca.