Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound   Target Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound

---

Query: UNIPROT:P43026 (lipopolysaccharide)
62,215 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Lysogenization of Salmonella typhimurium with either of the bacteriophages A3 and A4 results in O-acetylation of the L-rhamnose residues of the O-polysaccharide chain of the lipopolysaccharide of the bacterial cell envelope. The O-acetyl group is found on both O-2 and O-3 of the L-rhamnosyl residues. This lysogenic conversion prevents the adsorption of the A3 and A4 phages and also greatly reduces the rate of adsorption of phage P22 to the O-polysaccharide chain as measured by binding studies with whole bacteria. Isolated lipopolysaccharide from A3- and A4-lysogenized bacteria was also inefficient in inactivating these phages: the concentration required for 50% inactivation was 10,000-fold higher than that for lipopolysaccharide from S. typhimurium not lysogenized by any A phage. Binding of phages A3 and A4 is accompanied by hydrolysis of the alpha-1,3 linkage between rhamnose and galactose in the tetrasaccharide repeating unit of the O-polysaccharide. Phage hydrolysis generates saccharides of various lengths, the majority being dodecasaccharides, i.e., equivalent to three repeating units. It is surmised that O-acetylation of the rhamnosyl residue interferes with phage A3, A4, and P22 infection by preventing binding to and hydrolysis of the O-polysaccharide chain, the initial step in the phage infection cycle. The new O-acetyl-rhamnose entities did not elicit specific antibodies in rabbits in accordance with earlier experiences. The O-acetylation of O-2 and O-3 of rhamnose is a new, hitherto unknown, modification of the O-polysaccharide chain of S. typhimurium.
...
PMID:Lysogenic conversion of Salmonella typhimurium bacteriophages A3 and A4 consists of O-acetylation of rhamnose of the repeating unit of the O-antigenic polysaccharide chain. 354 60

Seven temperature-sensitive rough mutants of Salmonella typhimurium were found to be sensitive to smooth-specific phages at low temperature (25 C, 30 C) and resistant or partially resistant to rough-specific phages, whereas at high temperatures (37 C, 45 C) they were resistant or partially resistant to smooth-specific phages but sensitive to rough-specific phages. These data indicate that at low temperature each strain makes lipopolysaccharide which is relatively normal, but at high temperatures O-specific side chains are not added to the lipopolysaccharide. At 45 C, these strains have the R-res-1 or R-res-2 phage sensitivity phenotype, and their genetic lesions map by P22-mediated transduction in the rfa gene cluster between cysE-pyrE, suggesting a mutation in genes with transferase functions. P22-mediated joint transduction with temperature-sensitive rfa mutants, leaky rfa mutants, and rfa P22 lysogens have shown the following order of genes in the S. typhimurium linkage map: xyl-mtlA-mtlB-cysE-rfaF-rfaG-pyrE. An rfaE allele was not jointly transduced in the cysE-pyrE segment.
...
PMID:P22-mediated transduction analysis of the rough A (rfa) region of the chromosome of Salmonella typhimurium. 456 11

A class of galactose-resistant mutants has been derived from strains of Salmonella typhimurium which are defective in uridine diphosphoglucose-4-epimerase. Resistant strains are phenotypically similar to parent organisms but do not lyse in the presence of galactose. Low levels of functional epimerase can be detected in induced cells grown at 20 C but not at 37 C, and acid is not produced from galactose. Sufficient galactose is synthesized at reduced temperatures to fabricate smooth lipopolysaccharide and acceptor sites for phage P22 from galactose-deficient media. The leaky nature of these mutants may account for resistance to galactose death by maintaining galactose metabolites at a subcritical level. Glucose protects sensitive strains by control of levels of toxic metabolites by catabolite repression.
...
PMID:Resistance of Salmonella typhimurium mutants to galactose death. 489 80

The formation of complete cell wall core lipopolysaccharide (LPS) and O-antigenic side chains after addition of d-galactose to the uridine diphosphate-galactose-4-epimeraseless mutant, Salmonella typhimurium LT2-M1, has been studied by (i) determination of adsorption rates of smooth and rough specific bacteriophages, (ii) passive hemagglutination inhibition, and (iii) qualitative and quantitative determination of the polysaccharide composition and structure. A rapid synthesis of the complete core LPS and O side chains occurred in bacteria in the log phase and the early stationary phase. Phage C21, which attaches to unsubstituted Rc structures, was adsorbed by the bacteria for only 10 min after the addition of d-galactose. Unsubstituted Rc structures, however, could still be detected after 160 min by immunological and chemical assays. Attachment of the P22 phage, which requires O-specific side chains with more than one repeating unit for adsorption, was demonstrated 10 min after the addition of d-galactose. Attachment of the Felix O-1 phage, which requires a complete core, was observed between 20 and 80 min after the addition of d-galactose. The rough specific phages 6SR and Br2 did not adsorb to the bacteria at any time after the addition of d-galactose. By passive hemagglutination inhibition, the presence of O-specific structures could be demonstrated after 10 min. No antigenic activity of the Ra and Rb structures was observed in the LPS preparations isolated at any time after the addition of d-galactose. Methylation analysis of LPS preparations isolated at 10 and 160 min after the addition of d-galactose showed that the O-specific side chains contained an average of 11 and 15 repeating units, respectively. In the 10-min sample, every 25th "Rc structure" carried a side chain, compared to every 3rd residue in the 160-min sample.
...
PMID:Bacteriophage receptor development and synthesis of O-specific side chains after addition of D-galactose to the uridine diphosphate-galactose-4-epimeraseless mutant Salmonella typhimurium LT2-M1. 491 45

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. 5% of wild-type kinase and uridyl transferase activities; also, some cultural properties of the mutant differed from those of mutants with complete defects of epimerase only. The mutant was not galactose sensitive, presumably because of its kinase defect. Although the mutant had the phage pattern (including C21-sensitivity) of an epimerase mutant, it was susceptible to transduction by phage P22 and was O-agglutinable, even when grown on defined medium; its LPS must therefore contain some O polymer, including endogenous galactose, resulting from residual epimerase activity. Growth on galactose-supplemented medium restored smooth phage sensitivity; since the mutant was partly inducible this may result, at least in part, from increased endogenous production of UDP-galactose. The mutant was made galactose positive by introduction of an F'-gal(+) plasmid. Base-change and frame-shift mutagens did not increase the frequency of reversion above the spontaneous rate. An insertion into the operator-promoter region of the gal operon seems the most likely mechanism of the mutation.
...
PMID:Properties of a Salmonella typhimurium mutant with an incomplete deficiency of uridinediphosphogalactose-4-epimerase. 493 17

The general transducing phage P22 attacks only smooth (S) Salmonella with O antigen 12, determined by the oligosaccharide repeating unit constituting the distal part of the somatic lipopolysaccharide (LPS) side chain; non-S mutants, whose LPS contain few or no O repeating units, appear to be resistant. Auxotrophic non-S mutants of Salmonella typhimurium LT2 were tested as transductional recipients. Some transductants (0.5 to 5% as many as from S recipients) were obtained from most semirough recipients, either of class D (presumed leaky rouA mutants) or of a class due to mutation near his (presumed leaky rouB mutants), and from recipients lacking uridine diphosphogalactose epimerase or phosphomannose isomerase. Transductants were not obtained from several rouA, rouB, "heptose-negative," and glucose-1-transferase mutants, nor from most semirough class C mutants, whose LPS side chains each bear a single O oligosaccharide unit. Most transductants evoked from non-S recipients by temperate (c(+)) phage P22 were nonlysogenic, and virulent P22.c2 phage was about as effective as P22.c(+) in transduction to non-S recipients; probably all P22 transducing particles neither lysogenize nor kill. The extended-host-range mutant P22h gave qualitatively similar results,but evoked 5- to 30-fold more transductants from some non-S recipients than did P22. Probably, the LPS of non-S mutants susceptible to transduction contains a few O-specific oligosaccharide units, conferring a slight ability to adsorb P22 and a greater ability to adsorb P22h.
...
PMID:Transduction by bacteriophage P22 in nonsmooth mutants of Salmonella typhimurium. 533 45

The method for the isolation of transfectable salmonellae by growing them in a liquid medium for a long time and selecting R-clones, subsequently tested in the Ca2+-dependent transfection of the DNA of bacteriophage P22 H5, was developed. The probability of obtaining transfectable clones varied between 18.3% and 48.3% in different Salmonella strains. Testing their sensitivity to specific bacteriophages used for the determination of structural distortions in the lipopolysaccharide layer of the cell wall made it possible to divide transfectable Salmonella clones into 3 phenotypical groups. The effectiveness of the formation of transfectants in the Ca2+-dependent transfection of the DNA of bacteriophage P22 H5 increased to 4.0 X 10(-8) - 8.0 X 10(-8) in the isolated R-clones of S. typhimurium strain SU453. In contrast to the initial strain, these R-clones were characterized not only by more effective transfection, but also by the possibility of plasmid transformation.
...
PMID:[Characteristics of Salmonella mutants competent for isolated nucleic acids]. 635 10

The results of the Ca2+-dependent transfection of the DNA of bacteriophage P22 H5 to constructed Salmonella typhimurium F'- and R+-strains LT2 WT-R and SA118 demonstrated that in these salmonellae the effectiveness of transfection depended on the specificity of the interrelation of plasmids with host strains. Plasmids RA1, R538-1 and RP1 stimulated the transfection of S. typhimurium strain LT2 WT-R, but suppressed the transfection ability of S. typhimurium strain SA118. At the same time the expression of the function of plasmids R446b and R64-11 did not depend on the host strain, as the former did not affect and the latter suppressed the release of transfectants in both Salmonella strains. The presence of plasmids R124, RA1, R64-11 and R724 in strain SA118, heat-sensitive in respect to the synthesis of cell-wall lipopolysaccharide, not only led to a decrease in the effectiveness of transfection; the effectiveness of the inoculation of bacteriophage P22 H5 was also suppressed 10(4) times in the presence of plasmid R124 and at least 10(10) times in the presence of 3 other plasmids. The development of resistance to S-specific bacteriophage P22 H5 was not linked with disturbances in the adsorption of this bacteriophage. Besides, the addition of CaCl2 into the medium completely removed the limitation of infection with bacteriophage P22 H5, determined by plasmid R124.
...
PMID:[Bacteriophage P22 H5 transfection and infection of plasmid Salmonella strains]. 635 20

To determine whether flagella, chemotaxis, and motility of Salmonella typhimurium are virulence factors in infected C57BL/6J mice, we constructed isogenic pairs of derivatives of the nonfimbriated virulent strain SL3201. Of each pair, one member contained a mutation in a single gene that is required for expression of normal chemotactically directed motility, whereas the other member contained the wild-type form of the gene. No additional differences between the members of a pair were evident. The phenotypic parameters examined for all derivatives included in vitro growth rate, sensitivity to P22 phage, amino acid auxotrophy, and biotype. For a flagellated and nonflagellated pair, the electron microscopic appearance of each member was examined as well as its lipopolysaccharide and outer membrane profiles by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. The virulence of the various derivatives was then assessed in mice challenged orally, intraperitoneally, or intravenously. The results established that flagella, whether functional or nonfunctional as organelles of motility, were S. typhimurium virulence factors and that neither chemotaxis nor motility was required for virulence.
...
PMID:Flagella of Salmonella typhimurium are a virulence factor in infected C57BL/6J mice. 638 63

Four bacteriophages, P22, P27, 9NA, and KB1, active on smooth Salmonella strains belonging to serogroups A, B, and D1 were investigated for endoglycosidase activity and specificity in enzyme hydrolysis assays. Purified phage was incubated with phenol-water-extracted lipopolysaccharide preparations which had been partially delipidated. Dialyzable oligosaccharides, released by phage glycosidase activity, were analyzed by sugar and methylation analyses. Phages P27, 9NA, and KB1, as well as P22 assayed earlier (U. Eriksson et al., J. Gen. Virol. 43: 503-511, 1979; S. Iwashita and S. Kanegasaki, Biochem. Biophys. Res. Commun. 55:403-409, 1973), were all found to have phage-associated endorhamnosidase activity hydrolyzing the O-polysaccharide chain common to bacteria of serogroups A, B, and D1 [Formula: see text] between the l-rhamnose and d-galactose residues. The nature of the R monosaccharide, abequose, tyvelose, or paratose, had no effect on the activity or specificity of the endorhamnosidase, whereas a change of the d-galactose --> d-mannose linkage from alpha1,2 to alpha1,6 made the O-polysaccharide chain resistant to the endorhamnosidases. Modification of the O chain by glucosylation of the d-galactose residue at O-4 or O-6 revealed two glycosidase specificities: the phage P22 and P27 enzymes hydrolyzed O chains glucosylated at O-4 but not O-6, whereas the phage 9NA and KB1 enzymes hydrolyzed chains glucosylated at O-6 but not O-4. Phage KB1, like P22 and P27, had a short, noncontractile tail containing a base plate with tail spikes (morphologically Bradley group C), whereas 9NA had a long, flexible tail ending with a base plate-like appendage (Bradley group B), which suggests that the endorhamnosidase activity can be associated with different tail structures.
...
PMID:Salmonella bacteriophage glycanases: endorhamnosidase activity of bacteriophages P27, 9NA, and KB1. 701 63


<< Previous 1 2 3 4 5 6 Next >>

---