Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UNIPROT:P43026 (lipopolysaccharide)
 62,215 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

A 6-megadalton plasmid, pHW400, of Shigella dysenteriae 1 strain W30864 was previously found to specify one or more functions for O-antigen production and bacterial virulence (H. Watanabe and K. N. Timmis, Infect. Immun. 43:391-396, 1984). The region of pHW401, a Tn801-tagged derivative of pHW400, responsible for O-antigen production has been localized by gene cloning and Tn5 transposon mutagenesis. Analysis of lipopolysaccharide isolated from S. dysenteriae 1 bacteria carrying mutant plasmids revealed that the determinant for O-antigen synthesis, designated rfp, codes for a function involved in the formation of the O-polysaccharide side chain structure of lipopolysaccharide. Analysis of radioactively labeled proteins synthesized in minicells of Escherichia coli carrying mutant plasmids identified the product of the rfp gene as a 41,000-dalton protein. Southern hybridization with a DNA fragment carrying the rfp gene demonstrated that this determinant is present on 6-megadalton plasmids in other isolates of S. dysenteriae 1 but is not present at all in a variety of other Shigella, E. coli, and Salmonella typhimurium strains that were tested.
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PMID:Small virulence plasmid of Shigella dysenteriae 1 strain W30864 encodes a 41,000-dalton protein involved in formation of specific lipopolysaccharide side chains of serotype 1 isolates. 638 48

The requirement for both plasmid and chromosomal genes in the biosynthesis of Shigella dysenteriae 1 lipopolysaccharide O antigen was demonstrated in Escherichia coli-Shigella hybrids. A 6-megadalton S. dysenteriae 1 plasmid, designated pWR23, was phenotypically tagged with the Tn3 ampicillin-resistance transposon. The tagged plasmid, designated pWR24, was transferred by transformation or conjugal mobilization to a rough E. coli K-12 recipient. Although the resultant hybrids were agglutinated in S. dysenteriae 1 antiserum, they did not remove all of the anti-Shiga agglutinins in absorption experiments. Modified lipid A core structure was detected in these hybrids, but Shiga O antigen was not expressed. When the his+ locus of the S. dysenteriae 1 chromosome was transferred by transduction to E. coli K-12 containing pWR24, complete Shiga O antigen was expressed. Lipopolysaccharide extracted from these hybrids was indistinguishable chemically, electrophoretically, and serologically from native S. dysenteriae 1 lipopolysaccharide.
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PMID:Expression of lipopolysaccharide O antigen in Escherichia coli K-12 hybrids containing plasmid and chromosomal genes from Shigella dysenteriae 1. 638 45

Following the administration of Di Luzio particulate glucan, Corynebacterium parvum, pyran (maleic anhydride vinyl ether 6), and lipopolysaccharide (Shigella) to inbred C57BL/6J mice, dose, route, and time-dependent studies were undertaken on antitumor activity and serum lysozyme levels to explore the possible relevance of serum lysozyme as a useful index of antitumor activity. Antitumor activity was assessed by measurement of the extent of loss of iv injected 125I-labeled 5-iodo-2'-deoxyuridine-labeled B16 tumor cells. Increases in serum lysozyme levels were dose-, route-, and time-dependent and varied greatly from one agent to another. The peak levels of antitumor activity were similar for all agents but were also critically dose- and time-dependent. Correlations of serum lysozyme levels and antitumor activity were inexact. The doses for peak lysozyme level increases were higher than those for peak antitumor activity. Antitumor activity peaked earlier and lasted longer than serum lysozyme level increases.
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PMID:Dose, route, and time dependence of serum lysozyme and antitumor activity following administration of glucan, Corynebacterium parvum, pyran, or lipopolysaccharide to mice. 694 57

One major stumbling block in the development of an effective means to immunize against shigellosis and other enteric diseases has been the lack of a means to assess sequential mucosal immune responses to different potential immunogens. In the present study, we compared the abilities of live invasive organisms, noninvasive organisms, and nonviable antigen preparations of shigella to elicit mucosal immune responses. Whereas previous studies have found that effective immunity was produced best by vaccination with live invasive strains of shigella, in the present study, live noninvasive strains that did not produce any histopathological damage were consistently able to produce local (immunoglobulin A) immune responses as vigorous as those of the invasive strains. Further, acetone-killed shigella antigen was also an effective mucosal immunogen, whereas hot phenol-water-extracted shigella lipopolysaccharide was ineffective, possibly due to the method of preparation. A single oral or parenteral priming was ineffective in enhancing the mucosal immune response when restimulated 1 month later with the same antigen. However, a mucosal memory response was found to be present several months after a triple mucosal stimulation with a locally invasive vaccine strain.
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PMID:Role of antigen form in development of mucosal immunoglobin A response to Shigella flexneri Antigens. 701 58

Guinea pig colonic epithelial cells released by treating sections of the colon with solutions containing EDTA, dithiothreitol, and citrate avidly adhered Shigella flexneri bacteria. Separation of the intestinal cells from nonbound bacteria was achieved by differential sedimentation on a Percoll gradient. Adherence of S. flexneri to the colonic cells was Ca2+ (1 mM) and time dependent. The pH optimum was pH 6.2, and almost no attachment (less than 5%) was observed at low temperature (4 degrees C). The average number of bacteria which bound to colonic cells was 70 bacteria per cell, whereas attachment to cells isolated from the ileum region was 6 bacteria per cell. Colonic cells obtained from the intestine of rabbits or rats did not adhere Shigella. Adherence to guinea pig colonic cells was inhibited (50%) by several carbohydrates, such as 0.1% fucose or 0.5% glucose, as well as by a lipopolysaccharide preparation (10 micrograms /ml) isolated from S. flexneri. Fixation of the bacteria with glutaraldehyde or preincubation of the bacteria with lectins or proteolytic enzymes did not affect their adherence. Proteolytic digestions or fixation of the epithelial cells, as well as pretreatments with lipopolysaccharide or fucose solutions, abolished their ability to adhere bacteria. These results indicate that a carbohydrate-binding substance on the surface of guinea pig colonic epithelial cells is responsible for the attachment of the Shigella bacilli.
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PMID:Adherence of Shigella flexneri to guinea pig intestinal cells is mediated by a mucosal adhesion. 704 Feb 46

Pretreatment of mouse splenocytes with Shigella lipopolysaccharide and concanavalin A followed by 50 ng/ml of cimicifugoside resulted in a 69% and 31% inhibition of blastogenesis compared to controls. The plaque forming colony assay using sheep erythrocytes (SRBC) showed a decreased number of plaque forming colonies after exposure of the splenic cells to 1 microgram/ml of cimicifugoside. Cimicifugoside, 0.1 mg/mouse i.p. suppressed the anti-SRBC response in the plaque forming assay. The major inhibition of the antibody response occurred when cimicifugoside was administered 1 day before the primary immunization with SRBC. The delayed type hypersensitivity to picryl chloride was suppressed after i.v. administration of cimicifugoside, 1.0-2.0 mg/mouse. The immunosuppressive activity of cimicifugoside is preferentially directed toward B-cell function with larger doses being required for suppression of T-cell function.
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PMID:The immune response of splenic lymphocytes after cimicifugoside treatment in vitro and pretreatment in vivo. 727 79

Data on the genetic basis of the classification of Shigella flexneri serological variants 1-5 are presented. Subserovars "a" are related to monolysogenic variants of the basic lipopolysaccharide (LPS) structure 0 antigen 3,4, "b" to bilysogenic ones. A scheme of their antigenic variability, with regard to loss of one or both prophages is presented. This scheme helps differentiate between antigenic variability and mixed or superinfections. Recent reports confirming our previously published suggestion to exclude serovar 6 (Shigella newcastle) from Shigella flexneri are analyzed. We propose that antigenic variability of S. flexneri 1-5 results from lysogenization of naturally occurring strains. The possibility of consecutive lysogenization of S. flexneri y (-:3,4) by bacteriophages 6 and 7 has been shown, as exemplified by the circulation of a previously unknown subserovar IV:7,8.
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PMID:Antigenic variability of Shigella flexneri serovars 1-5. 747 27

This study used the guinea pig keratoconjunctivitis model to examine the importance of route of administration (mucosal versus parenteral), frequency and timing of immunization (primary versus boosting immunization), and form of antigen given (live attenuated vaccine strain versus O-antigen-protein conjugate) on the production of protective immunity against Shigella infection. Since local immune response to the lipopolysaccharide (LPS) O-antigen of Shigella spp. is thought to be important for protection against disease, O-antigen-specific antibody-secreting cells (ASC) in the spleen and regional lymph nodes of immunized animals were measured by using an ELISPOT assay. Results indicated that protective efficacy was associated with a strong O-antigen-specific ASC response, particularly in the superficial ventral cervical lymph nodes draining the conjunctivae. In naive animals, a strong ASC response in the cervical lymph nodes and protection against challenge were detected only in animals that received a mucosal immunization. Protection in these animals was increased by a boosting mucosal immunization. While parenteral immunization alone with an O-antigen-protein conjugate vaccine did not protect naive animals against challenge, a combined parenteral-mucosal regimen elicited enhanced protection without the addition of a boosting immunization. Although O-antigen-specific serum immunoglobulin A titers were significantly higher in animals receiving a mucosal immunization, there was no apparent correlation between levels of serum antibody and protection against disease.
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PMID:Local immune response and protection in the guinea pig keratoconjunctivitis model following immunization with Shigella vaccines. 750 92

The O-antigen polysaccharide of the lipopolysaccharide of Shigella dysenteriae serotype 1 is encoded by determinants located on a 9 kb plasmid (rfp) and on the chromosome near the his locus (rfb). Molecular genetic and biochemical studies of the rfp determinant reported here show that the rfp region contains two genes, rfpA and rfpB, lying in an operon. rfpB was demonstrated to encode a membrane-bound galactosyl-transferase. The low G+C content of rfp DNA suggests that it did not originate in Shigella.
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PMID:Lipopolysaccharide O-antigen biosynthesis in Shigella dysenteriae serotype 1: analysis of the plasmid-carried rfp determinant. 752 Jan 13

The optimum conditions for obtaining sensitive K- and D-serovar-specific Klebsiella antigenic erythrocyte diagnosticum have been established. The methods of choice are sensitization with lipopolysaccharide antigens at pH 5.0 and in a neutral medium at a temperature of 45 degrees C for an hour. The reagents thus obtained have proved to be specific when tested in the passive hemagglutination test with antisera to Shigella, Salmonella and Escherichia.
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PMID:[The determination of optimal regimens for producing Klebsiella antigenic erythrocytic immunoreagents]. 752 Feb 4


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