Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0023241 (Legionella)
 6,990 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The major outer membrane protein of Legionella pneumophila exhibits an apparent molecular mass of 100 kDa. Previous studies revealed the oligomer to be composed of 28- and 31-kDa subunits; the latter subunit is covalently bound to peptidoglycan. These proteins exhibit cross-reactivity with polyclonal anti-31-kDa protein serum. In this study, we present evidence to confirm that the 31-kDa subunit is a 28-kDa subunit containing a bound fragment of peptidoglycan. Peptide maps of purified proteins were generated following cyanogen bromide cleavage or proteolysis with staphylococcal V8 protease. A comparison of the banding patterns resulting from sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) revealed a common pattern. Selected peptide fragments were sequenced on a gas phase microsequencer, and the sequence was compared with the sequence obtained for the 28-kDa protein. While the amino terminus of the 31-kDa protein was blocked, peptide fragments generated by cyanogen bromide treatment exhibited a sequence identical to that of the amino terminus of the 28-kDa protein, but beginning at amino acid four (glycine), which is preceded by methionine at the third position. This sequence, (Gly-Thr-Met)-Gly-Pro-Val-Trp-Thr-Pro-Gly-Asn ... , confirms that these proteins have a common amino terminus. An oligonucleotide synthesized from the codons of the common N-terminal amino acid sequence was used to establish by Southern and Northern (RNA) blot analyses that a single gene coded for both proteins. With regard to the putative porin structure, we have identified two major bands at 70 kDa and at approximately 120 kDa by nonreducing SDS-PAGE. The former may represent the typical trimeric motif, while the latter may represent either a double trimer or an aggregate. Analysis of these two forms by two-dimensional SDS-PAGE (first dimensions, nonreducing; second dimensions, reducing) established that both were composed of 31- and 28-kDa subunits cross-linked via interchain disulfide bonds. These studies confirm that the novel L. pneumophila major outer protein is covalently bound to peptidoglycan via a modified 28-kDa subunit (31-kDa anchor protein) and cross-linked to other 28-kDa subunits via interchain disulfide bonds.
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PMID:Molecular characterization of the 28- and 31-kilodalton subunits of the Legionella pneumophila major outer membrane protein. 131 95

Helicobacter pylori is associated with gastritis and peptic ulcer disease in humans. We have identified a homolog of the chaperonin cpn60 family of heat shock proteins in H. pylori, referred to as Hp54K. Hp54K, purified from water-extractable H. pylori proteins, migrated as a single band at 54 kDa by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. Its native molecular mass was 740 kDa; thus, Hp54K apparently comprises a 14-mer. The N-terminal 33 residues of Hp54K exhibited 60.6, 57.6, 54.5, 54.5, 51.5, and 51.5% identity with corresponding sequences in the following cpn60 homologs: HtpB (Legionella pneumophila), P1 (human mitochondria), GroEL (Escherichia coli), BA60K (Brucella abortus), HypB (Chlamydia trachomatis), and the 65-kDa immunodominant protein of Mycobacterium bovis BCG, respectively. Hp54K was the only protein recognized in whole-cell preparations of H. pylori by immunoblotting using monospecific antisera against cpn60 homologs from L. pneumophila, E. coli, C. trachomatis, and M. bovis BCG. Antiserum against Hp54K recognized proteins with molecular masses of 50 to 60 kDa in a large number of gram-negative bacteria, consistent with the known highly conserved nature of cpn60 proteins. Hp54K is a major protein and is immunogenic in humans infected with H. pylori. Thus, Hp54K shares many similarities with known cpn60 homologs. On the basis of the proposed role of other cpn60 proteins in induction of chronic inflammation, immune cross-reactivity between Hp54K and gastric tissue may provide an important link between H. pylori infection and gastritis.
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PMID:Identification and purification of a cpn60 heat shock protein homolog from Helicobacter pylori. 156 86

An invasiveness-defective mutant of the fish-pathogenic bacterium Vibrio anguillarum was isolated. Compared with the wild type, this mutant had a 1,000-fold higher 50% lethal dose after immersion infection of rainbow trout, Oncorhynchus mykiss, while after intraperitoneal infection, the mutant had only a 10-fold higher 50% lethal dose. In addition, the mutant showed a lower level of protease activity. Two forms of the protease (Pa and Pb) were found after sodium dodecyl sulfate-polyacrylamide gel electrophoresis of nonheated samples. Pa was found predominantly in protease preparations of the wild type, while Pb was the predominant form in the mutant. Conversion of Pb to Pa was observed in protease preparations after incubation at 4 degrees C. Characterization of the protease showed that it was an elastolytic enzyme which required Zn2+ for activity and Ca2+ for stability. The molecular mass of the protease was 36 kilodaltons. N-terminal amino acid sequence analysis of the protease of V. anguillarum revealed homology to the elastase of Pseudomonas aeruginosa and the protease of Legionella pneumophila.
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PMID:Identification and characterization of a zinc metalloprotease associated with invasion by the fish pathogen Vibrio anguillarum. 222 44

The enzyme-linked immunosorbent assay (ELISA) has been evaluated for the detection of antibodies against Legionella pneumophila. Three-grade antigens were prepared from Legionella pneumophila serogroup I. Crude antigen was made by enzyme digestion, sonication and centrifugation and then became half pure by ammonium sulfate precipitation. It was purified to form 60-kDa protein antigen by size-exclusion chromatography on a Sephacryl S400 column and ion-exchanged chromatography on a DEAE-5PW column. 60-kDa protein antigen was the most sensitive of the three antigens, but more cross reactive to K. pneumoniae type II than the other two antigens. It is suggested that crossreaction occurs on the grounds whether 60-kDa protein is antigen common to L. pneumophila serogroup I and K. pneumoniae type II or antigens of such two bacteria co-exist on 60-kDa protein.
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PMID:[Enzyme-linked immunosorbent assay (ELISA) for Legionella pneumophila using 60-kDa protein antigen]. 228 87

The protein composition of the outer membranes of eight serogroups of Legionella pneumophila has been determined by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE). Outer membranes were prepared by detergent extraction using sodium lauryl sarcosinate or by isopycnic sucrose gradient centrifugation. With both techniques one major outer membrane protein of about 29,000 daltons was found to be characteristic for the species L. pneumophila. It was the predominating feature in all 22 strains of L. pneumophila studied, regardless of serogroup. SDS-PAGE patterns of non inactivated L. pneumophila strains were compared with those following formaldehyde-, heat- or ether inactivation. Formaldehyde inactivation gave the fewest protein bands while the outer membrane protein profiles of non inactivated as well as of heat- or ether-inactivated strains revealed some additional minor components. With the exception of a 46,000 dalton band that showed, in some strains, an altered electrophoretic mobility of ca. 48,000 dalton, all strains and serogroups of L. pneumophila presented with the same outer membrane protein pattern. Analysis of outer membrane protein profiles by SDS-PAGE should therefore be a valuable tool for the identification of L. pneumophila. Comparing total membrane preparations the 29,000 dalton component was also the predominant feature, an appreciable number of additional bands, however, allow a clear discrimination between different strains. The protein profiles of outer and total membranes of L. pneumophila as determined by SDS-PAGE therefore may be used for taxonomical and epidemiological studies.
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PMID:Membrane proteins of legionellaceae. I. Membrane proteins of different strains and serogroups of Legionella pneumophila. 241 52

We studied the lipopolysaccharide (LPS) of Legionella pneumophila and six other Legionella species to determine whether strain differences were apparent. The LPS was purified by a cold ethanol extraction procedure, and total carbohydrates represented 10 to 20% of LPS weight. 2-keto-3-deoxyoctonate represented 1 to 13% of the total carbohydrate present in the LPS. By sodium dodecyl sulfate-polyacrylamide gel electrophoresis, all strains except L. dumoffi showed smooth-type LPS with multiple high-molecular-weight complexes. Proteinase K-treated, whole-cell lysates showed profiles similar to those of purified LPS. Each serogroup of L. pneumophila and each Legionella species had a distinct sodium dodecyl sulfate-polyacrylamide gel electrophoresis profile. L. pneumophila lipid A is antigenically related to the lipid A of Enterobacteriaceae. In immunoblot assays with the LPS of L. pneumophila serogroups 1 to 6 as antigens, serogroup-specific immune monkey sera recognized homologous purified LPS, but not the LPS of the five heterologous serogroups. These studies indicate that LPS composition may be a determinant of serogroup specificity as defined by the immunofluorescence-based serogrouping schema for L. pneumophila and other Legionella species.
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PMID:Serogroup specificity of Legionella pneumophila is related to lipopolysaccharide characteristics. 241 53

A monoclonal antibody (LP3IIG2) directed against a species-specific epitope of Legionella pneumophila is available from Genetic Systems Corp., Seattle, Wash., for use as a diagnostic reagent. Outer membrane protein-rich fractions were prepared from L. pneumophila serogroups 1 to 8 by treatment of cell envelopes with 2% Triton X-100. Immunoblots of sodium dodecyl sulfate-polyacrylamide gels demonstrated that each membrane fraction contained two bands that reacted with LP3IIG2. The monoclonal antibody bound preferentially to a 26,000-molecular-weight band that appears to result from modification of the 29,000-molecular-weight major outer membrane protein.
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PMID:Major outer membrane protein of Legionella pneumophila carries a species-specific epitope. 242 Aug 24

Mice were inoculated with Legionella pneumophila via an intratracheal route to establish an experimental model of infection. Lung lavage fluid obtained from infected mice contained a cytolytic factor identified as tumor necrosis factor (TNF). Peak levels of TNF were produced at about 24 h postinfection and rapidly declined thereafter. Treatment of the mice with dextran sulfate before inoculation with the bacteria resulted in lowered amounts of TNF in the lung lavage fluid, suggesting that macrophages were responsible for production of the cytokine. Furthermore, cultures of adherent lung leukocytes and a macrophage cell line, PU 5-1.8, were stimulated to produce TNF by exposure to Legionella antigens. In addition, adherent lung leukocytes from Legionella-infected mice spontaneously released TNF into the culture supernatant. Inoculation of mice with saline or latex particles failed to induce TNF in vivo, indicating that bacterial antigens or products were the stimulating signals. Since there was no detectable TNF activity in sera at any time after intratracheal inoculation, TNF production appeared to be confined to the site of infection. Pretreatment of PU 5-1.8 cultures with gamma interferon, which was detected in the lung lavage fluid before TNF, resulted in augmented TNF production, suggesting cooperativity may exist between the two cytokines, either in the pathogenicity of the bacterium or in a possible immunomodulatory function of TNF and interferon during infection.
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PMID:Induction of tumor necrosis factor by Legionella pneumophila. 243 20

The outer membrane proteins of Legionella pneumophila serogroups 1 to 8 were prepared from broken cells by selective solubilization using sodium lauryl sarcosinate. The isolated proteins were separated by sodium dodecyl sulfate-polyacrylamide gel electrophoresis and transferred to nitrocellulose sheets. Rabbit antisera against each of the eight serogroups of L. pneumophila were obtained by immunizing each animal with live bacteria. The transferred proteins were revealed using these antisera and peroxidase-labeled swine anti-rabbit immunoglobulins. Antigenic determinants common to all eight serogroups were found in at least three outer membrane antigens (19, 29, and 45 kilodaltons (kDa)). However, cross-absorption experiments revealed that these three antigens were immunologically related, but not identical among serogroups. The antigenic relationships observed with two of these three antigens correlated well with cross-reactions observed in immunofluorescence. When a monoclonal antibody directed against L. pneumophila serogroup 1 lipopolysaccharide was used to reveal a blot of serogroup 1 outer membrane antigens, the 29- and 45-kDa bands appeared. This demonstrates a strong association between lipopolysaccharide and outer membrane proteins.
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PMID:Antigenic variability of the outer membrane antigens of Legionella pneumophila serogroups 1 to 8. 244 23

In a previous study, all convalescent-phase sera from patients with culture-confirmed legionellosis reacted on immunoblots with a Legionella genus-wide 58-kilodalton (kDa) protein antigen (J.S. Sampson, B.B. Plikaytis, and H.W. Wilkinson, J. Clin. Microbiol. 23:92-99, 1986). The present study was done to immunologically characterize and determine the diagnostic relevance of this purified antigen. The antigen was precipitated from enriched cell extracts with ammonium sulfate and purified by high-pressure liquid chromatography. High-titered rabbit antiserum produced to the purified protein was used to show its presence on immunoblots in the 60-kDa range in 38 Legionella serogroups, representing 23 species, and in 39 non-Legionella bacteria. The antiserum was made specific for Legionella strains by sequential absorptions with Bordetella pertussis, Pseudomonas aeruginosa, and Pseudomonas fluorescens whole cells. Serum from legionellosis patients reacted with both specific and nonspecific epitopes. Results of indirect immunofluorescence experiments showed that neither specific nor nonspecific epitopes of the 60-kDa protein were surface exposed on Legionella cells and that cross-reactive epitopes were variably exposed on non-Legionella bacteria. The 60-kDa protein antigen should be useful in diagnostic tests for legionellosis if care is taken to expose cryptic epitopes and if the tests use or measure only the Legionella-specific epitopes.
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PMID:Purified 60-kilodalton Legionella protein antigen with Legionella-specific and nonspecific epitopes. 244 17


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