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)

Phospholipase C from the Dallas 1E strain of Legionella pneumophila serogroup 5 was purified from buffered yeast extract culture supernate by ion-exchange chromatography followed by fractionation by manganous chloride and ammonium sulphate precipitation steps. Enzyme activity was assayed by hydrolysis of p-nitrophenylphosphorylcholine and confirmed by release of radioactivity from tritiated L-alpha-dipalmitoylphosphatidylcholine labelled in the methyl groups of choline. After SDS-PAGE, the purified preparation yielded a single band upon Coomassie-blue staining. This protein migrated with an apparent Mr of 50,000-54,000. Phospholipase C activity was maximal at pH greater than or equal to 8.4 and was enhanced in the presence of sorbitol and of several nonionic detergents but was eliminated by SDS. EDTA, Cu2+, Fe2+ and Zn2+ inhibited enzyme activity, whereas Ba2+, Ca2+, Co2+, Mg2+ and Mn2+ restored activity to EDTA-treated material. No haemolytic activity was demonstrated with the purified enzyme.
J Gen Microbiol 1988 Feb
PMID:A phospholipase C from the Dallas 1E strain of Legionella pneumophila serogroup 5: purification and characterization of conditions for optimal activity with an artificial substrate. 317 47

Six discrete protease activities were recovered from the supernatant broth of Legionella pneumophila cultures by ion-exchange chromatography. One of these demonstrated in vitro activity against collagen, casein and gelatin. When administered into the lungs of guinea-pigs this protease elicited lesions which were pathologically similar to those seen in clinical and experimentally induced Legionnaires' disease.
J Gen Microbiol 1986 Jun
PMID:Separation of Legionella pneumophila proteases and purification of a protease which produces lesions like those of Legionnaires' disease in guinea pig lung. 354 9

Phenylalanineaminopeptidase was isolated and purified from the culture filtrate of Legionella pneumophila by affinity chromatography on O-tert-butyl-L-threonyl-L-phenylalanyl-L-prolylglycyl-aminosilo chrom and by gel-filtration; a 401-fold purification with a yield of 18% was achieved. The enzyme was a metalloenzyme with a molecular weight of 35000 and a pI of 5.8. It was stable at pH 7-9 and had an activity optimum in the range of pH 8-9.5 with L-phenylalanine p-nitroanilide as substrate. Enzyme activity was highest towards the latter compound, substantially lower towards L-leucine p-nitroanilide and only marginal towards other p-nitroanilides. Besides phenylalanineaminopeptidase, a metalloproteinase and a serine proteinase were also detected in L. pneumophila culture filtrate.
J Gen Microbiol 1986 Feb
PMID:Proteinases of Legionella: phenylalanineaminopeptidase of L. pneumophila. 371 61

A technique is described for mathematically normalizing whole-cell protein profiles after sodium dodecyl sulphate-polyacrylamide gel electrophoresis to obtain standardized absolute migration distances using two internal Mr standards. A soft laser scanning densitometer was used to measure protein band migration distances in wet, silver-stained gels. The normalized values were superior to the unnormalized migration distances and common RF values in reducing the inter- and intragel variability of the protein band positions. A procedure is described for clustering normalized bacterial protein profiles using a sample data set obtained from the type strains of four Legionella species.
J Gen Microbiol 1986 Sep
PMID:Numerical analysis of normalized whole-cell protein profiles after sodium dodecyl sulphate-polyacrylamide gel electrophoresis. 379 61

Legionella pneumophila attached to, penetrated and replicated within the three eukaryotic cell lines, MRC-5, HEp-2 and Vero. Multiplication occurred rapidly in these cells for an initial 48 h after inoculation and declined thereafter. Infected MRC-5 cell monolayers developed lytic-type cytopathic changes, with organisms being readily released. HEp-2 cells showed a more chronic infection, with slowly developing granular changes in the monolayers, and slow release of intracellular bacteria. In Vero cells, organisms were released rapidly along with a more progressively developing granular cytopathic effect in the monolayers. L. pneumophila was unable to grow in cell-free culture fluids. Uptake and intracellular development was similar for each cell type, and was initiated by 'bacteriopexis', a process in which the organisms bound via receptors and were surrounded by cellular microvilli which eventually fused, leading to bacterial engulfment. Replication of organisms in vacuoles within the cytoplasm of infected cells was confirmed by thorium labelling. These vacuoles were lined with ribosomes and, at the early stages of intracellular development, were found in close proximity to mitochondria, cytoplasmic filaments and banded enclosures. Ruthenium red staining showed that acid mucopolysaccharide capsular material was not present on these organisms during the attachment process or intracellular phase. Organism release was by lysis of the infected cells.
J Gen Microbiol 1985 Apr
PMID:Adhesion, penetration and intracellular replication of Legionella pneumophila: an in vitro model of pathogenesis. 398 10

To examine one possible mechanism of damage to leucocytes and tissue cells in legionellosis, seven species of Legionella were examined for cytolytic activity and for elaboration of phospholipase C, an enzyme that can damage mammalian cell membranes. Cytolysis was assessed using erythrocytes in agar. Phospholipase C was assayed by release of p-nitrophenol from p-nitrophenylphosphorylcholine and of tritiated phosphorylcholine from L-alpha-dipalmitoyl-[choline-methyl-3H]phosphatidylcholine. L. pneumophila, L. bozemanii, L. micdadei, L. dumoffii, L. gormanii, L. longbeachae and L. jordanis all lysed dog red blood cells, which have a high ratio of membrane phosphatidylcholine to sphingomyelin. The same strains hydrolysed varying amounts of p-nitrophenylphosphorylcholine; L. bozemanii exhibited the greatest activity. L. pneumophila, L. bozemanii, L. dumoffii, L. longbeachae and L. jordanis, but not L. micdadei, released tritiated phosphorylcholine from labelled substrate. These results indicate that several species of Legionella possess cytolytic capability; exotoxins with activity may play a role.
J Gen Microbiol 1985 Jun
PMID:Cytolytic and phospholipase C activity in Legionella species. 404 20

A virulent strain of Legionella pneumophila was inoculated into an enclosed system supplied with unsterilized water from a domestic hot water supply. Growth of bacteria was monitored over 10 weeks. An increase in the number of organisms other than legionellas occurred but few amoebae were observed and none could be cultured. Viable counts of L. pneumophila in the circulation fluid decreased slightly. However, particles of debris which accumulated in the apparatus and which were stained by the indirect fluorescent antibody technique were found to be almost totally composed of L. pneumophila. On dismantling the apparatus Legionella was isolated in moderately high numbers from several different types of surfaces, particularly natural rubber and silicone.
J Gen Microbiol 1984 Jul
PMID:Survival of Legionella pneumophila in a model hot water distribution system. 647 Jun 70

The effect of antimicrobial agents on the intracellular multiplication of Legionella pneumophila in cultured guinea-pig peritoneal macrophages was measured. Beta-lactam antibiotics at concentrations 5 to 400 times the MIC in vitro did not inhibit the intracellular growth of the organism. Gentamicin inhibited the growth considerably but failed to eliminate the organism from the phagocytic mixture. Chloramphenicol or tetracycline at 10 micrograms ml-1 (40 or 5 times the MIC in vitro respectively) did not eliminate the organism. At a higher concentration (30 micrograms ml-1), however, these drugs eliminated the bacterium from the mixture. Only erythromycin and rifampin were effective in killing the organism at very low concentration (1 microgram ml-1). Intracellular multiplication of L. pneumophila was observed clearly by light microscopy using Wright-Giemsa staining.
J Gen Microbiol 1984 Apr
PMID:Antibiotic susceptibility of Legionella pneumophia Philadelphia-1 in cultured guinea-pig peritoneal macrophages. 673 22

Ten strains representing six serogroups of Legionella pneumophila were examined by electron microscopy using freeze-etching, thin-sectioning and negative-staining techniques. In addition, selected strains were examined further as shadowed and freeze-dried preparations and by scanning electron microscopy. The cell envelope consisted of two membranes, evident in fractured specimens as four short ridges. The major fracture plane was through the inner membrane, and therefore the protoplasmic and extracellular fracture faces of this membrane were predominant. With the exception of one strain (Togus 1), the particle arrangement on these fracture faces was random. A peptidoglycan-like cell wall layer was revealed only in sections of partially plasmolysed cells. Membrane-bounded poly-beta-hydroxybutyrate-like granules were evident in the cytoplasm and these frequently showed plastic deformation due to fracturing. Although appendages were present, the surfaces of organisms and of isolated cell membranes showed no regular arrays of particles.
J Gen Microbiol 1982 Jul
PMID:Ultrastructure of the cell envelope layers and surface details of Legionella pneumophila. 711 42

A commercial DNA probe kit (Gen-probe) for the detection of rRNA from legionellae was evaluated for its accuracy in diagnosing Legionnaires' disease in 167 patients with pneumonia. The test was performed on freshly obtained clinical respiratory tract samples. Cultures and direct immunofluorescence antibody (DFA) staining of the samples and serological tests were performed simultaneously for all patients. The probe assay result was positive in six patients; five of them had other laboratory evidence of disease (positive cultures or positive serological results or both). Depending on the diagnostic criteria, the probe test had a sensitivity of 31-67%, a specificity of 99% and positive predictive values of 67-83%. The diagnostic performance of the DNA probe assay in this study was superior to that of the DFA test. The results indicate that the examination of respiratory tract secretions by the Gen-probe kit is a suitable screening test for the diagnosis of Legionnaires' disease.
 ...
PMID:Diagnostic efficacy of a DNA probe in pneumonia caused by Legionella species. 768 Nov 12


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