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

Legionella pneumophila adheres to the slime coat of Fischerella spp. This was shown by microscopic examination and by a decline in L. pneumophila CFU in samples removed from coincubation mixtures of both organisms. Binding of partially purified Fischerella slime by L. pneumophila was most efficient by young, less hydrophobic L. pneumophila cells than by older, more hydrophobic cells. Uptake of crystal violet and partitioning into hexadecane were used to measure hydrophobicity of L. pneumophila. Purified soluble Legionella antigen also bound to Fischerella slime, as shown by indirect immunofluorescence. Adherence was not specific for L. pneumophila, since a variety of gram-negative, gram-positive, and acid-fast bacteria also bound to Fischerella slime.
 ...
PMID:Characterization of surfaces involved in adherence of Legionella pneumophila to Fischerella species. 641 13

When cultured in broth to the transmissive phase, Legionella pneumophila infects macrophages by inhibiting phagosome maturation, whereas replicative-phase cells are transported to the lysosomes. Here we report that the ability of L. pneumophila to inhibit phagosome-lysosome fusion correlated with developmentally regulated modifications of the pathogen's surface, as judged by its lipopolysaccharide profile and by its binding to a sialic acid-specific lectin and to the hydrocarbon hexadecane. Likewise, the composition of membrane vesicles shed by L. pneumophila was developmentally regulated, based on binding to the lectin and to the lipopolysaccharide-specific monoclonal antibody 3/1. Membrane vesicles were sufficient to inhibit phagosome-lysosome fusion by a mechanism independent of type IV secretion, since only approximately 25% of beads suspended with or coated by vesicles from transmissive phase wild type or dotA secretion mutants colocalized with lysosomal probes, whereas approximately 75% of beads were lysosomal when untreated or presented with vesicles from the L. pneumophila letA regulatory mutant or E. coli. As observed previously for L. pneumophila infection of mouse macrophages, vesicles inhibited phagosome-lysosome fusion only temporarily; by 10 h after treatment with vesicles, macrophages delivered approximately 72% of ingested beads to lysosomes. Accordingly, in the context of the epidemiology of the pneumonia Legionnaires' disease and virulence mechanisms of Leishmania and Mycobacteria, we discuss a model here in which L. pneumophila developmentally regulates its surface composition and releases vesicles into phagosomes that inhibit their fusion with lysosomes.
 ...
PMID:Membrane vesicles shed by Legionella pneumophila inhibit fusion of phagosomes with lysosomes. 1671 56