FLAGELLA AND FIMBRIq ON LEGIONELLA ORGANISMS

Rodgers, Frank G.; Greaves, P W; Macrae, A.D.

doi:10.1016/s0140-6736(79)90691-3

Cited by 15 publications

(7 citation statements)

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“…Regarding the ligands on the bacterial surface responsible for the increased levels of mRNAs observed in our studies, we emphasized flagella and fimbriae, since L. pneumophila (36) and S. typhimurium both display these structures. By using flagellum-and fimbria-negative mutants, we observed the importance of flagella in the induction of GM-CSF mRNA but not that of MIP-2 ( Fig.…”

Section: Discussionmentioning

confidence: 89%

Induction of cytokine granulocyte-macrophage colony-stimulating factor and chemokine macrophage inflammatory protein 2 mRNAs in macrophages by Legionella pneumophila or Salmonella typhimurium attachment requires different ligand-receptor systems

1996

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The attachment of bacteria to macrophages is mediated by different ligands and receptors and induces various intracellular molecular responses. In the present study, induction of cytokines and chemokines, especially granulocyte-macrophage colony-stimulating factor (GM-CSF) and macrophage inflammatory protein 2 (MIP-2), was examined, following bacterial attachment, with regard to the ligand-receptor systems involved. Attachment of Legionella pneumophila or Salmonella typhimurium to cultured mouse peritoneal macrophages increased the steady-state levels of cellular mRNAs for the cytokines interleukin 1␤ (IL-1␤), IL-6, and GM-CSF as well as the chemokines MIP-1␤, MIP-2, and KC. However, when macrophages were treated with ␣-methyl-D-mannoside (␣MM), a competitor of glycopeptide ligands, induction of cytokine mRNAs was inhibited, but the levels of chemokine mRNAs were not. Pretreatment of the bacteria with fresh mouse serum enhanced the level of GM-CSF mRNA but not the level of MIP-2 mRNA. In addition, serum treatment reduced the inhibitory effect of ␣MM on GM-CSF mRNA. These results indicate that bacterial attachment increases the steady-state levels of the cytokine and chemokine mRNAs tested by at least two distinct receptor-ligand systems, namely, one linked to cytokine induction and involving mannose or other sugar residues and the other linked to chemokine induction and relatively ␣MM insensitive. Furthermore, opsonization with serum engages other pathways in the cytokine response which are relatively independent of the ␣MM-sensitive system. Regarding bacterial surface ligands involved in cytokine mRNA induction, evidence is presented that the flagellum may be important in stimulating cytokine GM-CSF message but not chemokine MIP-2 message. Analysis of cytokine GM-CSF and chemokine MIP-2 signaling pathways with protein kinase inhibitors revealed the involvement of calmodulin and myosin light-chain kinase in GM-CSF but not MIP-2 mRNA induction, adding further evidence that several distinct receptor systems are engaged during the process of bacterial attachment and induction of cytokines and chemokines, such as GM-CSF and MIP-2, respectively.

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Section: Discussionmentioning

confidence: 89%

Induction of cytokine granulocyte-macrophage colony-stimulating factor and chemokine macrophage inflammatory protein 2 mRNAs in macrophages by Legionella pneumophila or Salmonella typhimurium attachment requires different ligand-receptor systems

1996

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“…Surface pili were first observed on the surface of Legionella bacteria not long after the discovery of this genus (Rodgers et al , 1979, 1980). Since then, L. pneumophila has been shown to possess both short (0.1–0.6 μm) and long (0.8–1.5 μm) pili (Stone & Abu Kwaik, 1998).…”

Section: Introductionmentioning

confidence: 99%

Twitching motility inLegionella pneumophila

Coil¹,

Anné²

2009

FEMS Microbiology Letters

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Twitching motility is a form of bacterial translocation over solid or semi-solid surfaces mediated by the extension, tethering, and subsequent retraction of type IV pili. These pili are also known to be involved in virulence, biofilm formation, formation of fruiting bodies, horizontal gene transfer, and protein secretion. We have characterized the presence of twitching motility on agar plates in Legionella pneumophila, the etiological agent of Legionnaires' disease. By examining twitching motility zones, we have demonstrated that twitching motility was dependent on agar thickness/concentration, the chemical composition of the media, the presence of charcoal and cysteine, proximity to other bacteria, and temperature. A knockout mutant of the pilus subunit, pilE, exhibited a total loss of twitching motility at 37 degrees C, but not at 27 degrees C, suggesting either the existence of a compensating pilus subunit or of another twitching motility system in this organism.

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“…One of the L. pneumophila attachment factors that has been recently described is the pili (50). Expression of pili by L. pneumophila was originally identified by electron microscopy (41,42). The pili can be categorized as short (0.1 to 0.6 m) or long (0.8 to 1.5 m) (50).…”

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confidence: 99%

Natural Competence for DNA Transformation by Legionella pneumophila and Its Association with Expression of Type IV Pili

1999

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We have recently described the expression of two pili of different lengths on the surface of Legionella pneumophila (B. J. Stone and Y. Abu Kwaik, Infect. Immun. 66:1768–1775, 1998). Production of long pili requires a functional pilE L locus, encoding a type IV pilin protein. Since type IV pili in Neisseria gonorrhoeaeare associated with competence for DNA transformation, we examined the competence of L. pneumophila for DNA transformation under conditions that allowed the expression of type IV pili. We show that L. pneumophila is naturally competent for DNA transformation by isogenic chromosomal DNA and by plasmid DNA containing L. pneumophila DNA. Many different L. pneumophila loci are able to transform L. pneumophilaafter addition of plasmid DNA, including gspA,ppa, asd, and pilE L. The transformation frequency is reduced when competing DNA containing either L. pneumophila DNA or vector sequences is added to the bacteria, suggesting that uptake-specific sequences may not be involved in DNA uptake. Competence for DNA transformation correlates with expression of the type IV pili, and apilE L mutant defective in expression of type IV pili is not competent for DNA transformation. Complementation of the mutant for competence is restored by the reintroduction of a cosmid that restores production of type IV pili. Minimal competence is restored to the mutant by introduction of pilE Lalone. We conclude that competence for DNA transformation in L. pneumophila is associated with expression of the type IV pilus and results in recombination of L. pneumophila DNA into the chromosome. Since expression of type IV pili also facilitates attachment of L. pneumophila to mammalian cells and protozoa, we designated the type IV pili CAP (for competence- and adherence-associated pili).

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FLAGELLA AND FIMBRIq ON LEGIONELLA ORGANISMS

Cited by 15 publications

References 0 publications

Induction of cytokine granulocyte-macrophage colony-stimulating factor and chemokine macrophage inflammatory protein 2 mRNAs in macrophages by Legionella pneumophila or Salmonella typhimurium attachment requires different ligand-receptor systems

Induction of cytokine granulocyte-macrophage colony-stimulating factor and chemokine macrophage inflammatory protein 2 mRNAs in macrophages by Legionella pneumophila or Salmonella typhimurium attachment requires different ligand-receptor systems

Twitching motility inLegionella pneumophila

Natural Competence for DNA Transformation by Legionella pneumophila and Its Association with Expression of Type IV Pili

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