[The splitting of the acceptor proteins of the protein kinase system in eukaryotic cells by Legionella cytolysin].
0
Citation
0
Reference
10
Related Paper
Abstract:
In the process of protein kinase reaction carried out in the mixture consisting of tris-HCl buffer, EDTA, MgCl2, gamma-32P-ATP and the cytoplasmic fraction of rabbit pulmonary cells the phosphorylation of proteins with molecular weights of 150 and 55 kD took place. The addition of L. pneumophila culture fluid to the reaction mixture resulted in the splitting of phosphorylated proteins with the formation of the component having a molecular weight of 45 kD. These disturbances in protein kinase reaction were found to occur due to the involvement of Legionella cytoplasm, a previously characterized protein with a molecular weight of 37 kD, into the process. In this connection, the participation of cytolysin in the pathogenesis of Legionella infection may also be considered from the viewpoint of the effect produced by cytolysin on the regulatory processes affecting the metabolism of target cells.Keywords:
Cytolysin
Legionella
Cite
Effect of three pivotal environmental factors, cooling tower water, ferric ion and temperature, on the intracellular proliferation of the fateful opportunistic pathogen Legionella pneumophila within ciliate host was investigated by the Legionella Tetrahymena model built previously. The results showed that the cooling tower water, although containing much lower concentration of Fe(superscript 3+) than medium, was more suitable for intracellular survival and proliferation of L. pneumophila compared to PYG buffer even at 10 of MOI. The results also demonstrated that the ciliate host could enrich Fe(superscript 3+) from infection buffer, thus providing enough Fe(superscript 3+) for intracellular multiplication of L. pneumophila. The enriched Fe(superscript 3+) promoted intracellular proliferation remarkably even at concentration of 0.05×10^(-6) in the buffer. On the other hand, the intracellular proliferation rate of the bacteria was similar at 0.1×10^(-6) and 0.5×10^(-6) of Fe(superscript 3+) in the buffer. Higher temperature also promoted intracellular multiplication of L. pneumophila. At 35℃, L. pneumophila could proliferate within the host cells even at 10 of MOI, which finally led to lysis of host cells.
Legionella
Intracellular parasite
Cite
Citations (0)
The protective properties of Legionella antigenic preparations were studied on guinea pigs with experimental Legionella infection. Preliminary immunization of guinea pigs with serotypic antigen, cytolysin, as well as live or formalin-treated Legionella cells, did not protect the animals from the subsequent aerogenic infection with 10(5) colony-forming units of virulent L. pneumophila. Immunization with the main outer membrane protein ensured the survival of 70% of the animals and inhibited the proliferation of the infective agent in the lungs of guinea pigs subjected to aerogenic infection with 10(5) colony-forming units of virulent L. pneumophila. The data obtained in this study indicate that the main outer membrane protein of L. pneumophila is capable of stimulating protective immunity.
Legionella
Cytolysin
Yersinia pestis
Cite
Citations (1)
The fusion of spleen cells, taken from BALB/c mice immunized with the purified preparation of L. pneumophila cytolysin, with cells Sp2/0 and NP has been carried out. As a result, hybridoma cells producing IgG1, IgG3 and IgM antibodies to this protein have been obtained. All monoclonal antibodies (McAb) thus obtained react with L. pneumophila strain lysates in the precipitation test, while IgG3 and IgM antibodies react with erythrocyte diagnostic agents prepared from the lysate of L. pneumophila cells in the hemagglutination test. In the Western blot assay, McAb react with the 37 KD protein (cytolysin) and a number of other proteins from L. pneumophila cultures and L. pneumophila cell lysate, but do not react with the species-specific protein with a molecular weight of 29 KD, contained in the outer membrane of L. pneumophila, as well as with other species: L. bozemanii, L. dumoffii, L. longbeachae, L. micdadei. The possibility of using these McAb conjugated with FITC and peroxidase for the rapid diagnosis of Legionella infection is shown.
Cytolysin
Legionella
Cite
Citations (0)
Sucrose synthase from the etiolated seedlings of rice (Oryza sativa L. cv. Tainung 67) was phosphory- lated both in vivo and in vitro. Four protein kinases that phosphorylated recombinant rice sucrose synthase 1 (RSuS1) in a Mn 2+ -dependent manner were partially purified and characterized from etiolated rice seedlings. These four kinases, designated as RPK1, RPK2, RPK3 and RPK4, are monomeric enzymes with apparent molecular masses of 34 kDa, 57 kDa, 30 kDa, and 30 kDa, respectively. Phosphoamino acid analysis of the 32 P-labeled phosphorylated recombi- nant RSuS1 indicated that it was phosphorylated at serine residues by these four RPKs. RP-HPLC/ESI-MS analysis of the tryptic peptides of phosphorylated RSuS suggested that the serine residues in the tryptic peptides 13-LHSVR- 17 and 168-HLSSK-172 were the target residues for phosphorylation. For confirmation of this finding, mutant re- combinant RSuS1, S15A, S170A and S15A/S170A, were purified and subjected to phosphorylation by the four partially purified kinases. The results showed that both Ser15 and Ser170 residues were target residues for RPK1, PRK2 and PRK3 and Ser15 was the major phosphorylation site in RSuS1. Phosphorylation of RSuS1 may not occur exclu- sively at these two sites since weak phosphorylation of the double mutant protein S15A/S170A was also observed. Phosphorylation of the mutant S15A and S15A/S170A by RPK4 was undetectable, indicating that Ser15 was the only target residue for this kinase.
Etiolation
Phosphoserine
Residue (chemistry)
Cite
Citations (3)
A fragment of the gene for cytolysin has been cloned. The product of the gene has been earlier identified as an immunoserological marker of Legionella pneumophila. Clones were selected by immunodetection of cytolysin gene product expression. An EcoRI 3.8 kb fragment of the genomic DNA from Legionella pneumophila strain Philadelphia-1 was used as a DNA probe that hybridized with the bacterial colonies of 20 Legionella pneumophila strains but not with the colonies of 10 other Legionella species or 8 other bacterial genera. The cloned fragment has been shown to be unique for Legionella pneumophila. The region of homology is suggested to be longer than a possible dimension of the cytolysin gene.
Cytolysin
Legionella
genomic DNA
Homology
Cite
Citations (0)
Coagglutination test (CoaT), radioimmunoassay (RIA) and ELISA were used for detection of cytolysin produced by L. pneumophila. The sensitivity of RIA was 100 ng/ml, CoaT--10-20 ng/ml, ELISA--1 ng/ml. To determine cytolysin production among various strains and species of Legionella, the authors studied bacterial ultrasonic lysates. All 11 strains of L. pneumophila tested were cytolysin-positive. L. longbeachae, L. bozemanii and L. dumoffii strains failed to produce cytolysin. The authors believe that an antigen of cytolysin can be used for identification of L. pneumophila.
Cytolysin
Legionella
Cite
Citations (1)
Mitogen-activated protein kinases (MAPKs) phosphorylate target proteins in both the cytoplasm and nucleus, and a strong correlation exists between the subcellular localization of MAPK and resulting cellular responses. It was thought that MAPK phosphorylation was always followed by rapid nuclear translocation. However, we and others have found that MAPK phosphorylation is not always sufficient for nuclear translocation in vivo. In the developing Drosophila wing, MAPK-mediated signaling is required both for patterning and for cell proliferation, although the mechanism of this differential control is not fully understood. Here, we show that phosphorylated MAPK (pMAPK) is held in the cytoplasm in differentiating larval and pupal wing vein cells, and we show that this cytoplasmic hold is required for vein cell fate. At the same time, we show that MAPK does move into the nucleus of other wing cells where it promotes cell proliferation. We propose a novel Ras pathway bifurcation in Drosophila and our results suggest a mechanism by which MAPK phosphorylation can signal two different cellular outcomes (differentiation versus proliferation) based on the subcellular localization of MAPK.
Cite
Citations (45)
A molecular DNA probe has been obtained on the basis of recombinant plasmid pNIG carrying the Legionella cytolysin gene. The use of this probe for the identification of different Legionella species and other microorganisms has shown that it may serve as the species-specific marker of L. pneumophila. The probe has been used for the identification of new Legionella-like strains isolated from the environment.
Cytolysin
Legionella
Identification
Cite
Citations (0)
Autophagy-related protein 13
Autophagosome
Cite
Citations (169)
Cytolysin
Intracellular parasite
Legionella
Cite
Citations (40)