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)

In experiments on conjugation the transfer of a number of R-plasmids having a wide range of hosts, such as plasmids RP1, R68.45, RP4, N3, RK2, S-a, those having a narrow range of hosts, such as plasmid R64, to strains of different Legionella species was shown. The frequency of transfer varied from 3.1 X 10(-3) to 9.4 X 10(-7). The fact that the conjugation transfer was confirmed by the reverse transfer of plasmids from Legionella transconjugates to Escherichia coli strain K12, as well as by the detection of the DNA of the transferred plasmid by means of electrophoresis in agar gel. Plasmid RP1 showed different behavior in transconjugates of various Legionella species after several passages in a medium free of antibiotics. In the Legionella strain under study the unstable preservation of plasmid R64 was observed.
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PMID:[The conjugational transfer of plasmids to Legionella strains]. 218 66

The plasmids RP4 and pPH1JI::Mu::Tn5 were transferred with moderate frequency from Escherichia coli to Legionella pneumophila (strain Bloomington 2) and Fluoribacter (Legionella) bozemanae (strain WIGA). The frequency of transfer to Tatlockia (Legionella) micdadei (strain Tatlock) was much lower. In these transconjugant strains the plasmids were maintained following at least 10 nonselective passages. However, the introduced plasmids could not be transferred from these strains to several other strains of Legionella or Tatlockia with a detectable frequency, yet they could be transferred to a restriction-modification deficient (rm-) E. coli strain with moderate frequency. This suggests not only that the expression of transfer genes may be repressed but that the legionellae are poorer recipients than are the rm- E. coli.
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PMID:Plasmid transfer into members of the family Legionellaceae. 649 66

Derivatives of the self-transmissible F plasmid of Escherichia coli can be introduced into Legionella pneumophila by conjugation and maintained within only upon selection. In L. pneumophila. F-based replicons seem to exist as extrachromosomal elements since they were readily lost when F-containing L. pneumophila was grown on nonselective medium. The F-based plasmids were not self-transmissible in L. pneumophila. The mating defect may be due to an inability to form the F pilus since F-containing strains of L. pneumophila could neither be infected with the pilus-specific phage M13 nor transduced with f1-packaged ColE1 replicons. Currently, the most commonly used transfer system for introducing genetic information into L. pneumophila employs E. coli donors with a chromosomally integrated copy of RP4::Mu to mobilize plasmids bearing the RK2 origin of transfer (oriT). Use of this system to deliver TnphoA for mutagenesis of the L. pneumophila chromosome led to transconjugants that all contained cryptic DNA alterations that involved the plasmid RP4 and phage Mu. No TnphoA transposition was observed in L. pneumophila. The fact that F-mediated conjugation can be used to efficiently transfer plasmids containing the oriT of F to L. pneumophila provides an important alternative to the RP4-based plasmid transfer system and may avoid DNA anomalies in transconjugants that impede genetic analysis. Furthermore, our results demonstrate the promiscuous nature of the F conjugal transfer and replication systems.
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PMID:Escherichia coli F plasmid transfers to and replicates within Legionella pneumophila: an alternative to using an RP4-based system for gene delivery. 789 13

A plasmid designated pLPG36 was isolated from the naturally occurring Legionella pneumophila serogroup-1 and purified by CsCl buoyant density centrifugation. A restriction map of this 58 kb plasmid was constructed and provided the basis for cloning four BamHI fragments into the unique BamHI site of pUC18. The four recombinant plasmids were investigated for the mobilization function in Escherichia coli strains. Only one of these, pFLJ2, was mobilized by the IncP plasmids RP4, pRK231 and R702, but not by plasmids pSa, R40a, R387, pN3 or R16. The derivative plasmid pFLJ2 was mobilized more efficiently by R702 than by RP4 or pRK231. By genetic and deletion analysis, the mobilization region of pLPG36 was located to a 6 kb EcoRI fragment of the plasmid.
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PMID:Cloning, mapping and conjugal mobility of pLPG36, a common plasmid from Legionella pneumophila serogroup-1. 812 36

Type IV secretion systems (TFSS) mediate secretion or direct cell-to-cell transfer of virulence factors (proteins or protein-DNA complexes) from many Gram-negative animal, human and plant pathogens, such as Agrobacterium tumefaciens, Bartonella tribocorum, Bordetella pertussis, Brucella suis, Helicobacter pylori, Legionella pneumophila and Rickettsia prowazekii, into eukaryotic cells. Bacterial conjugation is also classified as a TFSS-like process mediating the spread of broad-host-range plasmids between Gram-negative bacteria such as RP4 and R388, which carry antibiotic resistance genes. Genetic, biochemical, cell biological and structural biology experiments led to significant progress in the understanding of several aspects of TFSS processes. X-ray crystallography revealed that homologues of the A. tumefaciens inner membrane-associated proteins VirB11 and VirD4 from H. pylori and R388, respectively, may form channels for substrate translocation or assembly of the transmembrane TFSS machinery. Biochemical and cell biological experiments revealed interactions between components of the periplasmic core components VirB8, VirB9 and VirB10, which may form the translocation channel. Analysis of A. tumefaciens virulence proteins VirE2 and VirF suggested that the periplasmic translocation route of the pertussis toxin from B. pertussis may be more generally valid than previously anticipated. Secretion and modification of toxins from H. pylori and L. pneumophila profoundly affect host cell metabolism, thus entering the discipline of cellular microbiology. Finally, results from genome sequencing projects revealed the presence of up to three TFSS in a single organism, and the analysis of their interplay and adaptation to different functions will be a future challenge. TFSS-carrying plasmids were discovered in different ecosystems, suggesting that genetic exchange may speed up their evolution and adaptation to different cell-cell interactions.
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PMID:Bacterial secrets of secretion: EuroConference on the biology of type IV secretion processes. 1191 19