Cytolytic and Phospholipase C Activity in Legionella Species

Baine, William B.

doi:10.1099/00221287-131-6-1383

Cited by 39 publications

(38 citation statements)

References 38 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…The existence of both acid and alkaline phosphatases is known in legionellae (15,31). Next, we examined the hydrolysis of It is known that PLC, PLD, the combined action of PLA 1 and PLA 2 , or the collaboration of PLA and acyltransferase are each able to release tritiated water-soluble components such as 3 H-PrC, 3 H-choline, and 3 H-GPC from 3 H-PC, respectively. Since we could demonstrate that Legionella possesses PLA (Fig.…”

Section: Resultsmentioning

confidence: 99%

“…The same strains hydrolyzed various amounts of p-NPPC; L. bozemanii exhibited the greatest activity. In decreasing quantity, L. pneumophila, L. dumoffii, L. jordanis, L. bozemanii, and L. longbeachae, but not L. micdadei, released a radioactive water-soluble product from 3 H-PC which was assumed to be 3 H-PrC. Baine concluded that five of the six Legionella species under investigation possessed PLC activity (3).…”

mentioning

confidence: 99%

See 1 more Smart Citation

Novel Phospholipase A Activity Secreted by Legionella Species

et al. 2000

View full text Add to dashboard Cite

Bacterial phospholipases are regarded as a major virulence factor in infection. In bacteria associated with pneumonia, destruction of lung surfactant and host cell membranes by bacterial phospholipases secreted during infection is thought to contribute to the disease. Phospholipase C (PLC) activity has been described in several Legionella species (W. B. Baine, J. Gen. Microbiol. 134:489-498, 1988; W. B. Baine, J. Gen. Microbiol. 131:1383-1391, 1985). By using detection methods such as thin-layer chromatography and mass spectrometry, PLC activity could not be detected in several strains of Legionella pneumophila. Instead, phospholipid degradation was identified to be caused by a novel PLA activity. We could demonstrate that PLA secretion starts at the mid-exponential-growth phase when bacteria were grown in liquid culture. Several Legionella species secreted different amounts of PLA. Legionella PLA may act as a powerful agent in the mediation of pathogenicity due to destruction of lung surfactant and epithelial cells.

show abstract

Section: Resultsmentioning

confidence: 99%

mentioning

confidence: 99%

Novel Phospholipase A Activity Secreted by Legionella Species

et al. 2000

View full text Add to dashboard Cite

show abstract

“…The cytopathology of lungs infected by L. pneumophila suggests involvement of extracellular proteolytic enzymes or taxins in the pathogenesis of Legionella [2,18]. In order to select cloned toxin determinants of Legionella the recombinant E. coli K-12 clones were screened on blood agar plates containing human and canine erythrocytes.…”

Section: Expression Of Toxinsmentioning

confidence: 99%

Intrazelluläres Überleben und Expression der Virulenzdeterminanten von Legionella pneumophila

et al. 1991

View full text Add to dashboard Cite

“…For the determination of p-NPPC hydrolase, 100 l L. pneumophila culture supernatant or lysate (diluted at 1:2 with 40 mM Tris-HCl, pH 7.5, 25°C) were incubated with the same volume of substrate mixture containing 10 mM p-NPPC (Sigma-Aldrich, Taufkirchen, Germany), 6 mM NaN 3 , 1% (vol/vol) Triton X-100, and 10 mM MnCl 2 in 40 mM Tris-HCl (pH 7.5, 25°C) at 37°C and with continuous agitation at 100 to 170 rpm for 20 to 50 h. Subsequently the release of p-nitrophenol (p-NP) was measured optically at a wavelength of 405 nm and compared to p-NP (SigmaAldrich, Taufkirchen, Germany) standard solutions (9,22). BYE broth and 40 mM Tris-HCl, pH 7.5 (25°C), were used as negative controls.…”

Section: Methodsmentioning

confidence: 99%

“…L. pneumophila secretes a p-NPPC-hydrolyzing activity into its culture supernatant and the PlcA protein contributes to this activity (5,9,22). p-NPPC is an artificial substrate for phosphodiesterases, for example, phospholipases C, and has additionally been shown to be cleaved by phosphatases (22,23,66).…”

Section: Vol 188 2006 Control Of Hydrolytic Activities In L Pneumomentioning

confidence: 99%

The Global Regulatory Proteins LetA and RpoS Control Phospholipase A, Lysophospholipase A, Acyltransferase, and Other Hydrolytic Activities of Legionella pneumophila JR32

et al. 2006

View full text Add to dashboard Cite

Legionella pneumophila possesses a variety of secreted and cell-associated hydrolytic activities that could be involved in pathogenesis. The activities include phospholipase A, lysophospholipase A, glycerophospholipid: cholesterol acyltransferase, lipase, protease, phosphatase, RNase, and p-nitrophenylphosphorylcholine (p-NPPC) hydrolase. Up to now, there have been no data available on the regulation of the enzymes in L. pneumophila and no data at all concerning the regulation of bacterial phospholipases A. Therefore, we used L. pneumophila mutants in the genes coding for the global regulatory proteins RpoS and LetA to investigate the dependency of hydrolytic activities on a global regulatory network proposed to control important virulence traits in L. pneumophila. Our results show that both L. pneumophila rpoS and letA mutants exhibit on the one hand a dramatic reduction of secreted phospholipase A and glycerophospholipid: cholesterol acyltransferase activities, while on the other hand secreted lysophospholipase A and lipase activities were significantly increased during late logarithmic growth phase. The cell-associated phospholipase A, lysophospholipase A, and p-NPPC hydrolase activities, as well as the secreted protease, phosphatase, and p-NPPC hydrolase activities were significantly decreased in both of the mutant strains. Only cell-associated phosphatase activity was slightly increased. In contrast, RNase activity was not affected. The expression of plaC, coding for a secreted acyltransferase, phospholipase A, and lysophospholipase A, was found to be regulated by LetA and RpoS. In conclusion, our results show that RpoS and LetA affect phospholipase A, lysophospholipase A, acyltransferase, and other hydrolytic activities of L. pneumophila in a similar way, thereby corroborating the existence of the LetA/RpoS regulation cascade.Legionella pneumophila is an intracellular bacterial pathogen which infects protozoa, such as amoebae, present in fresh water sources. When inhaled by susceptible humans, the bacteria infect and multiply in human lung macrophages and cause the potentially fatal pneumonia Legionnaires' disease (20). When nutrients become rare after replication in a modified phagosome (1), L. pneumophila exits the spent host cell by disruption of the eukaryotic phagosomal and cell membranes and infects a new host (49, 67). Accordingly, the life cycle of L. pneumophila can be differentiated into two phases where the bacterium needs to adapt to specific conditions: intracellular replication within the host cell and host cell exit and transmission to a new host (50). Furthermore, it was shown that L. pneumophila develops a mature infectious form that is different from in vitro grown stationary phase cells with regard to infectivity and resistance to antibiotics (30).Adaptation between replicative and transmissive phases in L. pneumophila is strictly regulated on the genetic level. Virulence properties such as motility (8,14,36,37), cytotoxicity (2,14,33), and resistance to stress such as nutrient limitatio...

show abstract

Cytolytic and Phospholipase C Activity in Legionella Species

Cited by 39 publications

References 38 publications

Novel Phospholipase A Activity Secreted by Legionella Species

Novel Phospholipase A Activity Secreted by Legionella Species

Intrazelluläres Überleben und Expression der Virulenzdeterminanten von Legionella pneumophila

The Global Regulatory Proteins LetA and RpoS Control Phospholipase A, Lysophospholipase A, Acyltransferase, and Other Hydrolytic Activities of Legionella pneumophila JR32

Contact Info

Product

Resources

About