Biochemical and Genetic Aspects of Pseudomonas Aeruginosa Virulence

Lory, Stephen; Tai, Phang C.

doi:10.1007/978-3-642-70586-1_4

Cited by 22 publications

(15 citation statements)

References 88 publications

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“…A large number of virulence factors elaborated by P. aeruginosa contribute to the severity of the infection. These include a number of extracellular proteins such as exotoxin A, exoenzyme S, alkaline protease, elastase, several haemolytic factors and a leukocidin (Lory and Tai, 1985). Several surface-associated cellular components have been implicated as virulence factors.…”

Section: Introductionmentioning

confidence: 99%

The filA (rpoF) gene of Pseudomonas aeruginosa encodes an alternative sigma factor required for flagellin synthesis

Starnbach

Lory

1992

Molecular Microbiology

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In order to better understand the regulation of Pseudomonas aeruginosa flagellin expression we cloned the sigma factor of RNA polymerase used to transcribe the flagellin gene. It is a member of the sigma 28 class of alternative sigma factors described in several bacterial genera. Using the published sequence of the fliA gene encoding the sigma 28 from Salmonella typhimurium, we designed two oligonucleotides and, using the polymerase chain reaction, isolated the fliA gene from S. typhimurium chromosomal DNA. This heterologous probe was used in the DNA blot analysis of restriction digests of P. aeruginosa DNA. A 1.7 kb SalI-EcoRI fragment reacted with the probe and this fragment was cloned into the pBluescript vectors. The P. aeruginosa fliA gene was able to complement the motility defect of an Escherichia coli fliA mutant, but only when transcription was driven from the vector promoter. Insertional inactivation of the fliA gene with a gentamicin gene cassette rendered P. aeruginosa nonmotile and unable to express the flagellin gene. The 1.7 kb cloned fragment was sequenced and shown to contain the entire fliA gene. P. aeruginosa FliA shares 67% amino acid similarity with the homologous S. typhimurium sequence. Transcriptional analysis of the fliA gene showed that its expression was not dependent on RpoN, a sigma factor shown also to be required for flagellin synthesis. A reading frame downstream of fliA was found to encode the P. aeruginosa homologue of the enterobacterial cheY gene.

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Section: Introductionmentioning

confidence: 99%

The filA (rpoF) gene of Pseudomonas aeruginosa encodes an alternative sigma factor required for flagellin synthesis

Starnbach

Lory

1992

Molecular Microbiology

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122

106

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“…P. aeruginosa is armed with many virulence factors such as proteases, cytotoxins, phospholipases, neuraminidase, capsular polysaccharides, and lipopolysaccharides, contributing to its ability to colonize, penetrate, and survive against host immune defense (9,26,35). Moreover, P. aeruginosa is intrinsically resistant and easily acquires resistance to antibiotics commonly used to treat bacterial infections (23). Furthermore, its ability to form biofilm enhances the bacterial resistance to various antimicrobial agents (1,6).…”

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Growth Phase-Dependent Invasion of Pseudomonas aeruginosa and Its Survival within HeLa Cells

Jin

2001

Infect Immun

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Clinical isolates of Pseudomonas aeruginosa are classified into invasive and noninvasive (cytolytic) strains. In a noninvasive PA103 background, ExoS and ExoT have recently been shown to function as anti-internalization factors. However, these two factors seemed not to have such a function in an invasive strain PAK background. In this study, using HeLa tissue culture cells, we observed that the internalization of invasive strain PAK is dependent on its growth phases, with the stationary-phase cells internalized about 100-fold more efficiently than the exponential-phase cells. This growth phase-dependent internalization was not observed in the noninvasive PA103 strain. Further analysis of various mutant derivatives of the invasive PAK and the noninvasive PA103 strains demonstrated that ExoS or ExoT that is injected into host cells by a type III secretion machinery functions as an anti-internalization factor in both types of strains. In correlation with the growth phasedependent internalization, the invasive strain PAK translocates much higher amount of ExoS and ExoT into HeLa cells when it is in an exponential-growth phase than when it is in a stationary-growth phase, whereas the translocation of ExoT by the noninvasive strain PA103 is consistently high regardless of the growth phases, suggesting a difference in the regulatory mechanism of type III secretion between the two types of strains. Consistent with the invasive phenotype of the parent strain, an internalized PAK derivative survived well within the HeLa cells, whereas the viability of internalized PA103 derivative was dramatically decreased and completely cleared within 48 h. These results indicate that the invasive strains of P. aeruginosa have evolved the mechanism of intracellular survival, whereas the noninvasive P. aeruginosa strains have lost or not acquired the ability to survive within the epithelial cells.

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“…Exotoxin A (ETA) is one of several virulence factors secreted by Pseudomonas aeruginosa (17,19,30,33). The production of ETA is highly regulated.…”

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confidence: 99%

Effect of regB on expression from the P1 and P2 promoters of the Pseudomonas aeruginosa regAB operon

et al. 1991

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Exotoxin A production in Pseudomonas aeruginosa is dependent on two regulatory genes, regA and regB, which are located in tandem on the chromosome. Expression of regA and regB is controlled by two promoters (P1 and P2) situated upstream of the regAB locus. We have studied the effect of the regA and regB genV products on transcription from the regAfl promoters. Transcriptional and translational fusions, under the control of the P. aeruginosa regA promoters, were used to analyze the regulation of these promoters in a variety of genetic backgrounds. When the regA P1 promoter was supplied in trans to strains lacking expression of regB (PAO1) or lacking transcription of the regAB operon (PA103-29), little activity from the P1 promoter was detected. In

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Biochemical and Genetic Aspects of Pseudomonas Aeruginosa Virulence

Cited by 22 publications

References 88 publications

The filA (rpoF) gene of Pseudomonas aeruginosa encodes an alternative sigma factor required for flagellin synthesis

The filA (rpoF) gene of Pseudomonas aeruginosa encodes an alternative sigma factor required for flagellin synthesis

Growth Phase-Dependent Invasion of Pseudomonas aeruginosa and Its Survival within HeLa Cells

Effect of regB on expression from the P1 and P2 promoters of the Pseudomonas aeruginosa regAB operon

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