Protease-deficient Mutants of Pseudomonas aeruginosa: Pleiotropic Changes in Activity of Other Extracellular Enzymes

Wretlind, Bengt; Sjöberg, Lennart; Wadström, Torkel

doi:10.1099/00221287-103-2-329

Cited by 66 publications

(38 citation statements)

References 17 publications

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“…In addition, mutants of S. staphylolyticus which have lost the ability to produce any one of the three enzymes have invariably lost all three (G. L. Sloan, unpublished results). Such pleiotropic modifications of extracellular enzyme production in bacteria have been reported by several investigators (Forsgren et al, 1971;Omenn & Friedman, 1970;Wretlind et al, 1977;Yoshikawa et al, 1974).…”

Section: R E S U L T S a N D Discussionsupporting

confidence: 61%

The Characteristics of Extracellular Protein Secretion by Staphylococcus staphylolyticus

1980

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The differential rate of extracellular protein formation by Staphylococcus staphylolyticus, the lysostaphin-producing organism, was biphasic with a low rate of exoprotein secretion during exponential growth and an increased rate during the post-exponential phase of growth. After 20 h, when no further exoprotein was secreted, exoprotein accounted for 5% of the total protein in the culture. The secretion of three extracellular enzymes was monitored and found to represent a constant proportion of total exoprotein at exoprotein concentrations greater than 0.1 mg ml-l.

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Section: R E S U L T S a N D Discussionsupporting

confidence: 61%

The Characteristics of Extracellular Protein Secretion by Staphylococcus staphylolyticus

1980

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“…The production of staphylolytic (LasA) activity was determined as described previously (Hamood et al, 1996a;Wretlind et al, 1977). Lyophilized Staphylococcus aureus cells (Sigma-Aldrich) were suspended in 0 .…”

Section: Methodsmentioning

confidence: 99%

Analysis of quorum sensing-deficient clinical isolates of Pseudomonas aeruginosa

Schaber

Carty

McDonald

et al. 2004

Journal of Medical Microbiology

192

201

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Pseudomonas aeruginosa produces multiple virulence factors and causes different types of infections. Previous clinical studies identified P. aeruginosa isolates that lack individual virulence factors. However, the impact of losing several virulence factors simultaneously on the in vivo virulence of P. aeruginosa is not completely understood. The P. aeruginosa cell-to-cell communication system, or quorum sensing (QS), controls the production of several virulence factors. Animal studies using constructed QS mutants indicated that loss of the QS system severely impacts the virulence of P. aeruginosa. In this study, we tried to determine if deficiency within the QS system compromises the ability of P. aeruginosa to establish infections in humans. We have identified five QS-deficient strains through screening 200 isolates from patients with urinary tract, lower respiratory tract and wound infections. These strains lacked LasB and LasA activities and produced either no or very low levels of the autoinducers N-(3-oxododecanoyl) homoserine lactone and N-butyryl homoserine lactone. PCR analysis revealed that three isolates contained all four QS genes (lasI, lasR, rhlI and rhlR) while two isolates lacked both the lasR and rhlR genes. We also examined the five isolates for other virulence factors. The isolates produced variable levels of exotoxin A and, with one exception, were deficient in pyocyanin production. One isolate produced the type III secretion system (TTSS) effector proteins ExoS and ExoT, two isolates produced ExoT only and two isolates produced no TTSS proteins. The isolates produced weak to moderate biofilms on abiotic surfaces. Analysis of the patients' data revealed that two of the isolates represented a single strain that was isolated twice from the same patient within a 1 month interval. One QSdeficient clinical isolate (CI-1) lacked all tested virulence factors and produced a weak biofilm. These results suggest that naturally occurring QS-deficient strains of P. aeruginosa do occur and are capable of causing infections; and, that besides the known virulence factors, additional factors may contribute to the ability of certain strains such as CI-1 to establish an infection.

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“…Previous studies have shown that mutations which specifically affect elastase secretion are difficult to obtain and that most mutations described affect the secretion of a number of extracellular proteins in addition to elastase (40,41). Ohman et al (29) isolated a strain with a mutation called lasAl that resulted in the production of a defective elastase which is temperature sensitive for elastolytic activity; other exo-* Corresponding author.…”

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confidence: 99%

Activation of an elastase precursor by the lasA gene product of Pseudomonas aeruginosa

Goldberg

Ohman

1987

J Bacteriol

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To study the role of the lasA gene product in the secretion of enzymatically active elastase by Pseudomonas aeruginosa, we constructed mutants by gene replacement with in vitro-derived insertion and deletion mutations in the cloned lasA gene. lasA mutants were deficient in the production of elastolytic activity. A membraneassociated, higher-molecular-weight (approximately 47,000) precursor of elastase was observed in both the wild-type and the lasA mutants. Unlike the wild-type strain, the lasA mutant accumulated the 47,000-molecular weight elastase species in the soluble fraction of the cell, suggesting that the lasA gene product has a role in elastase secretion. Although lasA mutants were deficient in elastolytic activity, they produced a proelastase with a mature molecular weight (approximately 37,000) that still retained general proteolytic activity. Final yields of elastase-related material were approximately the same in both the wild-type strain and lasA mutant supernatants. The lasA gene was expressed in Escherichia coli, and the approximate molecular weight of the lasA gene product was 31,000. Extracts of E. coli containing the lasA gene product were shown in vitro to activate the proelastase produced by P. aeruginosa lasA mutants to an enzyme with elastolytic activity. Thus the lasA gene product has a direct effect on broadening the substrate specificity of secreted proelastase, as well as a second role (direct or indirect) in the secretion of elastase.

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Protease-deficient Mutants of Pseudomonas aeruginosa: Pleiotropic Changes in Activity of Other Extracellular Enzymes

Cited by 66 publications

References 17 publications

The Characteristics of Extracellular Protein Secretion by Staphylococcus staphylolyticus

The Characteristics of Extracellular Protein Secretion by Staphylococcus staphylolyticus

Analysis of quorum sensing-deficient clinical isolates of Pseudomonas aeruginosa

Activation of an elastase precursor by the lasA gene product of Pseudomonas aeruginosa

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