A Plate Assay for Elastase

Sbarra, Anthony J.; Gilfillan, Rutherford S.; Bardawil, Wadi A.

doi:10.1038/188322b0

Cited by 56 publications

(18 citation statements)

References 2 publications

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“…The plates were incubated for 48 h at 37 • C unless stated otherwise. Diameters of clear or turbid halos around the inocula indicated a positive reaction and were measured in centimetres (Habermann and Hardt, 1972;Sbarra et al, 1960).…”

Section: Extracellular Enzyme Activity Assaysmentioning

confidence: 99%

Genotypic and phenotypic characterization of Pseudomonas aeruginosa isolates from urinary tract infections

Tielen

Narten

Rosin

et al. 2011

International Journal of Medical Microbiology

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Section: Extracellular Enzyme Activity Assaysmentioning

confidence: 99%

Genotypic and phenotypic characterization of Pseudomonas aeruginosa isolates from urinary tract infections

Tielen

Narten

Rosin

et al. 2011

International Journal of Medical Microbiology

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“…LB agar plates containing 2% skim milk were used to assess total proteolytic activity of the variants (32). Elastase activity was determined using 0.5% elastin-containing nutrient broth plates (33). Phospholipase C activity was assessed using the method described by Habermann and Hardt (34).…”

Section: Methodsmentioning

confidence: 99%

Evolution of Pseudomonas aeruginosa Virulence as a Result of Phage Predation

Hosseinidoust

Ven

Tufenkji

2013

Appl Environ Microbiol

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The rapid increase in the emergence of antibiotic-resistant bacteria has attracted attention to bacteriophages for treating and preventing bacterial infections. Bacteriophages can drive the diversification of Pseudomonas aeruginosa, giving rise to phageresistant variants with different phenotypes from their ancestral hosts. In this study, we sought to investigate the effect of phage resistance on cytotoxicity of host populations toward cultured mammalian cells. The library of phage-resistant P. aeruginosa PAO1 variants used was developed previously via experimental evolution of an isogenic host population using phages PP7 and E79. Our results presented herein indicate that the phage-resistant variants developed in a heterogeneous phage environment exhibit a greater ability to impede metabolic action of cultured human keratinocytes and have a greater tendency to cause membrane damage even though they cannot invade the cells in large numbers. They also show a heightened resistance to phagocytosis by model murine macrophages. Furthermore, all isolates produced higher levels of at least one of the secreted virulence factors, namely, total proteases, elastase, phospholipase C, and hemolysins. Reverse transcription-quantitative PCR (RT-qPCR) revealed upregulation in the transcription of a number of genes associated with virulence of P. aeruginosa for the phage-resistant variants. The results of this study indicate a significant change in the in vitro virulence of P. aeruginosa following phage predation and highlight the need for caution in the selection and design of phages and phage cocktails for therapeutic use.

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“…(vJv) sterile skimmed milk (Brown and Foster). Elastase was assayed on elastin agar plates (Sbarra et al, 1960). The egg-yolk reaction was determined on egg-yolk agar prepared according to Lundbeck and Tirunarayanan.…”

Section: Methodsmentioning

confidence: 99%

Production of Enzymes and Toxins by Hospital Strains of Pseudomonas Aeruginosain Relation to Serotype and Phage-Typing Pattern

Wretlind

Hedén

Sjöberg

et al. 1973

Journal of Medical Microbiology

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LITTLE is known about the way in which Pseudomonas aeruginosa exerts its damaging effects on the host. The endotoxin of this organism has a rather low toxicity (Homrna, 1968), but various extracellular proteins are formed that are toxic not only to man and animals but also to insects, tissue-culture cells, plants, and some Gram-positive cocci (Caselitz, 1966;Heckly, 1970). Liu (1966) showed that P. aeruginosa produced both a lecithinase and a protease that were toxic and produced necrosis in various organs after intravenous injection. Recently, Meinke et al. (1970) reported that a partially purified elastase was lethal to mice when injected by several routes. Other cell-associated and extracellular proteins with no known enzymatic activities are toxic in animal experiments (Berk, 1964; Liu; Homma; Bartell, Orr and Garcia, 1968). A factor that inhibits mouse-liver mitochondria1 respiration was recently described (Armstrong, Stewart-Tull and Roberts, 1971). Wahba and Darrell (1965) found that atypical strains of P. aeruginosa, many of which were later identified as P. jluorescens, did not produce extracellular protease, and that marked collagenase activity was found only in strains of P. aeruginosa. Brown and Foster (1970) later confirmed that only strains of P. aeruginosa formed a protease detectable on a milk medium. Chakrabarty, Adhya and Pramanik (1970) detected lipolytic activity on Tween-80 agar in eight of 20 strains of P. aeruginosa. From earlier studies on microbial lipases and esterases it is obvious that Staphylococcus aureus,

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A Plate Assay for Elastase

Cited by 56 publications

References 2 publications

Genotypic and phenotypic characterization of Pseudomonas aeruginosa isolates from urinary tract infections

Genotypic and phenotypic characterization of Pseudomonas aeruginosa isolates from urinary tract infections

Evolution of Pseudomonas aeruginosa Virulence as a Result of Phage Predation

Production of Enzymes and Toxins by Hospital Strains of Pseudomonas Aeruginosain Relation to Serotype and Phage-Typing Pattern

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