Antiphagocytic Effect of Slime from a Mucoid Strain of
            <i>Pseudomonas aeruginosa</i>

Schwarzmann, Stephen W.; Boring, John R.

doi:10.1128/iai.3.6.762-767.1971

Cited by 222 publications

(83 citation statements)

References 14 publications

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“…The microorganisms switch from a planktonic phenotype in fluid to a sessile phenotype on the tooth surface, triggering the formation of the polysaccharide-rich EPS and decreasing the mitotic activity of the bacterial cell (Jakubovics & Kolenbrander, 2010). The EPS provides a physical barrier that inhibits attachment to macrophages and phagocytes, while the reduced metabolic activity precludes the use of antibiotics that act on bacteria during growth periods (Schwarzmann & Boring, 1971;Whitnack et al, 1981). The EPS can also contribute to resistance to antibiotics through the formation of bacterial 'towers' surrounded by polysaccharide to reduce physical contact between the antimicrobials and viable cells (Hoyle & Costerton, 1991;Xiao et al, 2012).…”

Section: Introductionmentioning

confidence: 99%

Comparison of SEM and VPSEM imaging techniques with respect toStreptococcus mutansbiofilm topography

Weber

Délben

Bromage

et al. 2013

FEMS Microbiol Lett

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The study compared images of mature Streptococcus mutans biofilms captured at increasing magnification to determine which microscopy method is most acceptable for imaging the biofilm topography and the extracellular polymeric substance (EPS). In vitro S. mutans biofilms were imaged using (1) scanning electron microscopy (SEM), which requires a dehydration process; (2) SEM and ruthenium red (SEM-RR), which has been shown to support the EPS of biofilms during the SEM dehydration; and (3) variable pressure scanning electron microscopy (VPSEM), which does not require the intensive dehydration process of SEM. The dehydration process and high chamber vacuum of both SEM techniques devastated the biofilm EPS, removed supporting structures, and caused cracking on the biofilm surface. The VPSEM offered the most comprehensive representation of the S. mutans biofilm morphology. VPSEM provides similar contrast and focus as the SEM, but the procedure is far less time-consuming, and the use of hazardous chemicals associated with SEM dehydration protocol is avoided with the VPSEM. The inaccurate representations of the biofilm EPS in SEM experimentation is a possible source of inaccurate data and impediments in the study of S. mutans biofilms.

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Section: Introductionmentioning

confidence: 99%

Comparison of SEM and VPSEM imaging techniques with respect toStreptococcus mutansbiofilm topography

Weber

Délben

Bromage

et al. 2013

FEMS Microbiol Lett

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“…The mucoid phenotype of CF strains results from the production of copious amounts of an exopolysaccharide called alginate (Evans and Linker, 1973). Alginate confers increased protection from immune-and non-immune-mediated killing by the host (Schwarzmann and Boring, 1971;Baltimore and Mitchell, 1982;Simpson et al ., 1988) and plays a role in the formation of a protective biofilm containing microcolonies (Lam et al ., 1980;Nivens et al ., 2001).…”

Section: Introductionmentioning

confidence: 99%

The dual roles of AlgG in C‐5‐epimerization and secretion of alginate polymers in Pseudomonas aeruginosa

Jain

Franklin

Ertesvåg

et al. 2003

Molecular Microbiology

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SummaryPseudomonas aeruginosa strains causing chronic pulmonary infections in cystic fibrosis patients produce high levels of alginate, an exopolysaccharide that confers a mucoid phenotype. Alginate is a linear polymer of D -mannuronate (M) and variable amounts of its C-5-epimer, L -guluronate (G). AlgG is a periplasmic C-5-epimerase that converts poly D -mannuronate to the mixed M + + + + G sequence of alginate. To understand better the role and mechanism of AlgG activity, a mutant was constructed in the mucoid strain FRD1 with a defined non-polar deletion of algG . Instead of producing poly mannuronate, the algG deletion mutant secreted dialysable uronic acids, as does a mutant lacking the periplasmic protein AlgK. High levels of unsaturated ends and the nuclear magnetic resonance spectroscopy pattern revealed that the small, secreted uronic acids were the products of extensive polymer digestion by AlgL, a periplasmic alginate lyase co-expressed with AlgG and AlgK.Thus, AlgG is bifunctional with (i) epimerase activity and (ii) a role in protecting alginate from degradation by AlgL during transport through the periplasm. AlgK appears to share the second role. AlgG and AlgK may be part of a periplasmic protein complex, or scaffold, that guides alginate polymers to the outer membrane secretin (AlgE). To characterize the epimerase activity of AlgG further, the algG4 allele of poly mannuronateproducing FRD462 was shown to encode a protein lacking only the epimerase function. The sequence of algG4 has a Ser-272 to Asn substitution in a serinethreonine-rich and conserved region of AlgG, which revealed a critical residue for C-5-epimerase activity.

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“…The mucoid phenotype in P. aeruginosa is the result of production of a viscous exopolysaccharide called alginate (Evans and Linker, 1973;Linker and Jones, 1966). P. aeruginosa alginate confers antiphagocytic properties (Schwarzmann and Boring, 1971), acts as a physical barrier to macrophages (Simpson et ai, 1988), and blocks immunodeterminants for opsonic antibodies (Baltimore and Mitchell, 1980;Marrie et a/.,1979). The viscous nature of P. aeruginosa alginate may contribute to the high viscosity of secretions in the CF lung, thereby resulting in obstruction of small airways and interference with the natural clearance mechanisms of the lung (Govan and Harris, 1986).…”

Section: Introductionmentioning

confidence: 99%

Pseudomonas aeruginosa AlgB, which modulates the expression of alginate, is a member of the NtrC subclass of prokaryotic regulators

Goldberg

Dahnke

1992

Molecular Microbiology

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The Pseudomonas aeruginosa exopolysaccharide alginate is an important virulence factor in chronic pulmonary infections of cystic fibrosis patients. We determined the nucleotide sequence of the gene, algB, which regulates the level of exopolysaccharide produced by mucoid P. aeruginosa. The predicted amino acid sequence of AlgB revealed a high degree of similarity to the regulatory proteins in the NtrC subclass of 'two-component regulatory systems'. AlgB expression in Escherichia coli minicells showed a molecular weight of approximately 50,000 Da, comparable to that of the inferred amino acid sequence (49,318 Da). We show that algB is transcriptionally active in mucoid strains of P. aeruginosa and regulates the expression of the alginate biosynthetic gene, algD, thereby resulting in increased expression of alginate in mucoid P. aeruginosa.

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Antiphagocytic Effect of Slime from a Mucoid Strain of Pseudomonas aeruginosa

Cited by 222 publications

References 14 publications

Comparison of SEM and VPSEM imaging techniques with respect toStreptococcus mutansbiofilm topography

Comparison of SEM and VPSEM imaging techniques with respect toStreptococcus mutansbiofilm topography

The dual roles of AlgG in C‐5‐epimerization and secretion of alginate polymers in Pseudomonas aeruginosa

Pseudomonas aeruginosa AlgB, which modulates the expression of alginate, is a member of the NtrC subclass of prokaryotic regulators

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