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Mucin promotes rapid surface motility in Pseudomonas aeruginosa.

Yeung AT, Parayno A, Hancock RE - MBio (2012)

Bottom Line: In this study, we added mucin to swimming media and found that it promoted the ability of P. aeruginosa to exhibit rapid surface motility.Interestingly, bacterial cells at the thick edge appeared piled up and lacked flagella, while cells at the motility center had flagella.Our data from various genetic and phenotypic studies suggest that mucin may be promoting a modified form of swarming or a novel form of surface motility in P. aeruginosa.

View Article: PubMed Central - PubMed

Affiliation: Centre for Microbial Diseases and Immunity Research, University of British Columbia, Vancouver, British Columbia, Canada.

ABSTRACT

Unlabelled: An important environmental factor that determines the mode of motility adopted by Pseudomonas aeruginosa is the viscosity of the medium, often provided by adjusting agar concentrations in vitro. However, the viscous gel-like property of the mucus layer that overlays epithelial surfaces is largely due to the glycoprotein mucin. P. aeruginosa is known to swim within 0.3% (wt/vol) agar and swarm on the surface at 0.5% (wt/vol) agar with amino acids as a weak nitrogen source. When physiological concentrations or as little as 0.05% (wt/vol) mucin was added to the swimming agar, in addition to swimming, P. aeruginosa was observed to undergo highly accelerated motility on the surface of the agar. The surface motility colonies in the presence of mucin appeared to be circular, with a bright green center surrounded by a thicker white edge. While intact flagella were required for the surface motility in the presence of mucin, type IV pili and rhamnolipid production were not. Replacement of mucin with other wetting agents indicated that the lubricant properties of mucin might contribute to the surface motility. Based on studies with mutants, the quorum-sensing systems (las and rhl) and the orphan autoinducer receptor QscR played important roles in this form of surface motility. Transcriptional analysis of cells taken from the motility zone revealed the upregulation of genes involved in virulence and resistance. Based on these results, we suggest that mucin may be promoting a new or highly modified form of surface motility, which we propose should be termed "surfing."

Importance: An important factor that dictates the mode of motility adopted by P. aeruginosa is the viscosity of the medium, often provided by adjusting agar concentrations in vitro. However, the gel-like properties of the mucous layers that overlay epithelial surfaces, such as those of the lung, a major site of Pseudomonas infection, are contributed mostly by the production of the glycoprotein mucin. In this study, we added mucin to swimming media and found that it promoted the ability of P. aeruginosa to exhibit rapid surface motility. These motility colonies appeared in a circular form, with a bright green center surrounded by a thicker white edge. Interestingly, bacterial cells at the thick edge appeared piled up and lacked flagella, while cells at the motility center had flagella. Our data from various genetic and phenotypic studies suggest that mucin may be promoting a modified form of swarming or a novel form of surface motility in P. aeruginosa.

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Related in: MedlinePlus

Example images of mucin-promoted surface motilities of PA14 WT and a fliC flagellar mutant (A), a chpB type IV pilus mutant (B), a fliC pilA flagellar and type IV pilus double mutant (C), a rhlI quorum-sensing mutant with and without addition of C4-HSL (D), and a lasI quorum-sensing mutant with and without addition of 3-oxo-C12-HSL (E). P. aeruginosa bacteria were spotted onto MSCFM plates with 0.3% agar and 0.4% mucin and incubated at 37°C for 13 h. For surface motility restoration, 10 µM of either C4-HSL or 3-oxo-C12-HSL was added.
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fig4: Example images of mucin-promoted surface motilities of PA14 WT and a fliC flagellar mutant (A), a chpB type IV pilus mutant (B), a fliC pilA flagellar and type IV pilus double mutant (C), a rhlI quorum-sensing mutant with and without addition of C4-HSL (D), and a lasI quorum-sensing mutant with and without addition of 3-oxo-C12-HSL (E). P. aeruginosa bacteria were spotted onto MSCFM plates with 0.3% agar and 0.4% mucin and incubated at 37°C for 13 h. For surface motility restoration, 10 µM of either C4-HSL or 3-oxo-C12-HSL was added.

Mentions: Mutants with transposon insertion in genes involved in the assembly of type IV pili exhibited surface motility zones on mucin plates comparable to that of the WT (Fig. 3B and 4B). Moreover, a fliC pilA double mutant (defective in flagella and type IV pili [15]) had completely lost its surface motility on mucin plates (Fig. 4C) as expected, given its flagella deficiency.


Mucin promotes rapid surface motility in Pseudomonas aeruginosa.

Yeung AT, Parayno A, Hancock RE - MBio (2012)

Example images of mucin-promoted surface motilities of PA14 WT and a fliC flagellar mutant (A), a chpB type IV pilus mutant (B), a fliC pilA flagellar and type IV pilus double mutant (C), a rhlI quorum-sensing mutant with and without addition of C4-HSL (D), and a lasI quorum-sensing mutant with and without addition of 3-oxo-C12-HSL (E). P. aeruginosa bacteria were spotted onto MSCFM plates with 0.3% agar and 0.4% mucin and incubated at 37°C for 13 h. For surface motility restoration, 10 µM of either C4-HSL or 3-oxo-C12-HSL was added.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3569861&req=5

fig4: Example images of mucin-promoted surface motilities of PA14 WT and a fliC flagellar mutant (A), a chpB type IV pilus mutant (B), a fliC pilA flagellar and type IV pilus double mutant (C), a rhlI quorum-sensing mutant with and without addition of C4-HSL (D), and a lasI quorum-sensing mutant with and without addition of 3-oxo-C12-HSL (E). P. aeruginosa bacteria were spotted onto MSCFM plates with 0.3% agar and 0.4% mucin and incubated at 37°C for 13 h. For surface motility restoration, 10 µM of either C4-HSL or 3-oxo-C12-HSL was added.
Mentions: Mutants with transposon insertion in genes involved in the assembly of type IV pili exhibited surface motility zones on mucin plates comparable to that of the WT (Fig. 3B and 4B). Moreover, a fliC pilA double mutant (defective in flagella and type IV pili [15]) had completely lost its surface motility on mucin plates (Fig. 4C) as expected, given its flagella deficiency.

Bottom Line: In this study, we added mucin to swimming media and found that it promoted the ability of P. aeruginosa to exhibit rapid surface motility.Interestingly, bacterial cells at the thick edge appeared piled up and lacked flagella, while cells at the motility center had flagella.Our data from various genetic and phenotypic studies suggest that mucin may be promoting a modified form of swarming or a novel form of surface motility in P. aeruginosa.

View Article: PubMed Central - PubMed

Affiliation: Centre for Microbial Diseases and Immunity Research, University of British Columbia, Vancouver, British Columbia, Canada.

ABSTRACT

Unlabelled: An important environmental factor that determines the mode of motility adopted by Pseudomonas aeruginosa is the viscosity of the medium, often provided by adjusting agar concentrations in vitro. However, the viscous gel-like property of the mucus layer that overlays epithelial surfaces is largely due to the glycoprotein mucin. P. aeruginosa is known to swim within 0.3% (wt/vol) agar and swarm on the surface at 0.5% (wt/vol) agar with amino acids as a weak nitrogen source. When physiological concentrations or as little as 0.05% (wt/vol) mucin was added to the swimming agar, in addition to swimming, P. aeruginosa was observed to undergo highly accelerated motility on the surface of the agar. The surface motility colonies in the presence of mucin appeared to be circular, with a bright green center surrounded by a thicker white edge. While intact flagella were required for the surface motility in the presence of mucin, type IV pili and rhamnolipid production were not. Replacement of mucin with other wetting agents indicated that the lubricant properties of mucin might contribute to the surface motility. Based on studies with mutants, the quorum-sensing systems (las and rhl) and the orphan autoinducer receptor QscR played important roles in this form of surface motility. Transcriptional analysis of cells taken from the motility zone revealed the upregulation of genes involved in virulence and resistance. Based on these results, we suggest that mucin may be promoting a new or highly modified form of surface motility, which we propose should be termed "surfing."

Importance: An important factor that dictates the mode of motility adopted by P. aeruginosa is the viscosity of the medium, often provided by adjusting agar concentrations in vitro. However, the gel-like properties of the mucous layers that overlay epithelial surfaces, such as those of the lung, a major site of Pseudomonas infection, are contributed mostly by the production of the glycoprotein mucin. In this study, we added mucin to swimming media and found that it promoted the ability of P. aeruginosa to exhibit rapid surface motility. These motility colonies appeared in a circular form, with a bright green center surrounded by a thicker white edge. Interestingly, bacterial cells at the thick edge appeared piled up and lacked flagella, while cells at the motility center had flagella. Our data from various genetic and phenotypic studies suggest that mucin may be promoting a modified form of swarming or a novel form of surface motility in P. aeruginosa.

Show MeSH
Related in: MedlinePlus