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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

Progression of P. aeruginosa PA14 surface motility zones over time. Mid-logarithmic-phase cultures of PA14 WT were spotted onto plates comprised of MSCFM with 0.3% (wt/vol) agar and 0.4% (wt/vol) mucin. Plates were incubated at 37°C, and pictures were taken every hour from h 5 to 13.
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fig2: Progression of P. aeruginosa PA14 surface motility zones over time. Mid-logarithmic-phase cultures of PA14 WT were spotted onto plates comprised of MSCFM with 0.3% (wt/vol) agar and 0.4% (wt/vol) mucin. Plates were incubated at 37°C, and pictures were taken every hour from h 5 to 13.

Mentions: When P. aeruginosa strain PA14 was spotted onto MSCFM swim plates with mucin (0.05% to 1% [wt/vol]) and incubated overnight at 37°C, the resultant surface motility zones were always greater, in diameter, than the swimming zones observed in the same plate. This led us to examine the rate of this form of surface colonization at various concentrations of mucin. Table 1 shows the average diameters of the motility zones at various concentrations of mucin, while Fig. 2 shows example images of the expanding surface motility zones in the presence of 0.4% (wt/vol) mucin taken every hour from 5 to 13 h. The resultant average motility zone diameter for swimming was 14 mm whereas the swarming zone was 30.4 mm, and the mucin-promoted surface motility zone ranged in size from 21.5 to 38.1 mm in 0.1% to 0.8% (wt/vol) mucin after 13 h of incubation at 37°C. Although swimming motility was found here to be the slowest of the three forms of motility, it should be noted that swimming is more tightly coupled to chemoattractant gradients and thus to growth and that chemoattractant metabolism would limit the rate of motility observed on 0.3% agar plates. Table 1 also shows the average changes in diameter of the motility zones after each hour. For all three forms of motility, the rate of motility increased as time progressed. The rates of swimming motility between h 5 and 13 increased from 0.5 mm/h to 1.5 mm/h, and swarming rates increased from 0 mm/h to 6.4 mm/h. At 0.1%, 0.4%, 0.6%, and 0.8% (wt/vol) mucin, surface motility zones increased from 0.5 to 3.5 mm/h, 1.1 to 4.5 mm/h, 1.3 to 5.2 mm/h, and 1.3 to 5.4 mm/h, respectively.


Mucin promotes rapid surface motility in Pseudomonas aeruginosa.

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

Progression of P. aeruginosa PA14 surface motility zones over time. Mid-logarithmic-phase cultures of PA14 WT were spotted onto plates comprised of MSCFM with 0.3% (wt/vol) agar and 0.4% (wt/vol) mucin. Plates were incubated at 37°C, and pictures were taken every hour from h 5 to 13.
© Copyright Policy - open-access
Related In: Results  -  Collection

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

fig2: Progression of P. aeruginosa PA14 surface motility zones over time. Mid-logarithmic-phase cultures of PA14 WT were spotted onto plates comprised of MSCFM with 0.3% (wt/vol) agar and 0.4% (wt/vol) mucin. Plates were incubated at 37°C, and pictures were taken every hour from h 5 to 13.
Mentions: When P. aeruginosa strain PA14 was spotted onto MSCFM swim plates with mucin (0.05% to 1% [wt/vol]) and incubated overnight at 37°C, the resultant surface motility zones were always greater, in diameter, than the swimming zones observed in the same plate. This led us to examine the rate of this form of surface colonization at various concentrations of mucin. Table 1 shows the average diameters of the motility zones at various concentrations of mucin, while Fig. 2 shows example images of the expanding surface motility zones in the presence of 0.4% (wt/vol) mucin taken every hour from 5 to 13 h. The resultant average motility zone diameter for swimming was 14 mm whereas the swarming zone was 30.4 mm, and the mucin-promoted surface motility zone ranged in size from 21.5 to 38.1 mm in 0.1% to 0.8% (wt/vol) mucin after 13 h of incubation at 37°C. Although swimming motility was found here to be the slowest of the three forms of motility, it should be noted that swimming is more tightly coupled to chemoattractant gradients and thus to growth and that chemoattractant metabolism would limit the rate of motility observed on 0.3% agar plates. Table 1 also shows the average changes in diameter of the motility zones after each hour. For all three forms of motility, the rate of motility increased as time progressed. The rates of swimming motility between h 5 and 13 increased from 0.5 mm/h to 1.5 mm/h, and swarming rates increased from 0 mm/h to 6.4 mm/h. At 0.1%, 0.4%, 0.6%, and 0.8% (wt/vol) mucin, surface motility zones increased from 0.5 to 3.5 mm/h, 1.1 to 4.5 mm/h, 1.3 to 5.2 mm/h, and 1.3 to 5.4 mm/h, respectively.

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