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Differential interaction forces govern bacterial sorting in early biofilms.

Oldewurtel ER, Kouzel N, Dewenter L, Henseler K, Maier B - Elife (2015)

Bottom Line: However, little is known about the associated changes in the physics of cell-cell interaction and its impact on the architecture of biofilms.The observed morphotypes were in remarkable agreement with the differential strength of adhesion hypothesis proposing that a tug-of-war among surface structures of different cells governs cell sorting.We conclude that in early biofilms the density and rupture force of bacterial surface structures can trigger cell sorting based on similar physical principles as in developing embryos.

View Article: PubMed Central - PubMed

Affiliation: Department of Physics, University of Cologne, Cologne, Germany.

ABSTRACT
Bacterial biofilms can generate micro-heterogeneity in terms of surface structures. However, little is known about the associated changes in the physics of cell-cell interaction and its impact on the architecture of biofilms. In this study, we used the type IV pilus of Neisseria gonorrhoeae to test whether variation of surface structures induces cell-sorting. We show that the rupture forces between pili are fine-tuned by post-translational modification. Bacterial sorting was dependent on pilus post-translational modification and pilus density. Active force generation was necessary for defined morphologies of mixed microcolonies. The observed morphotypes were in remarkable agreement with the differential strength of adhesion hypothesis proposing that a tug-of-war among surface structures of different cells governs cell sorting. We conclude that in early biofilms the density and rupture force of bacterial surface structures can trigger cell sorting based on similar physical principles as in developing embryos.

No MeSH data available.


Related in: MedlinePlus

Segregation dynamics of non-piliated PQ− green from P+ red*.(A) pilQ deletion strain PQ− green was inoculated at low density with a higher density of P+ red*. (B) Zoom of (A). Scale bar: 20 µm. Arrows depict PQ− green bacteria that later spread ring-like along the expanding front.DOI:http://dx.doi.org/10.7554/eLife.10811.013
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fig5s2: Segregation dynamics of non-piliated PQ− green from P+ red*.(A) pilQ deletion strain PQ− green was inoculated at low density with a higher density of P+ red*. (B) Zoom of (A). Scale bar: 20 µm. Arrows depict PQ− green bacteria that later spread ring-like along the expanding front.DOI:http://dx.doi.org/10.7554/eLife.10811.013

Mentions: Furthermore, segregation of strains with different pilus densities but similar growth rates was assessed. We generated the gonococcal strain PQ− green with a deletion of pilQ. Since the PilQ proteins form the pore through which the pilus is exported, this results in a P− phenotype. The generation time of PQ− green was slightly higher than the piliated strain P+ red*. We inoculated non-piliated PQ− green bacteria at a low density together with a higher density of piliated P+ red* bacteria (Figure 5—figure supplement 2A,B). Similar to P− green, the PQ− green close to the front of the expanding colony was expelled from P+ red* (Figure 5—figure supplement 2A). Once reaching the front, PQ− green expanded along the front and encircled the bulk of P+ red* cells. This control experiment confirms that loss of pili induces segregation independently of decreased generation time.


Differential interaction forces govern bacterial sorting in early biofilms.

Oldewurtel ER, Kouzel N, Dewenter L, Henseler K, Maier B - Elife (2015)

Segregation dynamics of non-piliated PQ− green from P+ red*.(A) pilQ deletion strain PQ− green was inoculated at low density with a higher density of P+ red*. (B) Zoom of (A). Scale bar: 20 µm. Arrows depict PQ− green bacteria that later spread ring-like along the expanding front.DOI:http://dx.doi.org/10.7554/eLife.10811.013
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4625442&req=5

fig5s2: Segregation dynamics of non-piliated PQ− green from P+ red*.(A) pilQ deletion strain PQ− green was inoculated at low density with a higher density of P+ red*. (B) Zoom of (A). Scale bar: 20 µm. Arrows depict PQ− green bacteria that later spread ring-like along the expanding front.DOI:http://dx.doi.org/10.7554/eLife.10811.013
Mentions: Furthermore, segregation of strains with different pilus densities but similar growth rates was assessed. We generated the gonococcal strain PQ− green with a deletion of pilQ. Since the PilQ proteins form the pore through which the pilus is exported, this results in a P− phenotype. The generation time of PQ− green was slightly higher than the piliated strain P+ red*. We inoculated non-piliated PQ− green bacteria at a low density together with a higher density of piliated P+ red* bacteria (Figure 5—figure supplement 2A,B). Similar to P− green, the PQ− green close to the front of the expanding colony was expelled from P+ red* (Figure 5—figure supplement 2A). Once reaching the front, PQ− green expanded along the front and encircled the bulk of P+ red* cells. This control experiment confirms that loss of pili induces segregation independently of decreased generation time.

Bottom Line: However, little is known about the associated changes in the physics of cell-cell interaction and its impact on the architecture of biofilms.The observed morphotypes were in remarkable agreement with the differential strength of adhesion hypothesis proposing that a tug-of-war among surface structures of different cells governs cell sorting.We conclude that in early biofilms the density and rupture force of bacterial surface structures can trigger cell sorting based on similar physical principles as in developing embryos.

View Article: PubMed Central - PubMed

Affiliation: Department of Physics, University of Cologne, Cologne, Germany.

ABSTRACT
Bacterial biofilms can generate micro-heterogeneity in terms of surface structures. However, little is known about the associated changes in the physics of cell-cell interaction and its impact on the architecture of biofilms. In this study, we used the type IV pilus of Neisseria gonorrhoeae to test whether variation of surface structures induces cell-sorting. We show that the rupture forces between pili are fine-tuned by post-translational modification. Bacterial sorting was dependent on pilus post-translational modification and pilus density. Active force generation was necessary for defined morphologies of mixed microcolonies. The observed morphotypes were in remarkable agreement with the differential strength of adhesion hypothesis proposing that a tug-of-war among surface structures of different cells governs cell sorting. We conclude that in early biofilms the density and rupture force of bacterial surface structures can trigger cell sorting based on similar physical principles as in developing embryos.

No MeSH data available.


Related in: MedlinePlus