Low Flagellar Motor Torque and High Swimming Efficiency of Caulobacter crescentus Swarmer Cells

Li, Guanglai; Tang, Jay X.

doi:10.1529/biophysj.106.080697

Cited by 71 publications

(81 citation statements)

References 35 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Further microrheology studies examining the breakdown of the linear response regime of mucin gels are warranted to determine if the material would yield at the same stress on the m length scales probed here, as in the bulk. Using the flagella frequency derived value as the basis for comparison, this average torque of 3.6 ϫ 10 Ϫ18 N m is approximately an order of magnitude higher than measurements by Li and Tang for Caulobacter Crescentus (3.5 ϫ 10 Ϫ19 N m) (51), and approximately a factor of three higher than torque measured by Reid et al for E. Coli (1.3 ϫ 10 Ϫ18 N m) (52). This is consistent with Li and Tang's hypothesis that the low motor torque and high swimming efficiency of C. Crescentus are necessary for survival in the extremely nutrient-poor fresh water environments it has adapted to survive in.…”

Section: Discussionmentioning

confidence: 62%

Helicobacter pylori moves through mucus by reducing mucin viscoelasticity

Celli

Turner

Afdhal

et al. 2009

Proc. Natl. Acad. Sci. U.S.A.

374

326

View full text Add to dashboard Cite

The ulcer-causing gastric pathogen Helicobacter pylori is the only bacterium known to colonize the harsh acidic environment of the human stomach. H. pylori survives in acidic conditions by producing urease, which catalyzes hydrolysis of urea to yield ammonia thus elevating the pH of its environment. However, the manner in which H. pylori is able to swim through the viscoelastic mucus gel that coats the stomach wall remains poorly understood. Previous rheology studies on gastric mucin, the key viscoelastic component of gastric mucus, indicate that the rheology of this material is pH dependent, transitioning from a viscous solution at neutral pH to a gel in acidic conditions. Bulk rheology measurements on porcine gastric mucin (PGM) show that pH elevation by H. pylori induces a dramatic decrease in viscoelastic moduli. Microscopy studies of the motility of H. pylori in gastric mucin at acidic and neutral pH in the absence of urea show that the bacteria swim freely at high pH, and are strongly constrained at low pH. By using two-photon fluorescence microscopy to image the bacterial motility in an initially low pH mucin gel with urea present we show that the gain of translational motility by bacteria is directly correlated with a rise in pH indicated by 2 ,7 -Bis-(2-Carboxyethyl)-5-(and-6)-carboxyfluorescein (BCECF), a pH sensitive fluorescent dye. This study indicates that the helicoidal-shaped H. pylori does not bore its way through the mucus gel like a screw through a cork as has previously been suggested, but instead achieves motility by altering the rheological properties of its environment.H. pylori ͉ bacterial motility ͉ rheology ͉ pH ͉ gelation

show abstract

Section: Discussionmentioning

confidence: 62%

Helicobacter pylori moves through mucus by reducing mucin viscoelasticity

Celli

Turner

Afdhal

et al. 2009

Proc. Natl. Acad. Sci. U.S.A.

374

326

View full text Add to dashboard Cite

show abstract

“…However, a diverse spectrum of flagellar swimming ability is seen across the bacterial kingdom. Caulobacter crescentus inhabits low-nutrient freshwater environments where it swims using a high-efficiency flagellar motor (1,2), whereas Vibrio species produce high-speed, sodium-driven polar flagella to capitalize on the high sodium gradient of their marine habitat (3). On the other hand, the e-proteobacteria and spirochetes, many of which thrive exclusively in association with a host, have evolved characteristically rapid and powerful swimming capabilities that enable them to bore through mucous layers coating epithelial cells or between tissues.…”

mentioning

confidence: 99%

Diverse high-torque bacterial flagellar motors assemble wider stator rings using a conserved protein scaffold

Beeby

Ribardo

Brennan

et al. 2016

Proc. Natl. Acad. Sci. U.S.A.

176

262

View full text Add to dashboard Cite

Although it is known that diverse bacterial flagellar motors produce different torques, the mechanism underlying torque variation is unknown. To understand this difference better, we combined genetic analyses with electron cryo-tomography subtomogram averaging to determine in situ structures of flagellar motors that produce different torques, from Campylobacter and Vibrio species. For the first time, to our knowledge, our results unambiguously locate the torque-generating stator complexes and show that diverse high-torque motors use variants of an ancestrally related family of structures to scaffold incorporation of additional stator complexes at wider radii from the axial driveshaft than in the model enteric motor. We identify the protein components of these additional scaffold structures and elucidate their sequential assembly, demonstrating that they are required for stator-complex incorporation. These proteins are widespread, suggesting that different bacteria have tailored torques to specific environments by scaffolding alternative stator placement and number. Our results quantitatively account for different motor torques, complete the assignment of the locations of the major flagellar components, and provide crucial constraints for understanding mechanisms of torque generation and the evolution of multiprotein complexes.

show abstract

“…Stall torque estimates vary from 350 pN nm for Caulobacter crescentus [69], 1260 pN nm for E. coli [87] and 4000 pN nm for V. alginolyticus [95]. For comparison, we see that the computed flagellar torque shown in Table 4 for the 0.2 micron amplitude model bacterial cell converts to 5640 pN nm.…”

Section: Flagellar Parametersmentioning

confidence: 95%

A 3D Motile Rod-Shaped Monotrichous Bacterial Model

Hsu

Dillon

2009

Bull. Math. Biol.

View full text Add to dashboard Cite

We introduce a 3D model for a motile rod-shaped bacterial cell with a single polar flagellum which is based on the configuration of a monotrichous type of bacteria such as Pseudomonas aeruginosa. The structure of the model bacterial cell consists of a cylindrical body together with the flagellar forces produced by the rotation of a helical flagellum. The rod-shaped cell body is composed of a set of immersed boundary points and elastic links. The helical flagellum is assumed to be rigid and modeled as a set of discrete points along the helical flagellum and flagellar hook. A set of flagellar forces are applied along this helical curve as the flagellum rotates. An additional set of torque balance forces are applied on the cell body to induce counter-rotation of the body and provide torque balance. The three dimensional Navier-Stokes equations for incompressible fluid are used to described the fluid dynamics of the coupled fluid-microorganism system using Peskin's immersed boundary method. A study of numerical convergence is presented along with simulations of a single cell and the interaction of two model cells.

show abstract

Low Flagellar Motor Torque and High Swimming Efficiency of Caulobacter crescentus Swarmer Cells

Cited by 71 publications

References 35 publications

Helicobacter pylori moves through mucus by reducing mucin viscoelasticity

Helicobacter pylori moves through mucus by reducing mucin viscoelasticity

Diverse high-torque bacterial flagellar motors assemble wider stator rings using a conserved protein scaffold

A 3D Motile Rod-Shaped Monotrichous Bacterial Model

Contact Info

Product

Resources

About