Differential Dynamic Microscopy of Bacterial Motility

Wilson, Laurence G.; Martinez, Vincent A.; Schwarz-Linek, Jana; Tailleur, Julien; Bryant, Gary; Pusey, P. N.; Poon, Wilson

doi:10.1103/physrevlett.106.018101

Cited by 182 publications

(244 citation statements)

References 24 publications

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“…7. Then we emphasize again that for designing optimal devices a previous and accurate motility characterization of each species is needed [30] with better details in runs distribution and persistence. It is important to characterize each mutant motility not only in free swimming but close to surfaces [14] and inside constrictions or channels with dimensions comparable to the cell sizes.…”

Section: Single Wall Of Asymmetric Funnels Between Two Chambersmentioning

confidence: 99%

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Influence of swimming strategy on microorganism separation by asymmetric obstacles

et al. 2013

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It has been shown that a nanoliter chamber separated by a wall of asymmetric obstacles can lead to an inhomogeneous distribution of self-propelled microorganisms. Although it is well established that this rectification effect arises from the interaction between the swimmers and the noncentrosymmetric pillars, here we demonstrate numerically that its efficiency is strongly dependent on the detailed dynamics of the individual microorganism. In particular, for the case of run-and-tumble dynamics, the distribution of run lengths, the rotational diffusion, and the partial preservation of run orientation memory through a tumble are important factors when computing the rectification efficiency. In addition, we optimize the geometrical dimensions of the asymmetric pillars in order to maximize the swimmer concentration and we illustrate how it can be used for sorting by swimming strategy in a long array of parallel obstacles.

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Section: Single Wall Of Asymmetric Funnels Between Two Chambersmentioning

confidence: 99%

“…Both precise numerical calculations and accurate experimental data characterizing the swimmer dynamics are, therefore, of paramount importance. Better motility statistical characterization with improved techniques [30] is also needed for each species.…”

Section: A Swimmers In Unbounded Environmentsmentioning

confidence: 99%

Influence of swimming strategy on microorganism separation by asymmetric obstacles

et al. 2013

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“…To explore the population-level significance of our observation of osmokinesis in single cells, we next performed Differential Dynamic Microscopy (DDM) (see Methods) [Wilson et al, 2011, Martinez et al, 2012. DDM is a fast, high-throughput method for measuring the distribution of swimming speeds in populations of a range of different self-propelled particles, averaging over up to ∼ 10 4 particles at the same time.…”

Section: Osmotic Response Shows Osmokinesis Ie Changes In Motor Speedmentioning

confidence: 99%

Osmotaxis in Escherichia coli through changes in motor speed

Rosko

Martinez

Poon

et al. 2017

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

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Bacterial motility, and in particular repulsion or attraction towards specific chemicals, has been a subject of investigation for over 100 years, resulting in detailed understanding of bacterial chemotaxis and the corresponding sensory network in many bacterial species. For Escherichia coli most of the current understanding comes from the experiments with low levels of chemotactically-active ligands. However, chemotactically-inactive chemical species at concentrations found in the human gastrointestinal tract produce significant changes in E. coli's osmotic pressure, and have been shown to lead to taxis. To understand how these nonspecific physical signals influence motility, we look at the response of individual bacterial flagellar motors under step-wise changes in external osmolarity. We combine these measurements with a population swimming assay under the same conditions. Unlike for chemotactic response, a long term increase in swimming/motor speeds is observed, and in the motor rotational bias, both of which scale with the osmotic shock magnitude. We discuss how the speed changes we observe can lead to steady state bacterial accumulation.

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“…The strength of such a technique lies in the idea that local density is being measured, rather than the explicit location of particles. Scattering-based methods rapidly sample all cells, which provides precise, population-averaged measurements, making them well suited to fast screening applications in biology [10,11]. Computational scattering also presents further, unexplored opportunities.…”

Section: Introductionmentioning

confidence: 99%

Fast, high-throughput measurement of collective behaviour in a bacterial population

Colin¹,

Zhang

Wilson³

2014

J. R. Soc. Interface.

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Swimming bacteria explore their environment by performing a random walk, which is biased in response to, for example, chemical stimuli, resulting in a collective drift of bacterial populations towards 'a better life'. This phenomenon, called chemotaxis, is one of the best known forms of collective behaviour in bacteria, crucial for bacterial survival and virulence. Both single-cell and macroscopic assays have investigated bacterial behaviours. However, theories that relate the two scales have previously been difficult to test directly. We present an image analysis method, inspired by light scattering, which measures the average collective motion of thousands of bacteria simultaneously. Using this method, a time-varying collective drift as small as 50 nm s 21 can be measured. The method, validated using simulations, was applied to chemotactic Escherichia coli bacteria in linear gradients of the attractant a-methylaspartate. This enabled us to test a coarse-grained minimal model of chemotaxis. Our results clearly map the onset of receptor methylation, and the transition from linear to logarithmic sensing in the bacterial response to an external chemoeffector. Our method is broadly applicable to problems involving the measurement of collective drift with high time resolution, such as cell migration and fluid flows measurements, and enables fast screening of tactic behaviours.

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Differential Dynamic Microscopy of Bacterial Motility

Cited by 182 publications

References 24 publications

Influence of swimming strategy on microorganism separation by asymmetric obstacles

Influence of swimming strategy on microorganism separation by asymmetric obstacles

Osmotaxis in Escherichia coli through changes in motor speed

Fast, high-throughput measurement of collective behaviour in a bacterial population

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