Bacteria Use Type IV Pili to Walk Upright and Detach from Surfaces

Department of Bioengineering, California Nano Systems Institute,University of California, Los Angeles, CA 90024, USA.
Science (Impact Factor: 33.61). 10/2010; 330(6001):197. DOI: 10.1126/science.1194238
Source: PubMed


Bacterial biofilms are structured multicellular communities involved in a broad range of infections. Knowing how free-swimming bacteria adapt their motility mechanisms near surfaces is crucial for understanding the transition between planktonic and biofilm phenotypes. By translating microscopy movies into searchable databases of bacterial behavior, we identified fundamental type IV pili-driven mechanisms for Pseudomonas aeruginosa surface motility involved in distinct foraging strategies. Bacteria stood upright and "walked" with trajectories optimized for two-dimensional surface exploration. Vertical orientation facilitated surface detachment and could influence biofilm morphology.

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Available from: Maxsim L Gibiansky,
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    • "Unlike most other bacterial surface filaments with the exception of F-pili (Novotny et al., 1974), T4aP are dynamic and can be rapidly retracted, producing forces in excess of 100 pN per filament (Merz et al., 2000; Maier et al., 2002). Through their ability to repeatedly extend, adhere and retract, T4aP confer unique locomotion modalities including twitching, swarming, walking and sling shot motilities (Yeung et al., 2009; Gibiansky et al., 2010; Jin et al., 2011). These modalities use T4aP alone or in combination with other surface appendages such as flagella to achieve movement. "
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    ABSTRACT: Type IV pili (T4P) are bacterial virulence factors involved in a wide variety of functions including DNA uptake, surface attachment, biofilm formation, and twitching motility. While T4P are common surface appendages, the systems that assemble them and the regulation of their function differ between species. Pseudomonas aeruginosa, Neisseria spp., and Myxococcus xanthus are common model systems used to study T4P biology. This review focuses on recent advances in P. aeruginosa T4P structural biology, and the regulatory pathways controlling T4P biogenesis and function. This article is protected by copyright. All rights reserved.
    Environmental Microbiology 03/2015; DOI:10.1111/1462-2920.12849 · 6.20 Impact Factor
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    • "Membrane conditions are of interest in cases of foraging, phototaxis, magnetotaxis, or other phenomena resulting in oriented single cells [4] [5] [6] [7] [8] [9]. Embedded fluorophores may be useful to analyze bacterial behavior near surfaces [10] [11] [12]. Molecular dynamics (MD) simulations are commonplace because of their versatility and ability to capture complex motions of membranes and proteins [13]. "
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    ABSTRACT: Molecular dynamics are often used to analyze and interpret fluorophore motions in relation to observed fluorescence anisotropy measurements. The Soleillet method allows computation of fluorescence anisotropy from molecular dynamics for isotropically oriented fluorophores, but not for oriented fluorophores, such as might be used to study oriented bacterial cultures, oriented, functionalized nanotubes, or oriented, stacked planar bilayers. A numerical approach to distribute molecular dynamics systems appropriately into a larger experimental frame context, allowing prediction of time-resolved and steady-state anisotropies for fluorophores distributed in the crystal-like arrays, is presented. The classical principles of absorption selectivity and motional effects on fluorescence anisotropy for isotropically distributed fluorophores are confirmed. Fluorescence anisotropy for fluorophores distributed on oriented cylinders are predicted to show a rich cylinder-angle dependence.
    Journal of Computational Physics 01/2013; 232(1):482–497. DOI:10.1016/ · 2.43 Impact Factor
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    • "As wild-type bacteria detach at a higher rate from the surface than either appendage-deficient mutant, the launch sequence and other mechanisms of appendage cooperation may enhance the ability of bacteria to redistribute on surfaces and thereby affect the morphology of biofilms as they form. Some support for this idea is found in flow-cell experiments: TfP-deficient bacteria, which lack the launch sequence and cannot easily detach, form large clusters at the surface sites at which they originally attach, whereas wild-type bacteria that can freely detach and redistribute form a uniform and thin layer of cells (Gibiansky et al., 2010). In addition, P. aeruginosa bacteria that have flagella and TfP exhibit a higher probability of detaching from surfaces at short times when exposed to shear flow than appendage-deficient mutants (Lecuyer et al., 2011). "
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    ABSTRACT: We review physically-motivated studies of bacterial near-surface motility driven by flagella and type IV pili (TfP) in the context of biofilm formation. We describe the motility mechanisms that individual bacteria deploying flagella and TfP use to move on and near surfaces, and discuss how the interactions of motility appendages with fluid and surfaces promote motility, attachment and dispersal of bacteria on surfaces prior to biofilm formation. (C) 2012 Published by Elsevier Masson SAS on behalf of Institut Pasteur.
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