Thematische Bibliographien / Bacterial near-surface motion

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Auswahl der wissenschaftlichen Literatur zum Thema „Bacterial near-surface motion“

Autor: Grafiati

Veröffentlicht am 29. Juni 2021

Zuletzt aktualisiert am 18. Februar 2022

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Zeitschriftenartikel zum Thema "Bacterial near-surface motion"

Li, G., L. K. Tam und J. X. Tang. „Amplified effect of Brownian motion in bacterial near-surface swimming“. Proceedings of the National Academy of Sciences 105, Nr. 47 (17.11.2008): 18355–59. http://dx.doi.org/10.1073/pnas.0807305105.

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Ishimoto, Kenta. „Bacterial spinning top“. Journal of Fluid Mechanics 880 (10.10.2019): 620–52. http://dx.doi.org/10.1017/jfm.2019.714.

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We have investigated the dynamics of a monotrichous bacteria cell near a wall boundary, taking elastic hook flexibility into consideration. Combining theoretical linear stability analysis and direct numerical computations via the boundary element method, we have found that the elastohydrodynamic coupling between the hook elasticity and cell rotational motion enables a stable vertical spinning behaviour like a low-Reynolds-number spinning top. The forwardly rotated flagellum, which generates the force exertion pushing towards the cell body, typically destabilizes the vertical upright position and leads to a boundary-following motion. In contrast, the backward rotation of the flagellum, generating a force pulling the cell body, contributes to stable upright behaviour in a large range of hook rigidity. Further numerical investigations have demonstrated that the non-spherical geometry of the cell body and boundary adhesive interactions affect the bacterial dynamics, leading to complex behaviours such as horizontal spinning and unstable vertical spinning motions, both of which are experimentally observed in Pseudomonas aeruginosa bacteria. These results highlight the rich diversity of bacterial surface motility emerging from mechanical boundary interactions coupled with the cell swimming and hook flexibility.

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Shum, H., E. A. Gaffney und D. J. Smith. „Modelling bacterial behaviour close to a no-slip plane boundary: the influence of bacterial geometry“. Proceedings of the Royal Society A: Mathematical, Physical and Engineering Sciences 466, Nr. 2118 (13.01.2010): 1725–48. http://dx.doi.org/10.1098/rspa.2009.0520.

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We describe a boundary-element method used to model the hydrodynamics of a bacterium propelled by a single helical flagellum. Using this model, we optimize the power efficiency of swimming with respect to cell body and flagellum geometrical parameters, and find that optima for swimming in unbounded fluid and near a no-slip plane boundary are nearly indistinguishable. We also consider the novel optimization objective of torque efficiency and find a very different optimal shape. Excluding effects such as Brownian motion and electrostatic interactions, it is demonstrated that hydrodynamic forces may trap the bacterium in a stable, circular orbit near the boundary, leading to the empirically observable surface accumulation of bacteria. Furthermore, the details and even the existence of this stable orbit depend on geometrical parameters of the bacterium, as described in this article. These results shed some light on the phenomenon of surface accumulation of micro-organisms and offer hydrodynamic explanations as to why some bacteria may accumulate more readily than others based on morphology.

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Lee, Calvin K., Jaime de Anda, Amy E. Baker, Rachel R. Bennett, Yun Luo, Ernest Y. Lee, Joshua A. Keefe et al. „Multigenerational memory and adaptive adhesion in early bacterial biofilm communities“. Proceedings of the National Academy of Sciences 115, Nr. 17 (20.03.2018): 4471–76. http://dx.doi.org/10.1073/pnas.1720071115.

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Using multigenerational, single-cell tracking we explore the earliest events of biofilm formation byPseudomonas aeruginosa. During initial stages of surface engagement (≤20 h), the surface cell population of this microbe comprises overwhelmingly cells that attach poorly (∼95% stay <30 s, well below the ∼1-h division time) with little increase in surface population. If we harvest cells previously exposed to a surface and direct them to a virgin surface, we find that these surface-exposed cells and their descendants attach strongly and then rapidly increase the surface cell population. This “adaptive,” time-delayed adhesion requires determinants we showed previously are critical for surface sensing: type IV pili (TFP) and cAMP signaling via the Pil-Chp-TFP system. We show that these surface-adapted cells exhibit damped, coupled out-of-phase oscillations of intracellular cAMP levels and associated TFP activity that persist for multiple generations, whereas surface-naïve cells show uncorrelated cAMP and TFP activity. These correlated cAMP–TFP oscillations, which effectively impart intergenerational memory to cells in a lineage, can be understood in terms of a Turing stochastic model based on the Pil-Chp-TFP framework. Importantly, these cAMP–TFP oscillations create a state characterized by a suppression of TFP motility coordinated across entire lineages and lead to a drastic increase in the number of surface-associated cells with near-zero translational motion. The appearance of this surface-adapted state, which can serve to define the historical classification of “irreversibly attached” cells, correlates with family tree architectures that facilitate exponential increases in surface cell populations necessary for biofilm formation.

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Shrivastava, Abhishek, und Howard C. Berg. „A molecular rack and pinion actuates a cell-surface adhesin and enables bacterial gliding motility“. Science Advances 6, Nr. 10 (März 2020): eaay6616. http://dx.doi.org/10.1126/sciadv.aay6616.

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The gliding bacterium Flavobacterium johnsoniae is known to have an adhesin, SprB, that moves along the cell surface on a spiral track. Following viscous shear, cells can be tethered by the addition of an anti-SprB antibody, causing spinning at 3 Hz. Labeling the type 9 secretion system (T9SS) with a YFP fusion of GldL showed a yellow fluorescent spot near the rotation axis, indicating that the motor driving the motion is associated with the T9SS. The distance between the rotation axis and the track (90 nm) was determined after adding a Cy3 label for SprB. A rotary motor spinning a pinion of radius 90 nm at 3 Hz would cause a spot on its periphery to move at 1.5 μm/s, the gliding speed. We suggest the pinion drives a flexible tread that carries SprB along a track fixed to the cell surface. Cells glide when this adhesin adheres to the solid substratum.

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Klebba, Phillip E. „ROSET Model of TonB Action in Gram-Negative Bacterial Iron Acquisition“. Journal of Bacteriology 198, Nr. 7 (19.01.2016): 1013–21. http://dx.doi.org/10.1128/jb.00823-15.

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Therotationalsurveillance andenergytransfer (ROSET) model of TonB action suggests a mechanism by which the electrochemical proton gradient across the Gram-negative bacterial inner membrane (IM) promotes the transport of iron through ligand-gated porins (LGP) in the outer membrane (OM). TonB associates with the IM by an N-terminal hydrophobic helix that forms a complex with ExbBD. It also contains a central extended length of rigid polypeptide that spans the periplasm and a dimericC-terminal-ββαβ-domain (CTD) with LysM motifs that binds the peptidoglycan (PG) layer beneath the OM bilayer. The TonB CTD forms a dimer with affinity for both PG- and TonB-independent OM proteins (e.g., OmpA), localizing it near the periplasmic interface of the OM bilayer. Porins and other OM proteins associate with PG, and this general affinity allows the TonB CTD dimer to survey the periplasmic surface of the OM bilayer. Energized rotational motion of the TonB N terminus in the fluid IM bilayer promotes the lateral movement of the TonB-ExbBD complex in the IM and of the TonB CTD dimer across the inner surface of the OM. When it encounters an accessible TonB box of a (ligand-bound) LGP, the monomeric form of the CTD binds and recruits it into a 4-stranded β-sheet. Because the CTD is rotating, this binding reaction transfers kinetic energy, created by the electrochemical proton gradient across the IM, through the periplasm to the OM protein. The equilibration of the TonB C terminus between the dimeric and monomeric forms that engage in different binding reactions allows the identification of iron-loaded LGP and then the internalization of iron through their trans-outer membrane β-barrels. Hence, the ROSET model postulates a mechanism for the transfer of energy from the IM to the OM, triggering iron uptake.

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Shum, Henry. „Microswimmer Propulsion by Two Steadily Rotating Helical Flagella“. Micromachines 10, Nr. 1 (18.01.2019): 65. http://dx.doi.org/10.3390/mi10010065.

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Many theoretical studies of bacterial locomotion adopt a simple model for the organism consisting of a spheroidal cell body and a single corkscrew-shaped flagellum that rotates to propel the body forward. Motivated by experimental observations of a group of magnetotactic bacterial strains, we extended the model by considering two flagella attached to the cell body and rotating about their respective axes. Using numerical simulations, we analyzed the motion of such a microswimmer in bulk fluid and close to a solid surface. We show that positioning the two flagella far apart on the cell body reduces the rate of rotation of the body and increases the swimming speed. Near surfaces, we found that swimmers with two flagella can swim in relatively straight trajectories or circular orbits in either direction. It is also possible for the swimmer to escape from surfaces, unlike a model swimmer of similar shape but with only a single flagellum. Thus, we conclude that there are important implications of swimming with two flagella or flagellar bundles rather than one. These considerations are relevant not only for understanding differences in bacterial morphology but also for designing microrobotic swimmers.

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Kinde, Monica N., Vasyl Bondarenko, Daniele Granata, Weiming Bu, Kimberly C. Grasty, Patrick J. Loll, Vincenzo Carnevale et al. „Fluorine-19 NMR and computational quantification of isoflurane binding to the voltage-gated sodium channel NaChBac“. Proceedings of the National Academy of Sciences 113, Nr. 48 (15.11.2016): 13762–67. http://dx.doi.org/10.1073/pnas.1609939113.

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Voltage-gated sodium channels (NaV) play an important role in general anesthesia. Electrophysiology measurements suggest that volatile anesthetics such as isoflurane inhibit NaVby stabilizing the inactivated state or altering the inactivation kinetics. Recent computational studies suggested the existence of multiple isoflurane binding sites in NaV, but experimental binding data are lacking. Here we use site-directed placement of19F probes in NMR experiments to quantify isoflurane binding to the bacterial voltage-gated sodium channel NaChBac.19F probes were introduced individually to S129 and L150 near the S4–S5 linker, L179 and S208 at the extracellular surface, T189 in the ion selectivity filter, and all phenylalanine residues. Quantitative analyses of19F NMR saturation transfer difference (STD) spectroscopy showed a strong interaction of isoflurane with S129, T189, and S208; relatively weakly with L150; and almost undetectable with L179 and phenylalanine residues. An orientation preference was observed for isoflurane bound to T189 and S208, but not to S129 and L150. We conclude that isoflurane inhibits NaChBac by two distinct mechanisms: (i) as a channel blocker at the base of the selectivity filter, and (ii) as a modulator to restrict the pivot motion at the S4–S5 linker and at a critical hinge that controls the gating and inactivation motion of S6.

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Peng, Qingmei, Xin Zhou, Zhi Wang, Qingyi Xie, Chunfeng Ma, Guangzhao Zhang und Xiangjun Gong. „Three-Dimensional Bacterial Motions near a Surface Investigated by Digital Holographic Microscopy: Effect of Surface Stiffness“. Langmuir 35, Nr. 37 (18.08.2019): 12257–63. http://dx.doi.org/10.1021/acs.langmuir.9b02103.

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Asghar, Z., und N. Ali. „A mathematical model of the locomotion of bacteria near an inclined solid substrate: effects of different waveforms and rheological properties of couple-stress slime“. Canadian Journal of Physics 97, Nr. 5 (Mai 2019): 537–47. http://dx.doi.org/10.1139/cjp-2017-0906.

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Morphological mutations in bacterial cell make them the most miscellaneous microscopic group. Their non-flagellated species known as gliding bacteria exhibit self-powered motion and leave an adhesive trail of slime. The self-propelled motion in some gliding bacteria is achieved as a result of backward surface wave in the cell envelope. Motivated by this fact, an undulating surface on a layer of couple-stress fluid is used to model the motion of such gliding bacteria. Five different wave profiles, namely, sawtooth, sinusoidal, triangular, trapezoidal, and square profiles are used to model the waveform of the undulating wave in the outer cell surface. The inclination of the surface is also integrated into the model. The flow equations are set up under the lubrication assumption. Stream function is derived as an elementary function of an organism’s speed, undulation amplitude, and couple-stress parameter with its flow rate. Speed of the glider and flow rate (satisfying equilibrium conditions) are computed by employing modified Newton–Raphson method. These refined values are further utilized to compute the power dissipation. Effects of different waveforms, inclination angle, gravitational and couple-stress parameters on the speed of the microorganism and rate of energy expended are also quantified. Slime velocity is also plotted for fixed glider. In addition, making use of the obtained realistic set of values of the organism’s speed, flow rate, occlusion parameter, and couple-stress parameter, streamline patterns of the slime are plotted and discussed in detail.

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Dissertationen zum Thema "Bacterial near-surface motion"

Wang, Yiying. „Effect of Aligned Nanoscale Surface Structures on Microbial Adhesion“. Thesis, Virginia Tech, 2020. http://hdl.handle.net/10919/104040.

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Microbes in nature live collaboratively in adherent communities, known as biofilms. Biofilms can be contextually beneficial or detrimental. In medical implants, biofilms cause infections leading to additional healthcare costs of billions of dollars. Studies have found that micro/nanoscale surface topography can significantly alter (i.e., promote or hinder) the process of biofilm formation. The formation of biofilm starts with planktonic microbes attach to the surface. To further understand the biophysical underpinning of this process, the effect of aligned nanoscale surface structures on microbial adhesion was studied. To this end, aligned nanofiber coating with controlled fiber diameter and edge-to-edge spacing were manufactured using the Spinneret-based Tunable Engineered Parameters (STEP) techniques. The effect of surface topography on bacterial near-surface motility was studied. The experimental results showed that the bacterial attachment and near-surface motion can be greatly impacted by surface topography. Furthermore, the finding was applied to ureteral stents. The results showed that the aligned nanofiber can significantly reduce the biofilm formation process on ureteral stents.
Master of Science
Many microbes in nature live in adherent communities called biofilm. Biofilms contain individual microbes inside polymeric matrix which protect them from environmental stressors such as antibiotics. Biofilms are a significant contributor to the infection of implantable medical devices, which leads to additional healthcare costs of billions of dollars annually in the U.S. alone. Studies have found that sub-micron scale surface topography can significantly promote or hinder biofilm formation; however, the exact mechanism remains poorly understood. To further understand this process, the effect of aligned nanoscale surface structures on microbial adhesion was studied. The formation of microbial biofilm starts with swimming bacteria sensing the liquid-solid interface and attaching to the surface. Microbes are more likely to settle on a surface if a surface is favorable to attach. However, the decision-making process has not been fully understood. Our experimental results showed that the bacterial attachment and near-surface motion can be greatly influenced by surface topography. Furthermore, the finding was applied to ureteral stents, which is a type of medical implants used to maintain the flow of urine in the urinary tract. Ureteral stents serve great for medical purposes, but as foreign bodies, they also lead to urinary tract infection. The results showed that some types of aligned fiber coating increased microbial attachment density, while other types of aligned fiber coating reduced the bacterial surface coverage by up to 80%, which provides directions for future studies.

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Konferenzberichte zum Thema "Bacterial near-surface motion"

Khalil, Islam S. M., Ahmet Fatih Tabak, Tijmen Hageman, Mohamed Ewis, Marc Pichel, Mohamed E. Mitwally, Nermeen Serag El-Din, Leon Abelmann und Metin Sitti. „Near-surface effects on the controlled motion of magnetotactic bacteria“. In 2017 IEEE International Conference on Robotics and Automation (ICRA). IEEE, 2017. http://dx.doi.org/10.1109/icra.2017.7989705.

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Berichte der Organisationen zum Thema "Bacterial near-surface motion"

Frymier, P. D. Jr. Bacterial migration and motion in a fluid phase and near a solid surface. Office of Scientific and Technical Information (OSTI), Januar 1995. http://dx.doi.org/10.2172/573237.

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