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1
Robbins, Jennifer R., Angela I. Barth, Hélène Marquis, Eugenio L. de Hostos, W. James Nelson, and Julie A. Theriot. "Listeria monocytogenes Exploits Normal Host Cell Processes to Spread from Cell to Cell✪." Journal of Cell Biology 146, no. 6 (September 20, 1999): 1333–50. http://dx.doi.org/10.1083/jcb.146.6.1333.
Повний текст джерелаАнотація:
The bacterial pathogen, Listeria monocytogenes, grows in the cytoplasm of host cells and spreads intercellularly using a form of actin-based motility mediated by the bacterial protein ActA. Tightly adherent monolayers of MDCK cells that constitutively express GFP-actin were infected with L. monocytogenes, and intercellular spread of bacteria was observed by video microscopy. The probability of formation of membrane-bound protrusions containing bacteria decreased with host cell monolayer age and the establishment of extensive cell-cell contacts. After their extension into a recipient cell, intercellular membrane-bound protrusions underwent a period of bacterium-dependent fitful movement, followed by their collapse into a vacuole and rapid vacuolar lysis. Actin filaments in protrusions exhibited decreased turnover rates compared with bacterially associated cytoplasmic actin comet tails. Recovery of motility in the recipient cell required 1–2 bacterial generations. This delay may be explained by acid-dependent cleavage of ActA by the bacterial metalloprotease, Mpl. Importantly, we have observed that low levels of endocytosis of neighboring MDCK cell surface fragments occurs in the absence of bacteria, implying that intercellular spread of bacteria may exploit an endogenous process of paracytophagy.
2
Cossart, Pascale. "Actin-based bacterial motility." Current Opinion in Cell Biology 7, no. 1 (January 1995): 94–101. http://dx.doi.org/10.1016/0955-0674(95)80050-6.
Повний текст джерела
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Kurmasheva, Naziia, Vyacheslav Vorobiev, Margarita Sharipova, Tatyana Efremova, and Ayslu Mardanova. "The Potential Virulence Factors ofProvidencia stuartii: Motility, Adherence, and Invasion." BioMed Research International 2018 (2018): 1–8. http://dx.doi.org/10.1155/2018/3589135.
Повний текст джерелаАнотація:
Providencia stuartiiis the most commonProvidenciaspecies capable of causing human infections. CurrentlyP. stuartiiis involved in high incidence of urinary tract infections in catheterized patients. The ability of bacteria to swarm on semisolid (viscous) surfaces and adhere to and invade host cells determines the specificity of the disease pathogenesis and its therapy. In the present study we demonstrated morphological changes ofP. stuartiiNK cells during migration on the viscous medium and discussed adhesive and invasive properties utilizing the HeLa-M cell line as a host model. To visualize the interaction ofP. stuartiiNK bacterial cells with eukaryotic cellsin vitroscanning electron and confocal microscopy were performed. We found that bacteriaP. stuartiiNK are able to adhere to and invade HeLa-M epithelial cells and these properties depend on the age of bacterial culture. Also, to invade the host cells the infectious dose of the bacteria is essential. The microphotographs indicate that after incubation of bacterialP. stuartiiNK cells together with epithelial cells the bacterial cells both were adhered onto and invaded into the host cells.
4
Nakamura, Shuichi, and Tohru Minamino. "Flagella-Driven Motility of Bacteria." Biomolecules 9, no. 7 (July 14, 2019): 279. http://dx.doi.org/10.3390/biom9070279.
Повний текст джерелаАнотація:
The bacterial flagellum is a helical filamentous organelle responsible for motility. In bacterial species possessing flagella at the cell exterior, the long helical flagellar filament acts as a molecular screw to generate thrust. Meanwhile, the flagella of spirochetes reside within the periplasmic space and not only act as a cytoskeleton to determine the helicity of the cell body, but also rotate or undulate the helical cell body for propulsion. Despite structural diversity of the flagella among bacterial species, flagellated bacteria share a common rotary nanomachine, namely the flagellar motor, which is located at the base of the filament. The flagellar motor is composed of a rotor ring complex and multiple transmembrane stator units and converts the ion flux through an ion channel of each stator unit into the mechanical work required for motor rotation. Intracellular chemotactic signaling pathways regulate the direction of flagella-driven motility in response to changes in the environments, allowing bacteria to migrate towards more desirable environments for their survival. Recent experimental and theoretical studies have been deepening our understanding of the molecular mechanisms of the flagellar motor. In this review article, we describe the current understanding of the structure and dynamics of the bacterial flagellum.
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Matz, Carsten, and Klaus Jürgens. "High Motility Reduces Grazing Mortality of Planktonic Bacteria." Applied and Environmental Microbiology 71, no. 2 (February 2005): 921–29. http://dx.doi.org/10.1128/aem.71.2.921-929.2005.
Повний текст джерелаАнотація:
ABSTRACT We tested the impact of bacterial swimming speed on the survival of planktonic bacteria in the presence of protozoan grazers. Grazing experiments with three common bacterivorous nanoflagellates revealed low clearance rates for highly motile bacteria. High-resolution video microscopy demonstrated that the number of predator-prey contacts increased with bacterial swimming speed, but ingestion rates dropped at speeds of >25 μm s−1 as a result of handling problems with highly motile cells. Comparative studies of a moderately motile strain (<25 μm s−1) and a highly motile strain (>45 μm s−1) further revealed changes in the bacterial swimming speed distribution due to speed-selective flagellate grazing. Better long-term survival of the highly motile strain was indicated by fourfold-higher bacterial numbers in the presence of grazing compared to the moderately motile strain. Putative constraints of maintaining high swimming speeds were tested at high growth rates and under starvation with the following results: (i) for two out of three strains increased growth rate resulted in larger and slower bacterial cells, and (ii) starved cells became smaller but maintained their swimming speeds. Combined data sets for bacterial swimming speed and cell size revealed highest grazing losses for moderately motile bacteria with a cell size between 0.2 and 0.4 μm3. Grazing mortality was lowest for cells of >0.5 μm3 and small, highly motile bacteria. Survival efficiencies of >95% for the ultramicrobacterial isolate CP-1 (≤0.1 μm3, >50 μm s−1) illustrated the combined protective action of small cell size and high motility. Our findings suggest that motility has an important adaptive function in the survival of planktonic bacteria during protozoan grazing.
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Zegadło, Katarzyna, Monika Gieroń, Paulina Żarnowiec, Katarzyna Durlik-Popińska, Beata Kręcisz, Wiesław Kaca, and Grzegorz Czerwonka. "Bacterial Motility and Its Role in Skin and Wound Infections." International Journal of Molecular Sciences 24, no. 2 (January 15, 2023): 1707. http://dx.doi.org/10.3390/ijms24021707.
Повний текст джерелаАнотація:
Skin and wound infections are serious medical problems, and the diversity of bacteria makes such infections difficult to treat. Bacteria possess many virulence factors, among which motility plays a key role in skin infections. This feature allows for movement over the skin surface and relocation into the wound. The aim of this paper is to review the type of bacterial movement and to indicate the underlying mechanisms than can serve as a target for developing or modifying antibacterial therapies applied in wound infection treatment. Five types of bacterial movement are distinguished: appendage-dependent (swimming, swarming, and twitching) and appendage-independent (gliding and sliding). All of them allow bacteria to relocate and aid bacteria during infection. Swimming motility allows bacteria to spread from ‘persister cells’ in biofilm microcolonies and colonise other tissues. Twitching motility enables bacteria to press through the tissues during infection, whereas sliding motility allows cocci (defined as non-motile) to migrate over surfaces. Bacteria during swarming display greater resistance to antimicrobials. Molecular motors generating the focal adhesion complexes in the bacterial cell leaflet generate a ‘wave’, which pushes bacterial cells lacking appendages, thereby enabling movement. Here, we present the five main types of bacterial motility, their molecular mechanisms, and examples of bacteria that utilise them. Bacterial migration mechanisms can be considered not only as a virulence factor but also as a target for antibacterial therapy.
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Patankar, Yash R., Rustin R. Lovewell, Matthew E. Poynter, Jeevan Jyot, Barbara I. Kazmierczak, and Brent Berwin. "Flagellar Motility Is a Key Determinant of the Magnitude of the Inflammasome Response to Pseudomonas aeruginosa." Infection and Immunity 81, no. 6 (March 25, 2013): 2043–52. http://dx.doi.org/10.1128/iai.00054-13.
Повний текст джерелаАнотація:
ABSTRACTWe previously demonstrated that bacterial flagellar motility is a fundamental mechanism by which host phagocytes bind and ingest bacteria. Correspondingly, loss of bacterial motility, consistently observed in clinical isolates from chronicPseudomonas aeruginosainfections, enables bacteria to evade association and ingestion ofP. aeruginosaby phagocytes bothin vitroandin vivo. Since bacterial interactions with the phagocyte cell surface are required for type three secretion system-dependent NLRC4 inflammasome activation byP. aeruginosa, we hypothesized that reduced bacterial association with phagocytes due to loss of bacterial motility, independent of flagellar expression, will lead to reduced inflammasome activation. Here we report that inflammasome activation is reduced in response to nonmotileP. aeruginosa. NonmotileP. aeruginosaelicits reduced IL-1β production as well as caspase-1 activation by peritoneal macrophages and bone marrow-derived dendritic cellsin vitro. Importantly, nonmotileP. aeruginosaalso elicits reduced IL-1β levelsin vivoin comparison to those elicited by wild-typeP. aeruginosa. This is the first demonstration that loss of bacterial motility results in reduced inflammasome activation and antibacterial IL-1β host response. These results provide a critical insight into how the innate immune system responds to bacterial motility and, correspondingly, how pathogens have evolved mechanisms to evade the innate immune system.
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Lovewell, Rustin R., Sandra M. Hayes, George A. O'Toole, and Brent Berwin. "Pseudomonas aeruginosaflagellar motility activates the phagocyte PI3K/Akt pathway to induce phagocytic engulfment." American Journal of Physiology-Lung Cellular and Molecular Physiology 306, no. 7 (April 1, 2014): L698—L707. http://dx.doi.org/10.1152/ajplung.00319.2013.
Повний текст джерелаАнотація:
Phagocytosis of the bacterial pathogen Pseudomonas aeruginosa is the primary means by which the host controls bacterially induced pneumonia during lung infection. Previous studies have identified flagellar swimming motility as a key pathogen-associated molecular pattern (PAMP) recognized by phagocytes to initiate engulfment. Correspondingly, loss of flagellar motility is observed during chronic pulmonary infection with P. aeruginosa, and this likely reflects a selection for bacteria resistant to phagocytic clearance. However, the mechanism underlying the preferential phagocytic response to motile bacteria is unknown. Here we have identified a cellular signaling pathway in alveolar macrophages and other phagocytes that is specifically activated by flagellar motility. Genetic and biochemical methods were employed to identify that phagocyte PI3K/Akt activation is required for bacterial uptake and, importantly, it is specifically activated in response to P. aeruginosa flagellar motility. Based on these observations, the second important finding that emerged from these studies is that titration of the bacterial flagellar motility results in a proportional activation state of Akt. Therefore, the Akt pathway is responsive to, and corresponds with, the degree of bacterial flagellar motility, is independent of the actin polymerization that facilitates phagocytosis, and determines the phagocytic fate of P. aeruginosa. These findings elucidate the mechanism behind motility-dependent phagocytosis of extracellular bacteria and support a model whereby phagocytic clearance exerts a selective pressure on P. aeruginosa populations in vivo, which contributes to changes in pathogenesis during infections.
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Akahoshi, Douglas T., Dean E. Natwick, Weirong Yuan, Wuyuan Lu, Sean R. Collins, and Charles L. Bevins. "Flagella-driven motility is a target of human Paneth cell defensin activity." PLOS Pathogens 19, no. 2 (February 23, 2023): e1011200. http://dx.doi.org/10.1371/journal.ppat.1011200.
Повний текст джерелаАнотація:
In the mammalian intestine, flagellar motility can provide microbes competitive advantage, but also threatens the spatial segregation established by the host at the epithelial surface. Unlike microbicidal defensins, previous studies indicated that the protective activities of human α-defensin 6 (HD6), a peptide secreted by Paneth cells of the small intestine, resides in its remarkable ability to bind microbial surface proteins and self-assemble into protective fibers and nets. Given its ability to bind flagellin, we proposed that HD6 might be an effective inhibitor of bacterial motility. Here, we utilized advanced automated live cell fluorescence imaging to assess the effects of HD6 on actively swimming Salmonella enterica in real time. We found that HD6 was able to effectively restrict flagellar motility of individual bacteria. Flagellin-specific antibody, a classic inhibitor of flagellar motility that utilizes a mechanism of agglutination, lost its activity at low bacterial densities, whereas HD6 activity was not diminished. A single amino acid variant of HD6 that was able to bind flagellin, but not self-assemble, lost ability to inhibit flagellar motility. Together, these results suggest a specialized role of HD6 self-assembly into polymers in targeting and restricting flagellar motility.
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Palma, Victoria, María Soledad Gutiérrez, Orlando Vargas, Raghuveer Parthasarathy, and Paola Navarrete. "Methods to Evaluate Bacterial Motility and Its Role in Bacterial–Host Interactions." Microorganisms 10, no. 3 (March 4, 2022): 563. http://dx.doi.org/10.3390/microorganisms10030563.
Повний текст джерелаАнотація:
Bacterial motility is a widespread characteristic that can provide several advantages for the cell, allowing it to move towards more favorable conditions and enabling host-associated processes such as colonization. There are different bacterial motility types, and their expression is highly regulated by the environmental conditions. Because of this, methods for studying motility under realistic experimental conditions are required. A wide variety of approaches have been developed to study bacterial motility. Here, we present the most common techniques and recent advances and discuss their strengths as well as their limitations. We classify them as macroscopic or microscopic and highlight the advantages of three-dimensional imaging in microscopic approaches. Lastly, we discuss methods suited for studying motility in bacterial–host interactions, including the use of the zebrafish model.
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Sanchez, Hector Felipe, Daniel Hopkins, Sally Demirdjian, Cecilia Gutierrez, George O’Toole, and Brent Berwin. "Specific Cell-Surface Glycans on Phagocytes Mediate Binding of Pseudomonas aeruginosa." Journal of Immunology 204, no. 1_Supplement (May 1, 2020): 156.17. http://dx.doi.org/10.4049/jimmunol.204.supp.156.17.
Повний текст джерелаАнотація:
Abstract Pseudomonas aeruginosa is a Gram-negative bacterium that, as an opportunistic pathogen, substantially contributes to high morbidity and mortality rates in susceptible individuals such as those with cystic fibrosis or neutropenia. Previous studies identified that the downregulation or loss of bacterial flagellar motility, typically observed within chronic infections, enables bacteria to evade interactions with phagocytic cells that would result in phagocytic uptake. Our recent work demonstrated that exogenous addition of a negatively charged lipid, PIP3, induces binding and phagocytosis of non-motile strains of P. aeruginosa. Based on this work, we hypothesized that the engagement of P. aeruginosa by host innate cells, and subsequent phagocytosis, is mediated by motility-dependent interactions with cell-surface polyanions. We now report that endogenous polyanionic N-linked glycans and heparan sulfate mediate bacterial binding of P. aeruginosa by human monocytic cells. These specific cell-surface interactions result in P. aeruginosa phagocytosis, bacterial type 3 secretion system (T3SS)-mediated cellular intoxication and the IL-1β inflammatory response of the host innate immune cells. Concomitantly, inhibition of host cell N-glycan synthesis reduces T3SS-mediated cytotoxicity and the IL-1β response induced by the bacteria. Importantly, the bacterial interactions with the glycans were motility-dependent and could be recapitulated with purified, immobilized glycans. Therefore, this work describes novel interactions of P. aeruginosa with specific phagocyte cell-surface glycans that modulate relevant host innate immune responses to the bacteria, including phagocytosis, inflammation and cytotoxicity.
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Courcoubetis, George, Manasi S. Gangan, Sean Lim, Xiaokan Guo, Stephan Haas, and James Q. Boedicker. "Formation, collective motion, and merging of macroscopic bacterial aggregates." PLOS Computational Biology 18, no. 1 (January 4, 2022): e1009153. http://dx.doi.org/10.1371/journal.pcbi.1009153.
Повний текст джерелаАнотація:
Chemotactic bacteria form emergent spatial patterns of variable cell density within cultures that are initially spatially uniform. These patterns are the result of chemical gradients that are created from the directed movement and metabolic activity of billions of cells. A recent study on pattern formation in wild bacterial isolates has revealed unique collective behaviors of the bacteria Enterobacter cloacae. As in other bacterial species, Enterobacter cloacae form macroscopic aggregates. Once formed, these bacterial clusters can migrate several millimeters, sometimes resulting in the merging of two or more clusters. To better understand these phenomena, we examine the formation and dynamics of thousands of bacterial clusters that form within a 22 cm square culture dish filled with soft agar over two days. At the macroscale, the aggregates display spatial order at short length scales, and the migration of cell clusters is superdiffusive, with a merging acceleration that is correlated with aggregate size. At the microscale, aggregates are composed of immotile cells surrounded by low density regions of motile cells. The collective movement of the aggregates is the result of an asymmetric flux of bacteria at the boundary. An agent-based model is developed to examine how these phenomena are the result of both chemotactic movement and a change in motility at high cell density. These results identify and characterize a new mechanism for collective bacterial motility driven by a transient, density-dependent change in motility.
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Chien, Jeremy, Takayo Ota, Giovanni Aletti, Ravi Shridhar, Mariarosaria Boccellino, Lucio Quagliuolo, Alfonso Baldi, and Viji Shridhar. "Serine Protease HtrA1 Associates with Microtubules and Inhibits Cell Migration." Molecular and Cellular Biology 29, no. 15 (May 26, 2009): 4177–87. http://dx.doi.org/10.1128/mcb.00035-09.
Повний текст джерелаАнотація:
ABSTRACT HtrA1 belongs to a family of serine proteases found in organisms ranging from bacteria to humans. Bacterial HtrA1 (DegP) is a heat shock-induced protein that behaves as a chaperone at low temperature and as a protease at high temperature to help remove unfolded proteins during heat shock. In contrast to bacterial HtrA1, little is known about the function of human HtrA1. Here, we report the first evidence that human HtrA1 is a microtubule-associated protein and modulates microtubule stability and cell motility. Intracellular HtrA1 is localized to microtubules in a PDZ (PSD95, Dlg, ZO1) domain-dependent, nocodazole-sensitive manner. During microtubule assembly, intracellular HtrA associates with centrosomes and newly polymerized microtubules. In vitro, purified HtrA1 promotes microtubule assembly. Moreover, HtrA1 cosediments and copurifies with microtubules. Purified HtrA1 associates with purified α- and β-tubulins, and immunoprecipitation of endogenous HtrA1 results in coprecipitation of α-, β-, and γ-tubulins. Finally, downregulation of HtrA1 promotes cell motility, whereas enhanced expression of HtrA1 attenuates cell motility. These results offer an original identification of HtrA1 as a microtubule-associated protein and provide initial mechanistic insights into the role of HtrA1 in theregulation of cell motility by modulating microtubule stability.
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Tans-Kersten, Julie, Darby Brown, and Caitilyn Allen. "Swimming Motility, a Virulence Trait of Ralstonia solanacearum, Is Regulated by FlhDC and the Plant Host Environment." Molecular Plant-Microbe Interactions® 17, no. 6 (June 2004): 686–95. http://dx.doi.org/10.1094/mpmi.2004.17.6.686.
Повний текст джерелаАнотація:
Swimming motility allows the bacterial wilt pathogen Ralstonia solanacearum to efficiently invade and colonize host plants. However, the bacteria are essentially nonmotile once inside plant xylem vessels. To determine how and when motility genes are expressed, we cloned and mutated flhDC, which encodes a major regulator of flagellar biosynthesis and bacterial motility. An flhDC mutant was non-motile and less virulent than its wild-type parent on both tomato and Arabidopsis; on Arabidopsis, the flhDC mutant also was less virulent than a nonmotile fliC flagellin mutant. Genes in the R. solanacearum motility regulon had strikingly different expression patterns in culture and in the plant. In culture, as expected, flhDC expression depended on PehSR, a regulator of early virulence factors; and, in turn, FlhDC was required for fliC (flagellin) expression. However, when bacteria grew in tomato plants, flhDC was expressed in both wild-type and pehR mutant backgrounds, although PehSR is necessary for motility both in culture and in planta. Both flhDC and pehSR were significantly induced in planta relative to expression levels in culture. Unexpectedly, the fliC gene was expressed in planta at cell densities where motile bacteria were not observed, as well as in a nonmotile flhDC mutant. Thus, expression of flhDC and flagellin itself are uncoupled from bacterial motility in the host environment, indicating that additional signals and regulatory circuits repress motility during plant pathogenesis.
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Mignot, Tâm, John P. Merlie, and David R. Zusman. "Regulated Pole-to-Pole Oscillations of a Bacterial Gliding Motility Protein." Science 310, no. 5749 (November 3, 2005): 855–57. http://dx.doi.org/10.1126/science.1119052.
Повний текст джерелаАнотація:
Little is known about directed motility of bacteria that move by type IV pilus–mediated (twitching) motility. Here, we found that during periodic cell reversals ofMyxoccocus xanthus, type IV pili were disassembled at one pole and reassembled at the other pole. Accompanying these reversals, FrzS, a protein required for directed motility, moved in an oscillatory pattern between the cell poles. The frequency of the oscillations was controlled by the Frz chemosensory system, which is essential for directed motility. Pole-to-pole migration of FrzS appeared to involve movement along a filament running the length of the cell. FrzS dynamics may thus regulate cell polarity during directed motility.
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Kuehl, Carole J., Ana-Maria Dragoi, Arthur Talman, and Hervé Agaisse. "Bacterial spread from cell to cell: beyond actin-based motility." Trends in Microbiology 23, no. 9 (September 2015): 558–66. http://dx.doi.org/10.1016/j.tim.2015.04.010.
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Tokárová, Viola, Ayyappasamy Sudalaiyadum Perumal, Monalisha Nayak, Henry Shum, Ondřej Kašpar, Kavya Rajendran, Mahmood Mohammadi, et al. "Patterns of bacterial motility in microfluidics-confining environments." Proceedings of the National Academy of Sciences 118, no. 17 (April 19, 2021): e2013925118. http://dx.doi.org/10.1073/pnas.2013925118.
Повний текст джерелаАнотація:
Understanding the motility behavior of bacteria in confining microenvironments, in which they search for available physical space and move in response to stimuli, is important for environmental, food industry, and biomedical applications. We studied the motility of five bacterial species with various sizes and flagellar architectures (Vibrio natriegens, Magnetococcus marinus, Pseudomonas putida, Vibrio fischeri, and Escherichia coli) in microfluidic environments presenting various levels of confinement and geometrical complexity, in the absence of external flow and concentration gradients. When the confinement is moderate, such as in quasi-open spaces with only one limiting wall, and in wide channels, the motility behavior of bacteria with complex flagellar architectures approximately follows the hydrodynamics-based predictions developed for simple monotrichous bacteria. Specifically, V. natriegens and V. fischeri moved parallel to the wall and P. putida and E. coli presented a stable movement parallel to the wall but with incidental wall escape events, while M. marinus exhibited frequent flipping between wall accumulator and wall escaper regimes. Conversely, in tighter confining environments, the motility is governed by the steric interactions between bacteria and the surrounding walls. In mesoscale regions, where the impacts of hydrodynamics and steric interactions overlap, these mechanisms can either push bacteria in the same directions in linear channels, leading to smooth bacterial movement, or they could be oppositional (e.g., in mesoscale-sized meandered channels), leading to chaotic movement and subsequent bacterial trapping. The study provides a methodological template for the design of microfluidic devices for single-cell genomic screening, bacterial entrapment for diagnostics, or biocomputation.
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Zuo, Wenlong, and Yilin Wu. "Dynamic motility selection drives population segregation in a bacterial swarm." Proceedings of the National Academy of Sciences 117, no. 9 (February 14, 2020): 4693–700. http://dx.doi.org/10.1073/pnas.1917789117.
Повний текст джерелаАнотація:
Population expansion in space, or range expansion, is widespread in nature and in clinical settings. Space competition among heterogeneous subpopulations during range expansion is essential to population ecology, and it may involve the interplay of multiple factors, primarily growth and motility of individuals. Structured microbial communities provide model systems to study space competition during range expansion. Here we use bacterial swarms to investigate how single-cell motility contributes to space competition among heterogeneous bacterial populations during range expansion. Our results revealed that motility heterogeneity can promote the spatial segregation of subpopulations via a dynamic motility selection process. The dynamic motility selection is enabled by speed-dependent persistence time bias of single-cell motion, which presumably arises from physical interaction between cells in a densely packed swarm. We further showed that the dynamic motility selection may contribute to collective drug tolerance of swarming colonies by segregating subpopulations with transient drug tolerance to the colony edge. Our results illustrate that motility heterogeneity, or “motility fitness,” can play a greater role than growth rate fitness in determining the short-term spatial structure of expanding populations.
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Subramanian, Sundharraman, and Daniel B. Kearns. "Functional Regulators of Bacterial Flagella." Annual Review of Microbiology 73, no. 1 (September 8, 2019): 225–46. http://dx.doi.org/10.1146/annurev-micro-020518-115725.
Повний текст джерелаАнотація:
Bacteria move by a variety of mechanisms, but the best understood types of motility are powered by flagella ( 72 ). Flagella are complex machines embedded in the cell envelope that rotate a long extracellular helical filament like a propeller to push cells through the environment. The flagellum is one of relatively few biological machines that experience continuous 360° rotation, and it is driven by one of the most powerful motors, relative to its size, on earth. The rotational force (torque) generated at the base of the flagellum is essential for motility, niche colonization, and pathogenesis. This review describes regulatory proteins that control motility at the level of torque generation.
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O'Neil, Heather S., and Hélène Marquis. "Listeria monocytogenes Flagella Are Used for Motility, Not as Adhesins, To Increase Host Cell Invasion." Infection and Immunity 74, no. 12 (September 18, 2006): 6675–81. http://dx.doi.org/10.1128/iai.00886-06.
Повний текст джерелаАнотація:
ABSTRACT Flagellar structures contribute to the virulence of multiple gastrointestinal pathogens either as the effectors of motility, as adhesins, or as a secretion apparatus for virulence factors. Listeria monocytogenes is a food-borne, gram-positive pathogen that uses flagella to increase the efficiency of epithelial cell invasion (A. Bigot, H. Pagniez, E. Botton, C. Frehel, I. Dubail, C. Jacquet, A. Charbit, and C. Raynaud, Infect. Immun. 73:5530-5539, 2005; L. Dons, E. Eriksson, Y. Jin, M. E. Rottenberg, K. Kristensson, C. N. Larsen, J. Bresciani, and J. E. Olsen, Infect. Immun. 72:3237-3244, 2004). In this study, we aimed to elucidate the mechanism by which flagella contribute to L. monocytogenes invasion. To examine the role of flagella as adhesins, invasion and adhesion assays were performed with flagellated motile and nonmotile bacteria and nonflagellated bacteria. We observed that flagellated but nonmotile bacteria do not adhere to or invade human epithelial cells more efficiently than nonflagellated bacteria. These results indicated that flagella do not function as adhesins to enhance the adhesion of L. monocytogenes to targeted host cells. Instead, it appears that motility is important for tissue culture invasion. Furthermore, we tested whether motility contributes to early colonization of the gastrointestinal tract using a competitive index assay in which mice were infected orally with motile and nonmotile bacteria in a 1:1 ratio. Differential bacterial counts demonstrated that motile bacteria outcompete nonmotile bacteria in the colonization of the intestines at early time points postinfection. This difference is also reflected in invasion of the liver 12 h later, suggesting that flagellum-mediated motility enhances L. monocytogenes infectivity soon after bacterial ingestion in vivo.
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Nishiyama, Masayoshi, Yoshiyuki Sowa, Shigeichi Kumazaki, Yoshifumi Kimura, Michio Homma, Akihiko Ishijima, and Masahide Terazima. "2P240 How does high pressure affect on the bacterial motility?(39. Cell motility,Poster Session,Abstract,Meeting Program of EABS & BSJ 2006)." Seibutsu Butsuri 46, supplement2 (2006): S355. http://dx.doi.org/10.2142/biophys.46.s355_4.
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Lamason, Rebecca L., and Matthew D. Welch. "Actin-based motility and cell-to-cell spread of bacterial pathogens." Current Opinion in Microbiology 35 (February 2017): 48–57. http://dx.doi.org/10.1016/j.mib.2016.11.007.
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Cronenberg, Tom, Marc Hennes, Isabelle Wielert, and Berenike Maier. "Antibiotics modulate attractive interactions in bacterial colonies affecting survivability under combined treatment." PLOS Pathogens 17, no. 2 (February 1, 2021): e1009251. http://dx.doi.org/10.1371/journal.ppat.1009251.
Повний текст джерелаАнотація:
Biofilm formation protects bacteria from antibiotics. Very little is known about the response of biofilm-dwelling bacteria to antibiotics at the single cell level. Here, we developed a cell-tracking approach to investigate how antibiotics affect structure and dynamics of colonies formed by the human pathogen Neisseria gonorrhoeae. Antibiotics targeting different cellular functions enlarge the cell volumes and modulate within-colony motility. Focusing on azithromycin and ceftriaxone, we identify changes in type 4 pilus (T4P) mediated cell-to-cell attraction as the molecular mechanism for different effects on motility. By using strongly attractive mutant strains, we reveal that the survivability under ceftriaxone treatment depends on motility. Combining our results, we find that sequential treatment with azithromycin and ceftriaxone is synergistic. Taken together, we demonstrate that antibiotics modulate T4P-mediated attractions and hence cell motility and colony fluidity.
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Mounier, J., V. Laurent, A. Hall, P. Fort, M. F. Carlier, P. J. Sansonetti, and C. Egile. "Rho family GTPases control entry of Shigella flexneri into epithelial cells but not intracellular motility." Journal of Cell Science 112, no. 13 (July 1, 1999): 2069–80. http://dx.doi.org/10.1242/jcs.112.13.2069.
Повний текст джерелаАнотація:
Shigella flexneri, an invasive bacterial pathogen, promotes formation of two cytoskeletal structures: the entry focus that mediates bacterial uptake into epithelial cells and the actin-comet tail that enables the bacteria to spread intracellularly. During the entry step, secretion of bacterial invasins causes a massive burst of subcortical actin polymerization leading the formation of localised membrane projections. Fusion of these membrane ruffles leads to bacterial internalization. Inside the cytoplasm, polar expression of the IcsA protein on the bacterial surface allows polymerization of actin filaments and their organization into an actin-comet tail leading to bacterial spread. The Rho family of small GTPases plays an essential role in the organization and regulation of cellular cytoskeletal structures (i.e. filopodia, lamellipodia, adherence plaques and intercellular junctions). We show here that induction of Shigella entry foci is controlled by the Cdc42, Rac and Rho GTPases, but not by RhoG. In contrast, actin-driven intracellular motility of Shigella does not require Rho GTPases. Therefore, Shigella appears to manipulate the epithelial cell cytoskeleton both by Rho GTPase-dependent and -independent processes.
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Kerchove, Alexis J. de, and Menachem Elimelech. "Bacterial Swimming Motility Enhances Cell Deposition and Surface Coverage." Environmental Science & Technology 42, no. 12 (June 2008): 4371–77. http://dx.doi.org/10.1021/es703028u.
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Dowd, Georgina C., Roman Mortuza, Manmeet Bhalla, Hoan Van Ngo, Yang Li, Luciano A. Rigano, and Keith Ireton. "Listeria monocytogenes exploits host exocytosis to promote cell-to-cell spread." Proceedings of the National Academy of Sciences 117, no. 7 (February 3, 2020): 3789–96. http://dx.doi.org/10.1073/pnas.1916676117.
Повний текст джерелаАнотація:
The facultative intracellular pathogen Listeria monocytogenes uses an actin-based motility process to spread within human tissues. Filamentous actin from the human cell forms a tail behind bacteria, propelling microbes through the cytoplasm. Motile bacteria remodel the host plasma membrane into protrusions that are internalized by neighboring cells. A critical unresolved question is whether generation of protrusions by Listeria involves stimulation of host processes apart from actin polymerization. Here we demonstrate that efficient protrusion formation in polarized epithelial cells involves bacterial subversion of host exocytosis. Confocal microscopy imaging indicated that exocytosis is up-regulated in protrusions of Listeria in a manner that depends on the host exocyst complex. Depletion of components of the exocyst complex by RNA interference inhibited the formation of Listeria protrusions and subsequent cell-to-cell spread of bacteria. Additional genetic studies indicated important roles for the exocyst regulators Rab8 and Rab11 in bacterial protrusion formation and spread. The secreted Listeria virulence factor InlC associated with the exocyst component Exo70 and mediated the recruitment of Exo70 to bacterial protrusions. Depletion of exocyst proteins reduced the length of Listeria protrusions, suggesting that the exocyst complex promotes protrusion elongation. Collectively, these results demonstrate that Listeria exploits host exocytosis to stimulate intercellular spread of bacteria.
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Addy, Hardian S., Ahmed Askora, Takeru Kawasaki, Makoto Fujie та Takashi Yamada. "The Filamentous Phage ϕRSS1 Enhances Virulence of Phytopathogenic Ralstonia solanacearum on Tomato". Phytopathology® 102, № 3 (березень 2012): 244–51. http://dx.doi.org/10.1094/phyto-10-11-0277.
Повний текст джерелаАнотація:
Ralstonia solanacearum is the causative agent of bacterial wilt in many important crops. ϕRSS1 is a filamentous phage that infects R. solanacearum strains. Upon infection, it alters the physiological state and the behavior of host cells. Here, we show that R. solanacearum infected by ϕRSS1 becomes more virulent on host plants. Some virulence and pathogenicity factors, such as extracellular polysaccharide (EPS) synthesis and twitching motility, increased in the bacterial host cells infected with ϕRSS1, resulting in early wilting. Tomato plants inoculated with ϕRSS1-infected bacteria wilted 2 to 3 days earlier than those inoculated with wild-type bacteria. Infection with ϕRSS1 induced early expression of phcA, the global virulence regulator. phcA expression was detected in ϕRSS1-infected cells at cell density as low as 104 CFU/ml. Filamentous phages are assembled on the host cell surface and many phage particles accumulate on the cell surface. These surface-associated phage particles (phage proteins) may change the cell surface nature (hydrophobicity) to give high local cell densities. ϕRSS1 infection also enhanced PilA and type IV pilin production, resulting in increased twitching motility.
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Kim, Dokyum, Yongsam Kim, and Sookkyung Lim. "Effects of swimming environment on bacterial motility." Physics of Fluids 34, no. 3 (March 2022): 031907. http://dx.doi.org/10.1063/5.0082768.
Повний текст джерелаАнотація:
Swimming trajectories of bacteria can be altered by environmental conditions, such as background flow and physical barriers, that limit the free swimming of bacteria. We present a comprehensive model of a bacterium that consists of a rod-shaped cell body and a flagellum which is composed of a motor, a hook, and a filament. The elastic flagellum is modeled based on the Kirchhoff rod theory, the cell body is considered to be a rigid body, and the hydrodynamic interaction of a bacterium near a wall is described by regularized Stokeslet formulation combined with the image system. We consider three environmental conditions: (1) a rigid surface is placed horizontally and there is no shear flow, (2) a shear fluid flow is present and the bacterium is near the rigid surface, and (3) while the bacterium is near the rigid surface and is under shear flow, an additional sidewall which is perpendicular to the rigid surface is placed. Each environmental state modifies the swimming behavior. For the first condition, there are two modes of motility, trap and escape, whether the bacterium stays near the surface or moves away from the surface as we vary the physical and geometrical properties of the model bacterium. For the second condition, there exists a threshold of shear rate that classifies the motion into two types of paths in which the bacterium takes either a periodic coil trajectory or a linear trajectory. For the last condition, the bacterium takes upstream motility along the sidewall for lower shear rates and downstream motility for larger shear flow rates.
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de Kerchove, Alexis J., and Menachem Elimelech. "Impact of Alginate Conditioning Film on Deposition Kinetics of Motile and Nonmotile Pseudomonas aeruginosa Strains." Applied and Environmental Microbiology 73, no. 16 (June 15, 2007): 5227–34. http://dx.doi.org/10.1128/aem.00678-07.
Повний текст джерелаАнотація:
ABSTRACT The initial deposition of bacteria in most aquatic systems is affected by the presence of a conditioning film adsorbed at the liquid-solid interface. Due to the inherent complexity of such films, their impact on bacterial deposition remains poorly defined. The aim of this study was to gain a better understanding of the effect of a conditioning film on the deposition of motile and nonmotile Pseudomonas aeruginosa cells in a radial stagnation point flow system. A well-defined alginate film was used as a model conditioning film because of its polysaccharide and polyelectrolyte nature. Deposition experiments under favorable (nonrepulsive) conditions demonstrated the importance of swimming motility for cell transport towards the substrate. The impact of the flagella of motile cells on deposition is dependent on the presence of the conditioning film. We showed that on a clean substrate surface, electrostatic repulsion governs bacterial deposition and the presence of flagella increases cell deposition. However, our results suggest that steric interactions between flagella and extended polyelectrolytes of the conditioning film hinder cell deposition. At a high ionic strength (100 mM), active swimming motility and changes in alginate film structure suppressed the steric barrier and allowed conditions favorable for deposition. We demonstrated that bacterial deposition is highly influenced by cell motility and the structure of the conditioning film, which are both dependent on ionic strength.
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Oliveira, Nuno M., Kevin R. Foster, and William M. Durham. "Single-cell twitching chemotaxis in developing biofilms." Proceedings of the National Academy of Sciences 113, no. 23 (May 24, 2016): 6532–37. http://dx.doi.org/10.1073/pnas.1600760113.
Повний текст джерелаАнотація:
Bacteria form surface-attached communities, known as biofilms, which are central to bacterial biology and how they affect us. Although surface-attached bacteria often experience strong chemical gradients, it remains unclear whether single cells can effectively perform chemotaxis on surfaces. Here we use microfluidic chemical gradients and massively parallel automated tracking to study the behavior of the pathogenPseudomonas aeruginosaduring early biofilm development. We show that individual cells can efficiently move toward chemoattractants using pili-based “twitching” motility and the Chp chemosensory system. Moreover, we discovered the behavioral mechanism underlying this surface chemotaxis: Cells reverse direction more frequently when moving away from chemoattractant sources. These corrective maneuvers are triggered rapidly, typically before a wayward cell has ventured a fraction of a micron. Our work shows that single bacteria can direct their motion with submicron precision and reveals the hidden potential for chemotaxis within bacterial biofilms.
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Nugraheni, Irma Prasety Ayu, Derana Widyastika, Sofia Maulida, Heni Susilowati, and Alma Linggar Jonarta. "Effect of Red Onion (Allium cepa var ascalonicum) Skin Ethanolic Extract on the Motility and the Adhesion Index of Pseudomonas aeruginosa and Macrophage Phagocytosis Index." Majalah Obat Tradisional 24, no. 1 (April 30, 2019): 40. http://dx.doi.org/10.22146/mot.45532.
Повний текст джерелаАнотація:
Red onion skin (Allium cepa var ascalonicum) contains various ingredients that may function as antibacterial agents against microorganisms, as well as anti-inflammatory and immunomodulator agents for host cells, such as macrophages. Pseudomonas aeruginosa found in the oral cavity is commensal bacteria that may turn into opportunistic pathogen by utilizing its virulence factors such as motility and adhesion to the host cell. The purpose of this study was to investigate the effect of red-onion-skin ethanolic extract towards P. aeruginosa ATCC 9027 on the motility and adhesion ability, furthermore, to know its effect on the macrophage phagocytosis. The research was conducted into three parts of experiment using red-onion-skin ethanolic extract. Extract-induced bacterial motility test was carried out on semi-solid media, stained using 0.1% crystal violet, then the radial length of the bacterial movement was measured. The bacterial adhesion index to buccal cells was calculated after incubated for two hours and stained with Gram stain. Phagocytic activity of the host cells on P. aeruginosa was done by exposing the extract to the mouse peritoneal macrophages, then the phagocytosed bacteria were counted after Giemsa staining. Statistical test results from the three experiments showed significant differences between the test groups compared to the control groups (p <0.05). It was concluded that the red onion-skin ethanolic extract not only affects P. aeruginosa by reducing swarming motility and preventing bacterial adhesion to buccal epithelial cells, but also induces the host cells by increasing the ability of macrophage phagocytosis to these bacteria.
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Gou, Yi, Weiqi Liu, Jing Jing Wang, Ling Tan, Bin Hong, Linxia Guo, Haiquan Liu, Yingjie Pan, and Yong Zhao. "CRISPR-Cas9 knockout of qseB induced asynchrony between motility and biofilm formation in Escherichia coli." Canadian Journal of Microbiology 65, no. 9 (September 2019): 691–702. http://dx.doi.org/10.1139/cjm-2019-0100.
Повний текст джерелаАнотація:
Generally, cell motility and biofilm formation are tightly regulated. The QseBC two-component system (TCS) serves as a bridge for bacterial signal transmission, in which the protein QseB acts as a response regulator bacterial motility, biofilm formation, and virulence. The mechanisms that govern the interaction between QseBC and their functions have been studied in general, but the regulatory role of QseB on bacterial motility and biofilm formation is unknown. In this study, the CRISPR-Cas9 system was used to construct the Escherichia coli MG1655ΔqseB strain (strain ΔqseB), and the effects of the qseB gene on changes in motility and biofilm formation in the wild type (WT) were determined. The motility assay results showed that the ΔqseB strain had higher (p < 0.05) motility than the WT strain. However, there was no difference in the formation of biofilm between the ΔqseB and WT strains. Real-time quantitative PCR illustrated that deletion of qseB in the WT strain downregulated expression of the type I pili gene fimA. Therefore, we might conclude that the ΔqseB induced the downregulation of fimA, which led to asynchrony between motility and biofilm formation in E. coli, providing new insight into the functional importance of QseB in regulating cell motility and biofilm formation.
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Shrout, Joshua D., Tim Tolker-Nielsen, Michael Givskov, and Matthew R. Parsek. "The contribution of cell-cell signaling and motility to bacterial biofilm formation." MRS Bulletin 36, no. 5 (May 2011): 367–73. http://dx.doi.org/10.1557/mrs.2011.67.
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Achouri, Sarra, John A. Wright, Lewis Evans, Charlotte Macleod, Gillian Fraser, Pietro Cicuta, and Clare E. Bryant. "The frequency and duration of Salmonella –macrophage adhesion events determines infection efficiency." Philosophical Transactions of the Royal Society B: Biological Sciences 370, no. 1661 (February 5, 2015): 20140033. http://dx.doi.org/10.1098/rstb.2014.0033.
Повний текст джерелаАнотація:
Salmonella enterica causes a range of important diseases in humans and a in a variety of animal species. The ability of bacteria to adhere to, invade and survive within host cells plays an important role in the pathogenesis of Salmonella infections. In systemic salmonellosis, macrophages constitute a niche for the proliferation of bacteria within the host organism. Salmonella enterica serovar Typhimurium is flagellated and the frequency with which this bacterium collides with a cell is important for infection efficiency. We investigated how bacterial motility affects infection efficiency, using a combination of population-level macrophage infection experiments and direct imaging of single-cell infection events, comparing wild-type and motility mutants. Non-motile and aflagellate bacterial strains, in contrast to wild-type bacteria, collide less frequently with macrophages, are in contact with the cell for less time and infect less frequently. Run-biased Salmonella also collide less frequently with macrophages but maintain contact with macrophages for a longer period of time than wild-type strains and infect the cells more readily. Our results suggest that uptake of S. Typhimurium by macrophages is dependent upon the duration of contact time of the bacterium with the cell, in addition to the frequency with which the bacteria collide with the cell.
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DeHart, Tanner G., Mara R. Kushelman, Sherry B. Hildreth, Richard F. Helm, and Brandon L. Jutras. "The unusual cell wall of the Lyme disease spirochaete Borrelia burgdorferi is shaped by a tick sugar." Nature Microbiology 6, no. 12 (November 24, 2021): 1583–92. http://dx.doi.org/10.1038/s41564-021-01003-w.
Повний текст джерелаАнотація:
AbstractPeptidoglycan—a mesh sac of glycans that are linked by peptides—is the main component of bacterial cell walls. Peptidoglycan provides structural strength, protects cells from osmotic pressure and contributes to shape. All bacterial glycans are repeating disaccharides of N-acetylglucosamine (GlcNAc) β-(1–4)-linked to N-acetylmuramic acid (MurNAc). Borrelia burgdorferi, the tick-borne Lyme disease pathogen, produces glycan chains in which MurNAc is occasionally replaced with an unknown sugar. Nuclear magnetic resonance, liquid chromatography–mass spectroscopy and genetic analyses show that B. burgdorferi produces glycans that contain GlcNAc–GlcNAc. This unusual disaccharide is chitobiose, a component of its chitinous tick vector. Mutant bacteria that are auxotrophic for chitobiose have altered morphology, reduced motility and cell envelope defects that probably result from producing peptidoglycan that is stiffer than that in wild-type bacteria. We propose that the peptidoglycan of B. burgdorferi probably evolved by adaptation to obligate parasitization of a tick vector, resulting in a biophysical cell-wall alteration to withstand the atypical torque associated with twisting motility.
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Diep, Tai The, Sarah Helen Needs, Samuel Bizley, and Alexander D. Edwards. "Rapid Bacterial Motility Monitoring Using Inexpensive 3D-Printed OpenFlexure Microscopy Allows Microfluidic Antibiotic Susceptibility Testing." Micromachines 13, no. 11 (November 14, 2022): 1974. http://dx.doi.org/10.3390/mi13111974.
Повний текст джерелаАнотація:
Antibiotic susceptibility testing is vital to tackle the emergence and spread of antimicrobial resistance. Inexpensive digital CMOS cameras can be converted into portable digital microscopes using 3D printed x-y-z stages. Microscopic examination of bacterial motility can rapidly detect the response of microbes to antibiotics to determine susceptibility. Here, we present a new simple microdevice-miniature microscope cell measurement system for multiplexed antibiotic susceptibility testing. The microdevice is made using melt-extruded plastic film strips containing ten parallel 0.2 mm diameter microcapillaries. Two different antibiotics, ceftazidime and gentamicin, were prepared in Mueller-Hinton agar (0.4%) to produce an antibiotic-loaded microdevice for simple sample addition. This combination was selected to closely match current standard methods for both antibiotic susceptibility testing and motility testing. Use of low agar concentration permits observation of motile bacteria responding to antibiotic exposure as they enter capillaries. This device fits onto the OpenFlexure 3D-printed digital microscope using a Raspberry Pi computer and v2 camera, avoiding need for expensive laboratory microscopes. This inexpensive and portable digital microscope platform had sufficient magnification to detect motile bacteria, yet wide enough field of view to monitor bacteria behavior as they entered antibiotic-loaded microcapillaries. The image quality was sufficient to detect how bacterial motility was inhibited by different concentrations of antibiotic. We conclude that a 3D-printed Raspberry Pi-based microscope combined with disposable microfluidic test strips permit rapid, easy-to-use bacterial motility detection, with potential for aiding detection of antibiotic resistance.
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Treuner-Lange, Anke, Eric Macia, Mathilde Guzzo, Edina Hot, Laura M. Faure, Beata Jakobczak, Leon Espinosa, et al. "The small G-protein MglA connects to the MreB actin cytoskeleton at bacterial focal adhesions." Journal of Cell Biology 210, no. 2 (July 13, 2015): 243–56. http://dx.doi.org/10.1083/jcb.201412047.
Повний текст джерелаАнотація:
In Myxococcus xanthus the gliding motility machinery is assembled at the leading cell pole to form focal adhesions, translocated rearward to propel the cell, and disassembled at the lagging pole. We show that MglA, a Ras-like small G-protein, is an integral part of this machinery. In this function, MglA stimulates the assembly of the motility complex by directly connecting it to the MreB actin cytoskeleton. Because the nucleotide state of MglA is regulated spatially and MglA only binds MreB in the guanosine triphosphate–bound form, the motility complexes are assembled at the leading pole and dispersed at the lagging pole where the guanosine triphosphatase activating protein MglB disrupts the MglA–MreB interaction. Thus, MglA acts as a nucleotide-dependent molecular switch to regulate the motility machinery spatially. The function of MreB in motility is independent of its function in peptidoglycan synthesis, representing a coopted function. Our findings highlight a new function for the MreB cytoskeleton and suggest that G-protein–cytoskeleton interactions are a universally conserved feature.
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McMahon, Sean G., Stephen B. Melville, and Jing Chen. "Mechanical limitations of bacterial motility mediated by growing cell chains." Biophysical Journal 121, no. 3 (February 2022): 403a. http://dx.doi.org/10.1016/j.bpj.2021.11.750.
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McBride, Mark J. "Bacterial Gliding Motility: Multiple Mechanisms for Cell Movement over Surfaces." Annual Review of Microbiology 55, no. 1 (October 2001): 49–75. http://dx.doi.org/10.1146/annurev.micro.55.1.49.
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Casida Jr., L. E. "Arthrobacter species as a prey cell reservoir for nonobligate bacterial predators in soil." Canadian Journal of Microbiology 35, no. 5 (May 1, 1989): 559–64. http://dx.doi.org/10.1139/m89-089.
Повний текст джерелаАнотація:
The possibility was investigated that, in soil, Arthrobacter species might serve as a major reservoir of prey cells for the nonobligate bacterial predators in the soil. Previous evidence had indicated this. Arthrobacter globiformis cells added to soil caused an increase in the total bacterial count and the gram-negative bacteria count of the soil. Copper-resistant bacterial predators, such as Cupriavidus necator, also increased in number, apparently in response to the A. globiformis cells. Other bacterial predators did not respond to A. globiformis. Certain soil bacteria responded specifically and quickly (within 2.5 h) to the A. globiformis cell additions. They had gliding motility and could hydrolyze GELRITE (the solidifying agent for media). Addition of these hydrolyzer bacteria to soil caused marked increases in the total bacteria count, the gram-negative bacteria count, and the bacterial predator counts. These responses mimicked those for A. globiformis soil additions. The results from an alternative method of soil incubation that speeded up the processes, and from other observations, indicated that the large apparent bacterial predator attack on A. globiformis in soil may actually be on other bacteria in soil that respond to A. globiformis in a nonpredatory manner. Therefore, A. globiformis and other Arthrobacter species may not be serving as a major reservoir of prey cells in soil.Key words: predation, predators, prey, soil, Arthrobacter.
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Ishimoto, Kenta. "Bacterial spinning top." Journal of Fluid Mechanics 880 (October 10, 2019): 620–52. http://dx.doi.org/10.1017/jfm.2019.714.
Повний текст джерелаАнотація:
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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Wang, Jiahui, Jane E. King, Marie Goldrick, Martin Lowe, Frank B. Gertler, and Ian S. Roberts. "Lamellipodin Is Important for Cell-to-Cell Spread and Actin-Based Motility in Listeria monocytogenes." Infection and Immunity 83, no. 9 (July 13, 2015): 3740–48. http://dx.doi.org/10.1128/iai.00193-15.
Повний текст джерелаАнотація:
Listeria monocytogenesis a foodborne pathogen capable of invading a broad range of cell types and replicating within the host cell cytoplasm. This paper describes the colocalization of host cell lamellipodin (Lpd) with intracellularL. monocytogenesdetectable 6 h postinfection of epithelial cells. The association was mediated via interactions between both the peckstrin homology (PH) domain in Lpd and phosphatidylinositol (3,4)-bisphosphate [PI(3,4)P2] on the bacterial surface and by interactions between the C-terminal EVH1 (Ena/VASP [vasodilator-stimulated phosphoprotein] homology domain 1) binding domains of Lpd and the host VASP (vasodilator-stimulated phosphoprotein) recruited to the bacterial cell surface by the listerial ActA protein. Depletion of Lpd by short interfering RNA (siRNA) resulted in reduced plaque size and number, indicating a role for Lpd in cell-to-cell spread. In contrast, overexpression of Lpd resulted in an increase in the number ofL. monocytogenes-containing protrusions (listeriopods). Manipulation of the levels of Lpd within the cell also affected the intracellular velocity ofL. monocytogenes, with a reduction in Lpd corresponding to an increase in intracellular velocity. These data, together with the observation that Lpd accumulated at the interface between the bacteria and the developing actin tail at the initiation of actin-based movement, indicate a possible role for Lpd in the actin-based movement and the cell-to-cell spread ofL. monocytogenes.
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Geese, Marcus, Joseph J. Loureiro, James E. Bear, Jürgen Wehland, Frank B. Gertler, and Antonio S. Sechi. "Contribution of Ena/VASP Proteins to Intracellular Motility ofListeriaRequires Phosphorylation and Proline-rich Core but Not F-Actin Binding or Multimerization." Molecular Biology of the Cell 13, no. 7 (July 2002): 2383–96. http://dx.doi.org/10.1091/mbc.e02-01-0058.
Повний текст джерелаАнотація:
The Listeria model system has been essential for the identification and characterization of key regulators of the actin cytoskeleton such as the Arp2/3 complex and Ena/vasodilator-stimulated phosphoprotein (VASP) proteins. Although the role of Ena/VASP proteins in Listeria motility has been extensively studied, little is known about the contributions of their domains and phosphorylation state to bacterial motility. To address these issues, we have generated a panel of Ena/VASP mutants and, upon expression in Ena/VASP-deficient cells, evaluated their contribution to Ena/VASP function in Listeria motility. The proline-rich region, the putative G-actin binding site, and the Ser/Thr phosphorylation of Ena/VASP proteins are all required for efficientListeria motility. Surprisingly, the interaction of Ena/VASP proteins with F-actin and their potential ability to form multimers are both dispensable for their involvement in this process. Our data suggest that Ena/VASP proteins contribute toListeria motility by regulating both the nucleation and elongation of actin filaments at the bacterial surface.
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Yang, Zhaomin, Xiaoyuan Ma, Leming Tong, Heidi B. Kaplan, Lawrence J. Shimkets, and Wenyuan Shi. "Myxococcus xanthus dif Genes Are Required for Biogenesis of Cell Surface Fibrils Essential for Social Gliding Motility." Journal of Bacteriology 182, no. 20 (October 15, 2000): 5793–98. http://dx.doi.org/10.1128/jb.182.20.5793-5798.2000.
Повний текст джерелаАнотація:
ABSTRACT Myxococcus xanthus social (S) gliding motility has been previously reported by us to require the chemotaxis homologues encoded by the dif genes. In addition, two cell surface structures, type IV pili and extracellular matrix fibrils, are also critical to M. xanthus S motility. We have demonstrated here that M. xanthus dif genes are required for the biogenesis of fibrils but not for that of type IV pili. Furthermore, the developmental defects of dif mutants can be partially rescued by the addition of isolated fibril materials. Along with the chemotaxis genes of various swarming bacteria and the pilGHIJ genes of the twitching bacteriumPseudomonas aeruginosa, the M. xanthus dif genes belong to a unique class of bacterial chemotaxis genes or homologues implicated in the biogenesis of structures required for bacterial surface locomotion. Genetic studies indicate that the dif genes are linked to theM. xanthus dsp region, a locus known to be crucial forM. xanthus fibril biogenesis and S gliding.
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Dragoi, Ana-Maria, Arthur M. Talman, and Hervé Agaisse. "Bruton's Tyrosine Kinase Regulates Shigella flexneri Dissemination in HT-29 Intestinal Cells." Infection and Immunity 81, no. 2 (December 10, 2012): 598–607. http://dx.doi.org/10.1128/iai.00853-12.
Повний текст джерелаАнотація:
ABSTRACTShigella flexneriis a Gram-negative intracellular pathogen that infects the intestinal epithelium and utilizes actin-based motility to spread from cell to cell.S. flexneriactin-based motility has been characterized in various cell lines, but studies in intestinal cells are limited. Here we characterizedS. flexneriactin-based motility in HT-29 intestinal cells. In agreement with studies conducted in various cell lines, we showed thatS. flexnerirelies on neural Wiskott-Aldrich Syndrome protein (N-WASP) in HT-29 cells. We tested the potential role of various tyrosine kinases involved in N-WASP activation and uncovered a previously unappreciated role for Bruton's tyrosine kinase (Btk) in actin tail formation in intestinal cells. We showed that Btk depletion led to a decrease in N-WASP phosphorylation which affected N-WASP recruitment to the bacterial surface, decreased the number of bacteria displaying actin-based motility, and ultimately affected the efficiency of spread from cell to cell. Finally, we showed that the levels of N-WASP phosphorylation and Btk expression were increased in response to infection, which suggests thatS. flexneriinfection not only triggers the production of proinflammatory factors as previously described but also manipulates cellular processes required for dissemination in intestinal cells.
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Lacayo, Catherine I., and Julie A. Theriot. "Listeria monocytogenesActin-based Motility Varies Depending on Subcellular Location: A Kinematic Probe for Cytoarchitecture." Molecular Biology of the Cell 15, no. 5 (May 2004): 2164–75. http://dx.doi.org/10.1091/mbc.e03-10-0747.
Повний текст джерелаАнотація:
Intracellular Listeria monocytogenes actin-based motility is characterized by significant individual variability, which can be influenced by cytoarchitecture. L. monocytogenes was used as a probe to transmit information about structural variation among subcellular domains defined by mitochondrial density. By analyzing the movement of a large population of L. monocytogenes in PtK2 cells, we found that mean speed and trajectory curvature were significantly larger for bacteria moving in mitochondria-containing domains (generally perinuclear) than for bacteria moving in mitochondria-free domains (generally peripheral). Analysis of bacteria that traversed both mitochondria-containing and mitochondria-free domains revealed that these motile differences were not intrinsic to bacteria themselves. Disruption of mitochondrial respiration did not affect bacterial mean speed, speed persistence, or trajectory curvature. In contrast, microtubule depolymerization lead to decreased mean speed per bacterium and increased mean speed persistence of L. monocytogenes moving in mitochondria-free domains compared with untreated cells. L. monocytogenes were also observed to physically collide with mitochondria and push them away from the bacterial path of motion, causing bacteria to slow down before rapidly resuming their speed. Our results show that subcellular domains along with microtubule depolymerization may influence the actin cytoskeleton to affect L. monocytogenes speed, speed persistence, and trajectory curvature.
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Ivanković, Tomislav, Uzi Hadad, Ariel Kushmaro, Svjetlana Dekić, Josipa Ćevid, Marko Percela, and Jasna Hrenović. "Capillary bacterial migration on non-nutritive solid surfaces." Archives of Industrial Hygiene and Toxicology 71, no. 3 (September 1, 2020): 251–60. http://dx.doi.org/10.2478/aiht-2020-71-3436.
Повний текст джерелаАнотація:
AbstractHere we describe an additional type of bacterial migration in which bacterial cells migrate vertically across a non-nutritive solid surface carried by capillary forces. Unlike standard motility experiments, these were run on a glass slide inserted into a Falcon tube, partly immersed in a nutrient medium and partly exposed to air. Observations revealed that capillary forces initiated upward cell migration when biofilm was formed at the border between liquid and air. The movement was facilitated by the production of extracellular polymeric substances (EPS). This motility differs from earlier described swarming, twitching, gliding, sliding, or surfing, although these types of movements are not excluded. We therefore propose to call it “capillary movement of biofilm”. This phenomenon may be an ecologically important mode of bacterial motility on solid surfaces.
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Madkour, Mohamed H. F., and Frank Mayer. "Intracellular Cytoskeletal Elements and Cytoskeletons in Bacteria." Science Progress 90, no. 2-3 (July 2007): 73–102. http://dx.doi.org/10.3184/003685007x215913.
Повний текст джерелаАнотація:
Within a short period of time after the discovery of bacterial cytoskletons, major progress had been made in areas such as general spatial layout of cytoskeletons, their involvement in a variety of cell functions (shape control, cell division, chromosome segregation, cell motility). This progress was achieved by application of advanced investigation techniques. Homologs of eukaryotic actin, tubulin, and intermediate filaments were found in bacteria; cytoskeletal proteins not closely or not at all related to any of these major cytoskeletal proteins were discovered in a number of bacteria such as Mycoplasmas, Spiroplasmas, Spirochetes, Treponema, Caulobacter. A structural role for bacterial elongation factor Tu was indicated. On the basis of this new thinking, new approaches in biotechnology and new drugs are on the way.
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Simms, Amy N., and Harry L. T. Mobley. "PapX, a P Fimbrial Operon-Encoded Inhibitor of Motility in Uropathogenic Escherichia coli." Infection and Immunity 76, no. 11 (August 18, 2008): 4833–41. http://dx.doi.org/10.1128/iai.00630-08.
Повний текст джерелаАнотація:
ABSTRACT Motility and adherence are two integral aspects of bacterial pathogenesis. Adherence, often mediated by fimbriae, permits bacteria to attach to host cells and establish infection, whereas flagellum-driven motility allows bacteria to disseminate to sites more advantageous for colonization. Both fimbriae and flagella have been proven important for virulence of uropathogenic Escherichia coli (UPEC). Reciprocal regulation is one mechanism by which bacteria may reconcile the contradictory actions of adherence and motility. PapX, a P fimbrial gene product of UPEC strain CFT073, is a functional homolog of MrpJ of Proteus mirabilis; ectopic expression of papX in P. mirabilis reduces motility. To define the connection between P fimbria expression and motility in UPEC, the role of papX in the regulation of motility of strain CFT073 was examined. Overexpression of papX decreased motility of CFT073, which correlated with both a significant reduction in flagellin protein synthesized and flagella assembled on the cell surface. Conversely, an increase in motility and flagellin production was seen in an isogenic papX deletion mutant of CFT073. Microarray and quantitative reverse transcription-PCR analysis indicated that repression of motility of CFT073 by PapX appears to occur at the transcriptional level; expression of many motility-associated genes, including flhDC, the master regulator of motility, is decreased when papX is overexpressed. Transcription of motility genes is increased in the papX mutant compared to wild type. Electrophoretic mobility gel shift analysis revealed that PapX binds to the flhD promoter. We conclude that synthesis of P fimbriae regulates flagellum synthesis to repress motility via PapX.
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Bennett, Rachel R., Calvin K. Lee, Jaime De Anda, Kenneth H. Nealson, Fitnat H. Yildiz, George A. O'Toole, Gerard C. L. Wong, and Ramin Golestanian. "Species-dependent hydrodynamics of flagellum-tethered bacteria in early biofilm development." Journal of The Royal Society Interface 13, no. 115 (February 2016): 20150966. http://dx.doi.org/10.1098/rsif.2015.0966.
Повний текст джерелаАнотація:
Monotrichous bacteria on surfaces exhibit complex spinning movements. Such spinning motility is often a part of the surface detachment launch sequence of these cells. To understand the impact of spinning motility on bacterial surface interactions, we develop a hydrodynamic model of a surface-bound bacterium, which reproduces behaviours that we observe in Pseudomonas aeruginosa , Shewanella oneidensis and Vibrio cholerae , and provides a detailed dictionary for connecting observed spinning behaviour to bacteria–surface interactions. Our findings indicate that the fraction of the flagellar filament adhered to the surface, the rotation torque of this appendage, the flexibility of the flagellar hook and the shape of the bacterial cell dictate the likelihood that a microbe will detach and the optimum orientation that it should have during detachment. These findings are important for understanding species-specific reversible attachment, the key transition event between the planktonic and biofilm lifestyle for motile, rod-shaped organisms.