Bacterial Motility

12 Key excerpts on "Bacterial Motility"

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  Biofilms and Implantable Medical Devices

  Infection and Control

  • Ying Deng, Wei Lv(Authors)
  • 2016(Publication Date)
  • Woodhead Publishing

    (Publisher)

  Prior to adherence, bacteria must locate and physically make contact with a surface. Motility plays a key role in this initial step and is influenced by Brownian motion and the production of appendages that directly facilitate movement through fluids. Flagella are flexible, motor-based, filamentous appendages that utilize the flux of ions to rotate and propel bacteria through fluids (known as swimming motility) or enable gliding across a surface (known as swarming motility). Besides flagella, bacteria may harbor specific types of flexible adhesive fibers (pili) that can facilitate motility across a surface via a combination of adhesive properties and dynamic pilus movement. The different types of motility are described in greater detail below.

  3.2.1. Brownian motion

  Brownian motion is the random, uncontrolled movement of particles in a fluid as they constantly collide with other molecules (Mitchell and Kogure, 2006 ). Brownian motion is in part responsible for facilitating movement in bacteria that do not encode or express motility appendages, such as Streptococcus and Klebsiella species. Brownian motion can also affect “deliberate” movement exhibited by inherently motile bacteria that harbor pili or flagella. For example, an Escherichia coli cell that is swimming toward an area of higher oxygen concentration may fall “off-track” if it physically encounters a particle moving by Brownian motion or if such a particle(s) obstructs the bacterial cell’s path of motion. This form of “interference” adds to the stochasticity with which bacterial direction can change.

  3.2.2. Flagellar motility

  Anton van Leeuwenhoek first described bacterial flagella in 1675, and many bacterial species elaborate at least one flagellum to move through liquid environments (Berg and Anderson, 1973 ). A typical bacterial flagellum consists of three parts: the basal body, the hook, and the flexible filament (Berg and Anderson, 1973 ). The flexible filament, which can be made up of 20,000 flagellin subunits, can extend out nearly three times the length of the bacterial cell (Macnab, 2003 ). In some bacteria, such as Vibrio cholerae and Helicobacter pylori , the flagellar filament may have an additional external sheath. In the stomach pathogen H. pylori , this external sheath is an extension of the outer membrane and is thought to protect the acid-labile flagellar structure from attack by stomach acid (Geis et al., 1993

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  Structure

  • I.C. Gunsalus(Author)
  • 1960(Publication Date)
  • Academic Press

    (Publisher)

  154 CLAES WEIBULL spirochetes, fibrils winding tightly around the entire bacterial body. Capa-bility of locomotion is, however, also observed in the Myxobacteriales, the Beggiatoaceae, and in some fusobacteria, in spite of the fact that no well-defined motor organs have been revealed, not even with the aid of the elec-tron microscope. 1 3 The speed that these organisms may attain is rather moderate, not more than 5 microns per second 4 · 5 whereas flagellated or-ganisms may travel more than 50 microns per second. 68 The former kind of locomotion is generally referred to as gliding movement. Bacterial Motility has been extensively studied by means of direct observations and measurements, but many fundamental questions remain unsolved. This is no doubt to a great extent due to the limitations of the available experimental techniques, especially the microcinematographic methods. Another method used for attacking the motility problem has been the construction and testing of large-scale models but, unfortunately, it has sometimes not been taken into account that the hydrodynamic forces acting on microorganisms and macroscopic objects are different. 9,10 In the following the behavior of moving microorganisms will first be dis-cussed from a theoretical point of view. The inferences obtained will then be related to the empirical studies that have been carried out on various kinds of bacterial movements. Morphological, biochemical, and physiologi-cal facts that have a bearing on the motility problem will also be taken into account. II. Theoretical Aspects of the Movements of Bacteria A. HYDRODYNAMIC THEORY Attempts at treating the propulsion of microorganisms theoretically were made early 11 · 12 but not until recently have the hydrodynamics of such bodies been considered in detail. During the last few years, however, hydro-dynamical analyses of the swimming of microorganisms have been carried out by Taylor, 9 · 13 Hancock, 10 and Gray and Hancock.

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  Handbook of Cyanobacteria

  • T. A. Sarma(Author)
  • 2012(Publication Date)
  • CRC Press

    (Publisher)

  MOVEMENTS C HAPTER C HAPTER 5 I. TYPES OF MOVEMENTS 283 A) Gliding motility B) Swimming C) Twitching movements II. PHOTOTAXIS 293 A) Action spectra and nature of photoreceptors B) Pix-genes and mechanism of phototaxis Motility confers on the microorganisms the ability to survive in their natural habitats. In order to cope up with environmental conditions of excess or deficiency of light/nutrients (or chemicals) the microorganisms exhibit necessary adjusting movements. The first organ of motility that attracted the attention of Bacterial Motility is flagella. Ever since the discovery of bacteria it has served as an important taxonomic trait to distinguish bacterial species. Motility due to flagella is present in both eubacteria and archaebacteria. The bacterial flagella are composed of three parts, a basal body, the hook and the filament. The basal body acts as the motor, the hook joins the filament to the basal body and the filament acts as the propeller. The filament is composed of many thousands of molecules of a single protein known as flagellin and assumes a diameter of 20 nm. There are certain subtle differences between the organization of the proteins of the motor of eubacteria and archaebacteria. Moreover, the polar and lateral flagella differ in their structure while the former is sheathed and thicker the latter is unsheathed and thinner. In spirochetes the flagella are unusually located internally in the periplasmic space. Type IV pili (Tfp), junctional pore complex (JPC), ratchet structure and contractile cytoskeleton are the other motility structures present in eubacteria (Bardy et al ., 2003). The movements associated with Tfp are known as twitching movements. Pseudomonas aeruginosa and Neisseria gonorrhoeae are the classical examples that exhibit twitching movements. The myxobacterium Myxococcus xanthus exhibits two types of gliding motion, i.e. social gliding 282 Handbook of Cyanobacteria and adventurous gliding.

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  Keywords of Mobility

  Critical Engagements

  • Noel B. Salazar, Kiran Jayaram, Noel B. Salazar, Kiran Jayaram(Authors)
  • 2016(Publication Date)
  • Berghahn Books

    (Publisher)

  CHAPTER        7

  Motility

  Hege Høyer Leivestad

  Widely used in biology, the term motility, as referring to a potential to move, found its way into the social science literature more than a decade ago. Not least through the work of sociologist Kaufmann and colleagues (2002; 2004; 2008; and 2011), who use it as a means to understand human actors’ “capacities to move both socially and spatially.” When diving into the rapidly expanding interdisciplinary mobility literature, one finds that motility is increasingly applied in reference to human ability or potential to move, partly due to its inclusion in the “new mobilities paradigm” (Hannam, Sheller, and Urry 2006; Sheller 2011; Sheller and Urry 2006; Urry 2003, 2007; see Glick Schiller and Salazar 2013 for a critique).

  Etymologically, the noun “motility,” stemming from the Latin motus, can be traced back to the mid nineteenth century and is defined as “capacity of movement.” The adjective form is motile, meaning “capable of movement.”1 Motility has mostly been used as a biological concept, for instance in zoology and botany, to explain cells’ and single-celled organisms’ capability to move. According to Oxford Dictionaries, the concept can also be found within psychology, where it relates to responses that involve muscular sensations (as opposed to audiovisual). As a biological term, it is frequently used to explain gastric or gastrointestinal motility that refers to the movement of food from the mouth, through the inner parts of the body and out.

  When thinking of “movement” in the way that social scientists usually do, motility appears as a rather unfamiliar term. Because of an analytical need of finding new concepts for tackling the gap between mobility and immobility, motility emerges, I argue, as a concept able to identify the incompleteness of mobility. The keyword motility thus indicates a pinning down of one of mobility’s central elements; namely potential. Motility’s relative unfamiliarity makes room for, I suggest, a more general exploration of the concept’s trajectories and its analytical value for studies of mobility. Tracing motility’s trajectories from its origins in biological locomotion to a tool for understanding and theorizing multifaceted human (im)mobilities, this chapter critically engages with how notions of freedom and individual agency have assumed key roles in its conceptualization. Motility can nevertheless provide, I assert, a productive platform for thinking about human appropriation of both social and spatial mobility (Kaufmann 2002; Kellerman 2012).

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  Bacterial Energetics

  A Treatise on Structure and Function

  • Terry Krulwich(Author)
  • 2012(Publication Date)
  • Academic Press

    (Publisher)

  THE BACTERIA, VOL. XII CHAPTER 11 Motility SHAHID KHAN Departments of Anatomy and Structural Biology & Physiology and Biophysics. Albert Einstein College of Medicine, Bronx, New York 10461 I. Introduction 301 II. Mechanics 302 A. Cell Propulsion 302 B. Measurement 305 C. Motor Dynamics 310 III. Energetics 311 A. Techniques 312 B. Energy Relations 314 IV. Structure 320 A. Filament 321 B. Basal Ends 323 V. Mechanism 328 A. Concepts 328 B. Prospects 332 VI. Summary 333 References 334 I. Introduction Bacterial movement is engagingly diverse. Bacteria swim, roll, glide, flex, screw, and tumble. Ingenious instrumentation has been devised for studying the mechanics of their motion. Genetic and chemical methods are being developed for study of the molecular mechanism. The organelles for locomotion, flagella, comprise rigid helical filaments, connected by a flexible coupling, the hook, to tiny rotary motors embedded in the cytoplasmic membrane. There is a univer- sality of energy source, even though, in some, the locomotory organelles await identification. Transmembrane ion gradients energize all known forms of bacte- rial motility: in sharp distinction to eukaryotes where motility depends on ATP. The remarkable rotary motion and unique nature of the energy coupling puts Bacterial Motility in a special class among problems in bioenergetics. It is re- viewed here in this context. Several excellent reviews on mechanics and phys- iology (Canale-Parola, 1978; Berg et al, 1982; Pate, 1988), genetics and struc- ture (lino, 1977; Simon et al, 1978; Macnab, 1987a,b; Shapiro, 1985; Eisenbach, 1990) are available. These should be consulted for a critique of early 301 Copyright © 1990 by Academic Press, Inc. All rights of reproduction in any form reserved. 302 SHAHID KHAN work, the nature of the evidence for motor rotation, and questions concerned with expression and assembly of the flagellar apparatus.

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  The Perfect Slime

  Microbial Extracellular Polymeric Substances (EPS)

  • Hans-Curt Flemming, Thomas R. Neu, Jost Wingender(Authors)
  • 2016(Publication Date)
  • IWA Publishing

    (Publisher)

  Some planktonic cells swim in quest of better environments, such as a new interface to conquer. Once associated to a surface, bacteria move to spread and compete for space and nutrients with Chapter 9 Travelling through slime – bacterial movements in the EPS matrix 180 The Perfect Slime other biofilm inhabitants. Associated in the biofilm EPS, they move passively during biofilm expansion and under shear stress. Bacteria have developed a wealth of strategies to keep moving in these different environments; they can swim, glide, swarm, oscillate, vibe (Kearns, 2010). Some of these movements involve specific extracellular molecular effectors including flagella, pili, polysaccharides, surfactant or enzymes. Of particular interest for this review are flagella which are rigid extracellular helical filaments that propel motile cells by rotation in a liquid volume (swimming) or across a solid surface (swarming). In liquid, motile cell velocity can reach up to 160 µ m/s. Individual cell trajectory is not continuous, and involves a succession of cell runs and tumbles: a cell swims in one direction for a short period ( ≈ 1 s), moves erratically for a small fraction of second, and then swims steadily again in a different direction (Berg, 1973). The direction is not random, it results from the integration of signals generated by extracellular sensors that reckon the amount of molecules of interest in the surrounding microenvironment and their gradients (chemotaxis); cells go where grass is greener (Sourjik et al. 2004). Flagella appear at distinct location and in numbers that are characteristic of each bacterial species and of its corresponding environment: polar flagella are required for fast swimming in liquid ( Pseudomonas aeruginosa, Helicobacter pylori, Campylobacter jejuni ), and peritrichous flagellation (Figure 9.1) for moving through more viscous environments or over surfaces ( Escherichia coli, Bacillus subtilis) (Martinez et al. 2014; Schuhmacher et al. 2015).

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  Beneficial Plant-microbial Interactions

  Ecology and Applications

  • M. Belén Rodelas González, Jesús Gonzalez-López, M. Belén Rodelas González, Jesús Gonzalez-Lopez, M. Belén Rodelas González, Jesús Gonzalez-Lopez(Authors)
  • 2016(Publication Date)
  • CRC Press

    (Publisher)

  Moreover, motility is regulated at several levels, including transcriptional control of flagellar genes and signal-transduction cascades that govern chemotaxis. Flagella are regarded as an important virulence factor in bacterial pathogenesis, mainly because of their role in motility and chemotaxis, which is critical for colonization, penetration and invasion of tissues. However, recent evidence has denoted that the bacterial flagella participate in numerous additional processes, by acting as bacterial adhesins, promoting bacterial biofilm formation, translocating virulence proteins into host cells via special type III secretion systems, and triggering host immune responses through the Toll-like receptor signalling pathway (reviewed by Duan et al. 2012). Therefore, flagella might be involved in pathogenicity not just by enabling Bacterial Motility but also through other complex mechanisms. Biofilms are assemblages of microorganisms enclosed in a matrix that function as a cooperative consortium. In the mature biofilm, cells are enclosed in an extracellular matrix composed of proteins, exopolysaccharides and extracellular DNA (eDNA) (Flemming and Wingender 2010). In addition to immobilizing the bacteria, the matrix is a scaffold that traps nutrients and various biologically active molecules, such as cell-cell communication signals. The matrix may resemble an external digestion system, as it also accumulates enzymes that can degrade various matrix components as well as any nutrients or other substrates; once degraded, the products are then in close proximity to the cells, facilitating uptake. Moreover, the matrix acts as a shield against toxins, antimicrobials and predators. Microscopic studies reveal that biofilm formation occurs in a sequential process including transport of bacteria to a surface, initial attachment, formation of microcolonies and biofilm maturation (Tolker-Nielsen et al. 2000, Sauer et al. 2002).

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  Further Milestones in Biochemistry

  • M.G. Ord, L.A. Stocken(Authors)
  • 1997(Publication Date)
  • Elsevier Science

    (Publisher)

  This illustrates the change in approach to research, from the enthusiastic amateur through the early professional scientist with a broad based view of biology to the modern teams dissecting problems at a molecular level, and perhaps sometimes losing sight of the foundation of their research—bacterial swimming—in the minutia of genes and proteins. What is apparent is that the majority of us work away producing little snippets of data to add to the pile, while every now and then someone comes along and looks at the problem from a different angle and, often by means of a simple experiment, makes that great leap forward that can only leave the majority of us feeling suitably humble. Bacterial Motility 109 THEBIRTHOFASUBJEa It is arguable that the birth of bacteriology as a subject was completely dependent on bacterial swimming. There may be upwards of a million different bacteria species, a large percentage of them motile. If they hadn't been motile, the discovery of bacteria, the oldest of the living domains, would have had to wait at least another century, rather as if Captain James Cook had missed Australia and it had taken another century for an explorer to reach the largest of the free continents. The deliberate swimming movements of tiny particles in pepper water seen by Antony van Leeuwenhoek^ in 1676 convinced him he was looking at very little animalcules. The detailed descriptions and measurements of larger protozoa makes it more or less certain that he was looking at motile bacteria, and in all his experiments he used active movement as the definition of life. His descriptions show that he was well aware of the differences between what we now know as Brownian motion and deliberate swimming. [All the descriptions of Leeuwenhoek's work comes from an excellent biography and translation of his letters written in 1932 by C. Dobell (Dobell, 1932).] Leeuwenhoek was in many ways a very unusual man to be one of the founding fathers of a branch of science.

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  Ecology and Biomechanics

  A Mechanical Approach to the Ecology of Animals and Plants

  • Anthony Herrel, Thomas Speck, Nicholas P. Rowe, Anthony Herrel, Thomas Speck, Nicholas P. Rowe(Authors)
  • 2006(Publication Date)
  • CRC Press

    (Publisher)

  However, as the topic is generally well described (see Refs. [104,105] as well as the comprehensive introductions in Refs. [106,107]), I restrict myself to a brief overview here. Bacteria are so small and swim at such low velocities that swimming in a straight path is made impossible by Brownian motions. Instead they swim in what has been named the “random walk,” which involves alternating “runs” and “tumbles.” In the run, the bacterium swims in an almost straight path with the fl agella rotating in a bundle. In tumbles, the fl agella change the direction of the rotation, for example, from counterclockwise to clockwise, and the individual fl agella separate, which causes the bacterium to stop and change direction randomly (e.g., [108]). Though runs and tumbles always occur, the presence of attractant or repellents can change the frequency with which they occur (e.g., Refs. [103,109]). When swimming up a concentration gradient of a positive attractant or down a gradient of a negative repellant, the tumbles become less frequent and the runs consequently become longer. When swimming in the opposite direction, tumbles become more frequent. This occurs through a direct reaction of the bacterium to the attractants or repellents via chemoreceptors in the membrane [110]. This type of locomotion appears to be advantageous only for bacteria longer than about 0.6 m. Orientation to stimuli in bacteria smaller than this would be too inef fi cient, which explains why no motile bacteria shorter than 0.8 m have been found [111]. The orientation process of bacteria is random because it swims in a random direction after it tumbles. The changes in tumbling frequency, however, results in a higher probability that the net movement of the bacteria will be toward an attractant rather than away from it, or vice versa for repellents (Figure 13.11).

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  The Mycoplasmas V1

  Cell Biology

  • M.F. Barile(Author)
  • 2012(Publication Date)
  • Academic Press

    (Publisher)

  The concomitant loss of motil-ity and of pathogenicity in M. pulmonis after a few passages in vitro and the avirulence of the nonmotile mutant of M. pneumoniae strongly indi-cate such a correlation. However, not all mycoplasmas pathogenic for the respiratory tract are motile (e.g., M. suipneumoniae). Moreover, the motile laboratory strain F H of M. pneumoniae is not considered to be pathogenic. So motility is certainly just one of the many factors which may contribute to the virulence of pathogenic mycoplasma species. Motil-ity may help the organisms to penetrate the mucus layer of tracheal and bronchial epithelium and to reach the cell surface for final attachment. It could help them to actively invade intercellular spaces and fissures or membrane crypts, e.g., in macrophages, in which they can survive the attack of such host defense factors as complement (P. Erb and W. Bredt, unpublished observations). Finally, it may enable the parasites to leave areas in which the environment has become unfavorable. Considering the possible applications of locomotion in the host-parasite relationship it 152 Wolfgang Bredt seems likely that in vivo movements occur only temporarily, ceasing as soon as the cell has attached firmly to host tissue. However, it should be kept in mind that all studies on gliding motion of mycoplasmas so far have only been done on glass or plastic. Although all available data suggest similar movements in vivo, we still lack experimental confirmation. III. MOTILITY OF Spiroplasma A. Morphology and Physiology of M o v e m e n t s The discovery of wall-less helical-shaped microorganisms in diseased plants (Saglio et al., 1973) not only added a quite unique agent to the Mollicutes but also introduced a totally different type of motility into this class. Two types of movements were observed. The first was rapid rota-tory motion which could reverse, leading to minimal back and forth progress.

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  Biomechanics and Robotics

  • Marko B. Popovic(Author)
  • 2013(Publication Date)
  • Jenny Stanford Publishing

    (Publisher)

  Locomotion Definition Locomotion is the act of self-propulsion of the system in which entire, or most of, the system translates—that is, moves,—in space. Locomotion is the defining characteristic o f motive robotics systems which generate forces to produce self-propulsion. These are commonly referred to as mobile robots. Locomotion of biological systems is the act of self-propulsion of living organisms and is present even at the level of a single cell; the building block of life. Biological locomotion is not just macro-activity associated with animals. Plants can also move substantially in a self-propelled fashion. Some plant seeds shoot like tiny missiles and others drill themselves into the soil. Moreover, locomotion takes place even at the level of individual cell. Some cells swim using a flagellum, which is a lash-like appendage that protrudes from the cell body of certain prokaryotic (lack a nucleus) and eukaryotic (have a nucleus) cells. 1 1 An example of a prokaryotic flagellate bacterium is the ulcer-causing Helicobacter pylori with helical filaments, each with a bidirectional rotary motor at its base. An example of a eukaryotic flagellate cell is the mammalian sperm cell where the tail flagellates and propels the sperm cell, at about 1–3 mm/min in humans, by whipping in an elliptical cone. Chapter 5 Locomotion Biomechanics and Robotics Marko B. Popovic Copyright © 2014 Pan Stanford Publishing Pte. Ltd. ISBN 978-981-4411-37-0 (Hardcover), 978-981-4411-38-7 (eBook) www.panstanford.com 128 Locomotion Locomotion and General Principles of Physics According to Newton’s third law, force applied by a locomotive system to a medium is equal in magnitude and opposite in direction to the force the medium applies to the locomotive system. According to Newton’s second law, the latter force results in acceleration of the center of mass that changes the velocity of the locomotive system as a whole.

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  Molecular Biology of Assemblies and Machines

  • Alasdair Steven, Wolfgang Baumeister, Louise N. Johnson, Richard N. Perham(Authors)
  • 2016(Publication Date)
  • Garland Science

    (Publisher)

  chemotaxis.

  The navigation system of chemotactic bacteria is based on clusters of membrane-traversing receptor molecules (chemoreceptors) that detect ligands in the external milieu and respond by initiating a cascade of intracellular reactions (Figure 14.73 ). The pathway by which signals are detected, transformed, and relayed to the flagellar motor that is embedded in the bacterial cell wall and controls the direction of rotation of the flagellum is probably the simplest known behavioral response.

  Figure 14.73 Communication between chemoreceptors and flagellar motors in E. coli. The receptors cluster in an array at one pole of the cell. An adaptor, a kinase, and other regulators associate with this array. These proteins are designated Che (for che motaxis) followed by a capital letter. The level of phosphorylation of CheY (when phosphorylated, CheYp) is regulated by modulation of CheA kinase activity in response to ligands binding to the receptors. The probability of a motor switching from clockwise to counter-clockwise rotation is determined by the amount of CheYp.

  The rotary motor that drives flagellar motility is reversible and powered by ion gradients

  The flagellum consists of a long filament attached to the cell by its basal body, a structure that spans the inner membrane, cell wall, and outer membrane. Flagellated bacteria are classified on the basis of the number of flagella and their distribution over the cell surface (Figure 14.74 ). Two bacteria on which many of the fundamental studies of flagellar motility have been performed, Escherichia coli and Salmonella typhimurium, belong to the peritrichous class, which have flagella projecting in all directions that bundle together and rotate in concert. An additional class is exemplified by the spirochetes, long thin bacteria whose flagella, called axial filaments

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