from the center point of the cell at each time point. After the cell moved to position 3 after another 15 s, the angle of turning from position 2 to position 3 was defined as α, in which α > 0 was defined as turning in a clockwise direction as observed.Figure 13.33 Distribution of locomotion angle.Figure 13.34 Distribution of locomotion length.Figure 13.35 Histogram of locomoting rate of diatoms on different walls and the velocity distributions.Figure 13.36 Comparison of secretion amount of diatom mucus: (a) mucus (b) EPS. Scale bar in (a) 5 μm.18Figure 13.37 Diffusion and dissolution of diatom secretion.Figure 13.38 Comparison of simulation results (b) and measured results (a) of diatom locomotion trajectory.19Figure 13.39 Locomotion trajectories of diatoms under different perception parameters: (a) Perception angle = 0°, perception threshold = 1, (b) Perception angle = 0°, perception threshold = 5, (c) Perception angle = 45°, perception threshold = 1, (c) Perception angle = 45°, perception threshold = 5, (e) Perception angle = 90°, perception threshold = 1, (d) Perception angle = 90°, perception threshold = 5.Figure 13.40 Simulated results of diatom adhesion from NetLogo. (a) very strong aggregation, which VMR>20, (b) strong aggregation, which 20>VMR>10, and (c) moderate aggregation, which 10>VMR>1.Figure 13.41 Comparisons between simulated and experimental values of VMR under different perception thresholds either with (a) or without (b) the introduction of cell division, using different perception angles. The two horizontal dashed lines correspond to the 95% confidence intervals from the solid line representing the VMR value determined directly from diatom cultures.Figure 13.42 Simulation results of diatom adhesion under different conditions with proliferation: (a) Perception angle = 0°, perception threshold = 1, (b) Perception angle = 0°, perception threshold = 5, (c) Perception angle = 45°, perception threshold = 1, (d) Perception angle = 45°, perception threshold = 5, (e) Perception angle = 90°, perception threshold = 1, (f) Perception angle = 90°, perception threshold = 5, (g) Perception angle = 135°, perception threshold = 1, (h) Perception angle = 135°, perception threshold = 5.Figure 13.43 The movement trend of daughter cell diatoms after cell division: (a-c) cells stayed in place; (d-f) cell migrated away after cell division.2014 Chapter 14Figure 14.1 A whimsical view of diatom motility, “Cymbella, Epithemia and Licmophora” by the late Steve Edgar [14.95].Figure 14.2 Diatoms somersault via protruding muscles (1753). The oat-animal, the diatom Craticula cuspidata [14.308], with its two “muscles” protruding from the two ends was described having movements [14.20] analogous to somersaulting [14.108] (reprinted with permission of and designed by Freepik Company; Portrait of naturalist Henry Baker (1698-1774) [14.415] under the Creative Commons Attribution 4.0 International license).Figure 14.3 Andrew Pritchard, naturalist and microscopist [14.408] (1804-1882). 1843 daguerreotype by A.F.J. Claudet [14.351] (public domain image).Figure 14.4 Jean Baptiste Bory de Saint-Vincent, naturalist (1778-1846) [14.406] (public domain image).Figure 14.5 Pierre Jean François Turpin, artist and botanist (1775-1840) [14.404] [14.407] [14.410] (reprinted under the Creative Commons Attribution-Share Alike 4.0 International license).Figure 14.6 The waving fibril model for diatom motility of Robert Jarosch (1962). “Figures 1 to 4 illustrate the relation between the direction of movement of the submicroscopic transverse waves in the hypothetical protoplasmic fibrils and the consequent gliding movements. Figure 1. A single free fibril: the waves running in one direction (W) cause the shifting of the fibril in the opposite direction (P). Figure 2. Longitudinal section through a Chara cell: the undulations (W) of the fibrils, which are fixed to the cell wall (C), cause the shifting of the inner layer of protoplasm (P). Figure 3. Longitudinal section through a gliding organism: (W) direction of waves in extramembranous surface-fixed fibrils; (P) direction of gliding; (M) mucilage; (S) substrate. Figure 4. Direction of waves in extramembranous fibrils during a contraction of Bacillaria paradoxa: (A) an individual cell; (S) substrate” [14.177] (reprinted with permission of Robert Jarosch. Recent photo of Robert Jarosch courtesy of Angelika Jarosch and Ilsa Foissner).Figure 14.7 Diatoms crawl like snails (1838). The motile pennate diatom Epithemia smithii [14.352] as a snail, as described by Christian Gottfried Ehrenberg (1795-1876) in 1838 [14.98]. Right: Christian Gottfried Ehrenberg, naturalist, painted by Eduard Radke ca. 1855 [14.410] (public domain image). Left: His critic, Carl Nägeli, botanist (1817-1891)[14.409] (public domain image).Figure 14.8 The diatom motor is a jet engine (1849). Top: The diatom Gomphonema acuminatum [14.190] [14.348] (scale bar 10 µm) as a jet engine [14.69] (open access; not subject to copyright restriction; the latter reprinted with permission under a GNU Free Documentation License, Version 1.2). Middle left: Aeronautics engineer Francis Herbert Wenham (1824-1908) in 1866 [14.414] (public domain image). Middle right: Lothar Hofmeister, botanist and cell physiologist (1910-1977) [14.195] (reprinted with kind permission of P. Amand Kraml, Director, Observatory of Kremsmünster). Bottom: Diatomist Hamilton Lanphere Smith (1819-1903) [14.350].Figure 14.9 (a) Lesley Ann Edgar, diatomist (1955-2006) [14.65] (image reprinted with permission of Taylor & Francis). (b) Jeremy Pickett-Heaps in 1990 [14.281].Figure 14.10 Jabez Hogg (1817-1899), ophthalmic surgeon [14.260] (reprinted with kind permission of Andrew Tucker, Assistant Curator, Museum of Freemasonry, ©Museum of Freemasonry, London, UK).Figure 14.11 Rowing diatoms (1855). Top: “Quadremes were powerful warships with two banks of oars and multiple rowers per oar” [14.277]. Middle: The diatom oars seen by Jabez Hogg (1855) [14.161]. Next: Mucilage protruding from a raphe of Navicula cuspidata in an SEM of a critical point dried cell [14.90] (reprinted with permission of Springer Nature), scale bars 10 and 1 µm, contrast enhanced by histogram equalization [14.301]. Bottom left: “Navicula confervacea:… Raphe with organic material: valve without marginal spines,” scale bar = 1 µm [14.307] (reprinted with permission of John Wiley and Sons). Bottom right: Scanning electron micrograph showing a single file row of secreted fibrils in purported Pinnularia viridis. Scale bar 0.5 µm. (From [14.154] with permission of John Wiley and Sons). Note that the fibrils are not adjacent to one another, suggesting that they come out of the raphe below individually. See also [14.156].Figure 14.12 Bacteriologist Émile Pierre-Marie van Ermengem (1851-1932) [14.412] (public domain image).Figure 14.13 “Transverse section showing general cellular organization in the region of the pyrenoid [py]. Chloroplast (cp), region of the girdle (gi), intra-pyrenoid lamellae (1), mitochondria (m), nucleus (n), nucleolus (no), raphe (r)” [14.359] (reprinted with permission of Springer Nature). Note a single fibril in the top raphe extending inside past a gap to the cell membrane, below which is a pair of microfilament bundles. The distance between opposite raphes in Cocconeis diminuta is 3 µm [14.359]. Similar gaps have been imaged also by TEM [14.80].Figure 14.14 Left: Max Schultze, microscopic anatomist (1825-1874) [14.405] [14.417] (public domain image). Right: Theodor Wilhelm Engelmann (1843-1909), botanist, physiologist, and microbiologist [14.424] (public domain image).Figure 14.15 Diatoms have protoplasmic tank treads (1865). Top left: The diatom as a double tank tread in girdle view. In order to ensure independence of the two raphes, two tank treads would be necessary. (Adapted from [14.286]. Bottom left: The double tank tread model for diatom motility (1893): “I interpret these phenomena in such a way that a current of cytoplasm is driven through the pole cleft of the anterior end node into the outer cleft of the raphe, there is shifted towards the center and flows back into the cell interior through the outer central node channel” [14.252]. A similar diagram is shown in [14.44]. Right: Georg Ferdinand Otto Müller (1837-1917) [14.419] (public domain image) published a series of 8 papers on diatom motility [14.251] [14.252] [14.253] [14.254] [14.255] [14.256] [14.257] [14.258] [14.387].Figure 14.16 Left: In 2015: “We propose a model [for gliding of Flavobacterium johnsoniae] in which a pinion, connected to a rotary motor, drives a rack (a tread) that moves along a spiral track fixed to the rigid framework of the cell wall. SprB [a cell-surface adhesin], carried by the tread, adsorbs to the substratum and causes the cell to glide…. Tethered cells pinwheel around a fixed axis, suggesting that a rotary motor that generates high torque is a part of the gliding machinery [14.334]…. If 90 nm is the radius of a pinion rotating 3Hz (the maximum speed of rotation when a cell is tethered) then that pinion can drive a rack (a tread carrying adhesins) at 1.5 µm/s, which is the speed that cells glide. This suggests that nature has not only invented the wheel, it also has invented the likes of a microscopic snowmobile…. A model of the gliding machinery. (a) A cross-sectional view of a cell with a rotary gliding motor (blue), a mobile tread (green), a stationary track (red), and an adhesin (magenta). The rotary motor and the track are anchored to the peptidoglycan (PG), and the track is wound spirally around the cell. The rotary motor drives a pinion
