Analysis of the Flagellar Beat Pattern of Male Ectocarpus Siliculosus Gametes (Phaeophyta) in Relation to Chemotactic Stimulation by Female Cells

1981 ◽  
Vol 92 (1) ◽  
pp. 53-66
Author(s):  
ANNETTE GELLER ◽  
DIETER G. MÜLLER
Keyword(s):  
Linear Correlation ◽  
Mode Of Action ◽  
High Speed ◽  
Sex Attractant ◽  
Cell Axis ◽  
Ectocarpus Siliculosus ◽  
Bending Waves ◽  
Flagellar Beat ◽  
Beat Pattern ◽  
Negative Linear Correlation

Heterocontic male Ectocarpus siliculosus gametes respond to the sex-attractant ectocarpen by changing their locomotive behaviour. However, the mode of action of the flagella is not changed by the presence of ectocarpen. High-speed cinemicrography shows that gametes moving close to a coverglass perform planar bending waves with their front flagellum. Straight or slightly curved swimming paths are generated by enhanced upward bends of the front flagellum to compensate for the asymmetrical insertion of both flagella. Narrower curves are connected with increasing downward bends of the front flagellum. There is a negative linear correlation between the average deflexion of the front flagellum (μm) from the cell axis and the radius of track (correlation coefficient 0.94). Additionally, freely swimming gametes exhibit elliptical and rotary wave motions, suggesting a relationship between thigmotaxis and mode of action of the front flagellum. The rigid hind flagellum performs one rapid sideward beat when the gametes swim in narrow curves. This appears to provide a steering function.

scholarly journals Reconstruction of the three-dimensional beat pattern underlying swimming behaviors of sperm

2021 ◽  
Vol 44 (7) ◽  
Author(s):  
A. Gong ◽  
S. Rode ◽  
G. Gompper ◽  
U. B. Kaupp ◽  
J. Elgeti ◽  
...  
Keyword(s):  
Three Dimensional ◽  
Intrinsic Property ◽  
Human Sperm ◽  
Bending Waves ◽  
Flagellar Beat ◽  
Beat Pattern ◽  
Glass Interface ◽  
Two Space Dimensions ◽  
Swimming Trajectories ◽  
Physical And Chemical

Abstract  The eukaryotic flagellum propels sperm cells and simultaneously detects physical and chemical cues that modulate the waveform of the flagellar beat. Most previous studies have characterized the flagellar beat and swimming trajectories in two space dimensions (2D) at a water/glass interface. Here, using refined holographic imaging methods, we report high-quality recordings of three-dimensional (3D) flagellar bending waves. As predicted by theory, we observed that an asymmetric and planar flagellar beat results in a circular swimming path, whereas a symmetric and non-planar flagellar beat results in a twisted-ribbon swimming path. During swimming in 3D, human sperm flagella exhibit torsion waves characterized by maxima at the low curvature regions of the flagellar wave. We suggest that these torsion waves are common in nature and that they are an intrinsic property of beating axonemes. We discuss how 3D beat patterns result in twisted-ribbon swimming paths. This study provides new insight into the axoneme dynamics, the 3D flagellar beat, and the resulting swimming behavior. Graphic abstract

scholarly journals Control of helical navigation by three-dimensional flagellar beating

2020 ◽  
Author(s):  
Dario Cortese ◽  
Kirsty Y. Wan
Keyword(s):  
High Speed ◽  
Three Dimensional ◽  
Axial Rotation ◽  
Live Cells ◽  
High Speed Imaging ◽  
Flagellar Beat ◽  
Motile Cells ◽  
Beat Pattern ◽  
Swimming Trajectories ◽  
Realistic Geometries

Helical swimming is a ubiquitous strategy for motile cells to generate self-gradients for environmental sensing. The model biflagellate Chlamydomonas reinhardtii rotates at a constant 1 – 2 Hz as it swims, but the mechanism is unclear. Here, we show unequivocally that the rolling motion derives from a persistent, non-planar flagellar beat pattern. This is revealed by high-speed imaging and micromanipulation of live cells. We construct a fully-3D model to relate flagellar beating directly to the free-swimming trajectories. For realistic geometries, the model reproduces both the sense and magnitude of the axial rotation of live cells. We show that helical swimming requires further symmetry-breaking between the two flagella. These functional differences underlie all tactic responses, particularly phototaxis. We propose a control strategy by which cells steer towards or away from light by modulating the sign of biflagellar dominance.

scholarly journals Bark necrotic disease in a beech thicket

2019 ◽  
Vol 55 (No. 3) ◽  
pp. 181-190
Author(s):  
Milan Barna ◽  
Ivan Mihál
Keyword(s):  
Health Status ◽  
Linear Correlation ◽  
Western Carpathians ◽  
Regenerative Capacity ◽  
Lateral Shoot ◽  
Disease Characteristics ◽  
Negative Linear Correlation ◽  
Research Experiment ◽  
Terminal Shoot

Symptoms of non-specific bark necroses in beech trees of all ages have lately been described. We investigated the occurrence of bark necrotic disease in beech thicket and health status of the trees. Our objective was to examine how bark necrotic wounds persist and the regenerative potential of young beech thicket. The research experiment was carried out at two isolated localities in the Western Carpathians in the period 2015–2017. A terminal shoot (stem) and a lateral shoot (branch) of each of the 30 sampled beech trees were examined. Young beech stands were affected by the necrotic disease in 87–94% cases (stems 69–83%, branches 33–56%). Shoot diameter and age had a significantly negative linear correlation (P < 0.05) with the development of all analysed disease characteristics on the beech bark. The encouraging finding is a positive regenerative capacity of young beech trees. Over the same period more annual shoots were healed in comparison with those that were newly infected (10.8% on stems and 0.6% on branches). 

Clonal susceptibility and the influence of shade trees on the incidence of Glyptotermes dilatatus (Bugnion & Popoff) (Isoptera: Kalotermitidae) in tea

1980 ◽  
Vol 70 (1) ◽  
pp. 145-149 ◽  
Author(s):  
P. Sivapalan ◽  
A. A. C. Karunaratne ◽  
D. G. S. Jayatilleke
Keyword(s):  
Sri Lanka ◽  
Linear Correlation ◽  
Gliricidia Sepium ◽  
Percentage Change ◽  
Shade Trees ◽  
Steep Increase ◽  
Negative Linear Correlation ◽  
Termite Attack ◽  
The Mean ◽  
Criteria For Selection

AbstractAmongst 20 tea clones tested in Sri Lanka for susceptibility to Glyptotermes dilatatus (Bugnion & Popoff), five of the high-yielding soft-wooded clones, including the currently recommended and popular TRI 2023 and TRI 2026, were found very susceptible and to suffer a severe net loss in yield. A highly significant negative linear correlation was observed between the mean infestation percentage of clone with an infestation of over 30% and the mean percentage change in yield. In general, the high-yielding clones with soft-wooded sappy frames were particularly susceptible to termite attack. Since yield is one of the important criteria for selection, it is suggested that in areas prone to termite infestation, replanting should be limited to the high-yielding resistant clones such as GMT 9, KEN 16/3 and DG 39. The provision of shade with Gliricidia sepium may have prevented a steep increase in the incidence of infestation in the susceptible clones.

Population dynamics of Xyleborus fornicatus Eichhoff (Coleoptera: Scoly-tidae) in relation to yield trends in tea

1977 ◽  
Vol 67 (2) ◽  
pp. 329-335 ◽  
Author(s):  
P. Sivapalan
Keyword(s):  
Linear Correlation ◽  
Inverse Relationship ◽  
Direct Relationship ◽  
Critical Factor ◽  
Cambial Activity ◽  
Crop Size ◽  
Negative Linear Correlation ◽  
Weather Parameters ◽  
Yield Trends ◽  
Tea Plants

AbstractA highly significant negative linear correlation (r=– 0·911, P=0·001) was observed between Xyleborus fornicatus Eichh. population levels in tea plants and the crop size in the preceding month. A highly significant negative linear correlation (r=– 0·858, P=0·001) was also observed between Xyleborus population levels and the percentage of healed galleries of the respective samples. Cambial activity, which has a direct relationship with crop size, determines the rate of healing of brood galleries, and this seems to be the critical factor that regulates population size within a pruning cycle. Since the population has an inverse relationship to crop size and as the latter could be predicted in advance using weather parameters, it should be possible to predict population levels of Xyleborus in advance.

scholarly journals Targeted inactivation of the mouse epididymal beta-defensin 41 alters sperm flagellar beat pattern and zona pellucida binding

2016 ◽  
Vol 427 ◽  
pp. 143-154 ◽  
Author(s):  
Ida Björkgren ◽  
Luis Alvarez ◽  
Nelli Blank ◽  
Melanie Balbach ◽  
Heikki Turunen ◽  
...  
Keyword(s):  
Zona Pellucida ◽  
Flagellar Beat ◽  
Beat Pattern ◽  
Targeted Inactivation

scholarly journals A minimal robophysical model of quadriflagellate self-propulsion

2021 ◽  
Author(s):  
Kelimar Diaz ◽  
Tommie L. Robinson ◽  
Yasemin Ozkan Aydin ◽  
Enes Aydin ◽  
Daniel I. Goldman ◽  
...  
Keyword(s):  
Central Body ◽  
Swimming Performance ◽  
M Cell ◽  
Trot Gait ◽  
Flagellar Beat ◽  
Beat Pattern ◽  
Aqueous Environments ◽  
Cilia And Flagella ◽  
Microalgal Species ◽  
Phase Relationships

AbstractLocomotion at the microscale is remarkably sophisticated. Microorganisms have evolved diverse strategies to move within highly viscous environments, using deformable, propulsion-generating appendages such as cilia and flagella to drive helical or undulatory motion. In single-celled algae, these appendages can be arranged in different ways around an approximately 10µm cell body, and coordinated in distinct temporal patterns. Inspired by the observation that some quadriflagellates (bearing four flagella) have an outwardly similar morphology and flagellar beat pattern, yet swim at different speeds, this study seeks to determine whether variations in swimming performance could arise solely from differences in swimming gait. Robotics approaches are particularly suited to such investigations, where the phase relationships between appendages can be readily manipulated. Here, we developed autonomous, algae-inspired robophysical models that can self-propel in a viscous fluid. These macroscopic robots (length and width = 8.5 cm, height = 2 cm) have four independently actuated ‘flagella’ that oscillate back and forth under low-Reynolds number conditions (Re∼ 𝒪(10−1)). We tested the swimming performance of these robot models with appendages arranged in one of two distinct configurations, and coordinated in one of three distinct gaits. The gaits, namely the pronk, the trot, and the gallop, correspond to gaits adopted by distinct microalgal species. When the appendages are inserted perpendicularly around a central ‘body’, the robot achieved a net performance of 0.15−0.63 body lengths per cycle, with the trot gait being the fastest. Robotic swimming performance was found to be comparable to that of the algal microswimmers across all gaits. By creating a minimal robot that can successfully reproduce cilia-inspired drag-based swimming, our work paves the way for the design of next-generation devices that have the capacity to autonomously navigate aqueous environments.

Sign in / Sign up

Export Citation Format

Share Document